AngularJS module that can be reused in multiple Angular modules that are making POSTs to the backend.

angular-post-fix.js

// Modifies $httpProvider for correct server communication (POST variable format)
angular.module('http-post-fix', [], function($httpProvider) {
  // This code is taken from http://victorblog.com/2012/12/20/make-angularjs-http-service-behave-like-jquery-ajax/
  
  // Use x-www-form-urlencoded Content-Type
  $httpProvider.defaults.headers.post['Content-Type'] = 'application/x-www-form-urlencoded;charset=utf-8';

  // Override $http service's default transformRequest
  $httpProvider.defaults.transformRequest = [function(data) {
    /**
     * The workhorse; converts an object to x-www-form-urlencoded serialization.
     * @param {Object} obj
     * @return {String}
     */ 
    var param = function(obj) {
      var query = '';
      var name, value, fullSubName, subValue, innerObj, i;
      
      for(name in obj) {
        value = obj[name];
        
        if(value instanceof Array) {
          for(i=0; i<value.length; ++i) {
            subValue = value[i];
            fullSubName = name + '[' + i + ']';
            innerObj = {};
            innerObj[fullSubName] = subValue;
            query += param(innerObj) + '&';
          }
        } else if(value instanceof Object) {
          for(subName in value) {
            subValue = value[subName];
            fullSubName = name + '[' + subName + ']';
            innerObj = {};
            innerObj[fullSubName] = subValue;
            query += param(innerObj) + '&';
          }
        } else if(value !== undefined && value !== null) {
          query += encodeURIComponent(name) + '=' + encodeURIComponent(value) + '&';
        }
      }
      
      return query.length ? query.substr(0, query.length - 1) : query;
    };
    
    return angular.isObject(data) && String(data) !== '[object File]' ? param(data) : data;
  }];
});

The current name of the module in the downloaded file is 'httpPostFix', and not 'http-post-fix'.

Cheers
Edit :
Using ng-strict-di 😄

// Orginal code from: http://victorblog.com/2012/12/20/make-angularjs-http-service-behave-like-jquery-ajax/
// Copyrights: Ezekiel Victor

// Modifies $httpProvider for correct server communication (POST variable format)
angular.module('httpPostFix', [], ['$httpProvider', function($httpProvider)
{
// Use x-www-form-urlencoded Content-Type
$httpProvider.defaults.headers.post['Content-Type'] = 'application/x-www-form-urlencoded;charset=utf-8';

// Override $http service's default transformRequest
$httpProvider.defaults.transformRequest = [function(data)
{
    /**
     * The workhorse; converts an object to x-www-form-urlencoded serialization.
     * @param {Object} obj
     * @return {String}
     */
    var param = function(obj)
    {
        var query = '';
        var name, value, fullSubName, subName, subValue, innerObj, i;

        for(name in obj)
        {
            value = obj[name];

            if(value instanceof Array)
            {
                for(i=0; i<value.length; ++i)
                {
                    subValue = value[i];
                    fullSubName = name + '[' + i + ']';
                    innerObj = {};
                    innerObj[fullSubName] = subValue;
                    query += param(innerObj) + '&';
                }
            }
            else if(value instanceof Object)
            {
                for(subName in value)
                {
                    subValue = value[subName];
                    fullSubName = name + '[' + subName + ']';
                    innerObj = {};
                    innerObj[fullSubName] = subValue;
                    query += param(innerObj) + '&';
                }
            }
            else if(value !== undefined && value !== null)
            {
                query += encodeURIComponent(name) + '=' + encodeURIComponent(value) + '&';
            }
        }

        return query.length ? query.substr(0, query.length - 1) : query;
    };

    return angular.isObject(data) && String(data) !== '[object File]' ? param(data) : data;
}];

}]);

Still doesn't work with $http.put

I had to modify the script slightly in order to make it work with angular 1.3 (migrated from 1.2 to 1.3). Let me know, if I made something wrong:

        // Use x-www-form-urlencoded Content-Type
        $httpProvider.defaults.headers.post['Content-Type'] = 'application/x-www-form-urlencoded;charset=utf-8';
        $httpProvider.defaults.headers.put['Content-Type'] = 'application/x-www-form-urlencoded;charset=utf-8';

    /**
         * The workhorse; converts an object to x-www-form-urlencoded serialization.
         * @param {Object} obj
         * @return {String}
         */
        var param = function (obj) {
            var query = '', name, value, fullSubName, subName, subValue, innerObj, i;

            angular.forEach(obj, function(value, name) {
+                if(name.indexOf("$promise") != -1) {
+                    return;
+                }
                value = obj[name];


                if (value instanceof Array) {
                    for (i = 0; i < value.length; ++i) {
                        if(name == "$promise") {
                            continue;
                        }
                        subValue = value[i];
                        fullSubName = name + '[' + i + ']';
                        innerObj = {};
                        innerObj[fullSubName] = subValue;
                        query += param(innerObj) + '&';
                    }
                }
                else if (value instanceof Object) {
                    for (subName in value) {
                        subValue = value[subName];
                        fullSubName = name + '[' + subName + ']';
                        innerObj = {};
                        innerObj[fullSubName] = subValue;
                        query += param(innerObj) + '&';
                    }
                }
                else if (value !== undefined && value !== null)
                    query += encodeURIComponent(name) + '=' + encodeURIComponent(value) + '&';
            });

            return query.length ? query.substr(0, query.length - 1) : query;
        };