reactiveui · clairernovotny · Nov 24, 2020 · Nov 23, 2020 · Nov 23, 2020 · Nov 23, 2020
diff --git a/README.md b/README.md
@@ -684,7 +684,12 @@ At this time, multipart methods support the following parameter types:
  - Stream
  - FileInfo
 
-The parameter name will be used as the name of the field in the multipart data. This can be overridden with the `AliasAs` attribute.
+Name of the field in the multipart data priority prec
8000
edence:
+
+* multipartItem.Name if specified and not null (optional); dynamic, allows naming form data part at execution time.
+* [AliasAs] attribute  (optional) that decorate the streamPart parameter in the method signature (see below); static, defined in code.
+* MultipartItem parameter name (default) as defined in the method signature; static, defined in code.
+
 A custom boundary can be specified with an optional string parameter to the `Multipart` attribute. If left empty, this defaults to `----MyGreatBoundary`.
 
 To specify the file name and content type for byte array (`byte[]`), `Stream` and `FileInfo` parameters, use of a wrapper class is required.

diff --git a/Refit.Tests/MultipartTests.cs b/Refit.Tests/MultipartTests.cs
@@ -321,6 +321,37 @@ public async Task MultipartUploadShouldWorkWithStreamPart()
             var result = await fixture.UploadStreamPart(new StreamPart(stream, "test-streampart.pdf", "application/pdf"));
         }
 
+        [Fact]
+        public async Task MultipartUploadShouldWorkWithStreamPartWithNamedMultipart()
+        {
+            var handler = new MockHttpMessageHandler
+            {
+                Asserts = async content =>
+                {
+                    var parts = content.ToList();
+
+                    Assert.Single(parts);
+
+                    Assert.Equal("test-stream", parts[0].Headers.ContentDisposition.Name);
+                    Assert.Equal("test-streampart.pdf", parts[0].Headers.ContentDisposition.FileName);
+                    Assert.Equal("application/pdf", parts[0].Headers.ContentType.MediaType);

+                    using var str = await parts[0].ReadAsStreamAsync();
+                    using var src = GetTestFileStream("Test Files/Test.pdf");
+                    Assert.True(StreamsEqual(src, str));
+                }
+            };
+
+            var settings = new RefitSettings()
+            {
+                HttpMessageHandlerFactory = () => handler
+            };
+
+            using var stream = GetTestFileStream("Test Files/Test.pdf");
+            var fixture = RestService.For<IRunscopeApi>(BaseAddress, settings);
+            var result = await fixture.UploadStreamPart(new StreamPart(stream, "test-streampart.pdf", "application/pdf", "test-stream"));
+        }
+
         [Fact]
         public async Task MultipartUploadShouldWorkWithStreamPartAndQuery()
         {

diff --git a/Refit/MultipartItem.cs b/Refit/MultipartItem.cs
@@ -13,6 +13,13 @@ public MultipartItem(string fileName, string contentType)
             ContentType = contentType;
         }
 
+        public MultipartItem(string fileName, string contentType, string name) : this(fileName, contentType)
+        {
+            Name = name;
+        }
+
+        public string Name { get; }
+
         public string ContentType { get; }
 
         public string FileName { get; }
@@ -33,8 +40,8 @@ public HttpContent ToContent()
 
     public class StreamPart : MultipartItem
     {
-        public StreamPart(Stream value, string fileName, string contentType = null) :
-            base(fileName, contentType)
+        public StreamPart(Stream value, string fileName, string contentType = null, string name = null) :
+            base(fileName, contentType, name)
         {
             Value = value ?? throw new ArgumentNullException("value");
         }
@@ -49,8 +56,8 @@ protected override HttpContent CreateContent()
 
     public class ByteArrayPart : MultipartItem
     {
-        public ByteArrayPart(byte[] value, string fileName, string contentType = null) :
-            base(fileName, contentType)
+        public ByteArrayPart(byte[] value, string fileName, string contentType = null, string name = null) :
+            base(fileName, contentType, name)
         {
             Value = value ?? throw new ArgumentNullException("value");
         }
@@ -65,8 +72,8 @@ protected override HttpContent CreateContent()
 
     public class FileInfoPart : MultipartItem
     {
-        public FileInfoPart(FileInfo value, string fileName, string contentType = null) :
-            base(fileName, contentType)
+        public FileInfoPart(FileInfo value, string fileName, string contentType = null, string name = null) :
+            base(fileName, contentType, name)
         {
             Value = value ?? throw new ArgumentNullException("value");
         }

diff --git a/Refit/RequestBuilderImplementation.cs b/Refit/RequestBuilderImplementation.cs
@@ -182,7 +182,7 @@ async Task AddMultipartItemAsync(MultipartFormDataContent multiPartContent, stri
             if (itemValue is MultipartItem multipartItem)
             {
                 var httpContent = multipartItem.ToContent();
-                multiPartContent.Add(httpContent, parameterName, string.IsNullOrEmpty(multipartItem.FileName) ? fileName : multipartItem.FileName);
+                multiPartContent.Add(httpContent, multipartItem.Name ?? parameterName, string.IsNullOrEmpty(multipartItem.FileName) ? fileName : multipartItem.FileName);
                 return;
             }