Views 2 provides a well structured theming environment allowing presentation control for each element of your view. And in my humble opinion, it rocks!
Those with no past experience with Views 1 will find Views 2 uses standard PHPTemplate theming techniques. All of your experience theming Drupal can be used with Views.
Views 1 themers starting with Views 2 might be a bit confused at first. I was. The single callback in template.php where everything happened is gone, refactored into a consistent framework of template files. All of the freedom that existed in the single function still exists with the added benefit of a well defined structure.
Overview
Views handles querying the database and organizing the information for display. It creates the output display by converting retrieved data into variables and passing them through a series of templates. Each template handles a different "level" of output creation. The number of templates used to create a view's output depends on the view's type and style, as well as the number of fields involved. These templates exist as files (with a .tpl.php extension), in either the module's or the theme's directory, and follow PHPTemplate's theming conventions.
Generally speaking, the template levels are:
Field: When fields are used in the view ("Row style" = Fields), each field can be themed with a field specific template file. If "Row style" = Node, the node's .tpl.php file is used.
Row: Controls how the individual fields are assembled together into a row. This template isn't used for table styles
Style: Controls how the rows are assembled into the output. For example, in a list view a foreach loop places each row entry into the list entry (li) of an unordered list (ul).
Display: Controls the other information making up the view such as title, header and footer.
Each level becomes input variables for the next level up. The output of field templates are input variables for the row template, the output for the row template becomes input variables for the style template, and so on. There are also level specific variables available, such as row number. A diagram is available at http://views-help.doc.logrus.com/help/views/analyze-theme.
A template file naming convention is used to make the template highly specific or highly general. Through appropriate naming, a template file can apply to all views, a view of a specific type, or a specific display of a specific view. Where multiple files might apply to a view, the one with the most specific name is used.
Tuesday, December 30, 2008
Landmarks to see in Chennai
Chennai, being the gateway to south India is a very culturally rich city and offers something for everyone, with a south Indian flair. From Christian churches to Hindu temples, from military forts to motorcycle factories, there is something for everyone here.
If you are a history or a culture buff, then welcome to the melting pot of south India, for Chennai is its capital, and over the centuries has attracted people from not only over South India, but also from all over the world. A must visit place is Mylapore, with its numerous Temples depicting the classical architecture of South India over the centuries.
Chennai is more or less divided into 3 sections: George Town, Egmore and Central Chennai, and South Chennai. George Town, named in honor of King George V being crowned emperor of India, is reminiscent of Chennai's colonial past, where as the other parts of Chennai have a more ethnic feel.
Places to see in Chennai
George Town
1. High Court Building
2. Fort St. George
3. St. Mary's Church
If you are a history or a culture buff, then welcome to the melting pot of south India, for Chennai is its capital, and over the centuries has attracted people from not only over South India, but also from all over the world. A must visit place is Mylapore, with its numerous Temples depicting the classical architecture of South India over the centuries.
Chennai is more or less divided into 3 sections: George Town, Egmore and Central Chennai, and South Chennai. George Town, named in honor of King George V being crowned emperor of India, is reminiscent of Chennai's colonial past, where as the other parts of Chennai have a more ethnic feel.
Places to see in Chennai
George Town
1. High Court Building
2. Fort St. George
3. St. Mary's Church
Sending Mail with the hook_mail in Drupal 6
The Drupal 6 Mail API is used to provide mail-sending services to Drupal modules.
In most cases, using the Mail API is a two-step process:
1. Implement hook_mail() in your module.
2. Elsewhere in your module, use the drupal_mail() function to invoke
your hook_mail() implementation and also do additional formatting
and sending.
In the previous section, we briefly glanced at the drupal_mail() function. Here, we
will start by looking at the function in more detail. Inside emailusers_compose_
form_submit(), we called drupal_mail() with the following parameters:
drupal_mail(
'emailusers',
'composemessage',
$account->mail,
user_preferred_language($account),
$form_values,
variable_get('site_mail', null),
true // Automatically send
);
Seven parameters! To get an idea as to what is going on here, let's look at each
in turn.
The first parameter (emailusers) is the name of the module that contains an
implementation of hook_mail(). Later, we will look at the emailusers_mail()
hook that will be called when this drupal_mail() function is executed.
The second parameter, composemessage, is used as a key and passed on to the
hook_mail() implementation. As we will see shortly, the mail hook can then
determine how to treat the message based on the key. In other words, you can
use one mail hook to handle various different mail-sending tasks simply by using
different keys.
The third parameter should contain the destination address. In this case, an
administrator will be sending the message to the email address for the account he or
she is examining. This is stored in $account->mail.
The fourth parameter is the language that should be used by t() and other
translation facilities when translating the message. Why is it necessary to specify
this? Since the user receiving the message may prefer a different language than that
of the system administrator who is sending the message.Fortunately, the user_preferred_language() function, which takes an account
object (like the one returned from load_user()), can return the appropriate
locale information.
The fifth parameter holds an associative array of data that might be used when
generating the message. This data is passed on to the hook_mail() implementation,
and we will make use of it in a few moments. In this case, though, the data we want
happens to be the values submitted through our form. So we pass $form_values
here.
