1 DEBIAN GFORGE PLUGINS HOWTO
2 --------------------------------
4 Here is a short HOWTO explaining how plugins work in Debian
5 GForge, and how to make a new one.
7 It was written by Roland Mas <lolando@debian.org>.
9 WHAT PLUGINS ARE, AND WHY THEY ARE USEFUL
10 -----------------------------------------
12 Plugins are extensions to the "core" of GForge, providing extra
13 functionality without being tightly integrated within Sourceforge
14 proper. They are useful because they allow for independent
15 development of third-party functionality, and they add flexibility to
16 Sourceforge as to what features are available on a particular
19 As an example, it's been suggested to integrate a shared calendar
20 application in Sourceforge. It's a good idea and an interesting
21 feature, but not one that everybody wants. Thus, including it in the
22 GForge code would piss off someone. Additionnally, there might
23 be several competing implementations for such a calnedar application.
24 Choosing one among them would also piss off people. So it is made
25 possible to have a system so that different implementations can exist
26 and be installed separately.
31 It is expected that a plugin is just some new feature added to
32 GForge, and not a change in the behaviour of existing features.
33 A plug-in should therefore only add files, not change existing ones.
34 Whether these files be web pages, offline scripts, static
35 documentation or else is not relevant.
37 Of course, *some* changes will have to be made to the "core" files,
38 if only to add links to new web pages, for instance. These changes
39 are acceptable, and will be discussed below. Here come the details
40 about how the plugin system is implemented.
42 - A plugin will be identified primarily by a string handle, which will
43 be static across all installations of this plugin. It should be
44 composed of lowercase letters only, because it's going to be used in
45 table names and we don't want namespace conflicts. For instance, if
46 the ACME company writes a time tracking tool plugin, the handle for
47 that plugin could be "acmetimetracker". When installed, the plugin
48 will be assigned an integer identifier. This id might vary from site
49 to site, and should not be depended upon.
51 We [the GForge-proper maintainers team] will maintain some sort
52 of list of allocated plugin names so that different plugins get
53 different allocated identifiers, see below.
55 - Tables in the database schema: special tables have been added to the
56 database schema to keep track of installed plugins. They are
57 described below (simplified descriptions):
59 | CREATE TABLE plugins (plugin_id integer,
60 | plugin_name character(32),
62 | CONSTRAINT plugins_pkey PRIMARY KEY (plugin_id)
64 | CREATE TABLE group_plugin (group_plugin_id integer,
67 | CONSTRAINT PRIMARY KEY (plugin_id),
68 | CONSTRAINT FOREIGN KEY (group_id) REFERENCES groups(group_id)
70 | CREATE TABLE user_plugin (user_plugin_id integer,
73 | CONSTRAINT PRIMARY KEY (plugin_id),
74 | CONSTRAINT FOREIGN KEY (user_id) REFERENCES users(user_id)
78 TODO: add plugins_persistence, group_plugin_persistence, user_plugin_persistence
80 "plugins" lists the installed plugins, with the numeric id, the
81 string handle (say, "acmetimetracker") and a description.
83 "group_plugin" is a way to store the fact that a group "uses" a
84 plugin without needing to add a "uses_acmetimetracker" to the groups
85 table for each known plugin.
87 "user_plugin" is the same, for users.
89 - A plugin may create its own tables in the same database. These
90 tables must be named plugin_foo_* if the plugin's string identifier is
91 "foo". One suggested table is plugin_foo_meta_data, which should be
92 used to store the plugin meta-data, such as the installed version.
93 The plugin can then use some code like db-upgrade.pl if its database
94 schema changes over time.
96 [TODO: Standardise the command/script/something below]
97 These tables may have foreign key referential integrity constraints
98 going from them to standard tables, but not the other way round. If
99 they have, then a command/script/something must be provided so that
100 the main db-upgrade.pl can disable the constraints and re-enable them
101 afterwards in case some database schema changes are needed.
103 Similarly, a plugin may create sequences, indexes, views, etc,
104 provided that their names are prefixed with plugin_foo_ too.
106 A plugin should not modify the data in tables that do not belong to
107 it. If it really needs to, then please discuss it with us first,
108 there might be cases where it's needed/useful. Reading those data is
109 okay, but it must be careful not to leak any info to places/users
110 which normally wouldn't have had access to it.
