获取响应时发生错误，如果nodejs服务器在某些延迟后发送响应

Question

I am trying to upload the image, and then nodeJS server send the path of that image folder back as a response.

But When I sending the response after performing some task, nothing happening on angular-side.

this is my component.ts file.

uploadImage() {
    const formData = new FormData();
    formData.append('photo', this.image);
    const obj$ = this.userService.uploadData(formData); 
    obj$.subscribe(data => {
      console.log(data);   //// nothing happening.
      if (data.success) {
        this.uploadForm.patchValue({
          document: data.url
        });
      }
    });
  }

and my service.ts

uploadData (uploadImage) {
   return this.http.post<UploadPhoto>('/user/upload', uploadImage);
  }

and my app.js

router.post('/upload' ,upload.single('photo'), (req,res) => {

  console.log(req.file);
  const body = req.file;

  cloudinary.uploader.upload(body.path, (err, result) => {
    if (err) {
      console.log(err);
      return;
    }
    console.log(result);
    res.status(200).json({
      url: result.url,
      success: true
    });
  });
});

But when I am sending response without performing any task, it works fine like

router.post('/upload' ,upload.single('photo'), (req,res) => {

  console.log(req.file);
  const body = req.file;

  res.status(200).json({
       url: 'hello',
       success: true
  })

});

I don't know why is this happening.

Please someone help me.

Answer 1

When an error occurs in your uploader you're returning the error to the console and then ending execution. If there is an error in the asynchronous method you must pass it to the next() function so that express can handle it.

router.post('/upload' ,upload.single('photo'), (req,res, next) => {

  console.log(req.file);
  const body = req.file;

  cloudinary.uploader.upload(body.path, (err, result) => {
    if (err) {
      console.log(err);
      next(err);
    }
    else {
      console.log(result);
      res.status(200).json({ url: result.url, success: true });
    }
  });
});