Added JsonMatcher (#153)

src/WireMock.Net/Matchers/JsonMatcher.cs

@@ -0,0 +1,67 @@
+using JetBrains.Annotations;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Linq;
+using WireMock.Validation;
+
+namespace WireMock.Matchers
+{
+    /// <summary>
+    /// JsonMatcher
+    /// </summary>
+    public class JsonMatcher : IValueMatcher
+    {
+        private readonly string _value;
+
+        /// <inheritdoc cref="IMatcher.Name"/>
+        public string Name => "JsonMatcher";
+
+        /// <inheritdoc cref="IMatcher.MatchBehaviour"/>
+        public MatchBehaviour MatchBehaviour { get; }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="JsonMatcher"/> class.
+        /// </summary>
+        /// <param name="value">The value to check for equality.</param>
+        public JsonMatcher([NotNull] string value) : this(MatchBehaviour.AcceptOnMatch, value)
+        {
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="JsonMatcher"/> class.
+        /// </summary>
+        /// <param name="matchBehaviour">The match behaviour.</param>
+        /// <param name="value">The value to check for equality.</param>
+        public JsonMatcher(MatchBehaviour matchBehaviour, [NotNull] string value)
+        {
+            Check.NotNull(value, nameof(value));
+
+            MatchBehaviour = matchBehaviour;
+            _value = value;
+        }
+
+        /// <inheritdoc cref="IObjectMatcher.IsMatch"/>
+        public double IsMatch(object input)
+        {
+            bool match = false;
+            if (input != null)
+            {
+                try
+                {
+                    // Check if JToken or object
+                    JToken jtoken = input is JToken token ? token : JObject.FromObject(input);
+
+                    match = JToken.DeepEquals(JToken.Parse(_value), jtoken);
+                }
+                catch (JsonException)
+                {
+                    // just ignore JsonException
+                }
+            }
+
+            return MatchBehaviourHelper.Convert(MatchBehaviour, MatchScores.ToScore(match));
+        }
+
+        /// <inheritdoc cref="IValueMatcher.GetValue"/>
+        public string GetValue() => _value;
+    }
+}