Moving to the sixth parameter, we need to specify a delivery address. Who is
this message from? One of the values in Drupal's site-wide configuration is the
administration email address. We can use this address by retrieving the setting:
variable_get('site_mail', null). This will attempt to get the 'site_mail'
setting. If no such setting is found, this will return the default value null (in which
case the mailing library will attempt to assign an appropriate from address).
The last of the seven parameters is a Boolean flag to indicate whether or not the
message should be sent. When drupal_mail() is executed, it will return a specially
structured array, which can be passed to drupal_mail_send(). However, if this last
parameter is set to true, then the drupal_mail() function will send the mail before
returning. In that case, there is no need to call the drupal_mail_send() function or
even capture the data returned from drupal_mail().When drupal_mail() is called, it goes through a series of steps to take the data
passed in the seven parameters and create a suitable mail message. For example, it
sets default RFC 2822 mail headers and makes sure that certain values (like a from
address) are set.
Then it executes the hook_mail() implementation (if found).
After that, it proceeds through a few other steps, like executing any hook_mail_
alter() implementations before it (optionally) sends the email and returns a
formatted message.So the mail hook is executed right in the middle of this process. What does it do? In
a nutshell, it is responsible for setting appropriate fields (like the subject, CC, or BCC
fields) as well as creating a formatted body for the message.
In most cases, using the Mail API is a two-step process:
1. Implement hook_mail() in your module.
2. Elsewhere in your module, use the drupal_mail() function to invoke
your hook_mail() implementation and also do additional formatting
and sending.
In the previous section, we briefly glanced at the drupal_mail() function. Here, we
will start by looking at the function in more detail. Inside emailusers_compose_
form_submit(), we called drupal_mail() with the following parameters:
drupal_mail(
'emailusers',
'composemessage',
$account->mail,
user_preferred_language($account),
$form_values,
variable_get('site_mail', null),
true // Automatically send
);
Seven parameters! To get an idea as to what is going on here, let's look at each
in turn.
The first parameter (emailusers) is the name of the module that contains an
implementation of hook_mail(). Later, we will look at the emailusers_mail()
hook that will be called when this drupal_mail() function is executed.
The second parameter, composemessage, is used as a key and passed on to the
hook_mail() implementation. As we will see shortly, the mail hook can then
determine how to treat the message based on the key. In other words, you can
use one mail hook to handle various different mail-sending tasks simply by using
different keys.
The third parameter should contain the destination address. In this case, an
administrator will be sending the message to the email address for the account he or
she is examining. This is stored in $account->mail.
The fourth parameter is the language that should be used by t() and other
translation facilities when translating the message. Why is it necessary to specify
this? Since the user receiving the message may prefer a different language than that
of the system administrator who is sending the message.Fortunately, the user_preferred_language() function, which takes an account
object (like the one returned from load_user()), can return the appropriate
locale information.
The fifth parameter holds an associative array of data that might be used when
generating the message. This data is passed on to the hook_mail() implementation,
and we will make use of it in a few moments. In this case, though, the data we want
happens to be the values submitted through our form. So we pass $form_values
here.
Moving to the sixth parameter, we need to specify a delivery address. Who is
this message from? One of the values in Drupal's site-wide configuration is the
administration email address. We can use this address by retrieving the setting:
variable_get('site_mail', null). This will attempt to get the 'site_mail'
setting. If no such setting is found, this will return the default value null (in which
case the mailing library will attempt to assign an appropriate from address).
The last of the seven parameters is a Boolean flag to indicate whether or not the
message should be sent. When drupal_mail() is executed, it will return a specially
structured array, which can be passed to drupal_mail_send(). However, if this last
parameter is set to true, then the drupal_mail() function will send the mail before
returning. In that case, there is no need to call the drupal_mail_send() function or
even capture the data returned from drupal_mail().When drupal_mail() is called, it goes through a series of steps to take the data
passed in the seven parameters and create a suitable mail message. For example, it
sets default RFC 2822 mail headers and makes sure that certain values (like a from
address) are set.
Then it executes the hook_mail() implementation (if found).
After that, it proceeds through a few other steps, like executing any hook_mail_
alter() implementations before it (optionally) sends the email and returns a
formatted message.So the mail hook is executed right in the middle of this process. What does it do? In
a nutshell, it is responsible for setting appropriate fields (like the subject, CC, or BCC
fields) as well as creating a formatted body for the message.
Drupal core caching and content caching modules
Drupal core caching
Caching stores "elements" in a cache table in the database, so the data can be retrieved by a single query, rather that constructing the page from individual elements.
Drupal's core cache has two parts, stuff that gets caches no matter what, and stuff that is optional via an administrator defined settings.
The always on cache is for the menu (the hierarchy of callbacks/urls, with access information), the variable table (all the various settings and configuration), and filters (all processed texts).
The optional cache is the page cache, and it only applies for anonymous users.
For Drupal 4.7 and earlier, the cache table was a single table storing all of the above. As of Drupal 5.x, the cache table is split into cache_menu, cache_filter, cache_variable and cache_page to decrease contention. Also new in Drupal 5.x is aggressive caching mode.
Cache contention
On a large site, if you are using MyISAM, contention occurs in the database tables when the cache is forced to clear after a node or a comment is added. With tens of thousands of filter text snippets needing to be deleted, the table will be locked for a long period, and any accesses to it will be queued pending the purge of the data in it. The same is true for the page cache as well.
