Merge pull request #413 from AerisG222/http_capability_provider

[mono.git] / mcs / class / System.Web / System.Web / HttpRequest.cs

//
// System.Web.HttpRequest.cs 
//
// 
// Author:
//      Miguel de Icaza (miguel@novell.com)
//      Gonzalo Paniagua Javier (gonzalo@novell.com)
//      Marek Habersack <mhabersack@novell.com>
//

//
// Copyright (C) 2005-2010 Novell, Inc (http://www.novell.com)
// Copyright (C) 2011-2012 Xamarin, Inc (http://xamarin.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
using System.Text;
using System.Collections;
using System.Collections.Specialized;
using System.IO;
using System.Runtime.InteropServices;
using System.Security;
using System.Security.Permissions;
using System.Security.Principal;
using System.Web.Configuration;
using System.Web.Management;
using System.Web.UI;
using System.Web.Util;
using System.Globalization;

#if NET_4_0
using System.Security.Authentication.ExtendedProtection;
using System.Web.Routing;
#endif

namespace System.Web
{       
        // CAS - no InheritanceDemand here as the class is sealed
        [AspNetHostingPermission (SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
        public sealed partial class HttpRequest
        {
                HttpWorkerRequest worker_request;
                HttpContext context;
                WebROCollection query_string_nvc;

                //
                //string filename;
                string orig_url = null;
                UriBuilder url_components;

                string client_target;

                //
                // On-demand computed values
                //
                HttpBrowserCapabilities browser_capabilities;
                string file_path, base_virtual_dir, root_virtual_dir, client_file_path;
                string content_type;
                int content_length = -1;
                Encoding encoding;
                string current_exe_path;
                string physical_path;
                string unescaped_path;
                string original_path;
                string path_info;
                string raw_url;
                WebROCollection all_params;
                WebROCollection headers;
                Stream input_stream;
                InputFilterStream input_filter;
                Stream filter;
                HttpCookieCollection cookies;
                string http_method;

                WebROCollection form;
                HttpFileCollection files;
                
                ServerVariablesCollection server_variables;
                HttpClientCertificate client_cert;
                
                string request_type;
                string [] accept_types;
                string [] user_languages;
                Uri cached_url;
                TempFileStream request_file;

                readonly static System.Net.IPAddress [] host_addresses;
                
                // Validations
                bool validate_cookies, validate_query_string, validate_form;
                bool checked_cookies, checked_query_string, checked_form;
                static readonly UrlMappingCollection urlMappings;
                readonly static char [] queryTrimChars = {'?'};
#if NET_4_0
                bool lazyFormValidation;
                bool lazyQueryStringValidation;
                bool inputValidationEnabled;
                RequestContext requestContext;
                
                static bool validateRequestNewMode;
                internal static bool ValidateRequestNewMode {
                        get { return validateRequestNewMode; }
                }

                internal bool InputValidationEnabled {
                        get { return inputValidationEnabled; }
                }
                
                private static char[] RequestPathInvalidCharacters {
                        get; set;
                }

                private static char[] CharsFromList (string list)
                {
                        // List format is very strict and enforced by the Configuration 
                        // there must be a single char separated by commas with no trailing comma
                        // whitespace is allowed though and should be trimmed.
                        
                        string [] pieces = list.Split (',');

                        char [] chars = new char [pieces.Length];
                        for (int i = 0; i < chars.Length; i++) {
                                string trimmed = pieces [i].Trim ();
                                if (trimmed.Length != 1) {
                                        // This should have been caught by System.Web.Configuration
                                        // and throw a configuration error. This is just here for sanity
                                        throw new System.Configuration.ConfigurationErrorsException ();
                                }

                                chars [i] = trimmed [0];
                        }

                        return chars;
                }
#endif

                static HttpRequest ()
                {
                        try {
                                UrlMappingsSection ums = WebConfigurationManager.GetWebApplicationSection ("system.web/urlMappings") as UrlMappingsSection;
                                if (ums != null && ums.IsEnabled) {
                                        urlMappings = ums.UrlMappings;
                                        if (urlMappings.Count == 0)
                                                urlMappings = null;
                                }

#if NET_4_0
                                Version validationMode = HttpRuntime.Section.RequestValidationMode;

                                if (validationMode >= new Version (4, 0)) {
                                        validateRequestNewMode = true;
                                        string invalidChars = HttpRuntime.Section.RequestPathInvalidCharacters;
                                        if (!String.IsNullOrEmpty (invalidChars))
                                                RequestPathInvalidCharacters = CharsFromList (invalidChars);
                                }
#endif
                        } catch {
                                // unlikely to happen
                        }
                        
                        host_addresses = GetLocalHostAddresses ();
                }
                
                public HttpRequest (string filename, string url, string queryString)
                {
                        // warning 169: what are we supposed to do with filename?
                        
                        //this.filename = filename;

                        orig_url = url;
                        url_components = new UriBuilder (url);
                        url_components.Query = queryString;
                        
                        query_string_nvc = new WebROCollection ();
                        if (queryString != null)
                                HttpUtility.ParseQueryString (queryString, Encoding.Default, query_string_nvc);
                        query_string_nvc.Protect ();
                }

                internal HttpRequest (HttpWorkerRequest worker_request, HttpContext context)
                {
                        this.worker_request = worker_request;
                        this.context = context;
                }
                
                internal UriBuilder UrlComponents {
                        get {
                                if (url_components == null) {
                                        string query;
                                        byte[] queryStringRaw = worker_request.GetQueryStringRawBytes();
                                        if(queryStringRaw != null)
                                                query = ContentEncoding.GetString(queryStringRaw);
                                        else
                                                query = worker_request.GetQueryString();
                                        
                                        BuildUrlComponents (ApplyUrlMapping (worker_request.GetUriPath ()), query);
                                }
                                return url_components;
                        }
                }

                void BuildUrlComponents (string path, string query)
                {
                        if (url_components != null)
                                return;
                        url_components = new UriBuilder ();
                        url_components.Scheme = worker_request.GetProtocol ();
                        url_components.Host = worker_request.GetServerName ();
                        url_components.Port = worker_request.GetLocalPort ();
                        url_components.Path = path;
                        if (query != null && query.Length > 0)
                                url_components.Query = query.TrimStart (queryTrimChars);
                }

                internal string ApplyUrlMapping (string url)
                {
                        if (urlMappings == null)
                                return url;

                        string relUrl = VirtualPathUtility.ToAppRelative (url);
                        UrlMapping um = null;
                        
                        foreach (UrlMapping u in urlMappings) {
                                if (u == null)
                                        continue;
                                if (String.Compare (relUrl, u.Url, StringComparison.Ordinal) == 0) {
                                        um = u;
                                        break;
                                }
                        }

                        if (um == null)
                                return url;

                        string rawUrl = VirtualPathUtility.ToAbsolute (um.MappedUrl.Trim ());
                        Uri newUrl = new Uri ("http://host.com" + rawUrl);

                        if (url_components != null) {
                                url_components.Path = newUrl.AbsolutePath;
                                url_components.Query = newUrl.Query.TrimStart (queryTrimChars);
                                query_string_nvc = new WebROCollection ();
                                HttpUtility.ParseQueryString (newUrl.Query, Encoding.Default, query_string_nvc);
                                query_string_nvc.Protect ();
                        } else
                                BuildUrlComponents (newUrl.AbsolutePath, newUrl.Query);

