X-Git-Url: https://vcs.fsf.org/?a=blobdiff_plain;f=docs%2Fsource%2Fpluginwriter%2Fapi.rst;h=29adb69141ef818c48840e7158c174d08dd2853b;hb=67d303ffa96a80da3a3cf48d2f9231bc1a087a19;hp=819fac2d7845e0568044d2b60a02fe9026ef098a;hpb=b21220e931e80fa9005f71c026eaa66f5ea225f4;p=mediagoblin.git diff --git a/docs/source/pluginwriter/api.rst b/docs/source/pluginwriter/api.rst index 819fac2d..29adb691 100644 --- a/docs/source/pluginwriter/api.rst +++ b/docs/source/pluginwriter/api.rst @@ -26,6 +26,26 @@ moving target for a few releases. Please check the :ref:`release-notes` for updates! + +How are hooks added? Where do I find them? +------------------------------------------- + +Much of this document talks about hooks, both as in terms of regular +hooks and template hooks. But where do they come from, and how can +you find a list of them? + +For the moment, the best way to find available hooks is to check the +source code itself. (Yes, we should start a more official hook +listing with descriptions soon.) But many hooks you may need do not +exist yet: what to do then? + +The plan at present is that we are adding hooks as people need them, +with community discussion. If you find that you need a hook and +MediaGoblin at present doesn't provide it at present, please +`http://mediagoblin.org/pages/join.html `_! We'll +evaluate what to do from there. + + :mod:`pluginapi` Module ----------------------- @@ -49,6 +69,32 @@ example might look like:: This means that when people enable your plugin in their config you'll be able to provide defaults as well as type validation. +You can access this via the app_config variables in mg_globals, or you +can use a shortcut to get your plugin's config section:: + + >>> from mediagoblin.tools import pluginapi + # Replace with the path to your plugin. + # (If an external package, it won't be part of mediagoblin.plugins) + >>> floobie_config = pluginapi.get_config('mediagoblin.plugins.floobifier') + >>> floobie_dir = floobie_config['floobie_dir'] + # This is the same as the above + >>> from mediagoblin import mg_globals + >>> config = mg_globals.global_config['plugins']['mediagoblin.plugins.floobifier'] + >>> floobie_dir = floobie_config['floobie_dir'] + +A tip: you have access to the `%(here)s` variable in your config, +which is the directory that the user's mediagoblin config is running +out of. So for example, your plugin may need a "floobie" directory to +store floobs in. You could give them a reasonable default that makes +use of the default `user_dev` location, but allow users to override +it, like so:: + + [plugin_spec] + floobie_dir = string(default="%(here)s/user_dev/floobs/") + +Note, this is relative to the user's mediagoblin config directory, +*not* your plugin directory! + Context Hooks ------------- @@ -173,3 +219,104 @@ object, so you can access this in your templates like: A funny bunny + + +Additional hook tips +-------------------- + +This section aims to explain some tips in regards to adding hooks to +the MediaGoblin repository. + +WTForms hooks ++++++++++++++ + +We haven't totally settled on a way to tranform wtforms form objects, +but here's one way. In your view:: + + from mediagoblin.foo.forms import SomeForm + + def some_view(request) + form_class = hook_transform('some_form_transform', SomeForm) + form = form_class(request.form) + +Then to hook into this form, do something in your plugin like:: + + import wtforms + + class SomeFormAdditions(wtforms.Form): + new_datefield = wtforms.DateField() + + def transform_some_form(orig_form): + class ModifiedForm(orig_form, SomeFormAdditions) + return ModifiedForm + + hooks = { + 'some_form_transform': transform_some_form} + + +Interfaces +++++++++++ + +If you want to add a pseudo-interface, it's not difficult to do so. +Just write the interface like so:: + + class FrobInterface(object): + """ + Interface for Frobbing. + + Classes implementing this interface should provide defrob and frob. + They may also implement double_frob, but it is not required; if + not provided, we will use a general technique. + """ + + def defrob(self, frobbed_obj): + """ + Take a frobbed_obj and defrob it. Returns the defrobbed object. + """ + raise NotImplementedError() + + def frob(self, normal_obj): + """ + Take a normal object and frob it. Returns the frobbed object. + """ + raise NotImplementedError() + + def double_frob(self, normal_obj): + """ + Frob this object and return it multiplied by two. + """ + return self.frob(normal_obj) * 2 + + + def some_frob_using_method(): + # something something something + frobber = hook_handle(FrobInterface) + frobber.frob(blah) + + # alternately you could have a default + frobber = hook_handle(FrobInterface) or DefaultFrobber + frobber.defrob(foo) + + +It's fine to use your interface as the key instead of a string if you +like. (Usually this is messy, but since interfaces are public and +since you need to import them into your plugin anyway, interfaces +might as well be keys.) + +Then a plugin providing your interface can be like:: + + from mediagoblin.foo.frobfrogs import FrobInterface + from frogfrobber import utils + + class FrogFrobber(FrobInterface): + """ + Takes a frogputer science approach to frobbing. + """ + def defrob(self, frobbed_obj): + return utils.frog_defrob(frobbed_obj) + + def frob(self, normal_obj): + return utils.frog_frob(normal_obj) + + hooks = { + FrobInterface: lambda: return FrogFrobber}