How to upload just an image using Retrofit 2.0 - image

Trying to upload an image and it keeps sending as just bytes, not an image file. This is a very simple call, I don't need to send any params other than the image itself. I don't know how to format logs so I won't post the error here unless requested to.
The service:
public interface FileUploadService {
#Multipart
#POST("upload_profile_picture")
Call<ResponseBody> uploadProfilePicture(#Part("profile_picture") RequestBody file);
}
The call being made (a file is generated earlier, had to remove this code because SO needs the post to be mainly words..dumb..):
// Generate the service from interface
FileUploadService service = ServiceGenerator.createService(FileUploadService.class, this);
// Create RequestBody instance from file
RequestBody requestFile =
RequestBody.create(MediaType.parse("image/*"), imageFile);
Log.d(LOG_TAG, "formed file");
// finally, execute the request
Call<ResponseBody> call = service.uploadProfilePicture(requestFile);
Log.d(LOG_TAG, "sending call");
call.enqueue(new Callback<ResponseBody>() {
#Override
public void onResponse(Call<ResponseBody> call,
Response<ResponseBody> response) {
Log.d(LOG_TAG, "success");
Log.d(LOG_TAG, response.toString());
}
#Override
public void onFailure(Call<ResponseBody> call, Throwable t) {
Log.d(LOG_TAG, "failure");
Log.e(LOG_TAG, t.getMessage());
}
});
Is the issue with the MediaType.parse method? I've tried "multipart/form-data", "image/jpeg", and the above as well and nothing has worked.
The server team has said they are receiving the call, just as bytes and no image file.
I keep getting a 400 because it's sending all bytes. How can I just send this? Do I need to send as a multipart or what? From what I've seen, you just need to tag the param in the method with #Body and do the above and it should all work. Can anybody tell me why this is happening? Thanks!

This is a known issue in Retrofit 2.
Edit: Support for OkHttp's MultipartBody.Part has been added in the final 2.0 release.
In order to get it working, you need to change your interface a little bit first:
#Multipart
#POST("upload_profile_picture")
Call<ResponseBody> uploadProfilePicture(#Part MultipartBody.Part file);
Then you have to create the Part and make the call like this:
MultipartBody.Part file = MultipartBody.Part.createFormData(
"file",
imageFile.getName(),
RequestBody.create(MediaType.parse("image/*"), imageFile));
Call<ResponseBody> call = service.uploadProfilePicture(file);

Related

I use springBoot And Vue , i want send a response to vue , But response always is garbled

#Controller
#Slf4j
public class SeckillGoodsController {
#Autowired
RedisTemplate redisTemplate;
#GetMapping("/captcha")
public void verifyCode(Long userId,Long goodsId, HttpServletResponse response){
//set Header as pic
response.setContentType("image/gif");
// no cookie keep every flush is new captcha
response.setContentType("text/html;charset=UTF-8");
response.setCharacterEncoding("utf-8");
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);//never expires
//Use a util [enter image description here][1]
ArithmeticCaptcha captcha = new ArithmeticCaptcha(130, 32, 3);
redisTemplate.opsForValue().set("captcha:"+userId+":"+goodsId,captcha.text(),60, TimeUnit.SECONDS);
try {
System.out.println(response.getOutputStream().toString());
captcha.out(response.getOutputStream());
} catch (IOException e) {
log.error("Errot",e.getMessage());
}
}
}
I send a response to vue.js but use postman test the Body always is captcha, I've set the UTF-8, but it's still wrong
[1]: https://i.stack.imgur.com/04RKS.png
this has nothing to do with Spring Boot.
I'm not entirely sure what the ArithmeticCaptcha does but I guess it creates an image and stream it to the response stream
I don't know what you would expect... You are sending binary data (an image) so it is quite normal that you can't read it.
You are setting the content type twice. You can't do that. In addition, it seems to be png so you might want to check it out.
I guess that you want to would like to get a JSON back or similar. In that case, you need to change your code
Here is an example:
#ResponseBody
#RequestMapping("/captcha")
public JsonResult captcha(Long userId, Long goodsId, HttpServletResponse response) throws Exception {
ArithmeticCaptcha captcha = new ArithmeticCaptcha(130, 32, 3);
String key = "captcha:"+userId+":"+goodsId
redisTemplate.opsForValue().set(key, captcha.text(), 60, TimeUnit.SECONDS);
return JsonResult.ok().put("key", key).put("image", captcha.toBase64());
}
Might need some tweaks to fit 100% your case but this will return a json with a key that is the one you probably will need to match in your next step and the image base64 encoded so it would be (almost) readable.
You can then add the base64 encoded string from the response as the src of your img tag.