112 - Functions in Group.class.php and User.class.php: the Group and User classes
113 now have a usesPlugin() method. It takes a single parameter, the
114 "acmetimetracker" identifier for the module, and returns a boolean if
115 the particular user/group has turned on the use of that module. Also
116 provided are setPluginUsage() methods, taking a plugin name and a
117 boolean value as arguments and returning true on success and false on
120 - A plugin should not change the existing files. Of course, it will
121 need a way to adds links to its own web pages. This is done by a
122 "hook" system. Each plugin can hook itself up to a number of hook
123 points in the main code, and execute arbitrary code when that point is
124 reached. Basically, the plugin registers itself to a global object
125 (of the PluginManager class, if you want to know). You have to call
126 the register_plugin() function, providing it an object of a subclass
127 of the Plugin class that is provided by the main code. That object
128 must provide a GetHooks() method, which returns a list of hook names.
129 Whenever one of these hooks is encountered, the object's CallHook()
130 method is called with the hook name and extra parameters that depend
131 on the hook. Adding a link to your page in some place is just a
132 matter of "subscribing" yourself to the hook that is in the
133 appropriate place, and printing the appropriate link whenever your
134 CallHook() method is called from that place.
136 Registering your plugin is done by providing a
137 /usr/share/gforge/plugins/<pluginname>/include/<pluginname>-init.php.
138 It will be parsed by the PluginManager object. That file should
139 contain a call to register_plugin(), passing it an object of the
140 appropriate class. See the helloworld plugin for an example.
142 The hooks are managed centrally by the GForge code maintainers.
143 If you need one, please ask, we'll add it. The current list of
144 hooks is provided at the end of this document.
145 I rely on you plugins developers to provide more ideas :-)
147 - Plugin-specific web pages should reside either in the /plugin/*/
148 URL-space (that is, plugin "foo" will probably put its files in
149 /usr/share/gforge/www/plugins/foo/) or (if the web interface is not
150 written in PHP) in /plugin/*/cgi-bin/ URL-space (files in
151 /usr/lib/sourceforge/cgi-bin/plugins/foo/).
153 If possible, and as much as possible, a plugin should use the layout
154 functions defined by GForge (Layout.class.php, HTML.class.php, or
155 whatever they're called), to ensure a consistent look and themability.
157 Of course, the previous point only applies to plugins written in
158 PHP. Plugins written in other languages are not excluded by this
159 proposal, and there is no need to restrict them. Should they appear,
160 they might need to recode some of GForge's functions in Perl or
161 another language. I see no need to restrict that either. Only thing:
162 it would be better if the porting were as straightforward as possible.
163 Do not reimplement, please. Just translate from PHP to Perl or
164 whatever. If you do, please submit your translation to us, so that it
165 can be provided by GForge proper and maintained in common.
167 [TODO: Think about that, design, implement]
168 Speaking of languages... There should be some way to have
169 plugin-specific language files, so that the plugins can use the
170 standard methods used elsewhere in Sourceforge. I haven't thought
171 about that very deeply yet, but I think it will evolve into a
172 recommendation that the "handles" in the language files are
173 plugin_foo_page / item (as compared to the current page / item model
174 used for "core" GForge i18n strings).
176 - A plugin should register itself into the database using the provided
177 register-plugin script on its installation, and unregister itself
178 using unregister-plugin on removal. When unregistering, be careful
179 to delete all the rows in tables that contain a reference to your
180 plugin_id, so that the unregistration process (which deletes your row
181 in the plugins table) does not fail due to referential integrity errors.
183 HOW DO I MAKE A PLUGIN?
184 -----------------------
186 Your best bet would be to start with the sample "helloworld" plugin
187 and change parts of it. It shows an example of most of the things you
188 should need to make your plugin: PHP pages, configuration files, bits
189 of Apache configuration, cron jobs, etc. If you need something else,
190 please ask, we'll discuss it, (hopefully) reach an agreement on how to
191 Do It Right, and implement a sample in helloworld.
193 HOW TO NAME MY PLUGIN
194 ---------------------
196 If you plan on distributing your plugin to the public, please contact
197 the GForge maintainer with your proposed name, and we'll add it
198 to the list below. This ensures that no other plugin will use the
199 same name, so as to reduce the risk of name conflicts.
201 If you only intend to keep your plugin for yourself, you might still
202 contact us with your plugin name. If you're really nice, we might
203 consider adding it here too, so that other people who want to
204 distribute their plugin do not reuse the same name.
206 For reference, this is the list of currently used plugin names:
208 - helloworld, the plugin provided as an example.
