[dev] General Linking/Relationship/Reference

[j.huinink at wanadoo.nl]

Hello List,

This is my attempt at implementing a general Linking/Relationship/Reference 
mechanism within Horde. I decided on a classname of Horde_Links. I tried to 
follow the coding standards and also stick to other conventions which I thought 
that are in place, but I'm sure I must have missed some.

This mechanism allows you to e.g. create links between tasks (follow-up) tasks, 
links from tasks to clients or attach a comic to a task, client or specific 
meeting. 

I tried to generalize the mechanism as much as possible. At the moment an 
application that wants to allow incoming links must supply certain API's:
- LinkParameters
- LinkDescription
- addLink

If an application wants to allow outgoing links it must create an instance of 
Horde_Links and call the proper function (viewLinks) somewhere in their "view".

The implementation of the Add and Delete routines for links is rather crude and 
I am sure that this could be implemented better(efficient, user-friendly, 
cleaner coded). I just added them so the principle would be visible.

To activate: apply the patch and unpack the attached zipfile.
Run the scripts/db/links.sql script to create the required database table add
the following to your conf.php file:
---
/**
 ** Links
 **/
// Valid values: 'none', 'sql'. If a value of 'none' is specifed then no
// links are used.
$conf['links']['driver'] = 'sql';
---

The only application with 'outgoing' links is nag. Both nag and klutz 
allow 'incoming' links. The nag configuration needs a link parameter to specify 
the allowed link_types. Mine looks like this:
---
$this->applications['nag'] = array(
    'fileroot' => dirname(__FILE__) . '/../nag',
    'webroot' => $this->applications['horde']['webroot'] . '/nag',
    'icon' => $this->applications['horde']['webroot'] . '/nag/graphics/nag.gif',
    'name' => _("Tasks"),
    'allow_guests' => false,
    'status' => 'active',
    'provides' => 'tasks',
    'links' => array(
        'follow-up-to' => array(
            'provider' => 'tasks',
            'description' => _("Follow up task"),
            'reverse' => array(
                'description'=> _("Previous task"),
                'type' => 'follow-up-from',
                'readonly' => true,
            ),
        ),
        'comic' => array(
            'provider' => 'comics',
            'description' => _("Funny note"),
        ),
    ),
);
---

I consider this a prototype, but fit for inclusion into HEAD, if you like the 
idea at all.  I'll hear your opinions and feedback.

Regards,
Jeroen


__________________________________________________________


http://www.wanadoo.nl/
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