                        return url_components.Path;
                }

                string [] SplitHeader (int header_index)
                {
                        string [] result = null;
                        string header = worker_request.GetKnownRequestHeader (header_index);
                        if (header != null && header != "" && header.Trim () != "") {
                                result = header.Split (',');
                                for (int i = result.Length - 1; i >= 0; i--)
                                        result [i] = result [i].Trim ();
                        }
                        return result;
                }

                public string [] AcceptTypes {
                        get {
                                if (worker_request == null)
                                        return null;

                                if (accept_types == null)
                                        accept_types = SplitHeader (HttpWorkerRequest.HeaderAccept);

                                return accept_types;
                        }
                }

#if !TARGET_JVM
                public WindowsIdentity LogonUserIdentity {
                        get { throw new NotImplementedException (); }
                }
#endif
                
                string anonymous_id;
                public string AnonymousID {
                        get {
                                return anonymous_id;
                        }
                        internal set {
                                anonymous_id = value;
                        }
                }

                public string ApplicationPath {
                        get {
                                if (worker_request == null)
                                        return null;
                                return worker_request.GetAppPath ();
                        }
                }

                public HttpBrowserCapabilities Browser {
                        get {
                                if (browser_capabilities == null)
#if NET_4_0
                                        browser_capabilities = HttpCapabilitiesBase.BrowserCapabilitiesProvider.GetBrowserCapabilities (this);
#else
                                        browser_capabilities = (HttpBrowserCapabilities)
                                                HttpCapabilitiesBase.GetConfigCapabilities (null, this);
#endif

                                return browser_capabilities;
                        }

                        set {
                                browser_capabilities = value;
                        }
                }

                internal bool BrowserMightHaveSpecialWriter {
                        get {
                                return (browser_capabilities != null 
                                        || HttpApplicationFactory.AppBrowsersFiles.Length > 0);
                        }
                }

                internal bool BrowserMightHaveAdapters {
                        get {
                                return (browser_capabilities != null 
                                        || HttpApplicationFactory.AppBrowsersFiles.Length > 0);
                        }
                }

                public HttpClientCertificate ClientCertificate {
                        get {
                                if (client_cert == null)
                                        client_cert = new HttpClientCertificate (worker_request);
                                return client_cert;
                        }
                }

                static internal string GetParameter (string header, string attr)
                {
                        int ap = header.IndexOf (attr);
                        if (ap == -1)
                                return null;

                        ap += attr.Length;
                        if (ap >= header.Length)
                                return null;
                        
                        char ending = header [ap];
                        if (ending != '"')
                                ending = ' ';
                        
                        int end = header.IndexOf (ending, ap+1);
                        if (end == -1)
                                return (ending == '"') ? null : header.Substring (ap);

                        return header.Substring (ap+1, end-ap-1);
                }

                public Encoding ContentEncoding {
                        get {
                                if (encoding == null){
                                        if (worker_request == null)
                                                throw HttpException.NewWithCode ("No HttpWorkerRequest", WebEventCodes.RuntimeErrorRequestAbort);
                                        
                                        string content_type = ContentType;
                                        string parameter = GetParameter (content_type, "; charset=");
                                        if (parameter == null) {
                                                encoding = WebEncoding.RequestEncoding;
                                        } else {
                                                try {
                                                        // Do what the #1 web server does
                                                        encoding = Encoding.GetEncoding (parameter);
                                                } catch {
                                                        encoding = WebEncoding.RequestEncoding;
                                                }
                                        }
                                }
                                return encoding;
                        }

                        set {
                                encoding = value;
                        }
                }

                public int ContentLength {
                        get {
                                if (content_length == -1){
                                        if (worker_request == null)
                                                return 0;

                                        string cl = worker_request.GetKnownRequestHeader (HttpWorkerRequest.HeaderContentLength);

                                        if (cl != null) {
                                                try {
                                                        content_length = Int32.Parse (cl);
                                                } catch { }
                                        }
                                }

                                // content_length will still be < 0, but we know we gotta read from the client
                                if (content_length < 0)
                                        return 0;

                                return content_length;
                        }
                }

                public string ContentType {
                        get {
                                if (content_type == null){
                                        if (worker_request != null)
                                                content_type = worker_request.GetKnownRequestHeader (HttpWorkerRequest.HeaderContentType);

                                        if (content_type == null)
                                                content_type = String.Empty;
                                }
                                
                                return content_type;
                        }

                        set {
                                content_type = value;
                        }
                }

                public HttpCookieCollection Cookies {
                        get {
                                if (cookies == null) {
                                        if (worker_request == null) {
                                                cookies = new HttpCookieCollection ();
                                        } else {
                                                string cookie_hv = worker_request.GetKnownRequestHeader (HttpWorkerRequest.HeaderCookie);
                                                cookies = new HttpCookieCollection (cookie_hv);
                                        }
                                }

#if TARGET_J2EE
                                // For J2EE portal support we emulate cookies using the session.
                                GetSessionCookiesForPortal (cookies);
#endif
                                bool needValidation = validate_cookies;
#if NET_4_0
                                needValidation |= validateRequestNewMode;
#endif
                                if (needValidation && !checked_cookies) {
                                        // Setting this before calling the validator prevents
                                        // possible endless recursion
                                        checked_cookies = true;
                                        ValidateCookieCollection (cookies);
                                }

                                return cookies;
                        }

                }

                public string CurrentExecutionFilePath {
                        get {
                                if (current_exe_path != null)
                                        return current_exe_path;

                                return FilePath;
                        }
                }
#if NET_4_0
                public string CurrentExecutionFilePathExtension {
                        get { return global::System.IO.Path.GetExtension (CurrentExecutionFilePath); }
                }
#endif
                public string AppRelativeCurrentExecutionFilePath {
                        get {
                                return VirtualPathUtility.ToAppRelative (CurrentExecutionFilePath);
                        }
                }

                public string FilePath {
                        get {
                                if (worker_request == null)
                                        return "/"; // required for 2.0

                                if (file_path == null)
                                        file_path = UrlUtils.Canonic (ApplyUrlMapping (worker_request.GetFilePath ()));

                                return file_path;
                        }
                }

                internal string ClientFilePath {
                        get {
                                if (client_file_path == null) {
                                        if (worker_request == null)
                                                return "/";
                                        
                                        return UrlUtils.Canonic (ApplyUrlMapping (worker_request.GetFilePath ()));
                                }
                                
                                return client_file_path;
                        }

                        set {
                                if (value == null || value.Length == 0)
                                        client_file_path = null;
                                else
                                        client_file_path = value;
                        }
                }
                
                internal string BaseVirtualDir {
                        get {
                                if (base_virtual_dir == null){
                                        base_virtual_dir = FilePath;
                                        if (UrlUtils.HasSessionId (base_virtual_dir))
                                                base_virtual_dir = UrlUtils.RemoveSessionId (VirtualPathUtility.GetDirectory (base_virtual_dir), base_virtual_dir);
                                        