How is HttpServletResponse entangled with the fetch API when making a GET request for a BLOB?

Using Spring Boot, I am trying to implement a REST controller, which can handle a GET request asking to return a BLOB object from my database.
Googling around a little bit, and putting pieces together, I have created the following code snippet:
#GetMapping("student/pic/studentId")
public void getProfilePicture(#PathVariable Long studentId, HttpServletResponse response) throws IOException {
Optional<ProfilePicture> profilePicture;
profilePicture = profilePictureService.getProfilePictureByStudentId(studentId);
if (profilePicture.isPresent()) {
ServletOutputStream outputStream = response.getOutputStream();
outputStream.write(profilePicture.get().getPicture());
outputStream.close();
}
}
I am sending the GET request using VanillaJS and the fetch-API:
async function downloadPicture(profilePic, studentId) {
const url = "http://localhost:8080/student/pic/" + studentId;
const response = await fetch(url);
const responseBlob = await response.blob();
if (responseBlob.size > 0) {
profilePic.src = URL.createObjectURL(responseBlob);
}
}
Somehow, this works. That's great, but now I would like to understand the usage of HttpServletResponse in this context, which I am not familiar with. It seems to me that the fetch-API makes use of HttpServletResponse (maybe even creates it), since I am not creating this object or do anything with it.
What is very strange to me is that the return-type of my controller method getProfilePicture() is void, and still I am sending a response, which is most definitely not void.
Also, if the profilePicture was not found in my database, for example due to a non-existing studentId being passed, my controller-method does not do anything. But still, I am getting a response code of 200. That's why I have added the responseBlob.size > 0 part in my Javascript to check for a positive response.
Can someone explain this magic to me, please?
response.getOutputStream(); javadoc says "Returns a ServletOutputStream suitable for writing binary data in the response." It's literally the response stream and you write the picture bytes into it. It's not related to the client reading the response. Alternatively you could just return a byte array which will be automatically written into the response stream and the result will be the same.
To return a different http status code you should change the method return type to ResponseEntity<byte[]>:
#GetMapping("student/pic/studentId")
public ResponseEntity<byte[]> getProfilePicture(#PathVariable Long studentId, HttpServletResponse response) throws IOException {
Optional<ProfilePicture> profilePicture = profilePictureService.getProfilePictureByStudentId(studentId);
if (profilePicture.isPresent()) {
return ResponseEntity.ok(profilePicture.get().getPicture()); //status code 200
} else {
return ResponseEntity.notFound().build(); //status code 404
}
}
ResponseEntity is basically springs way to return different status codes/messages.
Is there a reason why you are manually downloading the image via javascript? You could just create a img element with the http link to the image and the browser will automatically display the image content: <img src="http://localhost:8080/student/pic/studentId">

How to write async data to remote endpoint without getting "No suitable writer found exception"?

I have the following controller method:
#PostMapping(consumes = MediaType.MULTIPART_FORM_DATA_VALUE, path = "/upload")
public Mono<SomeResponse> saveEnhanced(#RequestPart("file") Mono<FilePart> file) {
return documentService.save(file);
}
which calls a service method where I try to use a WebClient to put some data in another application:
public Mono<SomeResponse> save(Mono<FilePart> file) {
MultipartBodyBuilder bodyBuilder = new MultipartBodyBuilder();
bodyBuilder.asyncPart("file", file, FilePart.class);
bodyBuilder.part("identifiers", "some static content");
return WebClient.create("some-url").put()
.uri("/remote-path")
.syncBody(bodyBuilder.build())
.retrieve()
.bodyToMono(SomeResponse.class);
}
but I get the error:
org.springframework.core.codec.CodecException: No suitable writer found for part: file
I tried all variants of the MultipartBodyBuilder (part, asyncpart, with or without headers) and I cannot get it to work.
Am I using it wrong, what am I missing?
Regards,
Alex
I found the solution after getting a reply from one of the contributes on the Spring Framework Github issues section.
For this to work:
The asyncPart method is expecting actual content, i.e. file.content(). I'll update it to unwrap the part content automatically.
bodyBuilder.asyncPart("file", file.content(), DataBuffer.class)
.headers(h -> {
h.setContentDispositionFormData("file", file.name());
h.setContentType(file.headers().getContentType());
});
If both headers are not set then the request will fail on the remote side, saying it cannot find the form part.
Good luck to anyone needing this!

