Difference between revisions of "Drupal"

From Organic Design
(added link to [http://drupal.org/project/views_gallery Views Gallery])
(Drupal 7.x Taxonomy page)
Line 121: Line 121:
 
*[http://drupal.org/node/809650 Diaspora distributed social network vs Drupal: re-inventing the wheel?]
 
*[http://drupal.org/node/809650 Diaspora distributed social network vs Drupal: re-inventing the wheel?]
 
*[http://maymay.net/maymay/tech/semdrupal/presentation.html Drupal7 and the Semantic Web]
 
*[http://maymay.net/maymay/tech/semdrupal/presentation.html Drupal7 and the Semantic Web]
 +
*[http://drupal.org/taxonomy/term/120 Drupal 7.x Taxonomy page, daily post by all comers]
 
[[Category:Software]]
 
[[Category:Software]]

Revision as of 08:52, 25 November 2010

Drupal is a free and open source content management system (CMS) written in PHP and distributed under the GNU General Public License. It is used as a back-end system for at least 1% of all websites worldwide ranging from personal blogs to larger corporate and political sites including whitehouse.gov and data.gov.uk. It is also used for knowledge management and business collaboration.

The standard release of Drupal, known as Drupal core, contains basic features common to most CMSs. These include user account registration and maintenance, menu management, RSS-feeds, page layout customization, and system administration. The Drupal core installation can be used as a brochureware website, a single- or multi-user blog, an Internet forum, or a community website providing for user-generated content.

Over 6000 (as of October 2010) free community-contributed addons, known as contrib modules, are available to alter and extend Drupal's core capabilities and add new features or customize Drupal's behavior and appearance. Because of this plug-in extensibility and modular design, Drupal is sometimes described as a content management framework. Drupal is also described as a web application framework, as it meets the generally accepted feature requirements for such frameworks.

Although Drupal offers a sophisticated API for developers, no programming skills are required for basic website installation and administration.

Installation

Installation was straight forward and allowed me to install it into the existing database alongside MediaWiki, Joomla and Wordpress using a table prefix.

Structure

From the Drupal overview: If you want to go deeper with Drupal, you should understand how information flows between the system's layers. There are five main layers to consider:

DrupalFlow.gif

  1. At the base of the system is the collection of nodes—the data pool. Before anything can be displayed on the site, it must be input as data.
  2. The next layer up is where modules live. Modules are functional plugins that are either part of the Drupal core (they ship with Drupal) or they are contributed items that have been created by members of the Drupal community. Modules build on Drupal's core functionality, allowing you to customize the data items (fields) on your node types; set up e-commerce; programmatically sorting and display of content (custom output controlled by filters you define); and more. There are thousands of different options within the fast-growing repository of contributed Drupal modules. They represent the innovation and collaborative effort of everyone from individuals to large corporations.
  3. At the next layer, we find blocks and menus. Blocks often provide the output from a module or can be created to display whatever you want, and then can be placed in various spots in your template (theme) layout. Blocks can be configured to output in various ways, as well as only showing on certain defined pages, or only for certain defined users.
  4. Next are user permissions. This is where settings are configured to determine what different kinds of users are allow to do and see. Permissions are defined for various roles, and in turn, users are assigned to these roles in order to grant them the defined permissions.
  5. On the top layer is the site theme (the "skin"). This is made up predominantly of XHTML and CSS, with some PHP variables intermixed, so Drupal-generated content can go in the appropriate spots. Also included with each theme is a set of functions that can be used to override standard functions in the modules in order to provide complete control over how the modules generate their markup at output time. Templates can also be assigned on-the-fly based on user permissions.

User, Permission, Role

Every visitor to your site, whether they have an account and log in or visit the site anonymously, is considered a user to Drupal. Each user has a numeric user ID, and non-anonymous users also have a user name and an email address. Other information can also be associated with users by modules; for instance, if you use the core Profile module, you can define user profile fields to be associated with each user.

Anonymous users have a user ID of zero (0). The user with user ID one (1), which is the user account you create when you install Drupal, is special: that user has permission to do absolutely everything on the site.

Other users on your site can be assigned permissions via roles. To do this, you first need to create a role, which you might call "Content editor" or "Member". Next, you will assign permissions to that role, to tell Drupal what that role can and can't do on the site. Finally, you will grant certain users on your site your new role, which will mean that when those users are logged in, Drupal will let them do the actions you gave that role permission to do.

You can also assign permissions for the special built-in roles of "anonymous user" (a user who is not logged in) and "authenticated user" (a user who is logged in, with no special role assignments). Drupal permissions are quite flexible -- you are allowed to assign permission for any task to any role, depending on the needs of your site.

