AngularJS Formdata file array upload

Question

I'm trying to upload (actually POST) numerous small files in one go along with some key, value pairs:

                $scope.uploadFiles = function(files) {

                    if (files.length === 0) {
                        return;
                    }

                    var formData = new FormData();
                    formData.append('keyName1', 'keyValue1');
                    formData.append('keyName2', 'keyValue2');
                    formData.append('keyName3', 'keyValue3');
                    for (var i = 0; i < files.length; i++) {
                        formData.append('files[]', files[i]);
                    }

                    $http.post( '/myEndpoint', formData, {
                        headers: { 'Content-Type': undefined },
                        transformRequest: angular.identity
                    }).success(function (result) {
                        console.log('YAY');
                    }).error(function () {
                        console.log('NAY');
                    });                 
                }

Here's the Java backend:

@RequestMapping(value = "/myEndpoint", method = RequestMethod.POST)
@ResponseBody
public void uploadFiles(
        @RequestParam("files") List<MultipartFile> fileList,
        @RequestParam("keyName1") String keyName1,
        @RequestParam("keyName2") String keyName2,
        @RequestParam("keyName3") String keyName3,
        HttpServletResponse response, HttpSession session) throws Exception {

    log.debug(fileList.size()); // Always logs zero
}

The endpoint is being hit but the filesList length is zero. I've also changed

    List<MultipartFile> fileList to MultipartFile[] filesArray

but that didn't work wither.

Can anyone shed some light please?

Cheers,

Paul

for (var i = 0; i < files.length; i++) { formData.append('files[]', files[i]); } What is the purpose of this? — Rana_S, Nov 25 '15 at 16:18
Hi, the purpose is to append an array to FormData where the array contains n files. [link] (https://developer.mozilla.org/en-US/docs/Web/API/FormData/append) — user3034151, Nov 25 '15 at 17:31

score 6 · Answer 1 · answered Nov 25 '15 at 16:33

This might be helpful to you.

Angular:

$scope.uploadFiles = function(files) {
    if (files.length === 0) {
        return;
    }

    var formData = new FormData();
    formData.append('keyName1', 'keyValue1');
    formData.append('keyName2', 'keyValue2');
    formData.append('keyName3', 'keyValue3');
    for (var i = 0; i < files.length; i++) {
        formData.append('file'+i, files[i]);
    }

    $http.post( '/myEndpoint', formData, {
        headers: { 'Content-Type': undefined },
        transformRequest: angular.identity
    }).success(function (result) {
        console.log('YAY');
    }).error(function () {
        console.log('NAY');
    });                 
}

On Spring/Java Side:

RequestMapping(value = "/myEndpoint", method = RequestMethod.POST)
public @ResponseBody Object uploadFiles(MultipartHttpServletRequest request, HttpServletResponse response) throws IOException {
    //do stuff here...
    final String keyName1= request.getParameter('keyName1');
    //and so on......

    Iterator<String> iterator = request.getFileNames();
    MultipartFile multipartFile = null;
    while (iterator.hasNext()) {
        multipartFile = request.getFile(iterator.next());
        //do something with the file.....
    }
}

BTW, on you angular side, you can always end the file on one go or with multiple request. It's up to you how you want that implemented.

"Thanks, that worked nicely" - in which case, please accept the answer, in order to help others in future. — Mawg says reinstate Monica, Sep 03 '17 at 16:01
Rossi, if you repost this answer to my [question](https://stackoverflow.com/questions/60035869/empty-multipartfile-when-sending-files-from-vue-to-springboot-controller) I will accept it. I used Vue + vue-resource, so maybe your answer will help more people. — Hexronimo, Feb 06 '20 at 07:55

score 0 · Answer 2 · answered Nov 25 '15 at 16:17

I used a library on GitHub to help me accomplish this task with my Java Glassfish Server.

https://github.com/nervgh/angular-file-upload

I only needed to upload a single file, and here is the Java Backend to receive that file. This framework does have support to upload multiple files to the server.

@POST
@Path("/Endpoint")
@Consumes(MediaType.MULTIPART_FORM_DATA)
public Response whateverEndPoint(@FormDataParam("fileName") InputStream fileInputStream,
        @FormDataParam("fileName") FormDataContentDisposition contentDispositionHeader,
        @FormDataParam("additionalParameter") String additionalParameter) {

    System.out.println(contentDispositionHeader.getFileName());

    String output = "File Received on the server: ";

    return Response.status(200).entity(output).build();

}

Here is my angular controller that uses the framework:

angular.module('AppThing').controller('DemoController',function($rootScope,$scope,FileUploader){

//creating the uploader with the correct url
$scope.uploader = new FileUploader({
    url : 'Endpoint',
    method : 'POST',
    alias: 'fileName',
    autoUpload:true
});

//runs right after we add a file to the queue
$scope.uploader.onAfterAddingFile = function(item){
};

//runs right before we upload an item to the server
$scope.uploader.onBeforeUploadItem = function(item){
        console.log('This is just before the image upload');
        item.formData.push({'additionalParameter':  $rootScope.additionalParameter});
};

$scope.uploader.onSuccessItem = function(item, response, status, headers) {

};



});

Hope this helps

Hi, thanks for your post it's much appreciated. I've gone with Rossi Robinsion post as I do not want to use a JS library and preferred the Java MultipartHttpServletRequest approach. Once again thanks. — user3034151, Nov 25 '15 at 17:46

AngularJS Formdata file array upload

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