Convert OkHttp Request to Spring RestTemplate Request

I have a OkHttp request like:

public String createImageEditWithOkHttp(String prompt) throws IOException
{
OkHttpClient client = new OkHttpClient().newBuilder()
.connectTimeout(30, TimeUnit.SECONDS)
.callTimeout(30, TimeUnit.SECONDS)
.readTimeout(30, TimeUnit.SECONDS)
.writeTimeout(30, TimeUnit.SECONDS)
.build();
RequestBody body = new MultipartBody.Builder().setType(MultipartBody.FORM)
.addFormDataPart("image","file",
RequestBody.create(MediaType.parse("application/octet-stream"),
ResourceUtils.getFile("classpath:image_edit_original.png")))
.addFormDataPart("mask","file",
RequestBody.create(MediaType.parse("application/octet-stream"),
ResourceUtils.getFile("classpath:image_edit_mask.png")))
.addFormDataPart("prompt",prompt)
.addFormDataPart("n","1")
.addFormDataPart("size", ImageSize.SMALL.getSize())
.build();
Request request = new Request.Builder()
.url(IMAGE_EDIT_URL)
.method("POST", body)
.addHeader("Authorization", "Bearer " + OPENAI_API_KEY)
.build();
Response response = client.newCall(request).execute();
return response.body().string();
}

Here, read file from resources and send it as multipartfile with okhttp post request. OkHttp version works like expected. But when I try to convert it to resttemplate version, it couldn't find files on the request boy.

and I want to convert it to spring resttemplate request:

public String createImageEditWithRestTemplate(String prompt) throws FileNotFoundException
{
HttpEntity<MultiValueMap<String, Object>> requestEntity
= new HttpEntity<>(createBody(prompt), commonHttpHeaders());
ResponseEntity<String> response = restTemplate.postForEntity(IMAGE_EDIT_URL, requestEntity, String.class);
return response.getBody();
}
private MultiValueMap<String, Object> createBody(String prompt) throws FileNotFoundException
{
MultiValueMap<String,Object> body = new LinkedMultiValueMap<>();
body.add("image", ResourceUtils.getFile("classpath:image_edit_original.png"));
body.add("mask", ResourceUtils.getFile("classpath:image_edit_mask.png"));
body.add("prompt",prompt);
body.add("n","1");
body.add("size", ImageSize.SMALL.getSize());
return body;
}
private HttpHeaders commonHttpHeaders()
{
MultiValueMap<String,String> headers = new LinkedMultiValueMap<>();
headers.add("Authorization", "Bearer " + OPENAI_API_KEY);
headers.add("Content-Type", org.springframework.http.MediaType.MULTIPART_FORM_DATA_VALUE);
return new HttpHeaders(headers);
}

But it couldn't find image as file in the request. Any suggestion?

Ok, I found the problem. We need to send file with FileSystemResource wrapper.

private MultiValueMap<String, Object> createBody(String prompt) throws FileNotFoundException
{
MultiValueMap<String,Object> body = new LinkedMultiValueMap<>();
body.add("image", new FileSystemResource(ResourceUtils.getFile("classpath:image_edit_original.png")));
body.add("mask", new FileSystemResource(ResourceUtils.getFile("classpath:image_edit_mask.png")));
body.add("prompt",prompt);
body.add("n","1");
body.add("size", ImageSize.SMALL.getSize());
return body;
}

You need to use Resource instead of file object. As you reading file from classpath you can use ClassPathResource. Also, Headers you have method to set BearerAuth and Content-Type.

public String createImageEditWithRestTemplate(String prompt) throws FileNotFoundException {
    HttpEntity<MultiValueMap<String, Object>> requestEntity =
            new HttpEntity<>(createBody(prompt), commonHttpHeaders());
    ResponseEntity<String> response = restTemplate.postForEntity(IMAGE_EDIT_URL, requestEntity, String.class);
    return response.getBody();
}

private MultiValueMap<String, Object> createBody(String prompt) throws FileNotFoundException {
    MultiValueMap<String, Object> body = new LinkedMultiValueMap<>();
    body.add("image", new ClassPathResource("image_edit_original.png"));
    body.add("mask", new ClassPathResource("image_edit_mask.png"));
    body.add("prompt", prompt);
    body.add("n", "1");
    body.add("size", ImageSize.SMALL.getSize());
    return body;
}

private HttpHeaders commonHttpHeaders() {
    HttpHeaders headers = new HttpHeaders();
    headers.setBearerAuth(OPENAI_API_KEY);
    headers.setContentType(MediaType.MULTIPART_FORM_DATA);
    return headers;
}

Incase if you have not set the timeout in RestTemplate then use httpclient library and generate RestTemplate object as following.

public RestTemplate getRestTemplate() throws KeyManagementException, NoSuchAlgorithmException {
    SSLContext sslContext = SSLContexts.custom().build();
    SSLConnectionSocketFactory csf = new SSLConnectionSocketFactory(sslContext);
    CloseableHttpClient httpClient = HttpClients.custom().setSSLSocketFactory(csf).useSystemProperties().build();
    HttpComponentsClientHttpRequestFactory requestFactory = new HttpComponentsClientHttpRequestFactory();
    requestFactory.setHttpClient(httpClient);
    requestFactory.setConnectTimeout(30000);
    requestFactory.setReadTimeout(30000);
    requestFactory.setConnectionRequestTimeout(30000);
    return new RestTemplate(requestFactory);
}