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Aug 27 2012
Aug 27

I've been putting it off for a few years, but I finally decided to upgrade devbee.com to Drupal 6. 

I didn't really need to, but it bothered me that I wasn't running supported code and I figured I might learn something. And I did. Mostly obvious things that I should be familiar with already. 

Drush

I've only ever played around with this. I don't like learning new things unless they are going to be truly useful to me. Drush is definitely something I shouldn't have ignored for so long. It comes in particularly handy when doing a site upgrade as you can download and install modules, clear cache, set variables, run DB updates and a lot more all from the command line. This tool is crazy good if you're comfortable in a terminal.

Themeing didn't change much

I was able to convert my dated theme to 6 with very little effort. I created a .info file, changed the names of the region variables in my page.tpl.php file and tweaked a small amount of CSS. Took me about 20 minutes. Pretty painless. I was able to preserve my table-based layout so all you markup nazis will have an example of bad design.

Minimalism

The whole process was made much easier by the fact that I don't like using a lot of modules. I tend to go with a handful of the more popular modules such as Views, CKeditor, CCK, Pathauto, etc... Because I use only popular modules, I'm almost certainly going to have no trouble upgrading them. At least that's my experience.

Key things to remember

  1. Start with a brand new install of D6 with no contrib modules. It's tempting to try to force an upgrade on your existing site, but it's just not going to work. You must create a clean install. 
  2. Import your old database into the clean D6 database. I tried to skip this and just point D6 to my old database, but then  you end up with missing tables and a whole lot of brokenness.
  3. Run DB updates and get your core Drupal site working before worrying about contrib modules.
  4. Lastly, and this is where drush will save you time, download and enable the contrib modules you need one at a time. 

Unfortunately, the upgrade process is no longer something that can be done by the average site owner. There are going to be snags, and you're going to need to know how to interact with your database to get things up and running. I think this is the reason so many users are still on D5 and D6. I'd really like to see an upgrade path that was more accessible to non-developers, but at the same time, I'm also grateful that Drupal is upgradable and there is no need to manually migrate data for major upgrades. 

At this rate, I should be upgrading to D7 sometime around the end of the decade.

Jan 31 2012
Jan 31

“Why is your window transparent?” a coworker asked me when she noticed my screen. I told her about how I do my CSS theming, and she pulled another coworker over and made me repeat the explanation. Since that seems like something other people might find handy, here it is.

Sass: Syntactically Awesome Sytlesheets

I rarely do CSS/front-end theming work, but when I do, I try to make it as fun and easy as back-end development. I use Sass (Syntactically Awesome Stylesheets) so that I can use nested selectors, variables, and mixins. This makes my code cleaner and easier to write. You’ll need Ruby in order to install Sass, but the tool will give you CSS that you can use on any web platform.

Browser-based tools

I prefer doing the initial tweaking in Google Chrome, because I like the way that the developer tools make it easy to modify the stylesheet. The Chrome CSS Reloader extension is handy, too. Most of the time, I make my CSS changes in the text editor, then use the CSS Reloader to reload the stylesheet without refreshing the page. This makes it easy to manually toggle the display of some elements while allowing me to refresh style rules. If I want to figure out the values for a few simple changes, I’ll sometimes make the changes directly in Chrome (you can use arrow keys to adjust values), then copy the values to my Sass source file.

Colors, sizes, and spaces

A second monitor is totally awesome and well worth it.

Designs rarely specify all the colours, sizes, and spacing needed. To quickly get the color of a pixel, I use WhatColor. This shows the hex code for colors, and allows me to quickly copy the code with the F12 shortcut key. If you want to change the shortcut key, the source is available as an AutoHotkey script.

To make it easier to match sizes and spaces, I use WinWarden to make my browser window 20% translucent. Then I carefully position it over my design reference until the important features match. Magnifixer makes it easier to line things up because it can magnify a fixed portion of the screen. By focusing Magnifixer on the part I’m working on, I can tweak CSS without straining my eyes.

When I know I’m going to be making a lot of changes, I use AutoHotkey to map a shortcut so that I can refresh the CSS with one keystroke instead of several. When I happen to have my USB foot pedal handy, I rig it up to refresh my stylesheet.

