Definitive list of all interfaces

[Alec Thomas]

With the number of new plugins implementing interfaces, it would be nice to be able to inspect what is available. This patch adds the list trac.core.InterfaceMeta._interfaces. I envisage an about/interfaces page similar to the existing about/plugins.

trac/core.py

@@ -30 +30 @@
         self.show_traceback = show_traceback
 
 
+class InterfaceMeta(type):
+    _interfaces = []
+
+    def __new__(cls, name, bases, d):
+        new_class = type.__new__(cls, name, bases, d)
+        if name != 'Interface':
+            InterfaceMeta._interfaces.append(new_class)
+        return new_class
+
+
 class Interface(object):
     """Marker base class for extension point interfaces."""
 
+    __metaclass__ = InterfaceMeta
 
+
 class ExtensionPoint(property):
     """Marker class for extension points in components."""
 

[Christopher Lenz]

An interface is useless as long as it isn't bound to an ExtensionPoint. That information, however, should already be available from the component registry (although retrieving it isn't trivial).

In fact, the extension points offered by components are already displayed on the about/plugins page, no?

[Alec Thomas]

Perhaps a better place to track this would be in the ExtensionPoint classes, as you say.

And yes, it is available in the about/plugins page, but scouring through that page to find interfaces is not that fun, and it doesn't contain any information about the interface methods.

Perhaps the information collected could be used to generate a list of available extension points at the end of that page. Remove the description of the interfaces that's already there, leaving the list for each plugin though.

I envisaged something like the following:

---

trac.wiki.api.IWikiChangeListener

Extension point interface for components that should get notified about the creation, deletion and modification of wiki pages.

Interface

wiki_page_added(page)

Called whenever a new Wiki page is added.

wiki_page_changed(page, version, t, comment, author, ipnr)

Called when a page has been modified.

wiki_page_deleted(page)

Called when a page has been deleted.

wiki_page_version_deleted(page)

Called when a version of a page has been deleted.

[Alec Thomas]

Add an section on interfaces to about/plugins

[Alec Thomas]

The attached patch is just a modification of about/plugins. It adds a second section below the plugin list (with appropriate anchor links from the plugins themselves) for interfaces. Each interface encountered is listed, along with full method listing and documentation. There are anchors for each interface and method.

eg. ​http://localhost/trac-dev/about/plugins#trac.env.IEnvironmentSetupParticipant.environment_needs_upgrade

Doesn't require any changes to trac.core, which is good :)

[Alec Thomas]

It does make the page quite huge though. I guess I could add an about/interfaces page, and link between the two?