File Upload Using Feign - multipart/form-data

Question

I'm trying to accomplish a multipart file upload using feign, but I can't seem to find a good example of it anywhere. I essentially want the HTTP request to turn out similar to this:

...
Content-Type: multipart/form-data; boundary=AaB03x

--AaB03x
Content-Disposition: form-data; name="name"

Larry
--AaB03x
   Content-Disposition: form-data; name="file"; filename="file1.txt"
   Content-Type: text/plain

... contents of file1.txt ...
--AaB03x--

Or even...

------fGsKo01aQ1qXn2C
Content-Disposition: form-data; name="file"; filename="file.doc"
Content-Type: application/octet-stream

... binary data ...

------fGsKo01aQ1qXn2C--

Do I need to manually build the request body, including generating the multipart boundaries? That seems a bit excessive considering everything else this client can do.

Answer 1

No, you don't. You just need to define a kind of proxy interface method, specify the content-type as: multipart/form-data and other info such as parameters required by the remote API. Here is an example:

public interface FileUploadResource {

    @RequestLine("POST /upload")
    @Headers("Content-Type: multipart/form-data")
    Response uploadFile(@Param("name") String name, @Param("file") File file);

} 

The completed example can be found here: File Uploading with Open Feign

Answer 2

For spring boot 2 and spring-cloud-starter-openfeign use this code:

@PostMapping(value="/upload", consumes = "multipart/form-data" )
QtiPackageBasicInfo upload(@RequestPart("package") MultipartFile package);

You need to change @RequestParam to @RequestPart in the feign client call to make it work, and also add consumes to the @PostMapping.

Answer 3

If you are already using Spring Web, you can try my implementation of a Feign Encoder that is able to create Multipart requests. It can send a single file, an array of files alongwith one or more additional JSON payloads. Here is my test project . If you don't use Spring, you can refactor the code by changing the encodeRequest method in FeignSpringFormEncoder.

Answer 4

MBozic solution not full, you will also need to enable an Encoder for this:

---

public class FeignConfig {
     
    @Autowired
    private ObjectFactory<HttpMessageConverters> messageConverters;

    @Bean
    public Encoder feignFormEncoder () {
        return new SpringFormEncoder(new SpringEncoder(messageConverters));
    }
}

---

@FeignClient(name = "file", url = "http://localhost:8080", configuration = FeignConfig.class)
public interface UploadClient {
    @PostMapping(value = "/upload-file", consumes = MediaType.MULTIPART_FORM_DATA_VALUE)
    String fileUpload(@RequestPart(value = "file") MultipartFile file);
}

Answer 5

Let me add Answer for latest OpenFeign :

1. Add dependency for Feign-Form:

   io.github.openfeign.form feign-form 3.8.0

2. Add FormEncoder to your Feign.Builder like so:

SomeApi github = Feign.builder() .encoder(new FormEncoder()) .target(SomeApi.class, "http://api.some.org");

3. API endpoint

@RequestLine("POST /send_photo") @Headers("Content-Type: multipart/form-data") void sendPhoto (@Param("is_public") Boolean isPublic, @Param("photo") FormData photo);

Refer : https://github.com/OpenFeign/feign-form

Answer 6

Call from one service to another service for file transfer/upload/send using feign client interface:

@FeignClient(name = "service-name", url = "${service.url}", configuration = FeignTokenForwarderConfiguration.class)

public interface UploadFeignClient {

@PostMapping(value = "upload", headers = "Content-Type= multipart/form-data", consumes = "multipart/form-data")
public void upload(@RequestPart MultipartFile file) throws IOException;

}

**Actual API:**

@RestController

@RequestMapping("upload")

public class UploadController {

@PostMapping(value = "/upload", consumes = { "multipart/form-data" })   
public void upload(@RequestParam MultipartFile file) throws IOException {

//implementation

}

}