This often causes a "site hang" for a minute or two. During that time new requests keep piling up, and if you do not have the MaxClients parameter in Apache setup correctly, the system can go into thrashing because of excessive swapping.
Example of such cases exist here, and here.
If you change your database tables to InnoDB, you can avoid the table level locking, since it supports row level locking. However, you have to be careful of some InnoDB pitfalls that can cause other queries on the site to be slow, as well as eliminate the table locks as described in that same article.
Eliminating cache contention
To get rid of this contention, you have to first disable the page cache, which requires no code change. This is only possible if you have the CPU horsepower to generate the pages and filters for every page view. This means that you are on a dedicated server (which you need anyway if you have a large site), and that you have enabled one of the PHP op-code caches/accelerators.
Do disable the filter cache, you have to manually edit code in Drupal 4.7 (and remember to change it when you get a new release).
In filter.module, find the function check_markup(), then delete or comment out the following lines:
if ($cached = cache_get($id, 'cache_filter')) {
return $cached->data;
}
and
if ($cache) {
cache_set($id, 'cache_filter', $text, time() + (60 * 60 * 24));
}
With these lines removed/commented, you no longer have to worry about contention for the filter cache.
In Drupal 5.x, there is a nifty feature that allows you to create your own caching strategy, by replacing includes/cache.inc with a file you define.
Copy the includes/cache.inc file to sites/modules/cache_no_filter/cache_no_filter.inc, and then modify the file you just created like so:
In the cache_get() function, put the following at the start of the function:
if ($table == 'cache_filter') {
return 0;
}
And this in cache_set(), put this at the start of the function:
if ($table == 'cache_filter') {
return;
}
Then, in your settings.php file, you do the following:
$conf = array(
'cache_inc' => './sites/all/modules/cache_no_filter/cache_no_filter.inc',
);
A pre-patched version for Drupal 5.2 can be downloaded below towards the end of this article. Just rename the file to remove the .txt extension.
The beauty of this is that you do not modify Drupal core, yet hook into your custom cache.
Contributed caching modules
There are quite a few contributed modules that help with caching.
For example, there is a block cache module avoids the overhead of generating blocks for every page load.
Taking it a step further, there is an API module by the name pressflow preempt that allows other modules to cache any function.
Avoiding the database altogether is the ultimate in caching: if the pages are stored in HTML static files, they can be served faster.
Taking this approach, there is the fastpath fscache module, as well as the boost module.
Caching stores "elements" in a cache table in the database, so the data can be retrieved by a single query, rather that constructing the page from individual elements.
Drupal's core cache has two parts, stuff that gets caches no matter what, and stuff that is optional via an administrator defined settings.
The always on cache is for the menu (the hierarchy of callbacks/urls, with access information), the variable table (all the various settings and configuration), and filters (all processed texts).
The optional cache is the page cache, and it only applies for anonymous users.
For Drupal 4.7 and earlier, the cache table was a single table storing all of the above. As of Drupal 5.x, the cache table is split into cache_menu, cache_filter, cache_variable and cache_page to decrease contention. Also new in Drupal 5.x is aggressive caching mode.
Cache contention
On a large site, if you are using MyISAM, contention occurs in the database tables when the cache is forced to clear after a node or a comment is added. With tens of thousands of filter text snippets needing to be deleted, the table will be locked for a long period, and any accesses to it will be queued pending the purge of the data in it. The same is true for the page cache as well.
This often causes a "site hang" for a minute or two. During that time new requests keep piling up, and if you do not have the MaxClients parameter in Apache setup correctly, the system can go into thrashing because of excessive swapping.
Example of such cases exist here, and here.
If you change your database tables to InnoDB, you can avoid the table level locking, since it supports row level locking. However, you have to be careful of some InnoDB pitfalls that can cause other queries on the site to be slow, as well as eliminate the table locks as described in that same article.
Eliminating cache contention
To get rid of this contention, you have to first disable the page cache, which requires no code change. This is only possible if you have the CPU horsepower to generate the pages and filters for every page view. This means that you are on a dedicated server (which you need anyway if you have a large site), and that you have enabled one of the PHP op-code caches/accelerators.
Do disable the filter cache, you have to manually edit code in Drupal 4.7 (and remember to change it when you get a new release).
In filter.module, find the function check_markup(), then delete or comment out the following lines:
if ($cached = cache_get($id, 'cache_filter')) {
return $cached->data;
}
and
if ($cache) {
cache_set($id, 'cache_filter', $text, time() + (60 * 60 * 24));
}
With these lines removed/commented, you no longer have to worry about contention for the filter cache.
In Drupal 5.x, there is a nifty feature that allows you to create your own caching strategy, by replacing includes/cache.inc with a file you define.
Copy the includes/cache.inc file to sites/modules/cache_no_filter/cache_no_filter.inc, and then modify the file you just created like so:
In the cache_get() function, put the following at the start of the function:
if ($table == 'cache_filter') {
return 0;
}
And this in cache_set(), put this at the start of the function:
if ($table == 'cache_filter') {
return;
}
Then, in your settings.php file, you do the following:
$conf = array(
'cache_inc' => './sites/all/modules/cache_no_filter/cache_no_filter.inc',
);
A pre-patched version for Drupal 5.2 can be downloaded below towards the end of this article. Just rename the file to remove the .txt extension.
