How to transmit Multipart file object into Spring web RestClient post method

Question

I have two microservices:

• One for user authentication (authentication microservice).
• One for handling video file storage (videoStore microService).

Process :

• ("/create") belongs to authentication microservice
• ("/create") is accessible only with well formed token (JWT).
• ("/create") receives multipartFile
• ("/create") sends multipartFile to storage service
• ("/uploadfile") belongs to file storage microservice
• ("/uploadfile") performs the storage of the file into linux filesystem

@PostMapping(value ="/create")
 ResponseEntity<Response> createVideo(@RequestParam("file") MultipartFile multipartFile) 
 {  
    videoRestClientService.upload(multipartFile);
    return new ResponseEntity<Response>(new Response("video has been stored"), HttpStatus.OK);
 }

public Response upload(MultipartFile multipartFile){
    
    RestClient restClient = RestClient.create("http://localhost:8095");
    Response response = restClient.post()
     .uri("/uploadfile")
     .contentType(...)
     .body(multipartFile)
     .retrieve()
     .body(Response.class);
}

-> In videoStore microService

@PostMapping("/uploadfile") 
public ResponseEntity<Response> uploadFile(@RequestParam("file") MultipartFile multipartFile) {

    Response response = fileSystemStorage.storeFile(multipartFile);

    return new ResponseEntity<Response>(response, HttpStatus.OK);
}

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot</artifactId>
    <version>3.2.1</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-web</artifactId>
    <version>6.1.2</version>
</dependency>

Question :

• Is it possible to use restClient to post multipartFile ?

Remark :

• I don't have any getway implemented (don't have the skills yet).
• The authentication service is doing the getway job (to bad for clean archicture).

Answer 1

Is it possible to use restClient to post multipartFile ?

I don't know if you have solved this yet. But the answer is yes. I was doing the same thing and have just made it works after a day of researching. Here is what you need:

import org.springframework.web.client.RestClient;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;
import org.springframework.core.io.Resource;
import org.springframework.http.MediaType;

 
public Response upload (MultipartFile multipartFile) {
    // I am not create RestClient like this. I use @Autowired instead
    RestClient restClient = RestClient.create("http://localhost:8095");
    MultiValueMap<String, Resource> body = new LinkedMultiValueMap<>();
    body.add("file", multipartFile.getResource());
    Response response = restClient.post()
            .uri("/uploadfile")
//            .contentType(MediaType.MULTIPART_FORM_DATA)  // Not need
            .body(body)
            .retrieve()
            .body(Response.class);
    return response;
}