                                        int p = base_virtual_dir.LastIndexOf ('/');
                                        if (p != -1) {
                                                if (p == 0)
                                                        p = 1;
                                                base_virtual_dir = base_virtual_dir.Substring (0, p);
                                        } else
                                                base_virtual_dir = "/";
                                }
                                return base_virtual_dir;
                        }
                }
                
                public HttpFileCollection Files {
                        get {
                                if (files == null) {
                                        files = new HttpFileCollection ();
                                        if ((worker_request != null) && IsContentType ("multipart/form-data", true)) {
                                                form = new WebROCollection ();
                                                LoadMultiPart ();
                                                form.Protect ();
                                        }
                                }
                                return files;
                        }
                }

                public Stream Filter {
                        get {
                                if (filter != null)
                                        return filter;

                                if (input_filter == null)
                                        input_filter = new InputFilterStream ();

                                return input_filter;
                        }

                        set {
                                // This checks that get_ was called before.
                                if (input_filter == null)
                                        throw new HttpException ("Invalid filter");

                                filter = value;
                        }
                }

                // GetSubStream returns a 'copy' of the InputStream with Position set to 0.
                static Stream GetSubStream (Stream stream)
                {
#if !TARGET_JVM
                        if (stream is IntPtrStream)
                                return new IntPtrStream (stream);
#endif

                        if (stream is MemoryStream) {
                                MemoryStream other = (MemoryStream) stream;
                                return new MemoryStream (other.GetBuffer (), 0, (int) other.Length, false, true);
                        }

                        if (stream is TempFileStream) {
                                ((TempFileStream) stream).SavePosition ();
                                return stream;
                        }

                        throw new NotSupportedException ("The stream is " + stream.GetType ());
                }

                static void EndSubStream (Stream stream)
                {
                        if (stream is TempFileStream) {
                                ((TempFileStream) stream).RestorePosition ();
                        }
                }

                //
                // Loads the data on the form for multipart/form-data
                //
                void LoadMultiPart ()
                {
                        string boundary = GetParameter (ContentType, "; boundary=");
                        if (boundary == null)
                                return;

                        Stream input = GetSubStream (InputStream);
                        HttpMultipart multi_part = new HttpMultipart (input, boundary, ContentEncoding);

                        HttpMultipart.Element e;
                        while ((e = multi_part.ReadNextElement ()) != null) {
                                if (e.Filename == null){
                                        byte [] copy = new byte [e.Length];
                                
                                        input.Position = e.Start;
                                        input.Read (copy, 0, (int) e.Length);

                                        form.Add (e.Name, ContentEncoding.GetString (copy));
                                } else {
                                        //
                                        // We use a substream, as in 2.x we will support large uploads streamed to disk,
                                        //
                                        HttpPostedFile sub = new HttpPostedFile (e.Filename, e.ContentType, input, e.Start, e.Length);
                                        files.AddFile (e.Name, sub);
                                }
                        }
                        EndSubStream (input);
                }

                //
                // Adds the key/value to the form, and sets the argumets to empty
                //
                void AddRawKeyValue (StringBuilder key, StringBuilder value)
                {
                        string decodedKey = HttpUtility.UrlDecode (key.ToString (), ContentEncoding);
                        form.Add (decodedKey,
                                  HttpUtility.UrlDecode (value.ToString (), ContentEncoding));

                        key.Length = 0;
                        value.Length = 0;
                }

                //
                // Loads the form data from on a application/x-www-form-urlencoded post
                // 
#if TARGET_J2EE
                void RawLoadWwwForm ()
#else
                void LoadWwwForm ()
#endif
                {
                        using (Stream input = GetSubStream (InputStream)) {
                                using (StreamReader s = new StreamReader (input, ContentEncoding)) {
                                        StringBuilder key = new StringBuilder ();
                                        StringBuilder value = new StringBuilder ();
                                        int c;

                                        while ((c = s.Read ()) != -1){
                                                if (c == '='){
                                                        value.Length = 0;
                                                        while ((c = s.Read ()) != -1){
                                                                if (c == '&'){
                                                                        AddRawKeyValue (key, value);
                                                                        break;
                                                                } else
                                                                        value.Append ((char) c);
                                                        }
                                                        if (c == -1){
                                                                AddRawKeyValue (key, value);
                                                                return;
                                                        }
                                                } else if (c == '&')
                                                        AddRawKeyValue (key, value);
                                                else
                                                        key.Append ((char) c);
                                        }
                                        if (c == -1)
                                                AddRawKeyValue (key, value);

                                        EndSubStream (input);
                                }
                        }
                }

                bool IsContentType (string ct, bool starts_with)
                {
                        if (starts_with)
                                return StrUtils.StartsWith (ContentType, ct, true);

                        return String.Compare (ContentType, ct, true, Helpers.InvariantCulture) == 0;
                }

                internal WebROCollection FormUnvalidated {
                        get {
                                if (form == null){
                                        form = new WebROCollection ();
                                        files = new HttpFileCollection ();

                                        if (IsContentType ("multipart/form-data", true))
                                                LoadMultiPart ();
                                        else if (
                                                IsContentType ("application/x-www-form-urlencoded", true))
                                                LoadWwwForm ();

                                        form.Protect ();
                                }

                                return form;
                        }
                }
                
                public NameValueCollection Form {
                        get {
                                NameValueCollection form = FormUnvalidated;
#if NET_4_0
                                if (validateRequestNewMode && !checked_form) {
                                        if (!lazyFormValidation) {
                                                // Setting this before calling the validator prevents
                                                // possible endless recursion
                                                checked_form = true;
                                                ValidateNameValueCollection ("Form", form, RequestValidationSource.Form);
                                        }
                                } else
#endif
                                        if (validate_form && !checked_form){
                                                checked_form = true;
                                                ValidateNameValueCollection ("Form", form);
                                        }
                                
                                return form;
                        }
                }

                public NameValueCollection Headers {
                        get {
                                if (headers == null) {
                                        headers = new HeadersCollection (this);
#if NET_4_0
                                        if (validateRequestNewMode) {
                                                RequestValidator validator = RequestValidator.Current;
                                                int validationFailureIndex;

                                                foreach (string hkey in headers.AllKeys) {
                                                        string value = headers [hkey];
                                                        
                                                        if (!validator.IsValidRequestString (HttpContext.Current, value, RequestValidationSource.Headers, hkey, out validationFailureIndex))
                                                                ThrowValidationException ("Headers", hkey, value);
                                                }
                                        }
#endif
                                }
                                
                                return headers;
                        }
                }

                public string HttpMethod {
                        get {
                                if (http_method == null){
                                        if (worker_request != null)
                                                http_method = worker_request.GetHttpVerbName ();
                                        else
                                                http_method = "GET";
                                }
                                return http_method;
                        }
                }

                void DoFilter (byte [] buffer)
                {
                        if (input_filter == null || filter == null)
                                return;

                        if (buffer.Length < 1024)
                                buffer = new byte [1024];

                        // Replace the input with the filtered input
                        input_filter.BaseStream = input_stream;
                        MemoryStream ms = new MemoryStream ();
                        while (true) {
                                int n = filter.Read (buffer, 0, buffer.Length);
                                if (n <= 0)
                                        break;
                                ms.Write (buffer, 0, n);
                        }
                        // From now on input_stream has the filtered input
                        input_stream = new MemoryStream (ms.GetBuffer (), 0, (int) ms.Length, false, true);
                }

#if !TARGET_JVM
                const int INPUT_BUFFER_SIZE = 32*1024;