209 - extldapauth, a plugin allowing on-the-fly account creation from an
210 existing LDAP directory;
212 CURRENT LIST OF PLUGIN HOOKS
213 ----------------------------
215 The following is a list of hooks available in GForge for plugins to utilise.
216 Each hook is listed with its name, locations in the source code where the
217 hook is called, and parameters that are passed into the hook and a brief
218 description. There may be other hooks available, added after this section
221 Hook Name : session_set_entry
222 Locations : common/include/session.php
223 Description: Called before checking if the user is logged in by
224 reading session cookie.
225 You can use this hook to handle session setup specific
228 Hook Name : session_set_return
229 Locations : common/include/session.php
230 Description: Called after checking if the user is logged in by reading
232 You can use this hook to handle session setup specific
235 Hook Name : artifact_extra_detail
236 Parameters : artifact_id - The ID of a tracker item
237 Locations : www/tracker/detail.php
238 www/tracker/mod-limited.php
240 Description: Use this hook to provide additional information about a
241 tracker item based upon its ID.
243 Hook Name : before_logout_redirect
244 Locations : www/account/logout.php
245 Description: Called once the GForge user has had their session logged
246 out, and before the user is redirected to the homepage of
250 Locations : www/include/Layout.class.php
251 Description: Used to include a CSS link element to include in the page
252 layout. The hook should return a complete <link> element.
255 Locations : www/include/Layout.class.php
256 Description: Used to include inline CSS into the page layout. The
257 hook should return pure CSS, without surrounding
260 Hook Name : group_approved
261 Parameters : group_id - The numeric ID of the group
262 Locations : www/admin/approve-pending.php
263 Description: When a group is approved by a site admin, this hook is called.
265 Hook Name : groupisactivecheckboxpost
266 Parameters : group_id - The numeric ID of the group
267 Locations : www/project/admin/index.php
268 Description: Called when a plugin is activated for a specific group from
269 the group's Edit Public Info page. Use this to perform
270 actions to initialise the plugin for a specific group.
272 Hook Name : groupisactivecheckbox
273 Parameters : group_id - The numeric ID of the group
274 Locations : www/project/admin/index.php
275 Description: Used to display a portion of a form on a group's Edit
276 Public Info page. It should return a HTML <tr> line containing
279 Hook Name : groupmenu
280 Parameters : DIRS - A reference to the array of tab URLs
281 TITLES - A reference to the array of tab titles
282 toptab - A reference to a string containing the name of
283 the GForge tab menu in use (eg. admin, tracker)
284 selected - A reference to an array index of the tabs.
285 group - The numeric ID of the current group
286 Locations : www/include/Layout.class.php
287 Description: Used to provide a plugin specific tab in when viewing
289 [TODO: The use of the 'group' name as a parameter is inconsistent
290 with most other group plugin hooks - which use group_id.]
292 Hook Name : groupmenu_scm
293 Parameters : DIRS - A reference to the array of tab URLs
294 TITLES - A reference to the array of tab titles
295 toptab - A reference to a string containing the name of
296 the GForge tab menu in use (eg. admin, tracker)
297 selected - A reference to an array index of the tabs.
298 group_id - The numeric ID of the current group
299 Locations : www/include/Layout.class.php
300 Description: Provides a tab for the SCM system in the group pages.
302 Hook Name : headermenu
303 Parameters : toptab - A reference to a string containing the name of
304 the GForge tab menu in use (eg. admin, tracker)
305 template - An HTML template giving how to add the menu.
306 Locations : www/include/Layout.class.php
307 Description: Used to provide a plugin specific menu entry in the header
308 top menu (after: Login, Logout, My Account).
309 See plugin online_help for example of use.
311 Hook Name : javascript
312 Locations : www/include/Layout.class.php
313 www/include/LayoutSF.class.php
314 Description: Provides a place to add inline Javascript into the page.
315 The output of the hook should be pure Javascript, as it will
316 be placed within an existing <script> block.
317 [TODO: The output of the hook appears after the closing SGML comment marker
318 and before the closing </script> element. Is this what is really indended?]
320 Hook Name : project_admin_plugins
321 Parameters : group_id - The numeric ID of the group
322 Locations : www/project/admin/index.php
323 Description: Provides a place for plugin authors to add a link on the
324 group summary page to the admin page for a plugin.
326 Hook Name : project_after_description
327 Parameters : group_id - The numeric ID of the group
328 Locations : www/include/project_home.php
329 Description: Provides some space for plugin specific text on a group's
332 Hook Name : project_public_area
333 Parameters : group_id - The numeric ID of the group
334 Locations : www/include/project_home.php
335 Description: Used to provide plugin specific infos on a group's
338 Hook Name : scm_admin_update
339 Parameters : group_id - The numeric ID of the group
340 Parameters : scmradio
341 A number of scm specific values generated from the
342 form fields created by the scm_admin_page hook.