The beauty of this is that you do not modify Drupal core, yet hook into your custom cache.
Contributed caching modules
There are quite a few contributed modules that help with caching.
For example, there is a block cache module avoids the overhead of generating blocks for every page load.
Taking it a step further, there is an API module by the name pressflow preempt that allows other modules to cache any function.
Avoiding the database altogether is the ultimate in caching: if the pages are stored in HTML static files, they can be served faster.
Taking this approach, there is the fastpath fscache module, as well as the boost module.
Upgrade from Drupal 5 to Drupal 6
The module provides full upgrade scripts for a smooth transition to Drupal 6. However, due to some multilanguage features provided now by Drupal core and that the i18n package has been fully reworked, there are some special considerations. So please, read all this page before doing anything.
Drupal 6 upgrade notes
* To upgrade from 5.x, first upgrade to the latest 5.x stable release. To upgrade from 4.x, first upgrade to 5.x, then to 6.x
* Note that some old features and behaviors have been dropped and replaced by new Drupal 6 multilingual features. This module won't pretend to replace Drupal core available features but to build on them and provide extended ones.
* While the upgrade scripts already work for nodes and taxonomy, there's other data that is simply deleted by the main Drupal 6 core upgrade, like the menu items language.
* Other parts like the multilingual block system have been completely reworked and will need manual reconfiguration. Existing normal blocks won't be lost but the language settings will need manual reconfiguration.
* The module layout, dependencies and names have important changes, so it is advised to take your time, read the new modules descriptions, and decide on which ones you new enabled, that may be different from the Drupal 5 ones.
The upgrade process
1. As with any other upgrade, make a full back up of your database before and set the site in off-line mode.
2. Disable all i18n modules (Disabling all contributed modules is always recommended) before upgrading to Drupal 6.
3. Upgrade your codebase and run the Drupal 6 standard upgrade
4. First, enable Drupal 6 core Translation module. Internationalization now relies on it.
5. Go through the Inernationalization package module list and enable the ones you need.
6. Run the update script again (update.php) so i18n modules can update their data properly
7. Review *all* the language settings (Drupal 6 core settings have also changed), and reconfigure your multilingual menus, blocks and path aliases.
After upgrading
* If you are using multilingual variables, some variable names have changed in Drupal 6. Review and update your settings.
* Language prefixes in path aliases are not supported anymore. Instead use the new language setting for path aliases. You'll need to update them manually
Drupal 6 upgrade notes
* To upgrade from 5.x, first upgrade to the latest 5.x stable release. To upgrade from 4.x, first upgrade to 5.x, then to 6.x
* Note that some old features and behaviors have been dropped and replaced by new Drupal 6 multilingual features. This module won't pretend to replace Drupal core available features but to build on them and provide extended ones.
* While the upgrade scripts already work for nodes and taxonomy, there's other data that is simply deleted by the main Drupal 6 core upgrade, like the menu items language.
* Other parts like the multilingual block system have been completely reworked and will need manual reconfiguration. Existing normal blocks won't be lost but the language settings will need manual reconfiguration.
* The module layout, dependencies and names have important changes, so it is advised to take your time, read the new modules descriptions, and decide on which ones you new enabled, that may be different from the Drupal 5 ones.
The upgrade process
1. As with any other upgrade, make a full back up of your database before and set the site in off-line mode.
2. Disable all i18n modules (Disabling all contributed modules is always recommended) before upgrading to Drupal 6.
3. Upgrade your codebase and run the Drupal 6 standard upgrade
4. First, enable Drupal 6 core Translation module. Internationalization now relies on it.
5. Go through the Inernationalization package module list and enable the ones you need.
6. Run the update script again (update.php) so i18n modules can update their data properly
7. Review *all* the language settings (Drupal 6 core settings have also changed), and reconfigure your multilingual menus, blocks and path aliases.
After upgrading
* If you are using multilingual variables, some variable names have changed in Drupal 6. Review and update your settings.
* Language prefixes in path aliases are not supported anymore. Instead use the new language setting for path aliases. You'll need to update them manually
Monday, December 29, 2008
PHP Circle in Chennai
While many believe that the real action in the IT business happens in the large companies, there are very few who realise that there is life outside as well. There is a vast potential for Indian small-scale IT companies and the thousands of job-aspirant programmers/engineers who work with them.
A group of professionals and companies has joined hands to form Chennai’s first PHP professional forum, a free forum, called the ‘PHP Circle’.
While TCSes, Infosyses and Wipros are busy catering to the large US business segment for software development, there is a large, untapped segment viz., the US and European small online business market. This is one of the high growth markets today, especially in the US, as businesses built around strong revenue models are now emerging from the rubbles of the dot com bust.
Web applications market for small online business has its own characteristics. The size of each work is small, with low budgets (yet very viable for the Indian SSI IT market), and project management issues are more complex than the conventional software market. Still, Indian IT SSIs would do well to focus on these segments, as there is relatively less competition in this market from the established IT companies.
While Microsoft platforms and other higher-end tools are the preferred by medium of large-scale companies, small businesses prefer PHP and mySQL to develop their web applications in view of their being low-cost and being from the open source stable.