                TempFileStream GetTempStream ()
                {
                        string tempdir = AppDomain.CurrentDomain.SetupInformation.DynamicBase;
                        TempFileStream f = null;
                        string path;
                        Random rnd = new Random ();
                        int num;
                        do {
                                num = rnd.Next ();
                                num++;
                                path = System.IO.Path.Combine (tempdir, "tmp" + num.ToString("x") + ".req");

                                try {
                                        f = new TempFileStream (path);
                                } catch (SecurityException) {
                                        // avoid an endless loop
                                        throw;
                                } catch { }
                        } while (f == null);

                        return f;
                }

                void MakeInputStream ()
                {
                        if (input_stream != null)
                                return;

                        if (worker_request == null) {
                                input_stream = new MemoryStream (new byte [0], 0, 0, false, true);
                                DoFilter (new byte [1024]);
                                return;
                        }

                        //
                        // Use an unmanaged memory block as this might be a large
                        // upload
                        //
                        int content_length = ContentLength;
                        int content_length_kb = content_length / 1024;
                        HttpRuntimeSection config = HttpRuntime.Section;
                        if (content_length_kb > config.MaxRequestLength)
                                throw HttpException.NewWithCode (400, "Upload size exceeds httpRuntime limit.", WebEventCodes.RuntimeErrorPostTooLarge);

                        int total = 0;
                        byte [] buffer;
                        buffer = worker_request.GetPreloadedEntityBody ();
                        // we check the instance field 'content_length' here, not the local var.
                        if (this.content_length <= 0 || worker_request.IsEntireEntityBodyIsPreloaded ()) {
                                if (buffer == null || content_length == 0) {
                                        input_stream = new MemoryStream (new byte [0], 0, 0, false, true);
                                } else {
                                        input_stream = new MemoryStream (buffer, 0, buffer.Length, false, true);
                                }
                                DoFilter (new byte [1024]);
                                return;
                        }

                        if (buffer != null)
                                total = buffer.Length;

                        if (content_length > 0 && content_length_kb >= config.RequestLengthDiskThreshold) {
                                // Writes the request to disk
                                total = Math.Min (content_length, total);
                                request_file = GetTempStream ();
                                Stream output = request_file;
                                if (total > 0)
                                        output.Write (buffer, 0, total);

                                if (total < content_length) {
                                        buffer = new byte [Math.Min (content_length, INPUT_BUFFER_SIZE)];
                                        do {
                                                int n;
                                                int min = Math.Min (content_length - total, INPUT_BUFFER_SIZE);
                                                n = worker_request.ReadEntityBody (buffer, min);
                                                if (n <= 0)
                                                        break;
                                                output.Write (buffer, 0, n);
                                                total += n;
                                        } while (total < content_length);
                                }

                                request_file.SetReadOnly ();
                                input_stream = request_file;
                        } else if (content_length > 0) {
                                // Buffers the request in an IntPtrStream
                                total = Math.Min (content_length, total);
                                IntPtr content = Marshal.AllocHGlobal (content_length);
                                if (content == (IntPtr) 0)
                                        throw HttpException.NewWithCode (
                                                String.Format ("Not enough memory to allocate {0} bytes.", content_length),
                                                WebEventCodes.WebErrorOtherError);

                                if (total > 0)
                                        Marshal.Copy (buffer, 0, content, total);

                                if (total < content_length) {
                                        buffer = new byte [Math.Min (content_length, INPUT_BUFFER_SIZE)];
                                        do {
                                                int n;
                                                int min = Math.Min (content_length - total, INPUT_BUFFER_SIZE);
                                                n = worker_request.ReadEntityBody (buffer, min);
                                                if (n <= 0)
                                                        break;
                                                Marshal.Copy (buffer, 0, (IntPtr) ((long)content + total), n);
                                                total += n;
                                        } while (total < content_length);
                                }

                                input_stream = new IntPtrStream (content, total);
                        } else {
                                // Buffers the request in a MemoryStream or writes to disk if threshold exceeded
                                MemoryStream ms = new MemoryStream ();
                                Stream output = ms;
                                if (total > 0)
                                        ms.Write (buffer, 0, total);

                                buffer = new byte [INPUT_BUFFER_SIZE];
                                long maxlength = config.MaxRequestLength * 1024L;
                                long disk_th = config.RequestLengthDiskThreshold * 1024L;
                                int n;
                                while (true) {
                                        n = worker_request.ReadEntityBody (buffer, INPUT_BUFFER_SIZE);
                                        if (n <= 0)
                                                break;
                                        total += n;
                                        if (total < 0 || total > maxlength)
                                                throw HttpException.NewWithCode (400, "Upload size exceeds httpRuntime limit.", WebEventCodes.RuntimeErrorPostTooLarge);

                                        if (ms != null && total > disk_th) {
                                                // Swith to on-disk file.
                                                request_file = GetTempStream ();
                                                ms.WriteTo (request_file);
                                                ms = null;
                                                output = request_file;
                                        }
                                        output.Write (buffer, 0, n);
                                }

                                if (ms != null) {
                                        input_stream = new MemoryStream (ms.GetBuffer (), 0, (int) ms.Length, false, true);
                                } else {
                                        request_file.SetReadOnly ();
                                        input_stream = request_file;
                                }
                        }
                        DoFilter (buffer);

                        if (total < content_length)
                                throw HttpException.NewWithCode (411, "The request body is incomplete.", WebEventCodes.WebErrorOtherError);
                }
#endif

                internal void ReleaseResources ()
                {
                        Stream stream;
                        if (input_stream != null){
                                stream = input_stream;
                                input_stream = null;
                                try {
                                        stream.Close ();
                                } catch {}
                        }

                        if (request_file != null) {
                                stream = request_file;
                                request_file = null;
                                try {
                                        stream.Close ();
                                } catch {}
                        }
                }
#if NET_4_0
                public RequestContext RequestContext {
                        get {
                                if (requestContext == null)
                                        requestContext = new RequestContext (new HttpContextWrapper (this.context ?? HttpContext.Current), new RouteData ());

                                return requestContext;
                        }
                        
                        internal set { requestContext = value; }        
                }

                public ChannelBinding HttpChannelBinding {
                        get {
                                throw new PlatformNotSupportedException ("This property is not supported.");
                        }
                }
#endif
                public Stream InputStream {
                        get {
                                if (input_stream == null)
                                        MakeInputStream ();

                                return input_stream;
                        }
                }

                public bool IsAuthenticated {
                        get {
                                if (context.User == null || context.User.Identity == null)
                                        return false;
                                return context.User.Identity.IsAuthenticated;
                        }
                }

                public bool IsSecureConnection {
                        get {
                                if (worker_request == null)
                                        return false;
                                return worker_request.IsSecure ();
                        }
                }

                public string this [string key] {
                        [AspNetHostingPermission (SecurityAction.Demand, Level = AspNetHostingPermissionLevel.Low)]
                        get {
                                // "The QueryString, Form, Cookies, or ServerVariables collection member
                                // specified in the key parameter."
                                string val = QueryString [key];
                                if (val == null)
                                        val = Form [key];
                                if (val == null) {
                                        HttpCookie cookie = Cookies [key];
                                        if (cookie != null)
                                                val = cookie.Value;
                                }
                                if (val == null)
                                        val = ServerVariables [key];

