How to upload image in AngularJS with Rails backend.

application_helper.rb

# Sorry for not explaining basic stuff

module ApplicationHelper
	def decode_base64_image document
    if document[:base64] && document[:filetype] && document[:filename]
      decoded_data = Base64.decode64(document[:base64])

      data = StringIO.new(decoded_data)
      data.class_eval do
        attr_accessor :content_type, :original_filename
      end

      data.content_type = document[:filetype]
      data.original_filename = File.basename(document[:filename])

      data
    end
  end
end

user_controller.js

FooBar.controller('WhateverCtrl', ['$rootScope', '$scope', '$http', function($rootScope, $scope, $http) {
  $scope.user = {first_name: '', last_name: '', profile: ''};
  $scope.register = function(){
    submitForm('/hey/there/here/your/api/user_registeration.json', $scope.user, registerCallback, '#userRegister');
  }
  
  submitForm = function(url, params, callback, form){
    $http({
      url: url,
      method: 'POST', // mention your webservice type [POST, PUT]
      headers: {'Content-Type': 'application/json'}, // yes, it will work with application/json, don't worry
      data: params
    }).then(function(response){
      if(response.data.success){
        callback();
        $(form)[0].reset();
        $scope.user = {first_name: '', last_name: '', profile: ''};
      } else {
        // handle your error exception
      }
    });
  }
  
  registerCallback = function(){
    // after registration stuff here
  }
});

user_registration.html

<!--Based in https://github.com/adonespitogo/angular-base64-upload, Thank you to Adones Pitogo -->
<!--form starts-->
<form ng-submit="register()" id='agendaInsertForm'>
<input type='text' ng-model='user.first_name' required/>
<input type='text' ng-model='user.last_name' required/>
<input type='file' ng-model='user.profile' base-sixty-four-input required/>
<input type='submit' value='SAVE' />
</form>
<!--form ends-->

user_registration_controller.rb

class UserRegistrationController < Admin::BaseController
  def create
    user = User.create(first_name: params[:first_name], first_name: params[:last_name], profile: decode_base64_image(params[:profile]))
    render json: {success: true, message: 'Yeh! You are a rockstar!'}
  end
end