mcs/class/referencesource/System.ComponentModel.DataAnnotations/DataAnnotations/PhoneAttribute.cs

   1 namespace System.ComponentModel.DataAnnotations {
   2     using System;
   3     using System.ComponentModel.DataAnnotations.Resources;
   4     using System.Text.RegularExpressions;
   5
   6     [AttributeUsage(AttributeTargets.Property | AttributeTargets.Field | AttributeTargets.Parameter, AllowMultiple = false)]
   7     public sealed class PhoneAttribute : DataTypeAttribute {
   8         // see unit tests for examples
   9         private static Regex _regex = CreateRegEx();
  10         private const string _additionalPhoneNumberCharacters = "-.()";
  11
  12         public PhoneAttribute()
  13             : base(DataType.PhoneNumber) {
  14
  15             // DevDiv 468241: set DefaultErrorMessage not ErrorMessage, allowing user to set
  16             // ErrorMessageResourceType and ErrorMessageResourceName to use localized messages.
  17             DefaultErrorMessage = DataAnnotationsResources.PhoneAttribute_Invalid;
  18         }
  19
  20         public override bool IsValid(object value) {
  21             if (value == null) {
  22                 return true;
  23             }
  24
  25             string valueAsString = value as string;
  26
  27             // Use RegEx implementation if it has been created, otherwise use a non RegEx version.
  28             if (_regex != null) {
  29                 return valueAsString != null && _regex.Match(valueAsString).Length > 0;
  30             }
  31             else {
  32                 if (valueAsString == null) {
  33                     return false;
  34                 }
  35
  36                 valueAsString = valueAsString.Replace("+", string.Empty).TrimEnd();
  37                 valueAsString = RemoveExtension(valueAsString);
  38
  39                 bool digitFound = false;
  40                 foreach (char c in valueAsString) {
  41                     if (Char.IsDigit(c)) {
  42                         digitFound = true;
  43                         break;
  44                     }
  45                 }
  46
  47                 if (!digitFound) {
  48                     return false;
  49                 }
  50
  51                 foreach (char c in valueAsString)
  52                 {
  53                     if (!(Char.IsDigit(c)
  54                         || Char.IsWhiteSpace(c)
  55                         || _additionalPhoneNumberCharacters.IndexOf(c) != -1)) {
  56                         return false;
  57                     }
  58                 }
  59                 return true;
  60             }
  61         }
  62
  63         private static Regex CreateRegEx() {
  64             // We only need to create the RegEx if this switch is enabled.
  65             if (AppSettings.DisableRegEx) {
  66                 return null;
  67             }
  68
  69             const string pattern = @"^(\+\s?)?((?<!\+.*)\(\+?\d+([\s\-\.]?\d+)?\)|\d+)([\s\-\.]?(\(\d+([\s\-\.]?\d+)?\)|\d+))*(\s?(x|ext\.?)\s?\d+)?$";
  70             const RegexOptions options = RegexOptions.Compiled | RegexOptions.IgnoreCase | RegexOptions.ExplicitCapture;
  71
  72             // Set explicit regex match timeout, sufficient enough for phone parsing
  73             // Unless the global REGEX_DEFAULT_MATCH_TIMEOUT is already set
  74             TimeSpan matchTimeout = TimeSpan.FromSeconds(2);
  75
  76             try {
  77                 if (AppDomain.CurrentDomain.GetData("REGEX_DEFAULT_MATCH_TIMEOUT") == null) {
  78                     return new Regex(pattern, options, matchTimeout);
  79                 }
  80             }
  81             catch {
  82                 // Fallback on error
  83             }
  84
  85             // Legacy fallback (without explicit match timeout)
  86             return new Regex(pattern, options);
  87         }
  88
  89         private static string RemoveExtension(string potentialPhoneNumber) {
  90             int lastIndexOfExtension = potentialPhoneNumber
  91                 .LastIndexOf("ext.", StringComparison.InvariantCultureIgnoreCase);
  92             if (lastIndexOfExtension >= 0)  {
  93                 string extension = potentialPhoneNumber.Substring(lastIndexOfExtension + 4);
  94                 if (MatchesExtension(extension)) {
  95                     return potentialPhoneNumber.Substring(0, lastIndexOfExtension);
  96                 }
  97             }
  98
  99             lastIndexOfExtension = potentialPhoneNumber
 100                 .LastIndexOf("ext", StringComparison.InvariantCultureIgnoreCase);
 101             if (lastIndexOfExtension >= 0) {
 102                 string extension = potentialPhoneNumber.Substring(lastIndexOfExtension + 3);
 103                 if (MatchesExtension(extension)) {
 104                     return potentialPhoneNumber.Substring(0, lastIndexOfExtension);
 105                 }
 106             }
 107
 108
 109             lastIndexOfExtension = potentialPhoneNumber
 110                 .LastIndexOf("x", StringComparison.InvariantCultureIgnoreCase);
 111             if (lastIndexOfExtension >= 0) {
 112                 string extension = potentialPhoneNumber.Substring(lastIndexOfExtension + 1);
 113                 if (MatchesExtension(extension)) {
 114                     return potentialPhoneNumber.Substring(0, lastIndexOfExtension);
 115                 }
 116             }
 117
 118             return potentialPhoneNumber;
 119         }
 120
 121         private static bool MatchesExtension(string potentialExtension)  {
 122             potentialExtension = potentialExtension.TrimStart();
 123             if (potentialExtension.Length == 0) {
 124                 return false;
 125             }
 126
 127             foreach (char c in potentialExtension) {
 128                 if (!Char.IsDigit(c)) {
 129                     return false;
 130                 }
 131             }
 132
 133             return true;
 134         }
 135     }
 136 }