                                return val;
                        }
                }

                public NameValueCollection Params {
                        [AspNetHostingPermission (SecurityAction.Demand, Level = AspNetHostingPermissionLevel.Low)]
                        get {
                                if (all_params == null)
                                        all_params = new HttpParamsCollection (QueryString, Form, ServerVariables, Cookies);

                                return all_params;
                        }
                }

                internal string PathNoValidation {
                        get {
                                if (original_path == null) {
                                        if (url_components != null)
                                                // use only if it's already been instantiated, so that we can't go into endless
                                                // recursion in some scenarios
                                                original_path = UrlComponents.Path;
                                        else
                                                original_path = ApplyUrlMapping (worker_request.GetUriPath ());
                                }

                                return original_path;
                        }
                }
                
                public string Path {
                        get {
                                if (unescaped_path == null) {
                                        unescaped_path = PathNoValidation;
#if NET_4_0
                                        if (validateRequestNewMode) {
                                                RequestValidator validator = RequestValidator.Current;
                                                int validationFailureIndex;
                                                
                                                if (!validator.IsValidRequestString (HttpContext.Current, unescaped_path, RequestValidationSource.Path, null, out validationFailureIndex))
                                                        ThrowValidationException ("Path", "Path", unescaped_path);
                                        }
#endif
                                }
                                
                                return unescaped_path;
                        }
                }

                public string PathInfo {
                        get {
                                if (path_info == null) {
                                        if (worker_request == null)
                                                return String.Empty;
                                        path_info = worker_request.GetPathInfo () ?? String.Empty;
#if NET_4_0
                                        if (validateRequestNewMode) {
                                                RequestValidator validator = RequestValidator.Current;
                                                int validationFailureIndex;
                                                
                                                if (!validator.IsValidRequestString (HttpContext.Current, path_info, RequestValidationSource.PathInfo, null, out validationFailureIndex))
                                                        ThrowValidationException ("PathInfo", "PathInfo", path_info);
                                        }
#endif
                                }

                                return path_info;
                        }
                }

                public string PhysicalApplicationPath {
                        get {
                                if (worker_request == null)
                                        throw new ArgumentNullException (); // like 2.0, 1.x throws TypeInitializationException

                                string path = HttpRuntime.AppDomainAppPath;
                                if (SecurityManager.SecurityEnabled) {
                                        new FileIOPermission (FileIOPermissionAccess.PathDiscovery, path).Demand ();
                                }
                                return path;
                        }
                }

                public string PhysicalPath {
                        get {
                                if (worker_request == null)
                                        return String.Empty; // don't check security with an empty string!

                                if (physical_path == null) {
                                        // Don't call HttpRequest.MapPath here, as that one *trims* the input
                                        physical_path = worker_request.MapPath (FilePath);
                                }

                                if (SecurityManager.SecurityEnabled) {
                                        new FileIOPermission (FileIOPermissionAccess.PathDiscovery, physical_path).Demand ();
                                }
                                return physical_path;
                        }
                }

                internal string RootVirtualDir {
                        get {
                                if (root_virtual_dir == null){
                                        string fp = FilePath;
                                        int p = fp.LastIndexOf ('/');

                                        if (p < 1)
                                                root_virtual_dir = "/";
                                        else
                                                root_virtual_dir = fp.Substring (0, p);
                                }
                                return root_virtual_dir;
                        }
                }

                internal WebROCollection QueryStringUnvalidated {
                        get {
                                if (query_string_nvc == null) {
                                        query_string_nvc = new WebROCollection ();
                                        string q = UrlComponents.Query;
                                        if (q != null) {
                                                if (q.Length != 0)
                                                        q = q.Remove(0, 1);
                                        
                                                HttpUtility.ParseQueryString (q, ContentEncoding, query_string_nvc);
                                        }
                                        
                                        query_string_nvc.Protect();
                                }

                                return query_string_nvc;
                        }
                }
                
                public NameValueCollection QueryString {
                        get {
                                NameValueCollection query_string_nvc = QueryStringUnvalidated;
#if NET_4_0
                                if (validateRequestNewMode && !checked_query_string) {
                                        if (!lazyQueryStringValidation) {
                                                // Setting this before calling the validator prevents
                                                // possible endless recursion
                                                checked_query_string = true;
                                                ValidateNameValueCollection ("QueryString", query_string_nvc, RequestValidationSource.QueryString);
                                        }
                                } else
#endif
                                        if (validate_query_string && !checked_query_string) {
                                                // Setting this before calling the validator prevents
                                                // possible endless recursion
                                                checked_query_string = true;
                                                ValidateNameValueCollection ("QueryString", query_string_nvc);
                                        }
                                
                                return query_string_nvc;
                        }
                }

                public string RawUrl {
                        get {
                                if (raw_url == null) {
                                        if (worker_request != null)
                                                raw_url = worker_request.GetRawUrl ();
                                        else
                                                raw_url = UrlComponents.Path + UrlComponents.Query;
                                        
                                        if (raw_url == null)
                                                raw_url = String.Empty;
#if NET_4_0
                                        if (validateRequestNewMode) {
                                                RequestValidator validator = RequestValidator.Current;
                                                int validationFailureIndex;

                                                if (!validator.IsValidRequestString (HttpContext.Current, raw_url, RequestValidationSource.RawUrl, null, out validationFailureIndex))
                                                        ThrowValidationException ("RawUrl", "RawUrl", raw_url);
                                        }
#endif
                                }
                                
                                return raw_url;
                        }
                }

                //
                // "GET" or "SET"
                //
                public string RequestType {
                        get {
                                if (request_type == null){
                                        if (worker_request != null) {
                                                request_type = worker_request.GetHttpVerbName ();
                                                http_method = request_type;
                                        } else {
                                                request_type = "GET";
                                        }
                                }
                                return request_type;
                        }

                        set {
                                request_type = value;
                        }
                }

                public NameValueCollection ServerVariables {
                        [AspNetHostingPermission (SecurityAction.Demand, Level = AspNetHostingPermissionLevel.Low)]
                        get {
                                if (server_variables == null)
                                        server_variables = new ServerVariablesCollection (this);

                                return server_variables;
                        }
                }

                public int TotalBytes {
                        get {
                                Stream ins = InputStream;
                                return (int) ins.Length;
                        }
                }

                public Uri Url {
                        get {
                                if (cached_url == null) {
                                        if (orig_url == null)
                                                cached_url = UrlComponents.Uri;
                                        else
                                                cached_url = new Uri (orig_url);
                                }

                                return cached_url;                      
                        }
                }

                public Uri UrlReferrer {
                        get {
                                if (worker_request == null)
                                        return null;

                                string hr = worker_request.GetKnownRequestHeader (HttpWorkerRequest.HeaderReferer);
                                if (hr == null)
                                        return null;

                                Uri uri = null;
                                try {
                                        uri = new Uri (hr);
                                } catch (UriFormatException) {}
                                return uri;
                        }
                }

                public string UserAgent {
                        get {
                                if (worker_request == null)
                                        return null;

                                return worker_request.GetKnownRequestHeader (HttpWorkerRequest.HeaderUserAgent);
                        }
                }

                public string UserHostAddress {
                        get {
                                if (worker_request == null)
                                        return null;

                                return worker_request.GetRemoteAddress ();
                        }
                }

                public string UserHostName {
                        get {
                                if (worker_request == null)
                                        return null;

                                return worker_request.GetRemoteName ();
                        }
                }

                public string [] UserLanguages {
                        get {
                                if (worker_request == null)
                                        return null;