Due to the strong inroads that Microsoft ASP and .NET have made in providing easy tools to create web applications, and also due to the fact that India is favourably tilted towards Microsoft technology, there are not many trained programmers and solution-providers available to pursue PHP-based development. So, concerted efforts are required to develop manpower in PHP and mySQL. Companies willing to join these efforts are welcome to become members of this forum.
The activities proposed, all free of cost, include weekend classroom training for programmers, free tutorials, monthly forum meets with popular guest speakers, career-related contact opportunities, PHP Help Desk through bulletin boards, weekly newsletter with job postings by companies, sub-forums in engineering colleges and more.
Anyone with the required professional qualifications/programming experience and desirous of becoming a PHP programmer can become a free member of this circle. Since PHP is a fast expanding open source development tool, India can and must become the world leader in this widely used domain. And future prospects abound.
‘PHP Circle’ is a Chennai based non-profit forum. For More Information Click Here
A group of professionals and companies has joined hands to form Chennai’s first PHP professional forum, a free forum, called the ‘PHP Circle’.
While TCSes, Infosyses and Wipros are busy catering to the large US business segment for software development, there is a large, untapped segment viz., the US and European small online business market. This is one of the high growth markets today, especially in the US, as businesses built around strong revenue models are now emerging from the rubbles of the dot com bust.
Web applications market for small online business has its own characteristics. The size of each work is small, with low budgets (yet very viable for the Indian SSI IT market), and project management issues are more complex than the conventional software market. Still, Indian IT SSIs would do well to focus on these segments, as there is relatively less competition in this market from the established IT companies.
While Microsoft platforms and other higher-end tools are the preferred by medium of large-scale companies, small businesses prefer PHP and mySQL to develop their web applications in view of their being low-cost and being from the open source stable.
Due to the strong inroads that Microsoft ASP and .NET have made in providing easy tools to create web applications, and also due to the fact that India is favourably tilted towards Microsoft technology, there are not many trained programmers and solution-providers available to pursue PHP-based development. So, concerted efforts are required to develop manpower in PHP and mySQL. Companies willing to join these efforts are welcome to become members of this forum.
The activities proposed, all free of cost, include weekend classroom training for programmers, free tutorials, monthly forum meets with popular guest speakers, career-related contact opportunities, PHP Help Desk through bulletin boards, weekly newsletter with job postings by companies, sub-forums in engineering colleges and more.
Anyone with the required professional qualifications/programming experience and desirous of becoming a PHP programmer can become a free member of this circle. Since PHP is a fast expanding open source development tool, India can and must become the world leader in this widely used domain. And future prospects abound.
‘PHP Circle’ is a Chennai based non-profit forum. For More Information Click Here
Joomla 1.5 & Drupal 6.1 Performance Comparison
Alldrupalthemes.com did a performance comparision between Joomla 1.5 & Drupal 6.1. As the author of the post infers, the numbers collected may not mean much to the user in the "real world" and limitations in the test results should be noted. Nevertheless, numbers that compare Drupal and Joomla performance are always interesting.
The conclusions drawn from the results are:
1. Drupal is significantly faster than Joomla in all 4 setups
2. Drupal cuts down pageload time by ~74% when caching is enabled on the fresh install and ~86% with the more populated setup
3. Joomla cuts down pageload time by ~23% on the fresh install and ~20% on the more populated setup
These numbers are interesting and I bet the study pulls in a lot of visitors for All Drupal Themes. Not only are Drupal and Joomla users interested in these type of posts, but so are potential users shopping around the first time for a CMS. As always, you should judge a CMS by what it does for you and not what it does for others.
The conclusions drawn from the results are:
1. Drupal is significantly faster than Joomla in all 4 setups
2. Drupal cuts down pageload time by ~74% when caching is enabled on the fresh install and ~86% with the more populated setup
3. Joomla cuts down pageload time by ~23% on the fresh install and ~20% on the more populated setup
These numbers are interesting and I bet the study pulls in a lot of visitors for All Drupal Themes. Not only are Drupal and Joomla users interested in these type of posts, but so are potential users shopping around the first time for a CMS. As always, you should judge a CMS by what it does for you and not what it does for others.
Project usage overview
This page summarizes the usage of all projects on drupal.org. For each week beginning on the given date the figures show the number of sites that reported they are using (any version of) the project. Detailed usage information for each release of a project is available by clicking the project name.
These statistics are incomplete; only Drupal websites using the Update Status module are included in the data. As this module is now included with the download of Drupal since version 6.x, the data is heavily biased toward newer sites.For more information Click Here
These statistics are incomplete; only Drupal websites using the Update Status module are included in the data. As this module is now included with the download of Drupal since version 6.x, the data is heavily biased toward newer sites.For more information Click Here
Comparison Between Drupal And Joomla
Making comparisons between Joomla and Drupal are very common these days as they are currently considered the top two open source content management systems (CMS) out there. The forum post written by Steve Burge contains a link that takes you to a comparison table he did between Joomla and Drupal. While the table may not give the full picture of each CMS, I'm convinced that Burge tried to be as non-bias as he possibly could in his comparison.
