Move some classes and restructure.

src/WireMock/Matchers/Request/RequestMessageHeaderMatcher.cs

@@ -0,0 +1,73 @@
+using System;
+using System.Collections.Generic;
+using System.Text.RegularExpressions;
+using JetBrains.Annotations;
+using WireMock.Validation;
+
+namespace WireMock.Matchers.Request
+{
+    /// <summary>
+    /// The request header matcher.
+    /// </summary>
+    public class RequestMessageHeaderMatcher : IRequestMatcher
+    {
+        /// <summary>
+        /// The name.
+        /// </summary>
+        private readonly string _name;
+
+        /// <summary>
+        /// The patternRegex.
+        /// </summary>
+        private readonly Regex _patternRegex;
+
+        /// <summary>
+        /// The header function
+        /// </summary>
+        private readonly Func<IDictionary<string, string>, bool> _headerFunc;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="RequestMessageHeaderMatcher"/> class.
+        /// </summary>
+        /// <param name="name">
+        /// The name.
+        /// </param>
+        /// <param name="pattern">
+        /// The pattern.
+        /// </param>
+        /// <param name="ignoreCase">The ignoreCase.</param>
+        public RequestMessageHeaderMatcher([NotNull] string name, [NotNull, RegexPattern] string pattern, bool ignoreCase = true)
+        {
+            _name = name;
+            _patternRegex = ignoreCase ? new Regex(pattern, RegexOptions.IgnoreCase) : new Regex(pattern);
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="RequestMessageHeaderMatcher"/> class.
+        /// </summary>
+        /// <param name="func">
+        /// The func.
+        /// </param>
+        public RequestMessageHeaderMatcher([NotNull] Func<IDictionary<string, string>, bool> func)
+        {
+            Check.NotNull(func, nameof(func));
+            _headerFunc = func;
+        }
+
+        /// <summary>
+        /// Determines whether the specified RequestMessage is match.
+        /// </summary>
+        /// <param name="requestMessage">The RequestMessage.</param>
+        /// <returns>
+        ///   <c>true</c> if the specified RequestMessage is match; otherwise, <c>false</c>.
+        /// </returns>
+        public bool IsMatch(RequestMessage requestMessage)
+        {
+            if (_patternRegex == null)
+                return _headerFunc(requestMessage.Headers);
+
+            string headerValue = requestMessage.Headers[_name];
+            return _patternRegex.IsMatch(headerValue);
+        }
+    }
+}