One of the projects Beat and I wrapped up last February was the creation of a Captcha CB plugin. Since then it has been downloaded many times and I am sure it has helped many CB powered Joomla websites protect themselves against spammers.

The Captcha plugin is also listed in the Joomla extensions site (here) and has been discussed in our Joomlapolis forums (here). Some of the Captcha installations have encountered problems with the actual rendering of the image. The prerequisites in order to get the image generated include the existence of the GD library with Freetype support. No image can be generated without this library. The way the Captcha image was generated involved linking back to a specific site URL that directly invoked a CB specific function in the plugin. This site URL is redirected through the website template and is thus subject to whatever invisible characters are present either in the actual template file or even in the language file. Beat did a lot of debugging to figure out this problem. Unfortunately, many still have this problem and just don’t have the knowledge (or time) to fix it.

Well, the next version of the Captcha plugin is currently in testing. Unfortunately only 2 (!) people have expressed interest to help out with testing (here). What can I say … very disappointed.

This next version of the Captcha plugin (as the first one) is based upon the excellent work outlined here (http://www.white-hat-web-design.co.uk/articles/php-captcha.php). This was one of the first articles I found during the version 1 research period. I spent around 1 week just surfing around reading up on Captcha and anti-spam measures. The first thing that Beat and I decided for version 2 is to generate the image independent of the Joomla template and any language file. This would at least protect the generation process from stupid invisible characters in the template of language file and would also save us from a lot of frustrated users not understanding how something they cannot see could possible break the image.

The next major item – feature planned would be of course audio playback of the image characters for people browsing with vision problems. Well this was another research project. It took me 2-3 weeks (this time) to gather enough information and figure out how to go about this. I finally settled down to using the NATO phonetic alphabet (http://en.wikipedia.org/wiki/Nato_phonetic_alphabet) and to dynamically stitch together the individual image character sound elements to create one stream containing the entire security code audio playback. The sound elements in WAV form for this phonetic alphabet were found here (http://www.chimeric.de/projects/npa). We decided that it would be better to convert these WAV files to MP3 format (less space and easier stitching process). Fortunately, my (unfinished) work on the (next release of the) CB Gallery has at least provided me with a nice – cross browser – solution for popup media player which found its place nicely on in the Captcha audio playback process.

Now why am I blogging about this stuff? Well, I guess to illustrate how much real effort goes into anything the CB team releases. The amount of time spent for research, trial and errors, browser compatibility tests, etc, is just phenomenal and is often taken for granted. A quick hack that works on one site when viewed by one browser is nothing compared to a well tested, cleanly designed complete plugin. Hopefully, some reading this will appreciate such contributions just a little bit more.

I would like to thank Schelly, Mike(p9939068), Mikko,  Syrinx, Krystofiak  and others who have helped out on the forums enabling me to steal enough time to complete this effort. And of course Beat … who has come to my rescue many times during this process (a lot of late night collaboration between CH and GR).

For those of you wondering when this will be released … please take a look at this thread before asking … it will be released when it’s ready.

Comments

Excellent work guys! Written by skeptikal on 2008-04-02 01:46:16 I purchased a doc subscription and downloaded the Captcha plugin before anything else..I did have one install problem...which Nick easily solved for me having to do with sessions in Joomla globals nto being set to "none"....keep up the good work.    - Skeptikal

Written by anwar92 on 2007-10-18 18:01:00

I think there is limited interest in bet Written by jeffason on 2007-09-12 19:44:41 I think there is limited interest in beta testers...because maybe this is not that much a NEEDED feature. First, for many community websites...unless it is a blind/vision impaired/elderly community wouldn't see very much benefit from this in a cost/benefit point of view. Plus, you have seen how many problems people have with just the plain graphic CAPTCHA rendering, now add audio (yikes)! Additionally, I have seen more interesting methods to get past robots than the "garbled security code", for example a simple random question. All I am saying that is there is limited support for beta testers, maybe that means your time would be better spent elsewhere. Just an observation!

problems Written by sturgis on 2007-08-06 10:23:01 I also installed the captcha plug in, but because I have AEC component, I have to modify the language file, and when I touch it, then captcha does not work anymore... I really don't know what to do...

Loving your work Written by dinah on 2007-07-24 02:35:31 The captcha worked really well for me...nice piece of work...but I upgraded my site to PHP5 and it broke. Oh well - keep up the good work.

Saved my domain name Written by davidsmtol on 2007-06-18 20:05:22 I have recently taken on the task of rebuilding a website for a volunteer organization I belong to... naturally Joomla was my first choice and CB the first thing added.     What I didnt realize was the our spamming friends had really been attacking the existing domain name and as soon as the new site went up i started getting the erronious registrations from obvious spammers (lots from russia)    I just finished installing the captcha plugin and I cant thank you enough for this excellent plugin. It is allowing me to get back control of the site and saving the domain name.    Well Done!    David

I'm very impressed... Written by jsmith667 on 2007-05-18 11:16:59 ...by the emphasis of Nick & Beat developing CB to an all-embracing community-system.    Thank you very much.

Very nice work indeed, Nick :) Written by beat on 2007-05-16 18:27:50 Thanks for the really hard background work put into this second release.

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