Using AngularJS API service and Umbraco API controller to permit users to upload files to the server

file.upload.api.service.js

// The Angular service that will handle the API call to initialize the file upload to the server.

(function (app) {

    var fileApiService = function ($http) {

        var fileApiFactory = {};

        /**
         * @ngdoc method
         * @name importFile
         * @function
         * 
         * @param {file} file - File object acquired via File Upload API.
         * @description - Upload a file to the server.
         */
        fileApiFactory.uploadFileToServer = function (file) {
            var request = {
                file: file
            };
            return $http({
                method: 'POST',
                url: "/umbraco/api/FileUploadApi/UploadFileToServer",
                // If using Angular version <1.3, use Content-Type: false.
                // Otherwise, use Content-Type: undefined
                headers: { 'Content-Type': undefined },
                transformRequest: function (data) {
                    var formData = new FormData();
                    formData.append("file", data.file);
                    return formData;
                },
                data: request
            }).then(function (response) {
                if (response) {
                    var fileName = response.data;
                    return fileName;
                } else {
                    return false;
                }
            });
        };

        return fileApiFactory;

    };

    app.factory('fileApiService', fileApiService);

}(angular.module(appName)));

file.upload.controller.js

// The Angular controller to bind to your view.

(function (app) {

    var fileUploadController = function ($scope, fileApiService) {

        /*-------------------------------------------------------------------
         * Initialization Methods
         * ------------------------------------------------------------------*/

        /**
         * @ngdoc method
         * @name init
         * @function
         * 
         * @description - Called when the $scope is initalized.
         */
        $scope.init = function () {
            $scope.setVariables();
        };

        /**
         * @ngdoc method
         * @name setVariables
         * @function
         * 
         * @description - Sets the initial states of the $scope variables.
         */
        $scope.setVariables = function () {
			$scope.file = false;
			$scope.isUploading = false;
        };

        /*-------------------------------------------------------------------
         * Event Handler Methods
         *-------------------------------------------------------------------*/

        /**
         * @ngdoc method
         * @name fileSelected
         * @function
         * 
         * @param {array of file} files - One or more files selected by the HTML5 File Upload API.
         * @description - Get the file selected and store it in scope. This current example restricts the upload to a single file, so only take the first.
         */
        $scope.acceptSelectedFile = function (files) {
            if (files.length > 0) {
                $scope.file = files[0];
            }
        };

        /*-------------------------------------------------------------------
         * Helper Methods
         * ------------------------------------------------------------------*/

        /**
         * @ngdoc method
         * @name uploadFile
         * @function
         * 
         * @description - Uploads a file to the backend.
         */
        $scope.uploadFile = function () {
            if (!$scope.isUploading) {
                if ($scope.file) {
                    $scope.isUploading = true;
                    var promise = fileApiService.uploadFileToServer($scope.file);
                    promise.then(function (response) {
                        if (response) {
                            console.info('Saved to server with the filename ' + response);
                        }
						$scope.isUploading = false;
                    }, function (reason) {
                        console.info("File import failed.");
                        console.info(reason.message);
                        $scope.isUploading = false;
                    });
                } else {
                    console.info("Must select a file to import.");
                    $scope.isUploading = false;
                }
            }
        };

        /*-------------------------------------------------------------------*/

        $scope.init();

    };

    app.controller('FileUploadController', ['$scope', 'fileApiService', fileUploadController]);
}(angular.module(appName)));

fileUpload.html

<!DOCTYPE html>
<head>
    <title>File Upload</title>
</head>
<body>
  <!-- Example view to bind to your Angular -->
  <div id="content" data-ng-app="exampleApp" data-ng-controller="FileUploadController">
    <h1>Upload a file</h1>
    <!-- using ng-file-upload by Danial Farid -->
    <!-- See for https://github.com/danialfarid/ng-file-upload documentation on configuration -->
    <button ng-file-select ng-model="files" ng-file-change="fileSelected(files)" class="file button btn-primary" ng-multiple="false" accept=".jpg,.png,.gif" ng-show="!isUploading">
      Choose File
    </button>
    <button type="button" data-ng-click="uploadFile()">Upload</button>
  </div>
    <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.3.14/angular.min.js"></script>
    <!-- the ng-file-upload directive by Danial Farid https://github.com/danialfarid/ng-file-upload -->
    <script src="angular-file-upload.js"></script>
    <script src="ng.app.js"></script>
    <script src="file.upload.api.service.js"></script>
    <script src="file.upload.controller.js"></script>
</body>
</html>

FileUploadApiController.cs

// Use whatever namespacing works for your project.
namespace YourSite.Web.Controllers.Api
{
    using System.IO;
    using System.Linq;
    using System.Net;
    using System.Net.Http;
    using System.Threading.Tasks;
    using System.Web;
    using System.Web.Http;

    using Umbraco.Web.WebApi;

    // If you want this endpoint to only be accessible when the user is logged in, 
    // then use UmbracoAuthorizedApiController instead of UmbracoApiController
    public class FileUploadApiController : UmbracoApiController
    {
        public async Task<HttpResponseMessage> UploadFileToServer()
        {
            if (!Request.Content.IsMimeMultipartContent())
            {
                throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);
            }

            // Make this directory whatever makes sense for your project.
            var root = HttpContext.Current.Server.MapPath("~/App_Data/Temp/FileUploads");
            Directory.CreateDirectory(root);
            var provider = new MultipartFormDataStreamProvider(root);
            var result = await Request.Content.ReadAsMultipartAsync(provider);

            // Build a list of the filenames of the files saved from your upload, to return to sender.
            var fileName = result.FileData.Aggregate(string.Empty, (current, file) => current + ("," + file.LocalFileName));
            return Request.CreateResponse(HttpStatusCode.OK, fileName);
        }
    }
}

ng.app.js

// Example Angular app declaration.
// This example makes use of the ng-file-upload directive by Danial Farid https://github.com/danialfarid/ng-file-upload
// It needs to be injected into the Angular app.
// You could probably use the native HTML5 file upload API if you didn't want to rely on any external directives.

var appName = 'exampleApp';

(function () {
    var app = angular.module(appName, ['angularFileUpload']);
}());