Fixed failing admin requests when content type includes a charset (based on idea from Paul Roub) (#353)

* .

* #350

* fix

* .

src/WireMock.Net/Matchers/ContentTypeMatcher.cs

@@ -0,0 +1,73 @@
+using System.Net.Http.Headers;
+using JetBrains.Annotations;
+
+namespace WireMock.Matchers
+{
+    /// <summary>
+    /// ContentTypeMatcher which accepts also all charsets
+    /// </summary>
+    /// <seealso cref="RegexMatcher" />
+    public class ContentTypeMatcher : WildcardMatcher
+    {
+        private readonly string[] _patterns;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="ContentTypeMatcher"/> class.
+        /// </summary>
+        /// <param name="pattern">The pattern.</param>
+        /// <param name="ignoreCase">IgnoreCase (default false)</param>
+        public ContentTypeMatcher([NotNull] string pattern, bool ignoreCase = false) : this(new[] { pattern }, ignoreCase)
+        {
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="ContentTypeMatcher"/> class.
+        /// </summary>
+        /// <param name="matchBehaviour">The match behaviour.</param>
+        /// <param name="pattern">The pattern.</param>
+        /// <param name="ignoreCase">IgnoreCase (default false)</param>
+        public ContentTypeMatcher(MatchBehaviour matchBehaviour, [NotNull] string pattern, bool ignoreCase = false) : this(matchBehaviour, new[] { pattern }, ignoreCase)
+        {
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="ContentTypeMatcher"/> class.
+        /// </summary>
+        /// <param name="patterns">The patterns.</param>
+        /// <param name="ignoreCase">IgnoreCase (default false)</param>
+        public ContentTypeMatcher([NotNull] string[] patterns, bool ignoreCase = false) : this(MatchBehaviour.AcceptOnMatch, patterns, ignoreCase)
+        {
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="ContentTypeMatcher"/> class.
+        /// </summary>
+        /// <param name="matchBehaviour">The match behaviour.</param>
+        /// <param name="patterns">The patterns.</param>
+        /// <param name="ignoreCase">IgnoreCase (default false)</param>
+        public ContentTypeMatcher(MatchBehaviour matchBehaviour, [NotNull] string[] patterns, bool ignoreCase = false) : base(matchBehaviour, patterns, ignoreCase)
+        {
+            _patterns = patterns;
+        }
+
+        /// <inheritdoc cref="RegexMatcher.IsMatch"/>
+        public override double IsMatch(string input)
+        {
+            if (string.IsNullOrEmpty(input) || !MediaTypeHeaderValue.TryParse(input, out MediaTypeHeaderValue contentType))
+            {
+                return MatchBehaviourHelper.Convert(MatchBehaviour, MatchScores.Mismatch);
+            }
+
+            return base.IsMatch(contentType.MediaType);
+        }
+
+        /// <inheritdoc cref="IStringMatcher.GetPatterns"/>
+        public override string[] GetPatterns()
+        {
+            return _patterns;
+        }
+
+        /// <inheritdoc cref="IMatcher.Name"/>
+        public override string Name => "ContentTypeMatcher";
+    }
+}

src/WireMock.Net/Matchers/RegexMatcher.cs

@@ -71,7 +71,7 @@ namespace WireMock.Matchers
         }
 
         /// <inheritdoc cref="IStringMatcher.IsMatch"/>
-        public double IsMatch(string input)
+        public virtual double IsMatch(string input)
         {
             double match = MatchScores.Mismatch;
             if (input != null)