64 lines
2.3 KiB
Python
64 lines
2.3 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
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from django.http import HttpResponse, Http404
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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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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 = {'mimetype': kwargs.pop('mimetype', None)}
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return HttpResponse(loader.render_to_string(*args, **kwargs), **httpresponse_kwargs)
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load_and_render = render_to_response # For backwards compatibility.
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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 AssertionError 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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