Mock Django Request for testing

When testing your applications I sometimes find myself needing to mock a request object. Unfortunately it is quite hard to find a good fake request factory which mimics a normal request.

Django has a class included for this purpose called RequestFactory. However it doesn’t fake the session object, breaking most of my test code. To fix this I wrote a tiny snippet implementing the RequestFactory with session and user support. Hope it helps :)

from django.core.handlers.base import BaseHandler
from django.test.client import RequestFactory

class RequestMock(RequestFactory):
    def request(self, **request):
        "Construct a generic request object."
        request = RequestFactory.request(self, **request)
        handler = BaseHandler()
        for middleware_method in handler._request_middleware:
            if middleware_method(request):
                raise Exception("Couldn't create request mock object - "
                                "request middleware returned a response")
        return request

See the gist here.

Django &Fashiolista &Web Development tschellenbach 18 Apr 2011 17 Comments

Fashiolista raises $500,000 from Atomico :)

Some good news while new code is compiling :)
Champagne moment over here!

TechCrunch – Fashiolista raises funding from Skype founders

Business &Fashiolista &Web Development tschellenbach 12 Jan 2011 99 Comments

Twitter button to pull down the internet?

I was thrilled to see twitter releasing their own button. This is good news all around for us bloggers looking to promote our content. After looking at their code snippets a warning is in place though. The current twitter button implementation will severely break your site if their servers face load issues. Fortunately you can work around this issues by slightly modifying their implementation.

Technical explanation

For we have been writing a lot about the various techniques for implementing these type of buttons. Especially important here is the way the javascript is loaded. Twitter uses a simple blocking script approach, where as digg, facebook and fashiolista use the async dynamic script approach. There are two large differences:

  1. Blocking script loads make your site slower
  2. If twitter goes down, your site joins in


In this example we are faking slow twitter servers. (By routing it through google’s app engine and delaying the response). You can see the difference for yourself (be patient and be sure to clear your browser cache using CTRL F5).

Default twitter version
(note that site content is not loading until the twitter button is loaded)

Async twitter script
(everything loads and then we wait for twitter)


Solving this is quite simple. Simply change the way the twitter javascript is loaded from the first example to the second version.

Twitter version

<script type="text/javascript" src=""></script>

Async twitter implementation

<script type="text/javascript">  
  //async script, twitter button style  
  (function() {
   var s = document.createElement('SCRIPT');  
   var c = document.getElementsByTagName('script')[0];  
   s.type = 'text/javascript';  
   s.async = true;
   s.src = '';
   c.parentNode.insertBefore(s, c);  

Hope the difference won’t matter and Twitter will stay up :)

Follow me at:

Thanks for spreading the word:

Business &Fashiolista &Google app engine &Javascript &Web Development &YouTellMe tschellenbach 13 Aug 2010 80 Comments

Django open inviter – contact importer – python

Django open inviter is a python port of the PHP api client for‘s contact importer to work with Django. I build it for our fashion community,, where it is currently in production usage and fully functional. If you are a member of Fashiolista (which I highly doubt given the different audiences) you can test it by clicking find friends in your profile.

Usage is extremly straight forward:

from django_open_inviter.open_inviter import OpenInviter
o = OpenInviter()
contacts = o.contacts('', 'test')

Get the code here.

Django &Fashiolista &PHP &Python &Web Development &YouTellMe tschellenbach 09 Aug 2010 15 Comments

Creating your own Digg/Facebook/Tweetmeme button

This quick walkthrough is going to bring you up to speed on how to create your own social bookmarking button. The three prime examples are the famous Digg button, Facebook’s like functionality and the tweetmeme button. For an implementation look slightly above this paragraph or check out mashable’s version on the left of their post.

Our button will be focusing on Fashiolista is a social bookmarking site for fashion, which has seen rapid growth after launching at the next web. This tutorial explains the javascript (client side) aspects of the button. Feedback and improvements on the code would be greatly appreciated. You can find the full 450 lines of js on github.

This is what the end result looks like:

Compact Medium Large

Love it!

Love it!

Love it!

(If you are working on a shop in the fashion industry have a look at our installation instuctions.)

Step 1 – The markup

Its important to get the client side markup of the button right. Since other sites will be implementing this there is no way you can change it later on. The three major players each have their own way.

Facebook XFBML: Async script with XFBML or Iframe
Digg button: Async script with A elements
Tweetmeme: Normal script

<script type="text/javascript">
  //async script, version
  (function() {
   var s = document.createElement('SCRIPT');
   var c = document.getElementsByTagName('script')[0];
   s.type = 'text/javascript';
   s.async = true;
   s.src = '';
   c.parentNode.insertBefore(s, c);
<a class="fashiolista_button fashiolista_compact"
href="">Love it!</a>

For Fashiolista we have chosen an async script approach with A elements. Normally loading a script element is a blocking operation for the browser. Loading the script async ensures faster page load times and a better experience if your site would ever go down. (Note that not all browsers support this option so it is still recommended to include the script tag at the bottom of the page). The function wrapped around the code ensures we don’t pollute the global scope. Furthermore the insertBefore in combination with a script tag technique is used by GA so should work in any scenario.

Step 2 – Creating the buttons, Iframe vs Script

The next step is to convert our A elements into actual buttons. We can choose to replace these A elements by our button’s html (digg, delicious approach) or load an iframe in their place (facebook, tweetmeme). The difference between these two approaches is actually pretty large. For Fashiolista you can see both an iframe and script approach. These are the most important differences I encountered.