                                if (user_languages == null)
                                        user_languages = SplitHeader (HttpWorkerRequest.HeaderAcceptLanguage);

                                return user_languages;
                        }
                }

                public byte [] BinaryRead (int count)
                {
                        if (count < 0)
                                throw new ArgumentException ("count is < 0");

                        Stream s = InputStream;
                        byte [] ret = new byte [count];
                        if (s.Read (ret, 0, count) != count)
                                throw new ArgumentException (
                                        String.Format ("count {0} exceeds length of available input {1}",
                                                count, s.Length - s.Position));
                        return ret;
                }

                public int [] MapImageCoordinates (string imageFieldName)
                {
                        string method = HttpMethod;
                        NameValueCollection coll = null;
                        if (method == "HEAD" || method == "GET")
                                coll = QueryString;
                        else if (method == "POST")
                                coll = Form;

                        if (coll == null)
                                return null;

                        string x = coll [imageFieldName + ".x"];
                        if (x == null || x == "")
                                return null;

                        string y = coll [imageFieldName + ".y"];
                        if (y == null || y == "")
                                return null;

                        int [] result = new int [2];
                        try {
                                result [0] = Int32.Parse (x);
                                result [1] = Int32.Parse (y);
                        } catch {
                                return null;
                        }

                        return result;
                }

                public string MapPath (string virtualPath)
                {
                        if (worker_request == null)
                                return null;

                        return MapPath (virtualPath, BaseVirtualDir, true);
                }

                public string MapPath (string virtualPath, string baseVirtualDir, bool allowCrossAppMapping)
                {
                        if (worker_request == null)
                                throw HttpException.NewWithCode ("No HttpWorkerRequest", WebEventCodes.RuntimeErrorRequestAbort);

                        if (virtualPath == null)
                                virtualPath = "~";
                        else {
                                virtualPath = virtualPath.Trim ();
                                if (virtualPath.Length == 0)
                                        virtualPath = "~";
                        }

                        if (!VirtualPathUtility.IsValidVirtualPath (virtualPath))
                                throw HttpException.NewWithCode (String.Format ("'{0}' is not a valid virtual path.", virtualPath), WebEventCodes.RuntimeErrorRequestAbort);

                        string appVirtualPath = HttpRuntime.AppDomainAppVirtualPath;
                        if (!VirtualPathUtility.IsRooted (virtualPath)) {
                                if (StrUtils.IsNullOrEmpty (baseVirtualDir))
                                        baseVirtualDir = appVirtualPath;
                                virtualPath = VirtualPathUtility.Combine (VirtualPathUtility.AppendTrailingSlash (baseVirtualDir), virtualPath);
                                if (!VirtualPathUtility.IsAbsolute (virtualPath))
                                        virtualPath = VirtualPathUtility.ToAbsolute (virtualPath, false);
                        } else if (!VirtualPathUtility.IsAbsolute (virtualPath))
                                virtualPath = VirtualPathUtility.ToAbsolute (virtualPath, false);

                        bool isAppVirtualPath = String.Compare (virtualPath, appVirtualPath, RuntimeHelpers.StringComparison) == 0;
                        appVirtualPath = VirtualPathUtility.AppendTrailingSlash (appVirtualPath);
                        if (!allowCrossAppMapping){
                                if (!StrUtils.StartsWith (virtualPath, appVirtualPath, true))
                                        throw new ArgumentException ("MapPath: Mapping across applications not allowed");
                                if (appVirtualPath.Length > 1 && virtualPath.Length > 1 && virtualPath [0] != '/')
                                        throw HttpException.NewWithCode ("MapPath: Mapping across applications not allowed", WebEventCodes.RuntimeErrorRequestAbort);
                        }
                        
                        if (!isAppVirtualPath && !virtualPath.StartsWith (appVirtualPath, RuntimeHelpers.StringComparison))
                                throw new InvalidOperationException (String.Format ("Failed to map path '{0}'", virtualPath));
#if TARGET_JVM
                        return worker_request.MapPath (virtualPath);
#else
                        string path = worker_request.MapPath (virtualPath);
                        if (virtualPath [virtualPath.Length - 1] != '/' && path [path.Length - 1] == System.IO.Path.DirectorySeparatorChar)
                                path = path.TrimEnd (System.IO.Path.DirectorySeparatorChar);
                        return path;
#endif
                }

                public void SaveAs (string filename, bool includeHeaders)
                {
                        Stream output = new FileStream (filename, FileMode.Create);
                        if (includeHeaders) {
                                StringBuilder sb = new StringBuilder ();
                                string version = String.Empty;
                                string path = "/";
                                if (worker_request != null) {
                                        version = worker_request.GetHttpVersion ();
                                        path = UrlComponents.Path;
                                }
                                string qs = UrlComponents.Query;

                                sb.AppendFormat ("{0} {1}{2} {3}\r\n", HttpMethod, path, qs, version);
                                NameValueCollection coll = Headers;
                                foreach (string k in coll.AllKeys) {
                                        sb.Append (k);
                                        sb.Append (':');
                                        sb.Append (coll [k]);
                                        sb.Append ("\r\n");
                                }
                                sb.Append ("\r\n");
                                // latin1
                                byte [] bytes = Encoding.GetEncoding (28591).GetBytes (sb.ToString ());
                                output.Write (bytes, 0, bytes.Length);
                        }

                        // More than 1 call to SaveAs works fine on MS, so we "copy" the stream
                        // to keep InputStream in its state.
                        Stream input = GetSubStream (InputStream);
                        try {
                                long len = input.Length;
                                int buf_size = (int) Math.Min ((len < 0 ? 0 : len), 8192);
                                byte [] data = new byte [buf_size];
                                int count = 0;
                                while (len > 0 && (count = input.Read (data, 0, buf_size)) > 0) {
                                        output.Write (data, 0, count);
                                        len -= count;
                                }
                        } finally {
                                output.Flush ();
                                output.Close ();
                                EndSubStream (input);
                        }
                }

                public void ValidateInput ()
                {
                        validate_cookies = true;
                        validate_query_string = true;
                        validate_form = true;
#if NET_4_0
                        inputValidationEnabled = true;
#endif
                }
#if NET_4_0
                internal void Validate ()
                {
                        var cfg = HttpRuntime.Section;
                        string query = UrlComponents.Query;
                        
                        if (query != null && query.Length > cfg.MaxQueryStringLength)
                                throw new HttpException (400, "The length of the query string for this request exceeds the configured maxQueryStringLength value.");
                        
                        string path = PathNoValidation;
                        if (path != null) {
                                if (path.Length > cfg.MaxUrlLength)
                                        throw new HttpException (400, "The length of the URL for this request exceeds the configured maxUrlLength value.");
                                
                                char[] invalidChars = RequestPathInvalidCharacters;
                                if (invalidChars != null) {
                                        int idx = path.IndexOfAny (invalidChars);
                                        if (idx != -1)
                                                throw HttpException.NewWithCode (
                                                        String.Format ("A potentially dangerous Request.Path value was detected from the client ({0}).", path [idx]),
                                                        WebEventCodes.RuntimeErrorValidationFailure
                                                );
                                }
                        }

                        if (validateRequestNewMode)
                                ValidateInput ();
                }
#endif
#region internal routines
                internal string ClientTarget {
                        get {
                                return client_target;
                        }