Modules

Modules and themes are installed by downloading and unpacking them into sites/all/modules or sites/all/themes or to a domain-specific location such as /sites/foo.bar/modules. Note that modules and themes should always be installed under the sites structure, never directly to the modules/themes directories in the codebase root. To check if the module is installed properly, Go to the admin/build/modules page to enable/disable modules and ensure dependencies are satisfied, and also go to admin/reports/status to see if there are any problems or issues to attend to.

Modules we're using
Modules to check out
  • Extending user profiles
  • WikiTools - makes Drupal behave more like a wiki e.g. redirects and red-link ability
  • Diff - show diff links in revisions tab
  • Location Module
  • Pathauto module - automatically generates path aliases for various kinds of content (nodes, categories, users) without requiring the user to manually specify the path alias. This allows you to get aliases like /category/my-node-title.html instead of /node/123
  • Views Gallery - Integration with CCK, organic groups

Views

The Views module provides a flexible method for Drupal site designers to control how lists and tables of content (nodes in Views 1, almost anything in Views 2) are presented. Traditionally, Drupal has hard-coded most of this, particularly in how taxonomy and tracker lists are formatted.

This tool is essentially a smart query builder that, given enough information, can build the proper query, execute it, and display the results. It has four modes, plus a special mode, and provides an impressive amount of functionality from these modes.

Among other things, Views can be used to generate reports, create summaries, and display collections of images and other content.

Organic Groups

Organic Groups (OG) enables users to create and manage their own 'groups'. Each group can have subscribers, and maintains a group home page where subscribers communicate amongst themselves.

They do so by posting the usual node types: blog, story, page, etc. A block is shown on the group home page which facilitates these posts. The block also provides summary information about the group.

Groups may be selective or not. Selective groups require approval in order to become a member, or even invitation-only groups. There are lots of preferences to configure groups as you need.

Groups get their own theme, language, taxonomy, and so on. Integrates well and depends upon Views module

Security

Like MediaWiki, Drupal doesn't come with the ability to restrict read access out of the box. The most popular method for achieving this appears to be the Taxonomy Access Control module (TAC) for permitting access based on tagging and roles, or the TAC lite module to restrict by individual user.

However, sites that are using the Organic Groups module discussed above has its own access control mechanism based on the group structure which is more appropriate for sites already using that module.

Flag

Flag (previously known as Views Bookmark) is a flexible flagging system that is completely customizable by the administrator. Using this module, the site administrator can provide any number of flags for nodes, comments, or users. Some possibilities include bookmarks, marking important, friends, or flag as offensive. With extensive views integration, you can create custom lists of popular content or keep tabs on important content.

Flags may be per-user, meaning that each user can mark an item individually, or global, meaning that the item is either marked or it is not marked, and any user who changes that changes it for everyone.

In this way, additional flags (similar to published and sticky) can be put on nodes, or other items, and dealt with by the system however the administration likes.

Project management

Upgrading

The general upgrade procedure is to first put the site down for maintenance in admin/settings/site-maintenance. Then backup the file structure, replace with the latest download, then go to the /update.php script. After this has run, the original sites directory can be put back, and then go to admin/build/modules to see if any modules also require updating.

Skinning

Zen is the ultimate starting theme for Drupal. If you are building your own standards-compliant theme, you will find it much easier to start with Zen than to start with Garland or Bluemarine. This theme has fantastic online documentation and tons of code comments for both the PHP (template.php) and HTML (page.tpl.php, node.tpl.php).

The idea behind the Zen theme is to have a very flexible standards-compliant and semantically correct XHTML theme that can be highly modified through CSS and an enhanced version of Drupal’s template system.

Out of the box, Zen is clean and simple with either a one, two, or three column layout of fixed or liquid width. In addition, the HTML source order has content placed before sidebars or the navbar for increased accessibility and SEO.

The name is an homage to the CSS Zen Garden site where designers can redesign the page purely through the use of CSS.

Farming

Drupal is already set up with the farm model in mind. in addition to the global settings, modules and themes in the codebase root, there is also a directory called sites which is used to add additional global or site specific settings, modules and themes. The sites directory contains a directory called "all" and any number of other directories named by domain or domain segment.

Our Settings

When setting up Organic Groups, a decision must be made about whether to create duplicate node types for posts and pages etc that are allowed to be posted into groups (it seems that the two options are mutually exclusive). Our plan for Organic Groups is for it to be our main ontology structure and so all content should be in a group. So for our purposes we can set all node types to be standard or wiki group posts.

See also