I'm trying to add an attachment (PDF) to a card to Leankit. The request worked before an update from the server. After searching I saw (when using Postman) there's:

----WebKitFormBoundary

in the Content-Type.

I thought it might be the issue, but I don't know how to add it to my headers.

The code was working before an update Leankit side.

Here is my code:

public void attachmentUpload(String filename, String path, String cardId)throws JsonProcessingException
{ 
String url = leankitBaseUrl+"/card/"+cardId+"/attachment"; 
String filePath = path+filename; 
String description = "Dessin"; 
RestTemplate restTemplate = new RestTemplate();

    MultiValueMap<String, Object> body = new LinkedMultiValueMap<>();
    body.add("description", description);
    body.add("file", new FileSystemResource(new File(filePath)));

    HttpHeaders headers = new HttpHeaders();
    headers.setContentType(MediaType.MULTIPART_FORM_DATA);
   
    headers.set("Authorization",leankitAPIToken);
    headers.set("User-Agent", "Mozilla/5.0");
  headers.setContentLength(objectMapper.writeValueAsString(body).getBytes().length);
    HttpEntity<MultiValueMap<String, Object>> requestEntity = new HttpEntity<>(body, headers);

    ResponseEntity<String> response = restTemplate.exchange(url, HttpMethod.POST, requestEntity, String.class);

    System.out.println("Response status: " + response.getStatusCode());
    System.out.println("Response body: " + response.getBody());
}

And the error:

java.io.IOException: insufficient data written at java.base/sun.www.protocol.http.HttpURLConnection$StreamingOutputStream.close(HttpURLConnection.java:3887) ~[na:na] at .springframework.http.client.SimpleClientHttpRequest.executeInternal(SimpleClientHttpRequest.java:84) ~[spring-web-6.1.14.jar:6.1.14] at .springframework.http.client.AbstractStreamingClientHttpRequest.executeInternal(AbstractStreamingClientHttpRequest.java:70) ~[spring-web-6.1.14.jar:6.1.14] at .springframework.http.client.AbstractClientHttpRequest.execute(AbstractClientHttpRequest.java:66) ~[spring-web-6.1.14.jar:6.1.14] at .springframework.web.client.RestTemplate.doExecute(RestTemplate.java:889) ~[spring-web-6.1.14.jar:6.1.14] at .springframework.web.client.RestTemplate.execute(RestTemplate.java:790) ~[spring-web-6.1.14.jar:6.1.14] at .springframework.web.client.RestTemplate.exchange(RestTemplate.java:672) ~[spring-web-6.1.14.jar:6.1.14]

My idea might not be the solution I'm open to any idea if it can solve my problem.