Regression testing

Sometimes my CSS changes modify other rules. Instead of laboriously checking each page after changes, I’ve figured out how to use Selenium WebDriver to write a Java program that loads the pages in Mozilla Firefox and Internet Explorer, capturing screenshots and numbering them according to the pages in my design reference. This means that I can run the program in the background or start it before taking a break, and then flip through all the screenshots when I get back.

Cross-browser testing

What’s CSS theming without the requirement of browser compatibility? Someday, when I need to deal with more browsers, I might look into Selenium RC. In the meantime, I develop in Chrome, my Selenium-based program makes it easier to test in Firefox and IE, and it’s easy enough to try the URLs in Safari as well. Virtual machines handle the rest of the requirements. 

So that’s how I’ve been doing CSS theming on this project. What are your favourite tips?

Apr 01 2009
Apr 01

Developers are all familiar with the default behavior of the drupal menu systems "local tasks" (aka tabs). These appear throughout most Drupal sites, primarily in the administration area, but also on other pages like the user profile.

Generally, developers are pretty good about creating logical local tasks, meaning only those menu items which logically live under another menu item (like view, edit, revisions, workflow, etc... live under the node/% menu item).

But sometimes, these tabs either don't really make sense as tabs or you simply want to have the flexibility of working with the items as "normal menu items", or those menu items which appear under admin/build/menu.

I recently wanted to move some of the tabs on the user profile page (user/UID) into the main menu so that I could include them as blocks.

For some reason, developers think the user profile page is a great place to put tabs for user related pages such as friendslist, tracker, bookmarks, notifications and so on. But these types of items are less a part of the user's account information than they are resources for specific users. Personally, I would not think to look at my account information on a site to find stuff like favorites or buddies. I'd expect those items to be presented somewhere much more obvious like a navigation block.

Initially, this may seem like a trivial task. My first thought was to simply use hook_menu_alter() and change the 'type' value of the menu item from MENU_LOCAL_TASK to MENU_NORMAL_ITEM. However, for reasons I don't understand well enough to explain in detail, this does not work.

In order to achieve the desired result, you must change the path of the menu item and incorporate the '%user_uid_optional' argument, replacing the default '%user' argument.

All very confusing, I know. Let's look at an example.

The notifications module (which provides notification on changes to subscribed to content) uses the user profile page rather heavily. I don't want its links there, I want them in the sidebar where users can always see them.

/**
* Implementation of hook_menu_alter().
*/
function MODULENAME_menu_alter(&$callbacks) {
 
// NOTIFICATIONS MODULE
 
$callbacks['notifications/%user_uid_optional'] = $callbacks['user/%user/notifications'];
 
$callbacks['notifications/%user_uid_optional']['type'] = MENU_NORMAL_ITEM;
  unset(
$callbacks['user/%user/notifications']);
  <
SNIP>
}
?>

So I have moved the notifications menu into my own menu, changed the type, used %user_uid_optional instead of %user, and unset the original menu item.

This works fine except for the fact that you'll lose all of the other menu items under user/%user/notifications! You need to account for all menu items in the hierarchy to properly reproduce the tabs in the main menu system, so we add the following:

    $callbacks['notifications/%user_uid_optional/thread'] = $callbacks['user/%user/notifications/thread'];
    unset(
$callbacks['user/%user/notifications/thread']);

    </span>$callbacks['notifications/%user_uid_optional/nodetype'] = $callbacks['user/%user/notifications/nodetype'];
    unset(
$callbacks['user/%user/notifications/nodetype']);

    </span>$callbacks['notifications/%user_uid_optional/author'] = $callbacks['user/%user/notifications/author'];
    unset(
$callbacks['user/%user/notifications/author']);
?>

And of course, we don't want this code executing at all if our module is not enabled, so you'd want to wrap the whole thing in:

  if (module_exists('notifications')) {
 
  <
SNIP>

  }
?>

Keep in mind that not all modules implement menu items using hook_menu(). It's becoming more and more common for developers to rely on the views module to generate menu items, and this is a wise choice. Menus generated using views (ala bookmark module) can be modified to get the desired result without any custom code.

