Multipart request with AngularJS

问题

I have an API endpoint to which I must send a multipart HTTP request, composed of two parts, file (a file system file) and data (a JSON object).

After some research I found out how to do a multipart request in AngularJS:

$http({
   method: 'POST',
   url: url,
   headers: {
      'Content-Type': 'multipart/form-data'
   },
   data: {
      data: model,
      file: file
   },
   transformRequest: customFormDataObject
});

1) The customFormDataObject function initially had this form:

customFormDataObject formDataObject = function (data, headersGetter) {
   var fd = new FormData();
   angular.forEach(data, function (value, key) {
      fd.append(key, value);
   });

   var headers = headersGetter();
   delete headers['Content-Type'];

   return fd;
};

The outcome of this implementation is that the individual parts of the request do not have a contentType set to them.

2) After reading some more (https://stackoverflow.com/a/24535293/689216) I tried using a Blob for this, the customFormData object looking like this (a bit of a mess, basically the first part will be of contentType application/json, the second one image/png):

customFormDataObject = function (data, headersGetter) {
    var fd = new FormData();

    var contentType = 'application/json';
    angular.forEach(data, function (value, key) {
         fd.append(key, new Blob([JSON.stringify(value)], {
             type: contentType
         }));
         contentType = 'image/png';
    });

    var headers = headersGetter();
    delete headers['Content-Type'];

    return fd;
 };

This second approach sets the correct contentType for each part of the request, but it does not set any values for the parts.

Basically what happens is with 1) the correct values are set in the multiparts, but the contentType's are not set. With 2) the contentType's are set, but not the values for the multiparts.

Am I missing something? Is this functionality not supposed to work like this?

Thanks!

回答1:

The easiest way to upload files in Angular:

var fd = new FormData();
fd.append('file', file);
fd.append('data', 'string');
$http.post(uploadUrl, fd, {
   transformRequest: angular.identity,
   headers: {'Content-Type': undefined}
})
.success(function(){
})
.error(function(){
});

Absolutely essential are the following two properties of the config object:

transformRequest: angular.identity

overrides Angular's default serialization, leaving our data intact.

headers: {'Content-Type': undefined }

lets the browser detect the correct Content-Type as multipart/form-data, and fill in the correct boundary.

Nothing else worked for me! Courtesy of Lady Louthan's wonderful blogpost.

回答2:

Have you tried something like this:

$httpProvider.defaults.transformRequest = function(data) {
  if (data === undefined){
    return data;
  }

  var formData = new FormData();
  for (var key in data){
    if(typeof data[key] == 'object' && !(data[key] instanceof File)){
      formData.append(key, JSON.stringify(data[key]));
    }else{
      formData.append(key, data[key]);
    }
  }
  return formData;
};

回答3:

I just solve exactly the same problem.

After some tests, I had this situation that you've described:

Basically what happens is with 1) the correct values are set in the multiparts, but the contentType's are not set. With 2) the contentType's are set, but not the values for the multiparts.

To fix this problem, I had to use Blob and Post Ajax instead of $http Post.

It seems that $http does not work correctly in this case.

Code:

    var formData = new FormData();

    var blobId = new Blob([100], { 'type':'text/plain' });
    formData.append('testId', blobId);

    var blobImage = fileService.base64ToBlob(contentToDecode, 'image/jpeg');
    formData.append('file', blobImage, 'imagem' + (i + 1) + '.jpg');

Request:

    $.ajax({
      url: url,
      data: formData,
      cache: false,
      contentType: false,
      processData: false,
      type: 'POST',
      success: function(response) {
        deferred.resolve(response);
        $rootScope.requestInProgress = false;
      },
      error: function(error) {
        deferred.reject(error);
        $rootScope.requestInProgress = false;
      }
    });

回答4:

You can use https://github.com/danialfarid/ng-file-upload/.

In this file uploader, there is a provision for sending the file and data (in JSON format) separately as you mentioned in your question above.

For Ex:-

var upload = $upload.upload({
                 url: url,
                 file: file,
                 method: 'POST' or 'PUT', default POST,
                 headers: {'Content-Type': 'multipart/form-data'}, // only for html5
                 fileName: 'doc.jpg',
                 fileFormDataName: 'myFile',
                 data: {'data': model}
             });

In the above code, you can send either a POST or PUT request with 'multipart/form-data', file and data object as JSON separately.

For more information you can visit the above link and look at the ReadMe.md of the plug-in.

I know that my approach is a bit different from the one that you are currently following, but the objective is same.

回答5:

what i did to solve this was.

var formData = new FormData(document.getElementById('myFormId'));

then in my service

                var deferred = $q.defer();
                $http.post('myurl', formData, {
                    cache: false,
                    contentType: false,
                    processData: false,
                })
                    .success(function (response) {
                        deferred.resolve(response);
                    })
                    .error(function (reject) {
                        deferred.reject(reject);
                    });
                return deferred.promise;

来源：https://stackoverflow.com/questions/28902727/multipart-request-with-angularjs

标签

angularjs

multipartform-data

multipart