From d0cfa91fe7408aa864ad034ecf2ac1adb737f914 Mon Sep 17 00:00:00 2001
From: Stef Heyenrath <stef.heyenrath@gmail.com>
Date: Tue, 6 Jun 2023 20:02:05 +0200
Subject: [PATCH 1/2] Allow setting the Content-Length header for a HTTP method
 HEAD

---
 .../Http/HttpRequestMessageHelper.cs          | 22 ++++++++++++++-
 .../Http/HttpRequestMessageHelperTests.cs     | 27 +++++++++++++++++++
 2 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/src/WireMock.Net/Http/HttpRequestMessageHelper.cs b/src/WireMock.Net/Http/HttpRequestMessageHelper.cs
index 44fb37457..d6ce304f4 100644
--- a/src/WireMock.Net/Http/HttpRequestMessageHelper.cs
+++ b/src/WireMock.Net/Http/HttpRequestMessageHelper.cs
@@ -5,12 +5,18 @@
 using System.Net.Http.Headers;
 using Newtonsoft.Json;
 using Stef.Validation;
+using WireMock.Constants;
 using WireMock.Types;
 
 namespace WireMock.Http;
 
 internal static class HttpRequestMessageHelper
 {
+    private static readonly IDictionary<string, bool> ContentLengthHeaderAllowed = new Dictionary<string, bool>(StringComparer.OrdinalIgnoreCase)
+    {
+        { HttpRequestMethod.HEAD, true }
+    };
+
     internal static HttpRequestMessage Create(IRequestMessage requestMessage, string url)
     {
         Guard.NotNull(requestMessage);
@@ -25,6 +31,8 @@ internal static HttpRequestMessage Create(IRequestMessage requestMessage, string
             MediaTypeHeaderValue.TryParse(value, out contentType);
         }
 
+
+
         switch (requestMessage.BodyData?.DetectedBodyType)
         {
             case BodyType.Bytes:
@@ -50,7 +58,19 @@ internal static HttpRequestMessage Create(IRequestMessage requestMessage, string
             return httpRequestMessage;
         }
 
-        var excludeHeaders = new List<string> { HttpKnownHeaderNames.Host, HttpKnownHeaderNames.ContentLength };
+        var excludeHeaders = new List<string> { HttpKnownHeaderNames.Host };
+
+        var contentLengthHeaderAllowed = ContentLengthHeaderAllowed.TryGetValue(requestMessage.Method, out var allowed) && allowed;
+        if (contentLengthHeaderAllowed)
+        {
+            // Set Content to empty ByteArray to be able to set the Content-Length on the content in case of a HEAD method.
+            httpRequestMessage.Content ??= new ByteArrayContent(EmptyArray<byte>.Value);
+        }
+        else
+        {
+            excludeHeaders.Add(HttpKnownHeaderNames.ContentLength);
+        }
+
         if (contentType != null)
         {
             // Content-Type should be set on the content
diff --git a/test/WireMock.Net.Tests/Http/HttpRequestMessageHelperTests.cs b/test/WireMock.Net.Tests/Http/HttpRequestMessageHelperTests.cs
index 5de28dcc4..84307aafc 100644
--- a/test/WireMock.Net.Tests/Http/HttpRequestMessageHelperTests.cs
+++ b/test/WireMock.Net.Tests/Http/HttpRequestMessageHelperTests.cs
@@ -1,7 +1,9 @@
 using NFluent;
 using System.Collections.Generic;
+using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
+using FluentAssertions;
 using WireMock.Http;
 using WireMock.Models;
 using WireMock.Types;
@@ -160,4 +162,29 @@ public void HttpRequestMessageHelper_Create_String_With_ContentType_ApplicationX
         // Assert
         Check.That(message.Content.Headers.GetValues("Content-Type")).ContainsExactly("application/xml; charset=Ascii");
     }
+
+    [Theory]
+    [InlineData("HEAD", true)]
+    [InlineData("GET", false)]
+    [InlineData("PUT", false)]
+    [InlineData("POST", false)]
+    [InlineData("DELETE", false)]
+    [InlineData("TRACE", false)]
+    [InlineData("OPTIONS", false)]
+    [InlineData("CONNECT", false)]
+    [InlineData("PATCH", false)]
+    public void HttpRequestMessageHelper_Create_ContentLengthAllowedForMethod(string method, bool resultShouldBe)
+    {
+        // Arrange
+        var key = "Content-Length";
+        var value = 1234;
+        var headers = new Dictionary<string, string[]> { { key, new[] { "1234" } } };
+        var request = new RequestMessage(new UrlDetails("http://localhost/foo"), method, ClientIp, null, headers);
+
+        // Act
+        var message = HttpRequestMessageHelper.Create(request, "http://url");
+
+        // Assert
+        message.Content?.Headers.ContentLength.Should().Be(resultShouldBe ? value : null);
+    }
 }
\ No newline at end of file

From 9759522fb15cf672f2a885099db3adaf816270d9 Mon Sep 17 00:00:00 2001
From: Stef Heyenrath <stef.heyenrath@gmail.com>
Date: Tue, 6 Jun 2023 22:04:50 +0200
Subject: [PATCH 2/2] .

---
 src/WireMock.Net/Http/HttpRequestMessageHelper.cs | 2 --
 1 file changed, 2 deletions(-)

diff --git a/src/WireMock.Net/Http/HttpRequestMessageHelper.cs b/src/WireMock.Net/Http/HttpRequestMessageHelper.cs
index d6ce304f4..778fb7a18 100644
--- a/src/WireMock.Net/Http/HttpRequestMessageHelper.cs
+++ b/src/WireMock.Net/Http/HttpRequestMessageHelper.cs
@@ -31,8 +31,6 @@ internal static HttpRequestMessage Create(IRequestMessage requestMessage, string
             MediaTypeHeaderValue.TryParse(value, out contentType);
         }
 
-
-
         switch (requestMessage.BodyData?.DetectedBodyType)
         {
             case BodyType.Bytes: