# this is the abstract interface for Plugin instances # so it should be specialized in real plugin classes # like e.g. plugins.simplelist.SimpleList import json from django.template.loader import render_to_string from engine.prelude import Prelude #################### # set DEBUG to # . False : silent # . [ 'SliceList', 'TabbedView' ] : to debug these classes # . True : to debug all plugin #DEBUG= [ 'Tabs' ] DEBUG= False class Plugin: # using a simple incremental scheme to generate domids for now # we just need this to be unique in a page domid=0 @staticmethod def newdomid(): Plugin.domid += 1 return "plugin-%d"%Plugin.domid ########## # Constructor #### mandatory # . title: is used visually for displaying the widget #### optional # . togglable: whether it can be turned on and off (like PleKitToggle) # . toggled: if togglable, what's the initial status # . visible: if not set the plugin does not show up at all # (not quite sure what this was for) #### internal data # . domid: created internally, but can be set at creation time if needed # useful for hand-made css, or for selecting an active plugin in a composite # . rank: this is for plugins sons of a composite plugin #### custom # any other setting can also be set when creating the object, like # p=Plugin(foo='bar') # which will result in 'foo' being accessible to the template engine # def __init__ (self, title, domid=None, visible=True, togglable=True, toggled=True, **settings): # what is in this dictionary will get exposed to template and to javascript self._settings=settings self.title=title if not domid: domid=Plugin.newdomid() self.domid=domid self.classname=self._classname() self.add_to_settings ( ['title', 'domid', 'classname'] ) self.visible=visible self.togglable=togglable self.toggled=toggled self.add_to_settings( ['visible','togglable','toggled'] ) # we store as a dictionary the arguments passed to constructor # e.g. SimpleList (list=[1,2,3]) => _settings = { 'list':[1,2,3] } # our own settings are not made part of _settings but could be.. if self.need_debug(): print "Plugin.__init__ Created plugin with settings %s"%self._settings.keys() # subclasses might handle some fields in their own way, # in which case this call is needed to capture that setting # see e.g. SimpleList or SliceList for an example of that def add_to_settings (self, setting_name_s): if not isinstance (setting_name_s, list): self._settings[setting_name_s]=getattr(self,setting_name_s) else: for setting_name in setting_name_s: self._settings[setting_name]=getattr(self,setting_name) def _classname (self): try: return self.__class__.__name__ except: return 'Plugin' # shorthands to inspect _settings def get_setting (self, setting, default=None): if setting not in self._settings: return default else: return self._settings[setting] ########## def need_debug (self): if not DEBUG: return False if DEBUG is True: return True else: return self.classname in DEBUG # returns the html code for that plugin # in essence, wraps the results of self.render_content () def render (self, request): # initialize prelude placeholder if needed self._init_prelude (request) # call render_content plugin_content = self.render_content (request) # shove this into plugin.html env = {} env ['plugin_content']= plugin_content env.update(self._settings) result = render_to_string ('plugin.html',env) # expose _settings in json format to js, and add plugin_uuid: domid in the mix # NOTE this plugin_uuid thing might occur in js files, ** do not rename ** js_env = { 'plugin_uuid' : self.domid } js_env.update (self._settings) for k in self.exclude_from_json(): if k in js_env: del js_env[k] settings_json = json.dumps (js_env, separators=(',',':')) env ['settings_json' ] = settings_json # compute plugin-specific initialization js_init = render_to_string ( 'plugin-setenv.js', env ) self.add_js_chunks (request, js_init) # interpret the result of requirements () self.handle_requirements (request) return result # you may redefine this completely, but if you don't we'll just use methods # . template_file() to find out which template to use, and # . template_env() to compute a dictionary to pass along to the templating system def render_content (self, request): """Should return an HTML fragment""" template = self.template_file() env=self.template_env(request) if not isinstance (env,dict): raise Exception, "%s.template_env returns wrong type"%self.classname # expose this class's settings to the template # xxx we might need to check that this does not overwrite env.. env.update(self._settings) result=render_to_string (template, env) if self.need_debug(): print "%s.render_content: BEG --------------------"%self.classname print "template=%s"%template print "env.keys=%s"%env.keys() #print "env=%s"%env #print result print "%s.render_content: END --------------------"%self.classname return result #################### requirements/prelude management def _init_prelude (self, request): if not hasattr (request, 'plugin_prelude'): # include css/plugins.css request.plugin_prelude=Prelude(css_files='css/plugin.css') def inspect_request (self, request, message): has=hasattr(request,'plugin_prelude') get=getattr(request,'plugin_prelude','none-defined') print "INSPECT (%s), hasattr %s, getattr %s"%(message,has,get) # can be used directly in render_content() def add_js_files (self, request, files): self._init_prelude (request) request.plugin_prelude.add_js_files (files) def add_css_files (self, request, files): self._init_prelude (request) request.plugin_prelude.add_css_files (files) def add_js_chunks (self, request, chunks): self._init_prelude (request) request.plugin_prelude.add_js_chunks (chunks) def add_css_chunks (self, request, chunks): self._init_prelude (request) request.plugin_prelude.add_css_chunks (chunks) # or from the result of self.requirements() def handle_requirements (self, request): try: d=self.requirements() for (k,v) in d.iteritems(): if self.need_debug(): print "%s: handling requirement %s"%(self.classname,v) method_name='add_'+k method=Plugin.__dict__[method_name] method(self,request,v) except AttributeError: # most likely the object does not have that method defined, which is fine pass except: import traceback traceback.print_exc() pass ######################################## abstract interface # your plugin is expected to implement either # (*) def render_content(self, request) -> html fragment # -- or -- # (*) def template_file (self) -> filename # relative to STATIC # (*) def template_env (self, request) -> dict # this is the variable->value association used to render the template # in which case the html template will be used # if you see this string somewhere your template_file() code is not kicking in def template_file (self): return "undefined_template" def template_env (self, request): return {} # # tell the framework about requirements (for the document
) # # the notion of 'Media' in django provides for medium-dependant # # selection of css files # # as a first attempt however we keep a flat model for now # # can use one string instead of a list or tuple if needed, # # see requirements.py for details # def requirements (self): # return { 'js_files' : [], # a list of relative paths for js input files # 'css_files': [], # ditto for css, could have been a dict keyed on # # media instead # 'js_chunk' : [], # (lines of) verbatim javascript code # 'css_chunk': [], # likewise for css scripts # } # for better performance # you can specify a list of keys that won't be exposed as json attributes def exclude_from_json (self): return []