Horde Framework Module

The Horde Framework modules, also known as Horde Libraries, are an integral part of the Horde Application Framework. These modules are managed separately in our CVS repository but are included with the Horde packages that can be downloaded from our FTP servers. The modules are general purpose libraries that are being used by several Horde applications or the framework itself, but can also be utilized outside the Framework in custom PHP solutions.

The different modules are developed, packaged, and distributed similarly to the PEAR packages. They will even be downloadable and installable with the PEAR installer in the future, using a PEAR channel server.

CVS management

All libraries are managed in the framework CVS module. Each library has its own subdirectory inside the framework module. The directory names are unfortunately a bit inconsistent and match not always the library name exactly. The Util/ directory for example contains the Horde_Util package.

The following quote from the PEAR manual explains the package name format:

One of the most important tasks while contributing a new package to PEAR is finding an appropriate name for your package.

The general syntax for package names is <Category>_<Name>. The value for <Category> should be chosen from a predefined list of categories that are available in PEAR (e.g. "HTTP", "Net", "HTML"). The second part is the name of the package (like "Upload", "Portscan", "Table").

Each package directory contains a package.xml file with package descriptions, file listings, dependencies, change logs etc. As all Horde Libraries are following the PEAR standard, they can be installed using the PEAR installer:

pear install framework/Util/package.xml

The framework CVS module contains two scripts, install-packages.php and install-packages.bat (for Windows), that can be used to install all packages at once in your local PEAR repository. This is necessary if you install the Horde Application Framework from CVS. See the installation manual for details.

There is a different script in the horde CVS module, scripts/create-symlinks.php, that can be used to install the libraries without using the PEAR installer. This is useful for developers who develop on the framework libraries and want to see their changes in real-time without having to re-install the affected package. This script is also used to distribute the libraries with the Horde packages. And that leads us to ...

Distribution management

To save administrators from installing all necessary libraries, the libraries come pre-installed with each officially released Horde package that is downloaded from our FTP server. They are installed inside Horde's lib/ directory (which is almost empty if you download Horde from CVS), using the same filesystem structure like a PEAR repository. How this is working is best explained with a few examples:

The VFS package has the following structure in CVS:

framework/VFS/

    package.xml

    VFS.php

    VFS/

        file.php

        ftp.php

...

and is installed like so in the PEAR repository or the lib/ directory, which is exactly the same:

lib/

    VFS.php

    VFS/

        file.php

        ftp.php

...

But this is different with the Horde_Tree package. In CVS:

framework/Tree/

    package.xml

    Tree.php

    Tree/

        javascript.php

        html.php

...

After installation:

lib/

    Horde/

        Tree.php

        Tree/

            javascript.php

            html.php

...

A rule of thumb is, that each underscore in a package name is translated to an additional directory after installation.

Using the libraries

If PHP has been set up properly, the local PEAR repository should be in PHP's include_path. If installing the Horde Libraries either separately with the PEAR installer or using install-packages.php, they are available alongside PEAR's packages, and can be included in your custom code the same way:

// Include PEAR's DB package.

require_once 'DB.php';

// Include PEAR's Text_Wiki package.

require_once 'Text/Wiki.php';

// Include Horde's VFS package.

require_once 'VFS.php';

// Include Horde's Horde_Tree package.

require_once 'Horde/Tree.php';

// Include Horde's Text_Flowed package.

require_once 'Text/Flowed.php';

Some magic is applied to Horde when creating distribution packages. This is necessary because the libraries distributed with a Horde release are not installed inside the PEAR repository, but the administrators still shouldn't need to change their PHP's include_path. This magic happens in horde/lib/core.php and looks like this:

ini_set('include_path', dirname(__FILE__) . PATH_SEPARATOR . ini_get('include_path'));

What this code does, is to prepend the existing include_path with the horde/lib/ directory. If for example the include_path is set to .:/usr/share/php in php.ini, it will become /path/to/horde/lib:.:/usr/share/php. This means that library files included with include, include_once, require, or require_once statements without specifying a full path, are first searched in Horde's lib/ directory, then in the local directory (.), and finally in the PEAR repository. The side effect is that libraries that come with Horde and have the same name like a PEAR package, e.g. File_CSV, are used in favour of the PEAR package.