There is something interesting about the table posted at Burge's site. Specifically, take a look at which elements according to Burge each CMS excels in and which elements each CMS fails. Did you notice a particular pattern in where each CMS is considered to have failed? If not, perhaps you didn't see the excerpt I posted earlier from Gadgetopia's Deane Barker, titled Architecture and Functionality in Content Management.
Let me be more specific. In the table Drupal fails on such elements as Shopping Carts, Event Calendars, Document Management, and Themes. The majority of these items are functions or features which are considered lacking in the Drupal CMS. Regarding the other CMS, Joomla fails to deliver in such elements as user permission, content management, multi-site management, and standard's compliance. Joomla fails in elements that are more architecture centric.
Taking the flip side, Joomla as a CMS appears to excel in elements that can be identified as functional, while Drupal succeeds in the architectural elements. Which element is more important in a CMS, architecture or function? According to Deane Barker he believes it is more important for a CMS to have better architecture.
As a developer with the capability to write code, I find myself much more concerned with architectural matters. Functionality can be programmed, but I’m at the mercy of architecture. Put another way, give me the right tools and materials, and I can build anything. But give me nothing but a pile of sand and a toothbrush, and I’m pretty much screwed.
In other words, if you agree with Barker that architecture is more important than function you're likely going to want to choose Drupal. However, if you need to make a quick sell where function, third party integration, and eye candy is important right out the box...Joomla still has the advantage.
What does the future hold in the post-Drupal 5 and post-Joomla 1.5 era? It's hard to say, but I'm betting Drupal will likely become very competitive in functions as it currently is in architecture. Then again Joomla may still pull a few punches as it continues to shed it's roots with Mambo. Interesting times ahead and I'll be quite interested how comparison tables such as the one we have been looking at will look like a couple more years down the road.
There is something interesting about the table posted at Burge's site. Specifically, take a look at which elements according to Burge each CMS excels in and which elements each CMS fails. Did you notice a particular pattern in where each CMS is considered to have failed? If not, perhaps you didn't see the excerpt I posted earlier from Gadgetopia's Deane Barker, titled Architecture and Functionality in Content Management.
Let me be more specific. In the table Drupal fails on such elements as Shopping Carts, Event Calendars, Document Management, and Themes. The majority of these items are functions or features which are considered lacking in the Drupal CMS. Regarding the other CMS, Joomla fails to deliver in such elements as user permission, content management, multi-site management, and standard's compliance. Joomla fails in elements that are more architecture centric.
Taking the flip side, Joomla as a CMS appears to excel in elements that can be identified as functional, while Drupal succeeds in the architectural elements. Which element is more important in a CMS, architecture or function? According to Deane Barker he believes it is more important for a CMS to have better architecture.
As a developer with the capability to write code, I find myself much more concerned with architectural matters. Functionality can be programmed, but I’m at the mercy of architecture. Put another way, give me the right tools and materials, and I can build anything. But give me nothing but a pile of sand and a toothbrush, and I’m pretty much screwed.
In other words, if you agree with Barker that architecture is more important than function you're likely going to want to choose Drupal. However, if you need to make a quick sell where function, third party integration, and eye candy is important right out the box...Joomla still has the advantage.
What does the future hold in the post-Drupal 5 and post-Joomla 1.5 era? It's hard to say, but I'm betting Drupal will likely become very competitive in functions as it currently is in architecture. Then again Joomla may still pull a few punches as it continues to shed it's roots with Mambo. Interesting times ahead and I'll be quite interested how comparison tables such as the one we have been looking at will look like a couple more years down the road.
Sunday, December 28, 2008
Chimop For Indesign
layout tool in InDesign that allows for semi-automatic page layouts. Chimp has little to do with Drupal per se, but it has a lot to do with making print media more accessible for low-budget organisations and newsrooms. The beta we're running locally has cut about a third off our layout time, and we're aiming at chopping a full half of our time spent layouting. It's different from PrintCasting in that it's intended for small newsrooms (locals, student newspapers, ...) that have a layout-staff and want to be more productive, rather than providing a fully-automatic solution for people who can't afford designers. It's different from other automatic layout systems (like DTI PageMagic, the ISI docuboxx, ...) in that it'll be free rather than unaffordable for us mere mortals.
Thursday, December 25, 2008
Overriding Theme Functions in Modules Instead of Template.php
Drupal's theming system offers developers and designers a flexible way to override default HTML output when specific portions of the page are rendered. Everything from the name of the currently logged in user to the HTML markup of the entire page can be customized by a plugin "theme".
Unfortunately, this system can be its own worst enemy. Themes are very powerful, but in many cases they're the only place where specific output can be changed without hacking core. Because of this, themes on highly customized production sites can easily turn into code-monsters, carrying the weight of making 'Drupal' look like 'My Awesome Site.'
This can make maintenance difficult, and it also makes sharing these tweaks with other Drupal developers tricky. In fact, some downloadable modules also come with instructions on how to modify a theme to 'complete' the module's work. Wouldn't it be great if certain re-usable theme overrides could be packaged up and distributed as part of any Drupal? As it turns out, that is possible. In this article, we'll be exploring two ways to do it: a tweaky, hacky approach for Drupal 5, and a clean and elegant approach that's only possible in Drupal 6.