Feb 16 2008
Feb 16

The importance of project management tools is almost never fully appreciated. I am shocked at how common it is for a group of developers to go working without version control, ticket tracking, development documentation and so on. The very first thing I do when working with a new client is to make sure that they get these tools in place if they haven't already.

Those who are used to working without a complete set of project management tools never fail to appreciate the benefits of them once they are introduced. I consider it next to impossible for a team to work together without managing code and tasks in an efficient and highly organized way.[img_assist|nid=155|title=|desc=|link=none|align=right|width=250|height=156]

Hopefully you do not need to be sold on this idea and are using CVS or SVN to manage your project already. You likely have some sort of ticket system. It is a little less likely that you have both of these components integrated with each other.

When it comes to choosing a solution for project management software, a die-hard Drupal user has a dilemna. On one hand, Drupal seems as though it should be the perfect solution. It's fully customizable, has lots of nifty project management related modules and, most importantly, it's Drupal! Why would you not use it? "Eating your own dogfood" is the way to go, right? Meh...

Drupal is generally considered a content management system. Personally, I like to refer to it as a website management system. It is great at managing website related stuff like users, posts, permissions, categorization, and so on. Using contrib modules, you can customize and enhance this core functionality to almost no end. But at the end of the day, Drupal is designed to handle web content and the users that are accessing it. That's what a content management system is (and if content is king, that would make Drupal... well... God).

Managing a project, on the other hand, is a much different business from managing a website. Yes, you have many shared properties such as content and users. But the essence of project management involves things that have nothing to do with website management such as a revision controlled code base edited by multiple users, a need for efficient ticket management, and ideally full integration of everything. Essentials also include stuff like a nice repository browser, user management interface for repository access, fancy reporting for tickets, organization of tasks by milestone, date, person, severity, etc...

It's a very tall order. Yes, you can do all this in Drupal, but not very well. You can piece together something that sorta kinda resembles a project management solution, but in the end, you need to invest a relatively large amount of time to create something that is less than ideal and will require ongoing tweaking and modification. Unless your business is creating an effective project management solution in Drupal (something I dream of!), you should not be using Drupal for project management.

I'm a one man shop, and I do not have time to spare. I cannot justify spending any time at all kludging together a project management solution for a client when there are already far superior solutions available at low cost. I would much rather pay someone a few bucks a month and be done with it. Let them deal with SVN administration and enhancements; let me focus on my primary task which is building cool sites with Drupal.

While there are numerous project management related service providers out there (Fogbugz, Basecamp , Beanstalk to name a few), I want to talk about my personal favorite, Unfuddle. Unfuddle has taken obvious inspiration from the folks over at 37signals, innovators of the simple, clean, effective, it-just-works web application. Unfuddle is an instant project management solution that takes minutes to set up and costs a few dollars a month. The time you'll save in not having to set up SVN and manage SVN users alone makes it worth every penny.

[img_assist|nid=156|title=|desc=|link=none|align=left|width=250|height=221]What you get with a solution such as unfuddle is a ready-to-use repository with integrated documentation, ticketing and reporting. It takes seconds to set up a new user account with permission levels fit for everyone from a developer (gimme root!) or a suit (look but don't touch).

From a single interface, you can browse code, tickets and documentation. Every component integrates with the others. You can even resolve a ticket with an SVN commit message, saving you the trouble of having to go and edit the ticket after your commit! Users can individually subscribe to whatever level of email notificaton they would like to recieve and how often. The developer can shut off all notifications while the manager can get a nice daily summary each morning of milestone completion progress, new tickets, added documentation and so on. The project manager can glance over one of the ticket reports and group tickets into milestones for reasonable short vs long term goals.

SVN comments link back to the tickets they are related to. Tickets contain links to the changesets that resolved them. Viewing these changesets, you can see a beautiful code diff and quickly see what fixed the problem. Senior team members can quickly and easily review code changes submitted by junior staff.

With tools like this available these days, it's just not worth it spending any effort whatever on a lesser solution.