                        set {
                                client_target = value;
                        }
                }
                
                public bool IsLocal {
                        get {
                                string address = worker_request.GetRemoteAddress ();

                                if (StrUtils.IsNullOrEmpty (address))
                                        return false;

                                if (address == "127.0.0.1")
                                        return true;

                                System.Net.IPAddress remoteAddr = System.Net.IPAddress.Parse (address);
                                if (System.Net.IPAddress.IsLoopback (remoteAddr))
                                        return true;

                                for (int i = 0; i < host_addresses.Length; i++)
                                        if (remoteAddr.Equals (host_addresses [i]))
                                                return true;

                                return false;
                        }
                }

                internal void SetFilePath (string path)
                {
                        file_path = path;
                        physical_path = null;
                        original_path = null;
                }

                internal void SetCurrentExePath (string path)
                {
                        cached_url = null;
                        current_exe_path = path;
                        UrlComponents.Path = path + PathInfo;
                        // recreated on demand
                        root_virtual_dir = null;
                        base_virtual_dir = null;
                        physical_path = null;
                        unescaped_path = null;
                        original_path = null;
                }

                internal void SetPathInfo (string pi)
                {
                        cached_url = null;
                        path_info = pi;
                        original_path = null;

                        string path = UrlComponents.Path;
                        UrlComponents.Path = path + PathInfo;
                }
#if NET_4_0
                internal void SetFormCollection (WebROCollection coll, bool lazyValidation)
                {
                        if (coll == null)
                                return;
                        form = coll;
                        lazyFormValidation = lazyValidation;
                }

                internal void SetQueryStringCollection (WebROCollection coll, bool lazyValidation)
                {
                        if (coll == null)
                                return;
                        query_string_nvc = coll;
                        lazyQueryStringValidation = lazyValidation;
                }
#endif
                // Headers is ReadOnly, so we need this hack for cookie-less sessions.
                internal void SetHeader (string name, string value)
                {
                        WebROCollection h = (WebROCollection) Headers;
                        h.Unprotect ();
                        h [name] = value;
                        h.Protect ();
                }

                // Notice: there is nothing raw about this querystring.
                internal string QueryStringRaw {
                        get {
                                UriBuilder urlComponents = UrlComponents;

                                if (urlComponents == null) {
                                        string ret = worker_request.GetQueryString ();

                                        if (ret == null || ret.Length == 0)
                                                return String.Empty;

                                        if (ret [0] == '?')
                                                return ret;

                                        return "?" + ret;
                                }
                                
                                return UrlComponents.Query;
                        }

                        set {
                                UrlComponents.Query = value;
                                cached_url = null;
                                query_string_nvc = null;
                        }
                }

                // Internal, dont know what it does, so flagged as public so we can see it.
                internal void SetForm (WebROCollection coll)
                {
                        form = coll;
                }

                internal HttpWorkerRequest WorkerRequest {
                        get {
                                return worker_request;
                        }
                }

                internal HttpContext Context {
                        get { return context; }
                        set { context = value; }
                }

                static void ValidateNameValueCollection (string name, NameValueCollection coll)
                {
                        if (coll == null)
                                return;
                
                        foreach (string key in coll.Keys) {
                                string val = coll [key];
                                if (val != null && val.Length > 0 && IsInvalidString (val))
                                        ThrowValidationException (name, key, val);
                        }
                }
#if NET_4_0
                static void ValidateNameValueCollection (string name, NameValueCollection coll, RequestValidationSource source)
                {
                        if (coll == null)
                                return;

                        RequestValidator validator = RequestValidator.Current;
                        int validationFailureIndex;
                        HttpContext context = HttpContext.Current;

                        foreach (string key in coll.Keys) {
                                string val = coll [key];
                                if (val != null && val.Length > 0 && !validator.IsValidRequestString (context, val, source, key, out validationFailureIndex))
                                        ThrowValidationException (name, key, val);
                        }
                }

                [AspNetHostingPermission (SecurityAction.Demand, Level = AspNetHostingPermissionLevel.High)]
                public void InsertEntityBody ()
                {
                        throw new PlatformNotSupportedException ("This method is not supported.");
                }

                [AspNetHostingPermission (SecurityAction.Demand, Level = AspNetHostingPermissionLevel.High)]
                public void InsertEntityBody (byte[] buffer, int offset, int count)
                {
                        throw new PlatformNotSupportedException ("This method is not supported.");
                }
#endif
                static void ValidateCookieCollection (HttpCookieCollection cookies)
                {
                        if (cookies == null)
                                return;
                
                        int size = cookies.Count;
                        HttpCookie cookie;
#if NET_4_0
                        RequestValidator validator = RequestValidator.Current;
                        int validationFailureIndex;
                        HttpContext context = HttpContext.Current;
#endif
                        bool invalid;
                        
                        for (int i = 0 ; i < size ; i++) {
                                cookie = cookies[i];
                                if (cookie == null)
                                        continue;
                                
                                string value = cookie.Value;
                                string name = cookie.Name;

                                if (!String.IsNullOrEmpty (value)) {
#if NET_4_0
                                        if (validateRequestNewMode)
                                                invalid = !validator.IsValidRequestString (context, value, RequestValidationSource.Cookies, name, out validationFailureIndex);
                                        else
#endif
                                                invalid = IsInvalidString (value);

                                        if (invalid)
                                                ThrowValidationException ("Cookies", name, value);
                                }
                        }
                }

                static void ThrowValidationException (string name, string key, string value)
                {
                        string v = "\"" + value + "\"";
                        if (v.Length > 20)
                                v = v.Substring (0, 16) + "...\"";
                
                        string msg = String.Format ("A potentially dangerous Request.{0} value was " +
                                                    "detected from the client ({1}={2}).", name, key, v);
                
                        throw new HttpRequestValidationException (msg);
                }
#if NET_4_0
                internal static void ValidateString (string key, string value, RequestValidationSource source)
                {
                        if (String.IsNullOrEmpty (value))
                                return;
#pragma warning disable 219
                        int ignore;
#pragma warning restore 219
                        if (IsInvalidString (value, out ignore))
                                ThrowValidationException (source.ToString (), key, value);
                }
#endif
                internal static bool IsInvalidString (string val)
                {
#pragma warning disable 219
                        int validationFailureIndex;
#pragma warning restore 219
                        return IsInvalidString (val, out validationFailureIndex);
                }

                internal static bool IsInvalidString (string val, out int validationFailureIndex)
                {
                        validationFailureIndex = 0;

                        int len = val.Length;
                        if (len < 2)
                                return false;

                        char current = val [0];
                        for (int idx = 1; idx < len; idx++) {
                                char next = val [idx];
                                // See http://secunia.com/advisories/14325
                                if (current == '<' || current == '\xff1c') {
                                        if (next == '!' || next < ' '
                                            || (next >= 'a' && next <= 'z')
                                            || (next >= 'A' && next <= 'Z')) {
                                                validationFailureIndex = idx - 1;
                                                return true;
                                        }
                                } else if (current == '&' && next == '#') {
                                        validationFailureIndex = idx - 1;
                                        return true;
                                }

