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131 lines
4.5 KiB
Python
131 lines
4.5 KiB
Python
"""
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This module collects helper functions and classes that "span" multiple levels
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of MVC. In other words, these functions/classes introduce controlled coupling
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for convenience's sake.
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"""
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from django.template import loader, RequestContext
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from django.http import HttpResponse, Http404
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from django.http import HttpResponseRedirect, HttpResponsePermanentRedirect
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from django.db.models.manager import Manager
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from django.db.models.query import QuerySet
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from django.core import urlresolvers
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def render_to_response(*args, **kwargs):
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"""
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Returns a HttpResponse whose content is filled with the result of calling
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django.template.loader.render_to_string() with the passed arguments.
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"""
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httpresponse_kwargs = {'content_type': kwargs.pop('mimetype', None)}
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return HttpResponse(loader.render_to_string(*args, **kwargs), **httpresponse_kwargs)
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def render(request, *args, **kwargs):
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"""
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Returns a HttpResponse whose content is filled with the result of calling
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django.template.loader.render_to_string() with the passed arguments.
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Uses a RequestContext by default.
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"""
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httpresponse_kwargs = {
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'content_type': kwargs.pop('content_type', None),
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'status': kwargs.pop('status', None),
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}
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if 'context_instance' in kwargs:
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context_instance = kwargs.pop('context_instance')
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if kwargs.get('current_app', None):
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raise ValueError('If you provide a context_instance you must '
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'set its current_app before calling render()')
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else:
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current_app = kwargs.pop('current_app', None)
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context_instance = RequestContext(request, current_app=current_app)
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kwargs['context_instance'] = context_instance
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return HttpResponse(loader.render_to_string(*args, **kwargs),
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**httpresponse_kwargs)
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def redirect(to, *args, **kwargs):
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"""
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Returns an HttpResponseRedirect to the apropriate URL for the arguments
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passed.
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The arguments could be:
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* A model: the model's `get_absolute_url()` function will be called.
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* A view name, possibly with arguments: `urlresolvers.reverse()` will
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be used to reverse-resolve the name.
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* A URL, which will be used as-is for the redirect location.
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By default issues a temporary redirect; pass permanent=True to issue a
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permanent redirect
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"""
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if kwargs.pop('permanent', False):
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redirect_class = HttpResponsePermanentRedirect
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else:
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redirect_class = HttpResponseRedirect
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# If it's a model, use get_absolute_url()
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if hasattr(to, 'get_absolute_url'):
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return redirect_class(to.get_absolute_url())
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# Next try a reverse URL resolution.
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try:
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return redirect_class(urlresolvers.reverse(to, args=args, kwargs=kwargs))
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except urlresolvers.NoReverseMatch:
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# If this is a callable, re-raise.
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if callable(to):
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raise
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# If this doesn't "feel" like a URL, re-raise.
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if '/' not in to and '.' not in to:
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raise
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# Finally, fall back and assume it's a URL
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return redirect_class(to)
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def _get_queryset(klass):
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"""
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Returns a QuerySet from a Model, Manager, or QuerySet. Created to make
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get_object_or_404 and get_list_or_404 more DRY.
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"""
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if isinstance(klass, QuerySet):
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return klass
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elif isinstance(klass, Manager):
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manager = klass
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else:
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manager = klass._default_manager
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return manager.all()
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def get_object_or_404(klass, *args, **kwargs):
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"""
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Uses get() to return an object, or raises a Http404 exception if the object
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does not exist.
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klass may be a Model, Manager, or QuerySet object. All other passed
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arguments and keyword arguments are used in the get() query.
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Note: Like with get(), an MultipleObjectsReturned will be raised if more than one
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object is found.
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"""
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queryset = _get_queryset(klass)
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try:
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return queryset.get(*args, **kwargs)
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except queryset.model.DoesNotExist:
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raise Http404('No %s matches the given query.' % queryset.model._meta.object_name)
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def get_list_or_404(klass, *args, **kwargs):
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"""
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Uses filter() to return a list of objects, or raise a Http404 exception if
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the list is empty.
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klass may be a Model, Manager, or QuerySet object. All other passed
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arguments and keyword arguments are used in the filter() query.
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"""
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queryset = _get_queryset(klass)
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obj_list = list(queryset.filter(*args, **kwargs))
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if not obj_list:
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raise Http404('No %s matches the given query.' % queryset.model._meta.object_name)
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return obj_list
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