Nov 16 2006
Nov 16

Until the mid 90s, spam was a non-issue. It was exciting to get email. The web was also virtually spam-free. Netizens respected one another and everything was very pleasant. Spam Those days are long gone. Fortunately, there are some pretty amazing tools out there for fighting email spam. I use a combination of SpamAssassin on the server side and Thunderbird (with its wonderful built in junkmail filters) on the desktop. I am sent thousands of spam messages a day that I never see thanks to these tools.

But approximately five years ago, a new type of spam emerged which exploited not email but the web. Among this new wave of abuse, my personal favorite, comment spam.

I love getting comments on my blog. I also like reading comments on other blogs. However, it's not practical to simply allow anyone who wants to leave a comment, as within a very short period of time, blog comments will be overrun with spam generated by scripts that exploit sites with permissive comment privileges. To prevent this, most sites require that you log in to post a comment. But this may be too much to ask of someone who just wants to post a quick comment as they pass through. I often come across blog postings which I would like to contribute to, but I simply don't bother because the site requires me to create an account (which I'd likely only use once) before posting a comment. Not worth it. Another common practice is the use of "captchas" which require a user enter some bit of information to prove they are human and not a script. This works fairly well, however, it is still a hurdle that must be jumped before a user can post a comment. And as I've personally learned, captchas, particularly those that are image based, are prone to problems which may leave users unable to post a comment at all.

As email spam grew, there were various efforts to implement similar types of protection, requiring by the sender to somehow verify he was not a spammer (typically by resending the email with some special text in the subject line). None of these solutions are around anymore because they were just plain annoying. SpamAssassin and other similar tools are now used on most mail servers. Savvy email users will typically have some sort of junkmail filter built into their email client or perhaps as part of an anti-virus package. And spam is much less a nuisance as a result.

What we need for comment spam is a similar solution. One that works without getting in the way of the commenter or causing a lot of work for the blog owner. Turn it on, and it works. I've recently come across just such a solution for blogs which also happens to have a very nice Drupal module so you can quickly and easily put this solution to work on your own Drupal site.

Enter Akismet

It's called Akismet, and it works similarly to junkmail filters. After a comment (or virtually any piece of content) has been submitted, the Akismet module passes it to a server where it is analyzed. Content labeled as potential spam is then saved for review by the site admin and not posted to the blog.

Pricing

Akismet follows my absolute favorite pricing model. It's free for workaday Joes like me and costs money only if you're a large company that will be pumping lots of bits through the service. They realize that most small bloggers are not making any money on their sites, and they price their service accordingly. Very cool.

Installation

In order to use Akismet, you need to obtain a Wordpress API key. I'm not entirely sure why, but it is free and having a collection of API keys is fun. So get one if you have not already.

The Akismet Drupal module is appropriately named Akismet. It's not currently hosted on Drupal.org, but hopefully the author will eventually host it there as that is where most people find their Drupal modules. Instead, you will need to download the Akismet module from the author's own site. The installation process is standard. Unzip the contents into your site's modules directory, go to your admin/modules page and enable it. There is no need for additional Akismet code as all the spam checking is done on Akismet's servers.

Configuration

After installing Akismet, I was immediately impressed at how professional the module is. There were absolutely no problems after installation. Configuration options are powerful and very well explained. The spam queue is very nice and lets you quickly mark content as "ham" (ie not spam) and delete actual spam. As you build up a level of trust with the spam detection, you can configure the module to automatically delete spam after a period of time.

Spam filtering can be enabled on a per node type basis, allowing you to turn off filtering for node types submitted by trusted users (such as bloggers) and on for others (eg forums users). Comment filtering is configured separately.

Another sweet feature is the ability to customize responses to detected spammers. In addition to being able to delay response time by a configureable number of seconds, you can also configure an alternate HTTP response to the client, such as 503 (service unavailable) or 403 (access denied). Nice touch.

One small problem

I've only been working with Akismet for several days now. And I'd previously been using captcha, which I imagine got me out of the spammers sights for a while (spammers seem to spend most of their efforts on sites where their scripts can post content successfully). So far, Akismet has detected 12 spams, 2 of which were not actually spam. These were very short comments, and I imagine Akismet takes the length of the content into consideration. I assume that as the Akismet server processes more and more pieces of content, it will become more accurate in picking out spam versus legitimate content. Each time a piece of flagged content is marked as "ham", it is sent to Akismet where it can help refine their rule sets and make the service more accurate.