How to mock a multipart file upload when using Spring and Apache File Upload

The project I'm working on needs to support large file uploads and know the time taken during their upload.
To handle the large files I'm using the streaming API of Apache FileUpload, this also allows me to measure the time taken for the complete stream to be saved.
The problem I'm having is that I cannot seem to be able to utilise MockMvc in an Integration Test on this controller. I know that the controller works as I've successfully uploaded files using postman.
Simplified Controller Code:
#PostMapping("/upload")
public String handleUpload(HttpServletRequest request) throws Exception {
ServletFileUpload upload = new ServletFileUpload();
FileItemIterator iterStream = upload.getItemIterator(request);
while (iterStream.hasNext()) {
FileItemStream item = iterStream.next();
String name = item.getFieldName();
InputStream stream = item.openStream();
if (!item.isFormField()) {
// Process the InputStream
} else {
String formFieldValue = Streams.asString(stream);
}
}
}
Simplified Test Code:
private fun uploadFile(tfr: TestFileContainer) {
val mockFile = MockMultipartFile("file", tfr.getData()) // .getData*() returns a ByteArray
val receiveFileRequest = MockMvcRequestBuilders.multipart("/upload")
.file(mockFile)
.contentType(MediaType.MULTIPART_FORM_DATA)
val result = mockMvc.perform(receiveFileRequest)
.andExpect(status().isCreated)
.andExpect(header().exists(LOCATION))
.andReturn(
}
This is the error I'm currently getting
org.apache.tomcat.util.http.fileupload.FileUploadException: the
request was rejected because no multipart boundary was found
Can anyone help?
The MockMultipartFile approach won't work as Spring does work behind the scenes and simply passes the file around.
Ended up using RestTemplate instead as it actually constructs requests.

Send Status code and message in SpringMVC

I have the following code in my web application:
#ExceptionHandler(InstanceNotFoundException.class)
#ResponseStatus(HttpStatus.NO_CONTENT)
public ModelAndView instanceNotFoundException(InstanceNotFoundException e) {
return returnErrorPage(message, e);
}
Is it possible to also append a status message to the response? I need to add some additional semantics for my errors, like in the case of the snippet I posted I would like to append which class was the element of which the instance was not found.
Is this even possible?
EDIT: I tried this:
#ResponseStatus(value=HttpStatus.NO_CONTENT, reason="My message")
But then when I try to get this message in the client, it's not set.
URL u = new URL ( url);
HttpURLConnection huc = (HttpURLConnection) u.openConnection();
huc.setRequestMethod("GET");
HttpURLConnection.setFollowRedirects(true);
huc.connect();
final int code = huc.getResponseCode();
String message = huc.getResponseMessage();
Turns out I needed to activate custom messages on Tomcat using this parameter:
-Dorg.apache.coyote.USE_CUSTOM_STATUS_MSG_IN_HEADER=true
The message can be in the body rather than in header. Similar to a successful method, set the response (text, json, xml..) to be returned, but set the http status to an error value. I have found that to be more useful than the custom message in header. The following example shows the response with a custom header and a message in body. A ModelAndView that take to another page will also be conceptually similar.
#ExceptionHandler(InstanceNotFoundException.class)
public ResponseEntity<String> handle() {
HttpHeaders responseHeaders = new HttpHeaders();
responseHeaders.set("ACustomHttpHeader", "The custom value");
return new ResponseEntity<String>("the error message", responseHeaders, HttpStatus.INTERNAL_SERVER_ERROR);
}

Resources