343 Locations : www/scm/admin/index.php
344 Description: When the SCM admin page is submitted, this hook is called.
345 [TODO: Is scmradio actually used anywhere or is it legacy? A grep through
346 the source code seems to indicate its never used!]
348 Hook Name : scm_admin_page
349 Parameters : group_id - The numeric ID of the group
350 Locations : www/scm/admin/index.php
351 Description: Used to generate an administrative form for the SCM
352 plugin. All the form fields generated by this hook should
353 be named [pluginname]_[fieldname] where [pluginname] is the
354 SCM plugin name and [fieldname] is a field name for the
355 form element. Using this naming scheme ensures the fields
356 are properly passed as parameters to the scm_admin_update hook.
359 Parameters : group_id - The numeric ID of the group
360 Locations : www/scm/index.php
361 Description: Show a page for the SCM in use by a group.
363 Hook Name : scm_plugin
364 Parameters : scm_plugins - A reference to an array of plugins providing
365 SCM features. Each element is a plugin string name.
366 Locations : common/scm/SCMFactory.class.php
367 Description: This is used by GForge to identify SCM plugins. Any plugin that
368 provides SCM features should add itself to the scm_plugins array
369 when this hook is called.
371 Hook Name : scm_stats
372 Parameters : group_id - The numeric ID of the group
373 Locations : www/include/project_home.php
374 Description: Shows SCM specific statistics on the group's summary page.
376 Hook Name : search_engines
377 Locations : www/search/include/SearchManager.class.php
379 Hook Name : session_before_login
380 Parameters : loginname - The login as passed in from the user
381 passwd - The password as passed in from the user
382 Locations : common/include/session.php
383 Description: Authentication plugins can use this hook to authenticate
384 a user before GForge passes the authentication details on
385 to its own database. The hook should return true if the
386 authentication succeeds.
388 Hook Name : site_admin_option_hook
389 Locations : www/admin/index.php
390 Description: Use this to provide a link to the site wide administrative
391 pages for your plugin. The hook should return HTML within
392 a <li> block and will appear on the Site Admin page in the
395 Hook Name : site_admin_project_maintenance_hook
396 Locations : www/admin/index.php
397 Description: Use this to provide a link to the project maintenance pages
398 for your plugin. The hook should obey the plugin_hook_by_reference()
399 protocol and concatenate a <li> HTML block to params['result'] so
400 that it can appear in the "Plugins Project Maintenance" subsection
402 Hook Name : site_admin_user_maintenance_hook
403 Locations : www/admin/index.php
404 Description: Use this to provide a link to the user maintenance pages
405 for your plugin. The hook should obey the plugin_hook_by_reference()
406 protocol and concatenate a <li> HTML block to params['result'] so
407 that it can appear in the "Plugins User Maintenance" subsection
409 Hook Name : task_extra_detail
410 Parameters : task_id - The numeric ID for a task
411 Locations : www/pm/detail_task.php
413 Description: Provides a place to include extra information about a
414 task. The hook should return a <tr> row containing 2 cells
415 (or colspan'ed to 2).
418 Locations : www/include/html.php
419 Description: Prints out a tab to show when displaying user pages.
420 Unlike the groupmenu hook, this hook should use the PrintSubMenu
421 method to display the tab itself.
424 Locations : common/include/Role.class.php
425 Description: Provides a place to read role from another subsystem (LDAP, DB,
428 Hook Name : role_update
429 Locations : common/include/Role.class.php
430 Description: Triggered when new a role is updated
432 Hook Name : role_setuser
433 Locations : common/include/Role.class.php
434 Description: Provides a way to extend the way user information are stored
436 hook Name : outermenu
437 Parameters : DIRS - A reference to the array of tab URLs
438 TITLES - A reference to the array of tab titles
439 Location : www/include/Layout.class.php
440 Description: Used to provide a plugin specific tab in main menu.
442 Hook Name : project_public_area
443 Parameters : group_id - The numeric ID of the group
444 Locations : www/include/project_home.php
445 Description: Used to provide plugin specific infos on a group's
448 TODO : document user_logo (plugin_hook_by_reference) : returns in params['content']
450 TODO : document Auth plugins :
452 Hook Name : display_auth_form
453 Parameters : return_to
454 Locations : www/include/login-form.php
455 Description: returns a login dialog and/or a redirect URL :
456 it should return an HTML dialog appened to passed $params['html_snippets']
457 it may return a redirection URL appened to $params['transparent_redirect_urls']
459 -- Roland Mas <lolando@debian.org>