Bypassing Cloudflare

I use to automate many tasks in the web (such as triggering news and sorting them according to my interests) and some times I hit with Cloudflare’s DDoS protection, I mean client-side, I guess they will have some real DDoS protection server-side, as the client-side is very easy to break.
They use to change their algorithms from time to time, but the basics are always the same:

  1. curl the protected page and you will get an invisible form which auto-sends itself after making some client-side calculations. Currently this form is called challenge-form and has three hidden fields called jschl_vc, pass and jschl_answer.
  2. Compute the javascript you find in the curl-ed page and send the form (the results of the calculations will be populated to the jschl_answer field). You can emulate these calculations in your favorite language (Python, AppleScript, PHP, whatever) or have a JS engine to execute the scripts. I’ve used node for this, which is available as a command-line tool you can install and execute easilly.
  3. If everything is OK, you will have now two cookies: __cfduid and cf_clearance. Using that cookies, you can now surf freely the website.

The details may change from time to time, as Cloudflare updates their methods, but it’s been very similar across the years. Just take a look in your regular browser/developer tools and find the magic under the hoods.


JDownloader Mac memory issue + restart [fixed]

It seems that there is a memory problem. A restart of JDownloader is required to fix the problem. If even 2 restarts do not fix it, please visit our support chat.

Do you see this message oftenly? Try this:

  1. Go to the menu JDownloader > About JDownloader. You will see somewhere something like: Memory: Usage: 40 MB – Allocated: 44 MB – Max: 64 MB. This means that JDownloader is being launched with a max heap of 64 MB. Increasing this limit may fix your memory issues.
  2. Quit JDownloader.
  3. Right-click JDownloader’s icon in the Finder, then choose “Show Package Contents” in the context menu.
  4. Open the folder called “Contents”.
  5. Open the file called “vmoptions.txt”. If this file doesn’t exist, create it yourself using a plain text editor.
  6. Add the following:

This will increase the max memory to 256 MB. Some people add up to 512 or 1024 MB, but first let’s see if 256 is good enough.

Launch JDownloader, go again to the About JDownloader window and see if the Max field in the Memory section was correctly increased.

Collaborative development and flow diagrams

I find very useful working with flow diagrams when in the middle of complex development systems and it’s absolutely a must-have when you are part of a team. Nobody can access your mind, so nobody can be sure about your thots and the internal flow diagrams running and changing continuously in your brain. So, a flow diagram with read/write access is a great feature for all developers working together in the same cake.

flow diagram

Appart from that, you will find many times, when working in the graph, that you are missing something you must implement, something you forgot when you were in UI-mode fighting against fonts and colors.

That’s the difference between conceptual and abstract design.

WindowShade on the road again

Quite unrelated to Qilania’s development, but not absolutely unrelated at all, as various members in the Pescados Producciones team use Mac OS X as its main OS (in various areas, including design, client programming and contents management), and we’ve been missing WindowShade since we upgraded to 10.6 (aka Snow Leopard).

Now WindowShade is a working beta (5.0b2) and works flawlessly in my machine. Welcome again to a bunch of missing features, including window collapsing, transparency on-demand and much more things which will make my machine a top-10-productivity environment one more time.

You Mac (only 10.6.x) and WS users, can get the links through Twitter’s beta Haxies page, according to their blog.