Under the Hood
Before getting into the details, we'll look at how Drupal allows themes to override HTML rendering. This mechanism will be the key to our sneaky tricks.
Whenever 'themable' HTML is being generated, Drupal modules first assemble the basic data that should pre presented (an array of numbers, a content node...), then call the theme() function. For example:
$node = node_load(1); // Load node id 1 from the database
$output = theme('node', $node); // This generates themed HTML
print $output;
?>
The first paramater passed into the theme() function is the type of data being themed, while the second parameter is the 'thing' itself. When that function is called, Drupal walks through the following process:
1. Does the theme handle it?
The currently installed theme is first in line to render the object to HTML. Drupal checks for a function named theme-name_object-type(), and if it exists, calls it. For example, the Garland theme uses the function garland_breadcrumb() to control how the breadcrumb trail is displayed.
2. Does the theme engine handle it?
Next in line is the current 'theme engine.' In most cases, this is Drupal's default PHPTemplate theming engine. Smarty and PHPTal are other possibile engines. As with themes, Drupal checks for a function named theme-engine-name_object-type(), and if it exists, calls it. The PHPTemplate engine uses the function phptemplate_node() to control how nodes are displayed.
3. Let a module handle it.
Finally, if no overrides are found, Drupal checks for a function named theme_object-type() and calls it if it exists. These default theme functions are usually provided by modules to offer default HTML output for objects in case no one overrides them.
This approach is very flexible: it gives themes and the underlying theme engines a chance to override the HTML, lets modules provide a 'default' style of output, and it makes the complexities of the overriding process invisible to a developer who just wants to print out a node (or any other themable object) on a page. The only problem is that it doesn't provide a way for another module to jump in between steps 2 and 3, overriding the default HTML.
Drupal 5: Sneaky, Sneaky Hacks
In Drupal 5, there's no officially supported way to overcome this limitation, There is, however, a crafty trick you can use to override theme functions in your modules. Take a look back at step 2 in the explanation of Drupal's overriding process, again. Drupal checks to see whether a function named theme-engine-name_object-type() exists in order to see if a theme engine wants to override the rendering. If that function name exists, Drupal will use it -- even if it's implemented in your module, not the actual theme engine.
What does that mean? If your module implements the function phptemplate_username(), it will be treated as if it's the theme engine in step 2, overriding the default markup provided by Drupal core, without making any changes to the theme itself. Voila!
The downside, of course, is that if the theme engine you're using does provide its own override, no module can play this trick: the function name already exists, and trying to define it again in your module will cause PHP errors. It can still be a useful way to isolate site-specific chunks of theme code in a way that's easy to track, enable or disable, and so on.
Drupal 6: The Land of Milk and Honey
In Drupal 6, things are a bit different. The same basic hierarchy is still in place: first themes, then theme engines, then modules all get opportunities to render an object to HTML. However, Drupal now caches the information about what function should be used in an internal "theme registry." This saves Drupal the work of 'discovering' who's in charge each time the theme() function is called.
In addition to saving time, though, this cached "registry" of theme functions is something that modules can modify using the hook_theme_registry_alter() function. What does that mean? While a module can't insert itself between steps 2 and 3 in the discovery process, it can step in after the discovery process is complete, and replace the default function from step 1 with its own version -- even if it doesn't follow the naming conventions Drupal expects.
Let's take a quick look at how this works, stealing a snippet of code from the WordPress Comments module. It's a module that intercepts Drupal's default rendering of all form elements to tweak the appearance of labels and 'required' flags on certain forms.
function wp_comments_theme_registry_alter(&$theme_registry) {
if (!empty($theme_registry['form_element'])) {
$theme_registry['form_element']['function'] = 'wp_comments_form_element';
}
}
function wp_comments_form_element($element, $value) {
// Here, we provide our customized version of the
// theme_form_element function from theme.inc...
}
?>
The above code is pretty straightforward: in hook_theme_registry_alter(), it first checks to be sure that the form_element theme data is properly defined, then swaps in its own custom function (wp_comments_form_element) in place of the default one (theme_form_element).
The beautiful part of this system is that it continues to work cleanly with custom themes: if a theme overrides the form_element theming code as well, it will still take precedence over wp_comments' version. In addition, there's no chance of colliding function names, as it relies on the theme registry rather than 'magic' function names like phptemplate_form_element().
Unfortunately, this system can be its own worst enemy. Themes are very powerful, but in many cases they're the only place where specific output can be changed without hacking core. Because of this, themes on highly customized production sites can easily turn into code-monsters, carrying the weight of making 'Drupal' look like 'My Awesome Site.'
This can make maintenance difficult, and it also makes sharing these tweaks with other Drupal developers tricky. In fact, some downloadable modules also come with instructions on how to modify a theme to 'complete' the module's work. Wouldn't it be great if certain re-usable theme overrides could be packaged up and distributed as part of any Drupal? As it turns out, that is possible. In this article, we'll be exploring two ways to do it: a tweaky, hacky approach for Drupal 5, and a clean and elegant approach that's only possible in Drupal 6.
Under the Hood
Before getting into the details, we'll look at how Drupal allows themes to override HTML rendering. This mechanism will be the key to our sneaky tricks.