Iframe vs Script

  • + Popup communication possible
    The script approach cannot communicate with popups it creates due to the same origin restrictions. The iframe however can be of the same domain as the popup and freely communicate. This gives a better user experience when for instance logging in.
  • + Easier to develop
    The iframe approach is easier to develop and requires less code.
  • + Parallel download in IE
    IE doesn’t download the count scripts in parallel, but it does do so for the IFRAMEs. Making this approach somewhat faster.
  • Independent CSS
    External sites don’t interfere with your button’s css if you use an iframe technique. The disadvantage is that it makes things likes hovers impossible to integrate with the other site. (For example Fashiolista’s compact button).
  • Independent
    The iframe approach makes it very hard for other sites to game the users like/love action. With a script approach a foreign site can simply call your javascript to fake someone loving the product. This freedom can be abused but also allows for mashups.
  • – Slower dom load
    Creating iframes takes a lot more time for the browser.
  • – Slower perceived load
    The script approach allows you to format the buttons before the data is loaded. Vastly increasing the perceived load speed.
  • – No shared functionality
    Buttons can’t share functionality. So when someone logs in for one button its is not possible to update the others.

The best choice differs for each project. For Fashiolista the more open script approach is currently the default.

Step 3 – Cross site scripting using JSONP

Essential to the bookmarking button is requesting the count for the given url. Cross site policies prevent us from using Ajax so we will do so by creating a script element.

_makeRequest: function (url) {
	//Simple create script element functionality
        var s = document.createElement('script');
        var b = document.body;

        s.setAttribute('type', 'text/javascript');
        s.setAttribute('async', 'true');
        s.setAttribute('src', url);


The trouble with the script element is that you lack the nice APIs Ajax offers you. We work around this by using an url with a callback paramater, for example callback=button_loaded_3
The server side code then responds with something like this, executing the callback when the script is loaded.

button_loaded_3({"item_id": 26545, "url": "/item/26545/", "loves": 853})

This technique is often referred to as JSONP. We bind the response function to the global button_loaded_3 using the following code:

loadButtonInformation: function (buttonId) {
		//make a request to the script with the given callback
		var buttonInstance = this.buttonDict[buttonId];
		var buttonUrl = buttonInstance.lookupUrl;
		var path = '&url=' + encodeURIComponent(buttonUrl);
		var callbackFunctionName = 'button_loaded_' + buttonId;
		var scope = this;
		var callbackFunction = function(data) {
			//bind the scope and button id, buttonId, data);
		window[callbackFunctionName] = callbackFunction;
		this.makeRequest(this.countApi + path, callbackFunctionName, true);

Step 4 – Object oriented design

Since we are loading our code into someone else’s website we should be careful not to use similar variable names. We therefore hide as much code as possible in classes.

var fashiolistaClass = function(){ this.initialize.apply(this, arguments); };
fashiolistaClass.prototype = {
	//Base class implementing the fashiolista button
	initialize: function () {
		//load the buttons
		var fashiolistaButtons = this.findButtons();

Note that we are not simulating inheritance for these classes. Using them as simple namespaces is more than sufficient in this case.
The code is organized into 3 classes:

  • fashiolistaClass
  • fashiolistaUtilsClass
  • fashiolistaButtonClass

The first one acts as a manager (finding the buttons, instantiating fashiolistaButtonClasses and retrieving counts). Fashiolista button contains the logic for individual buttons and fashiolista utils contains some string parsing and dom load functionality.

Step 5 – Caching requests in the google app engine

appengineTo prevent our servers from getting flooded we are routing all traffic through google servers using the google app engine. is connected to a google app engine account which forwards and caches requests to This setup enables your button to withstand great amounts of traffic without killing your servers. Furthermore it immediately also acts as a cdn for our web requests, speeding up load times for our international visitors. Setting up caching in the google app engine would require another blog post though. Let us know in the comments if you would like to know more about it.


The full client side code can be found here. This blog post covered the most essential parts. Code review and questions are more than welcome. Be sure to let us know in the comments. Furthermore if you are running a webshop in the fashion industry consider implementing the button.

More information

Improvements/ Request for code review

  • The domload technique is rather verbose, does anyone know a better method?
  • The popup communication or lack thereof is not ideal for users, is there a better method?
  • Script or Iframe what do you prefer?
  • Suggestions to make it faster?

Django &Fashiolista &Google app engine &Javascript &JQuery &Python &Web Development &YouTellMe tschellenbach 03 Aug 2010 11 Comments

Django Facebook – Open graph API implementation

This blog post is outdated, a new and vastly upgraded version of Django Facebook is now available. Read more about it here.

For Fashiolista we needed to integrate with the Facebook Open Graph API. The open graph API is a very exciting facebook project, which you can read about more here and here. The code at allows you to register/login via facebook using the Open Graph API (similar to the old Facebook connect, but registration, instead of only logging in). Before you go try it out, is aimed primarily at females so your girl friends facebook account is probably a better fit.

Im releasing the source code for Django Facebook on github. Its a very early release, but it might help other developers trying to implement a facebook register/loging flow using the new open graph api. See Github for requirements and installation instructions.

Birthday formats are currently giving some troubles for some users.
Fixed and tests added to prevent future problems. (note may still give errors, will be resolved during our next release).

Django &Fashiolista &Javascript &Python &Web Development tschellenbach 17 May 2010 105 Comments

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