Quote multipart form parameter names by default (RFC 7578)

alexeyzimarev · claude · alexeyzimarev · commit 9b8293cf8aab · 2026-02-26T20:37:18.000+01:00
Change MultipartFormQuoteParameters default from false to true so that parameter names in Content-Disposition headers are quoted consistently with file parameter names, as required by RFC 7578. Fixes #2271 Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
diff --git a/src/RestSharp/Request/RestRequest.cs b/src/RestSharp/Request/RestRequest.cs
@@ -87,10 +87,9 @@ public RestRequest(Uri resource, Method method = Method.Get)
 
     /// <summary>
     /// When set to true, parameter values in a multipart form data requests will be enclosed in
-    /// quotation marks. Default is false. Enable it if the remote endpoint requires parameters
-    /// to be in quotes (for example, FreshDesk API). 
+    /// quotation marks. Default is true, as per RFC 7578.
     /// </summary>
-    public bool MultipartFormQuoteParameters { get; set; }
+    public bool MultipartFormQuoteParameters { get; set; } = true;
 
     /// <summary>
     /// When set to true, the form boundary part of the content type will be enclosed in
diff --git a/test/RestSharp.Tests.Integrated/MultipartFormDataTests.cs b/test/RestSharp.Tests.Integrated/MultipartFormDataTests.cs
@@ -31,7 +31,7 @@ public void Dispose() {
     const string ContentDispositionString = $"{KnownHeaders.ContentDisposition}: form-data;";
 
     const string Expected =
-        $"--{{0}}{LineBreak}{ContentTypeString}{LineBreak}{ContentDispositionString} name=foo{LineBreak}{LineBreak}bar{LineBreak}" +
+        $"--{{0}}{LineBreak}{ContentTypeString}{LineBreak}{ContentDispositionString} name=\"foo\"{LineBreak}{LineBreak}bar{LineBreak}" +
         $"--{{0}}{LineBreak}{ContentTypeString}{LineBreak}{ContentDispositionString} name=\"a name with spaces\"{LineBreak}{LineBreak}somedata{LineBreak}" +
         $"--{{0}}--{LineBreak}";
 
@@ -228,7 +228,7 @@ public async Task PostParameter_contentType_in_multipart_form() {
 
         var actual = capturer.Body!.Replace("\n", string.Empty).Split('\r');
         actual[1].Should().Be("Content-Type: application/json; charset=utf-8");
-        actual[2].Should().Be($"Content-Disposition: form-data; name={parameterName}");
+        actual[2].Should().Be($"Content-Disposition: form-data; name=\"{parameterName}\"");
         actual[4].Should().Be(parameterValue);
     }
 }

Original file line number	Diff line number	Diff line change
`@@ -31,7 +31,7 @@ public void Dispose() {`
`31`	`31`	`const string ContentDispositionString = $"{KnownHeaders.ContentDisposition}: form-data;";`
`32`	`32`
`33`	`33`	`const string Expected =`
`34`		`- $"--{{0}}{LineBreak}{ContentTypeString}{LineBreak}{ContentDispositionString} name=foo{LineBreak}{LineBreak}bar{LineBreak}" +`
	`34`	`+ $"--{{0}}{LineBreak}{ContentTypeString}{LineBreak}{ContentDispositionString} name=\"foo\"{LineBreak}{LineBreak}bar{LineBreak}" +`
`35`	`35`	`$"--{{0}}{LineBreak}{ContentTypeString}{LineBreak}{ContentDispositionString} name=\"a name with spaces\"{LineBreak}{LineBreak}somedata{LineBreak}" +`
`36`	`36`	`$"--{{0}}--{LineBreak}";`
`37`	`37`
`@@ -228,7 +228,7 @@ public async Task PostParameter_contentType_in_multipart_form() {`
`228`	`228`
`229`	`229`	`var actual = capturer.Body!.Replace("\n", string.Empty).Split('\r');`
`230`	`230`	`actual[1].Should().Be("Content-Type: application/json; charset=utf-8");`
`231`		`- actual[2].Should().Be($"Content-Disposition: form-data; name={parameterName}");`
	`231`	`+ actual[2].Should().Be($"Content-Disposition: form-data; name=\"{parameterName}\"");`
`232`	`232`	`actual[4].Should().Be(parameterValue);`
`233`	`233`	`}`
`234`	`234`	`}`