Whenever 'themable' HTML is being generated, Drupal modules first assemble the basic data that should pre presented (an array of numbers, a content node...), then call the theme() function. For example:
$node = node_load(1); // Load node id 1 from the database
$output = theme('node', $node); // This generates themed HTML
print $output;
?>
The first paramater passed into the theme() function is the type of data being themed, while the second parameter is the 'thing' itself. When that function is called, Drupal walks through the following process:
1. Does the theme handle it?
The currently installed theme is first in line to render the object to HTML. Drupal checks for a function named theme-name_object-type(), and if it exists, calls it. For example, the Garland theme uses the function garland_breadcrumb() to control how the breadcrumb trail is displayed.
2. Does the theme engine handle it?
Next in line is the current 'theme engine.' In most cases, this is Drupal's default PHPTemplate theming engine. Smarty and PHPTal are other possibile engines. As with themes, Drupal checks for a function named theme-engine-name_object-type(), and if it exists, calls it. The PHPTemplate engine uses the function phptemplate_node() to control how nodes are displayed.
3. Let a module handle it.
Finally, if no overrides are found, Drupal checks for a function named theme_object-type() and calls it if it exists. These default theme functions are usually provided by modules to offer default HTML output for objects in case no one overrides them.
This approach is very flexible: it gives themes and the underlying theme engines a chance to override the HTML, lets modules provide a 'default' style of output, and it makes the complexities of the overriding process invisible to a developer who just wants to print out a node (or any other themable object) on a page. The only problem is that it doesn't provide a way for another module to jump in between steps 2 and 3, overriding the default HTML.
Drupal 5: Sneaky, Sneaky Hacks
In Drupal 5, there's no officially supported way to overcome this limitation, There is, however, a crafty trick you can use to override theme functions in your modules. Take a look back at step 2 in the explanation of Drupal's overriding process, again. Drupal checks to see whether a function named theme-engine-name_object-type() exists in order to see if a theme engine wants to override the rendering. If that function name exists, Drupal will use it -- even if it's implemented in your module, not the actual theme engine.
What does that mean? If your module implements the function phptemplate_username(), it will be treated as if it's the theme engine in step 2, overriding the default markup provided by Drupal core, without making any changes to the theme itself. Voila!
The downside, of course, is that if the theme engine you're using does provide its own override, no module can play this trick: the function name already exists, and trying to define it again in your module will cause PHP errors. It can still be a useful way to isolate site-specific chunks of theme code in a way that's easy to track, enable or disable, and so on.
Drupal 6: The Land of Milk and Honey
In Drupal 6, things are a bit different. The same basic hierarchy is still in place: first themes, then theme engines, then modules all get opportunities to render an object to HTML. However, Drupal now caches the information about what function should be used in an internal "theme registry." This saves Drupal the work of 'discovering' who's in charge each time the theme() function is called.
In addition to saving time, though, this cached "registry" of theme functions is something that modules can modify using the hook_theme_registry_alter() function. What does that mean? While a module can't insert itself between steps 2 and 3 in the discovery process, it can step in after the discovery process is complete, and replace the default function from step 1 with its own version -- even if it doesn't follow the naming conventions Drupal expects.
Let's take a quick look at how this works, stealing a snippet of code from the WordPress Comments module. It's a module that intercepts Drupal's default rendering of all form elements to tweak the appearance of labels and 'required' flags on certain forms.
function wp_comments_theme_registry_alter(&$theme_registry) {
if (!empty($theme_registry['form_element'])) {
$theme_registry['form_element']['function'] = 'wp_comments_form_element';
}
}
function wp_comments_form_element($element, $value) {
// Here, we provide our customized version of the
// theme_form_element function from theme.inc...
}
?>
The above code is pretty straightforward: in hook_theme_registry_alter(), it first checks to be sure that the form_element theme data is properly defined, then swaps in its own custom function (wp_comments_form_element) in place of the default one (theme_form_element).
The beautiful part of this system is that it continues to work cleanly with custom themes: if a theme overrides the form_element theming code as well, it will still take precedence over wp_comments' version. In addition, there's no chance of colliding function names, as it relies on the theme registry rather than 'magic' function names like phptemplate_form_element().
Tuesday, December 23, 2008
Form Building in Drupal
It's the Form builder module: an AJAX, Drag and Drop interface for constructing forms in Drupal.The Form builder project reads and modifies Form API arrays. Using a well-known data-structure that most Drupal developers are familiar with should make for low barrier to entry for utilizing the new module.
The project uses a AJAX-based interface for updating form elements. As you modify properties such as "Title" or "Description", Form builder makes requests in the background to update the element through Drupal's internal FAPI system. The user gets a live preview of their changes without saving the form. This approach means that no additional JavaScript needs to be written by implementing modules, since the rendering is done in PHP and then sent to the client as needed. For Live Demo Click Here.This module is still very new, so it is not recommended using it on any production site.
The project uses a AJAX-based interface for updating form elements. As you modify properties such as "Title" or "Description", Form builder makes requests in the background to update the element through Drupal's internal FAPI system. The user gets a live preview of their changes without saving the form. This approach means that no additional JavaScript needs to be written by implementing modules, since the rendering is done in PHP and then sent to the client as needed. For Live Demo Click Here.This module is still very new, so it is not recommended using it on any production site.
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