                                current = next;
                        }

                        return false;
                }
                
                static System.Net.IPAddress [] GetLocalHostAddresses ()
                {
                        try {
                                string hostName = System.Net.Dns.GetHostName ();
                                System.Net.IPAddress [] ipaddr = System.Net.Dns.GetHostAddresses (hostName);
                                return ipaddr;
                        } catch {
                                return new System.Net.IPAddress[0];
                        }
                }
        }
#endregion

#region Helper classes
        
        //
        // Stream-based multipart handling.
        //
        // In this incarnation deals with an HttpInputStream as we are now using
        // IntPtr-based streams instead of byte [].   In the future, we will also
        // send uploads above a certain threshold into the disk (to implement
        // limit-less HttpInputFiles). 
        //
        
        class HttpMultipart {

                public class Element {
                        public string ContentType;
                        public string Name;
                        public string Filename;
                        public long Start;
                        public long Length;
                        
                        public override string ToString ()
                        {
                                return "ContentType " + ContentType + ", Name " + Name + ", Filename " + Filename + ", Start " +
                                        Start.ToString () + ", Length " + Length.ToString ();
                        }
                }
                
                Stream data;
                string boundary;
                byte [] boundary_bytes;
                byte [] buffer;
                bool at_eof;
                Encoding encoding;
                StringBuilder sb;
                
                const byte HYPHEN = (byte) '-', LF = (byte) '\n', CR = (byte) '\r';
                
                // See RFC 2046 
                // In the case of multipart entities, in which one or more different
                // sets of data are combined in a single body, a "multipart" media type
                // field must appear in the entity's header.  The body must then contain
                // one or more body parts, each preceded by a boundary delimiter line,
                // and the last one followed by a closing boundary delimiter line.
                // After its boundary delimiter line, each body part then consists of a
                // header area, a blank line, and a body area.  Thus a body part is
                // similar to an RFC 822 message in syntax, but different in meaning.
                
                public HttpMultipart (Stream data, string b, Encoding encoding)
                {
                        this.data = data;
                        boundary = b;
                        boundary_bytes = encoding.GetBytes (b);
                        buffer = new byte [boundary_bytes.Length + 2]; // CRLF or '--'
                        this.encoding = encoding;
                        sb = new StringBuilder ();
                }

                string ReadLine ()
                {
                        // CRLF or LF are ok as line endings.
                        bool got_cr = false;
                        int b = 0;
                        sb.Length = 0;
                        while (true) {
                                b = data.ReadByte ();
                                if (b == -1) {
                                        return null;
                                }

                                if (b == LF) {
                                        break;
                                }
                                got_cr = (b == CR);
                                sb.Append ((char) b);
                        }

                        if (got_cr)
                                sb.Length--;

                        return sb.ToString ();

                }

                static string GetContentDispositionAttribute (string l, string name)
                {
                        int idx = l.IndexOf (name + "=\"");
                        if (idx < 0)
                                return null;
                        int begin = idx + name.Length + "=\"".Length;
                        int end = l.IndexOf ('"', begin);
                        if (end < 0)
                                return null;
                        if (begin == end)
                                return "";
                        return l.Substring (begin, end - begin);
                }

                string GetContentDispositionAttributeWithEncoding (string l, string name)
                {
                        int idx = l.IndexOf (name + "=\"");
                        if (idx < 0)
                                return null;
                        int begin = idx + name.Length + "=\"".Length;
                        int end = l.IndexOf ('"', begin);
                        if (end < 0)
                                return null;
                        if (begin == end)
                                return "";

                        string temp = l.Substring (begin, end - begin);
                        byte [] source = new byte [temp.Length];
                        for (int i = temp.Length - 1; i >= 0; i--)
                                source [i] = (byte) temp [i];

                        return encoding.GetString (source);
                }

                bool ReadBoundary ()
                {
                        try {
                                string line = ReadLine ();
                                while (line == "")
                                        line = ReadLine ();
                                if (line [0] != '-' || line [1] != '-')
                                        return false;

                                if (!StrUtils.EndsWith (line, boundary, false))
                                        return true;
                        } catch {
                        }

                        return false;
                }

                string ReadHeaders ()
                {
                        string s = ReadLine ();
                        if (s == "")
                                return null;

                        return s;
                }

                bool CompareBytes (byte [] orig, byte [] other)
                {
                        for (int i = orig.Length - 1; i >= 0; i--)
                                if (orig [i] != other [i])
                                        return false;

                        return true;
                }

                long MoveToNextBoundary ()
                {
                        long retval = 0;
                        bool got_cr = false;

                        int state = 0;
                        int c = data.ReadByte ();
                        while (true) {
                                if (c == -1)
                                        return -1;

                                if (state == 0 && c == LF) {
                                        retval = data.Position - 1;
                                        if (got_cr)
                                                retval--;
                                        state = 1;
                                        c = data.ReadByte ();
                                } else if (state == 0) {
                                        got_cr = (c == CR);
                                        c = data.ReadByte ();
                                } else if (state == 1 && c == '-') {
                                        c = data.ReadByte ();
                                        if (c == -1)
                                                return -1;

                                        if (c != '-') {
                                                state = 0;
                                                got_cr = false;
                                                continue; // no ReadByte() here
                                        }

                                        int nread = data.Read (buffer, 0, buffer.Length);
                                        int bl = buffer.Length;
                                        if (nread != bl)
                                                return -1;

                                        if (!CompareBytes (boundary_bytes, buffer)) {
                                                state = 0;
                                                data.Position = retval + 2;
                                                if (got_cr) {
                                                        data.Position++;
                                                        got_cr = false;
                                                }
                                                c = data.ReadByte ();
                                                continue;
                                        }

                                        if (buffer [bl - 2] == '-' && buffer [bl - 1] == '-') {
                                                at_eof = true;
                                        } else if (buffer [bl - 2] != CR || buffer [bl - 1] != LF) {
                                                state = 0;
                                                data.Position = retval + 2;
                                                if (got_cr) {
                                                        data.Position++;
                                                        got_cr = false;
                                                }
                                                c = data.ReadByte ();
                                                continue;
                                        }
                                        data.Position = retval + 2;
                                        if (got_cr)
                                                data.Position++;
                                        break;
                                } else {
                                        // state == 1
                                        state = 0; // no ReadByte() here
                                }
                        }

                        return retval;
                }

                public Element ReadNextElement ()
                {
                        if (at_eof || ReadBoundary ())
                                return null;

                        Element elem = new Element ();
                        string header;
                        while ((header = ReadHeaders ()) != null) {
                                if (StrUtils.StartsWith (header, "Content-Disposition:", true)) {
                                        elem.Name = GetContentDispositionAttribute (header, "name");
                                        elem.Filename = StripPath (GetContentDispositionAttributeWithEncoding (header, "filename"));
                                } else if (StrUtils.StartsWith (header, "Content-Type:", true)) {
                                        elem.ContentType = header.Substring ("Content-Type:".Length).Trim ();
                                }
                        }

                        long start = data.Position;
                        elem.Start = start;
                        long pos = MoveToNextBoundary ();
                        if (pos == -1)
                                return null;

                        elem.Length = pos - start;
                        return elem;
                }

                static string StripPath (string path)
                {
                        if (path == null || path.Length == 0)
                                return path;
                        
                        if (path.IndexOf (":\\") != 1 && !path.StartsWith ("\\\\"))
                                return path;
                        return path.Substring (path.LastIndexOf ('\\') + 1);
                }
        }
#endregion
}