I recently found myself faced with an interesting little web dev challenge. Here's the scenario. You've got a site that's powered by a PHP CMS (in this case, Drupal). One of the pages on this site contains a number of HTML text blocks, each of which must be user-editable with a rich-text editor (in this case, TinyMCE). However, some of the HTML within these text blocks (in this case, the unordered lists) needs some fairly advanced styling – the kind that's only possible either with CSS3 (using, for example, nth-child pseudo-selectors), with JS / jQuery manipulation, or with the addition of some extra markup (for example, some first, last, and first-in-row classes on the list item elements).
Naturally, IE7+ compatibility is required – so, CSS3 selectors are out. Injecting element attributes via jQuery is a viable option, but it's an ugly approach, and it may not kick in immediately on page load. Since the users will be editing this content via WYSIWYG, we can't expect them to manually add CSS classes to the markup, or to maintain any markup that the developer provides in such a form. That leaves only one option: injecting extra attributes on the server-side.
When it comes to HTML manipulation, there are two general approaches. The first is Parsing HTML The Cthulhu Way (i.e. using Regular Expressions). However, you already have one problem to solve – do you really want two? The second is to use an HTML parser. Sadly, this problem must be solved in PHP – which, unlike some other languages, lacks an obvious tool of choice in the realm of parsers. I chose to use PHP5's built-in DOMDocument library, which (from what I can tell) is one of the most mature and widely-used PHP HTML parsers available today. Here's my code snippet.
My recent hobby hack-together, my photo cleanup tool FotoJazz, required me getting my hands dirty with threads for the first time (in Python or otherwise). Threads allow you to run a task in the background, and to continue doing whatever else you want your program to do, while you wait for the (usually long-running) task to finish (that's one definition / use of threads, anyway — a much less complex one than usual, I dare say).
However, if your program hasn't got much else to do in the meantime (as was the case for me), threads are still very useful, because they allow you to report on the progress of a long-running task at the UI level, which is better than your task simply blocking execution, leaving the UI hanging, and providing no feedback.
As part of coding up FotoJazz, I developed a re-usable architecture for running batch processing tasks in a thread, and for reporting on the thread's progress in both a web-based (AJAX-based) UI, and in a shell UI. This article is a tour of what I've developed, in the hope that it helps others with their thread progress monitoring needs in Python or in other languages.