Perhaps Akismet could provide an additional option that allows users to increase or decrease tolerance for spam. I would prefer to err on the side of caution and let comments through.

Nov 13 2006
Nov 13

PHP is an interpreted language. This means that each time a PHP generated page is requested, the server must read in the various files needed and "compile" them into something the machine can understand (opcode). A typical Drupal page requires more than a dozen of these bits of code be compiled.

Opcode cache mechanisms preserve this generated code in cache so that it need only be generated a single time to server hundreds or millions of subsequent requests.

Enabling opcode cache will reduce the time it takes to generate a page by up to 90%.

Vroom! PHP is known for its blazing speed. Why would you want to speed up your PHP applications even more? Well, first and foremost is the coolness factor. Next, you'll increase the capacity of your current server(s) many times over, thereby postponing the inevitable need to add new hardware as your site's popularity explodes. Lastly, high bandwidth, low latency visitors to your site who are currently seeing page load times in the 1-2 second range will be shocked to find your vamped up site serving up pages almost instantaneously. After enabling opcode cache on my own server, I saw page loads drop from about 1.5 seconds to as low as 300ms. Now that's good fun the whole family can enjoy.

Opcode Cache Solutions

There are a number of opcode caching solutions. For a rundown on some of them, read this article. After a bit of research and a lot of asking around, I concluded that Eaccelerator was the best choice for me. It's compatible with PHP5, is arguably the most popular of its kind, and is successfully used on sites getting far more traffic than you or I are ever likely to see.

Implementing Eaccelerator

This is the fun and exciting part. Implementing opcode cache is far easier than you might imagine. The only thing you'll need is admin (root) access to your server. If you're in a shared hosting environment, ask your service provider about implementing this feature if it is not in place already. These instructions apply to *nix environments only.

Poor Man's Benchmarking

If you would like to have some before and after numbers to show off to your friends, now is the time to get the 'before' numbers. Ideally, you will have access to a second host on the same local network as your server so that the running of the test does not affect the results. For those of us without such access, we'll just have to run the test on the actual webserver, so don't submit these results in your next whitepaper:

Apache comes with a handy benchmarking tool called "ab". This is what I use for quick and dirty testing. From the command line, simply type in the following:

ab -n 1000 -c 10 http://[YOURSITE.COM]/

Here is a portion of the results I got on my own test:

    Concurrency Level:      10
Time taken for tests:   78.976666 seconds
Complete requests:      1000
Failed requests:        0
Write errors:           0
Total transferred:      13269256 bytes
HTML transferred:       12911899 bytes
Requests per second:    12.66 [#/sec] (mean)
Time per request:       789.767 [ms] (mean)
Time per request:       78.977 [ms] (mean, across all concurrent requests)
Transfer rate:          164.07 [Kbytes/sec] received
Connection Times (ms)
min  mean[+/-sd] median   max
Connect:        0    7  51.3      0     617
Processing:    77  725 1704.4    300   21390
Waiting:        0  673 1697.5    266   21383
Total:         77  732 1706.2    307   21390
Percentage of the requests served within a certain time (ms)
50%    307
66%    468
75%    625
80%    639
90%    805
95%   3808
98%   6876
99%   8529
100%  21390 (longest request)

The single most useful number is 'Requests per second', which in my case was 12.66.

Download, Build and Install

First, download the source code.

Get it to your server and do the following (I'm assuming you have gcc on your system, if not, get it):

tar jxvf  eaccelerator-0.9.5.tar.bz2
cd eaccelerator-0.9.5
phpize
./configure
make
make install

Configure Apache and Restart

If you have an /etc/php.d directory, create the file /etc/php.d/eaccelerator.ini for your new settings. Alternatively, you can put them in your php.ini file. Your configuration should look something like this:

zend_extension="/usr/lib/php/modules/eaccelerator.so"
eaccelerator.shm_size="32"
eaccelerator.cache_dir="/var/cache/eaccelerator"
eaccelerator.enable="1"
eaccelerator.optimizer="1"
eaccelerator.check_mtime="1"
eaccelerator.debug="0"
eaccelerator.filter=""
eaccelerator.shm_max="0"
eaccelerator.shm_ttl="0"
eaccelerator.shm_prune_period="0"
eaccelerator.shm_only="0"
eaccelerator.compress="1"
eaccelerator.compress_level="9"
eaccelerator.log_file = "/var/log/httpd/eaccelerator_log"
; eaccelerator.allowed_admin_path = "/var/www/html/control.php"

Adjust values according to your particular distribution. For more details on configuring eaccelerator, see the settings documentation.

