Drupal tips and tricks

It is usually considered a given that "private" downloads, going through Drupal, are slower than "public" downloads, which can be served directly by Apache, or whatever web server the site is running on. This is indeed true in the general case; however, for low-cost hosting, this apparent axiom needs to be revisited.

Context

I recently had to install Drupal 6.x for a french government agency on a low-cost hosting plan. Although the site performed reasonably well considering the limitations of the chosen hosting plan, I soon noticed it was missing mod_deflate and mod_expires, which caused pages to be served uncompressed and every static file to be served without an expiration date.

And, of course, the site had quite a few images: photos on most pages, and several logos at the bottom of each page.

Now, when mod_deflate is missing, using the "Page compression" option on http://example.com/admin/settings/performance is a good workaround for the download page size, but what about the static files ?

Checking a few cheap hosting plans, it appeared these limitations are actually quite common. And without mod_expires, there is no way to tell Apache to serve static content with specific headers. Luckily for us, with Drupal we have a trick up our sleeves, the so-called "private" file downloads.

The problem : Drupal awfully slow on Vista (and Seven) with Wampserver

For some time now, I'd been severiously annoyed by the (utter lack of) performance of Drupal 6 and 7 on my home PC, which happens to be running Microsoft Vista: considering I was used to getting page times around 200ms on a fractional Celeron with Apache 2.2 on a Linux server hosted comparatively far across the net from that same machine, I felt the 5 to 15 seconds response time per page on this local machine with a quad core and 3 GB RAM were really making me lose my time.

The solution

After some time spend googling around, I stumbled upon an incredibly simple tip, which made the 5 to 15 seconds per page drop down to around 1 second when logged in, and well below 500 ms when not logged in. It's incredible what ONE single character in a plain text file gets you under Vista :-)

UPDATE 2010-01-23: David Hogg tells us (see below) that this works for Windows Seven too

If all of a sudden you notice that the SELECT elements in your Drupal forms increases to 4 and any smaller size is ignored...

... maybe you've already forgotten you were using Chrome, and it is not a Drupal bug : this is a "usability" feature of WebKit. See http://trac.webkit.org/browser/trunk/WebCore/rendering/RenderListBox.cpp#L67.

Safari users are probably used to it, but for users of other browsers, this is a bit disconcerting.

Using a graphics library, be GD, ImageMagick or anything else, is convenient, but carries a price to pay: unlike most Drupal parts, which are generally database-bound, image generation is typically CPU-bound: generating many images on the fly can significantly increase the CPU load on a system, while Drupal setups are typically not optimized for this, and could result in problems if you are using Drupal on a shared hosting account. So what ?

In the previous post, we saw how to create a XHTML progress bar widget for Forms API, using theme_progress_bar. The next logical step is now to create a graphical equivalent to that progress bar, as an example for far more advanced fully graphical widgets made possible using a similar mechanism.

As a Drupal user, you certainly noticed that update.php displays a nice progress bar to make you wait during its batch operations. And maybe you also noticed theme_progress_bar in the API reference.

The question

Wouldn't it be nice to have that progress bar available as an extended version of markup that would graphically display a value in your forms without stuffing it in a markup element ?

For some reason or another, I've noticed several new Drupal developers these last few days sweating on Forms API, and thought it would be nice to have a smallish example to complement the unavoidable FAPI reference and Guick start guide, for a typical non-basic form: one including set of checkboxes in a table, with a customized display, like the core user, content or modules administration forms. So follow me while we build this example.

If you are [considering] working on an e-Commerce site, and are coming to the Szeged Drupalcon, you may be interested in several sessions around the theme. In order for your session(s) of choice to stand a chance of being actually part of the conference program, you should vote for the sessions you would like to attend.

Subjet to approval by the conference board, I will be animating/presenting a session about the internals of the e-Commerce suite: see http://szeged2008.drupalcon.org/program/sessions/developing-e-commerce for more details. If this is of interest to you, vote on the session to make sure it will indeed be included in the conference program.

In summer 2006, I created the img_relocator module, which was published to my sandbox, and apparently picked up by some Drupal admins, although it was never promoted to full-fledged project status.

I was working on an existing site today, and after installing the e-commerce 3.4 suite (EC), noticed something was very weird: product type modules were enabled, all basic EC modules were there too, and yet, when I created products by hand, the "Anonymous purchase" fieldset appeared, but nothing else from EC.

Worse, when saving the new products, they were properly created in the {node} table, but never appeared in the {ec_product} table, which caused them never to appear as products in the admin products list of the product view available to users. What could be going on ?