CodecException: No suitable writer found for part [SPR-16601]

[spring-projects-issues]

Marc-Christian Schulze opened SPR-16601 and commented

Following test case (full example attached):

Flux<DataBuffer> content = Flux.empty();

MultipartBodyBuilder builder = new MultipartBodyBuilder();
builder.asyncPart("file", content, DataBuffer.class).headers(h -> {
	h.setContentDispositionFormData("file", "someFile.bin");
	h.setContentType(MediaType.APPLICATION_OCTET_STREAM);
});

WebClient.create("http://whatever.de") 
		.post() 
		.uri("/any/path") 
		.contentType(MediaType.MULTIPART_FORM_DATA) 
		.body(BodyInserters.fromMultipartData(builder.build())) 
		.exchange() 
		.block();

Throws an exception:

org.springframework.core.codec.CodecException: No suitable writer found for part: file

Dependencies:

• org.springframework:spring-webflux:5.0.4.RELEASE
• io.projectreactor.ipc:reactor-netty:0.7.5.RELEASE

---

Affects: 5.0.4

Attachments:

• sample.tar.gz (1.04 kB)

Referenced from: commits 842c291

[spring-projects-issues]

Rossen Stoyanchev commented

You don't need to use BodyInserters in this case. This works:

WebClient.create("http://whatever.de").post() 
		.uri("/any/path") 
		.syncBody(builder.build()) 
		.exchange() 
		.block();

That said what you tried should not fail, so I'm scheduling for a fix in 5.0.5.