See Eaccelerator in Action

The value eaccelerator.allowed_admin_path, if enabled, should point to a web accessible directory with a copy of 'control.php' (which comes with the eaccelerator source code). Edit this script, changing the username and password. You can then access this control panel and see exactly what eaccelerator is caching

See the results

After enabling Eaccelerator on devbee.com, I ran my benchmark again, and here are the results:

    Concurrency Level:      10
Time taken for tests:   10.472143 seconds
Complete requests:      1000
Failed requests:        0
Write errors:           0
Total transferred:      13129000 bytes
HTML transferred:       12773000 bytes
Requests per second:    95.49 [#/sec] (mean)
Time per request:       104.721 [ms] (mean)
Time per request:       10.472 [ms] (mean, across all concurrent requests)
Transfer rate:          1224.30 [Kbytes/sec] received
Connection Times (ms)
min  mean[+/-sd] median   max
Connect:        0    0   0.1      0       4
Processing:    20  103  52.1     96     345
Waiting:       17   92  50.1     83     342
Total:         20  103  52.1     96     345
Percentage of the requests served within a certain time (ms)
50%     96
66%    122
75%    137
80%    147
90%    176
95%    201
98%    225
99%    248
100%    345 (longest request)

We are now serving up 95.49 requests per second. That's 754% increase in server capacity. Had I been able to run the tests from another machine on the same network, I believe the numbers would be even more dramatic.

Jul 23 2006
Jul 23

The number one quality that separates Drupal from other popular CMS is its API (most often referred to as "the Drupal API).  Drupal is designed explicitly to allow for adding, altering or removing core functionality. Thanks to this API, there are hundreds of third party modules available for Drupal. Some of these modules provide very specialized features. Others provide integration with the most popular services on the web (including Google Maps, Flickr, del.icio.us, Digg and more). All take advantage of the Drupal API and none include modification of core (again, the basic code base required to run Drupal).

Hacking

Enhancing software that doesn't provide an API usually involves modifying its core code directly. If software doesn't open up its functionality to developers, then developers are left to go in and manipulate the original source code to achieve their goals. In many cases, this is just how you have to do things. Drupal is not one of those cases.

To be clear, when I refer to 'hacked Drupal core', I'm referring specifically to modifications of the files that come with the standard distribution of Drupal, most importantly, the files that are in the /includes/ and /modules/ directories. All of the same concepts apply as well to third party modules, but that's not what I'll be focusing on here.

Who Cares?

Does it really make a difference whether you do things correctly as long as they work? Absolutely. While it may seem much more effective at first to edit Drupal core to add the features you want, this is a big mistake. Let's talk about some of the problems you will run into.

Updates

The first problem you'll likely run into is applying Drupal updates. The Drupal team is excellent about patching security vulnerabilities. This means that if you are steadfast in keeping your Drupal instance updated, your chances of getting 'hacked' are greatly reduced. However, if your team has modified Drupal core, applying updates becomes a painful process requiring careful scrutiny of each update and possibly an even more painful merge of those changes with your hacked core files. In my experience, rather than go through this unpleasant process, owners of sites with a hacked core tend to postpone applying patches and updates. The more the owner procrastinates, the more likely his site is to suffer an attack using a known exploit. Once your site has been exploited, there's no telling how long your site may be down or how long it will take you to recover.

