django/contrib/databrowse/sites.py

   1 from django import http
   2 from django.db import models
   3 from django.contrib.databrowse.datastructures import EasyModel, EasyChoice
   4 from django.shortcuts import render_to_response
   5 from django.utils.safestring import mark_safe
   6
   7 class AlreadyRegistered(Exception):
   8     pass
   9
  10 class NotRegistered(Exception):
  11     pass
  12
  13 class DatabrowsePlugin(object):
  14     def urls(self, plugin_name, easy_instance_field):
  15         """
  16         Given an EasyInstanceField object, returns a list of URLs for this
  17         plugin's views of this object. These URLs should be absolute.
  18
  19         Returns None if the EasyInstanceField object doesn't get a
  20         list of plugin-specific URLs.
  21         """
  22         return None
  23
  24     def model_index_html(self, request, model, site):
  25         """
  26         Returns a snippet of HTML to include on the model index page.
  27         """
  28         return ''
  29
  30     def model_view(self, request, model_databrowse, url):
  31         """
  32         Handles main URL routing for a plugin's model-specific pages.
  33         """
  34         raise NotImplementedError
  35
  36 class ModelDatabrowse(object):
  37     plugins = {}
  38
  39     def __init__(self, model, site):
  40         self.model = model
  41         self.site = site
  42
  43     def root(self, request, url):
  44         """
  45         Handles main URL routing for the databrowse app.
  46
  47         `url` is the remainder of the URL -- e.g. 'objects/3'.
  48         """
  49         # Delegate to the appropriate method, based on the URL.
  50         if url is None:
  51             return self.main_view(request)
  52         try:
  53             plugin_name, rest_of_url = url.split('/', 1)
  54         except ValueError: # need more than 1 value to unpack
  55             plugin_name, rest_of_url = url, None
  56         try:
  57             plugin = self.plugins[plugin_name]
  58         except KeyError:
  59             raise http.Http404('A plugin with the requested name does not exist.')
  60         return plugin.model_view(request, self, rest_of_url)
  61
  62     def main_view(self, request):
  63         easy_model = EasyModel(self.site, self.model)
  64         html_snippets = mark_safe(u'\n'.join([p.model_index_html(request, self.model, self.site) for p in self.plugins.values()]))
  65         return render_to_response('databrowse/model_detail.html', {
  66             'model': easy_model,
  67             'root_url': self.site.root_url,
  68             'plugin_html': html_snippets,
  69         })
  70
  71 class DatabrowseSite(object):
  72     def __init__(self):
  73         self.registry = {} # model_class -> databrowse_class
  74         self.root_url = None
  75
  76     def register(self, model_or_iterable, databrowse_class=None, **options):
  77         """
  78         Registers the given model(s) with the given databrowse site.
  79
  80         The model(s) should be Model classes, not instances.
  81
  82         If a databrowse class isn't given, it will use DefaultModelDatabrowse
  83         (the default databrowse options).
  84
  85         If a model is already registered, this will raise AlreadyRegistered.
  86         """
  87         databrowse_class = databrowse_class or DefaultModelDatabrowse
  88         if issubclass(model_or_iterable, models.Model):
  89             model_or_iterable = [model_or_iterable]
  90         for model in model_or_iterable:
  91             if model in self.registry:
  92                 raise AlreadyRegistered('The model %s is already registered' % model.__class__.__name__)
  93             self.registry[model] = databrowse_class
  94
  95     def unregister(self, model_or_iterable):
  96         """
  97         Unregisters the given model(s).
  98
  99         If a model isn't already registered, this will raise NotRegistered.
 100         """
 101         if issubclass(model_or_iterable, models.Model):
 102             model_or_iterable = [model_or_iterable]
 103         for model in model_or_iterable:
 104             if model not in self.registry:
 105                 raise NotRegistered('The model %s is not registered' % model.__class__.__name__)
 106             del self.registry[model]
 107
 108     def root(self, request, url):
 109         """
 110         Handles main URL routing for the databrowse app.
 111
 112         `url` is the remainder of the URL -- e.g. 'comments/comment/'.
 113         """
 114         self.root_url = request.path[:len(request.path) - len(url)]
 115         url = url.rstrip('/') # Trim trailing slash, if it exists.
 116
 117         if url == '':
 118             return self.index(request)
 119         elif '/' in url:
 120             return self.model_page(request, *url.split('/', 2))
 121
 122         raise http.Http404('The requested databrowse page does not exist.')
 123
 124     def index(self, request):
 125         m_list = [EasyModel(self, m) for m in self.registry.keys()]
 126         return render_to_response('databrowse/homepage.html', {'model_list': m_list, 'root_url': self.root_url})
 127
 128     def model_page(self, request, app_label, model_name, rest_of_url=None):
 129         """
 130         Handles the model-specific functionality of the databrowse site, delegating
 131         to the appropriate ModelDatabrowse class.
 132         """
 133         model = models.get_model(app_label, model_name)
 134         if model is None:
 135             raise http.Http404("App %r, model %r, not found." % (app_label, model_name))
 136         try:
 137             databrowse_class = self.registry[model]
 138         except KeyError:
 139             raise http.Http404("This model exists but has not been registered with databrowse.")
 140         return databrowse_class(model, self).root(request, rest_of_url)
 141
 142 site = DatabrowseSite()
 143
 144 from django.contrib.databrowse.plugins.calendars import CalendarPlugin
 145 from django.contrib.databrowse.plugins.objects import ObjectDetailPlugin
 146 from django.contrib.databrowse.plugins.fieldchoices import FieldChoicePlugin
 147
 148 class DefaultModelDatabrowse(ModelDatabrowse):
 149     plugins = {'objects': ObjectDetailPlugin(), 'calendars': CalendarPlugin(), 'fields': FieldChoicePlugin()}