Functionality

The next problem you may run into is broken functionality. By altering Drupal core files, you may be inadvertently modifying functionality depended upon by other parts of the system. You are messing around inside the "black box" that Drupal as a whole depends on. While you may think it's clever to go in and modify the phptemplate engine directly, what you could be very well doing is creating bugs somewhere else in your site. By the time you come across the problem, it is unlikely that you'll immediately realize that it is caused by the changes you made to phptemplate. And, friend, you are now in for a lot of hurt as you rip apart code trying to fix it.

Maintainability and Longevity

Drupal's API is known by hundreds of developers all around the globe. The hacks introduced by your $20/hr programmer found on craigslist are known only to one developer. Should you ever need to update or extend your site, you better have that $25/hr developer on staff or you better be using the Drupal API. If you play by the rules, you can hire any experienced Drupal developer.

Bottom Line

There are legitimate reasons to modify Drupal core. If you've found an actual bug in Drupal, the best thing you can do as a developer is to fix it and submit a patch. Likewise, if you've come up with an enhancement that you feel should live in core, submit it. Aside from these two reasons, neither you nor anyone in your employ should be touching anything in that drupal .tgz file.

If you want to develop extended functionality for Drupal, use the API. If you're hiring a Drupal consultant, find one who is familiar with the Drupal API. Find a developer who's active in the Drupal community. Hiring a knowledge Drupal developer may cost more initially, but if you plan on maintaining your site for any length of time, this investment is sure to pay off down the road.

Jul 10 2006
Jul 10

A search for "blank page" of the Drupal.org domain yields about 37,000 results.

This is probably one of the more common and frustrating problems for Drupal admins.

I've had the problem dozens of times myself. For no apparent reason, pages will simply come up blank. Drupal returns nothing at all, not even a set of empty HTML tags. As a developer, I'm used to seeing broken sites and fixing them. But the typical site administrator may not have the knowledge or experience necessary to debug something like a blank page.

The first thing you want to do is gather all available debugging info. The two primary places you'll find this information is in Drupal's logs (Administer >> Logs) and in your Apache log files (/var/log/httpd on Linux systems). If you're lucky, these logs will provide obvious clues as to what's wrong. Whether or not your able to gather any clues as to the source of your problem, below is a list of the most common causes of empty server responses:

  1. Memory: In your php.ini file there is a value called memory_limit, which is set to 8 megabytes by default. If you've installed a lot of modules, you can easily exceed 8 megs on a given page request. The solution is to increase this limit (I set mine to 32 megs because I have lots of memory on my host and few domains being served on it). If you're in a shared host environment, you won't be able to modify this value. In this case, you'll need to disable modules or get a new host.
  2. Buggy Modules: If you're problem began after installing and activating a new module, move the module's directory outside of /ROOT/modules/. Experimenting with modules is probably the easiest way to "break" your site. My suggestion is to test all modules on a non-production Drupal installation. Move them to your production site only after making sure they work properly (This message approved by Captain Obvious).
  3. Incompatible Modules: Using 4.6 modules on a 4.7 site is also a great way to break stuff. Make sure you've installed the module versions that match your Drupal version.
  4. Broken Themes: A buggy theme can easily render a site unusable. My suggestion is to preview themes at the Drupal Theme Garden or on a non-production Drupal installation. If it's too late for that and you're experiencing blank pages, you should try setting the theme to a "safe", stock theme. If you cannot access your administrative pages (http://.../admin/themes), you will need to move your custom theme from your /themes/ directory to another temporary location. Alternatively, you can run this SQL command on your Drupal database: UPDATE variable SET value = 's:10:"bluemarine";' WHERE name = 'theme_default';

I don't believe I've ever seen the 'blank page' problem in a production release of Drupal core. The problem only crops up when installing and playing around with new modules. So the bottom line is be very careful when experimenting with modules. I almost always use a sandbox installation of Drupal to test modules before installing them on a production site. (updated: Thu Jul 13 14:11:27 2006)

About Drupal Sun

Drupal Sun is an Evolving Web project. It allows you to:

  • Do full-text search on all the articles in Drupal Planet (thanks to Apache Solr)
  • Facet based on tags, author, or feed
  • Flip through articles quickly (with j/k or arrow keys) to find what you're interested in
  • View the entire article text inline, or in the context of the site where it was created

See the blog post at Evolving Web

Evolving Web