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stbi/Lib/site-packages/django/shortcuts.py

+"""
+This module collects helper functions and classes that "span" multiple levels
+of MVC. In other words, these functions/classes introduce controlled coupling
+for convenience's sake.
+"""
+from django.http import (
+    Http404, HttpResponse, HttpResponsePermanentRedirect, HttpResponseRedirect,
+)
+from django.template import loader
+from django.urls import NoReverseMatch, reverse
+from django.utils.functional import Promise
+
+
+def render(request, template_name, context=None, content_type=None, status=None, using=None):
+    """
+    Return a HttpResponse whose content is filled with the result of calling
+    django.template.loader.render_to_string() with the passed arguments.
+    """
+    content = loader.render_to_string(template_name, context, request, using=using)
+    return HttpResponse(content, content_type, status)
+
+
+def redirect(to, *args, permanent=False, **kwargs):
+    """
+    Return an HttpResponseRedirect to the appropriate URL for the arguments
+    passed.
+
+    The arguments could be:
+
+        * A model: the model's `get_absolute_url()` function will be called.
+
+        * A view name, possibly with arguments: `urls.reverse()` will be used
+          to reverse-resolve the name.
+
+        * A URL, which will be used as-is for the redirect location.
+
+    Issues a temporary redirect by default; pass permanent=True to issue a
+    permanent redirect.
+    """
+    redirect_class = HttpResponsePermanentRedirect if permanent else HttpResponseRedirect
+    return redirect_class(resolve_url(to, *args, **kwargs))
+
+
+def _get_queryset(klass):
+    """
+    Return a QuerySet or a Manager.
+    Duck typing in action: any class with a `get()` method (for
+    get_object_or_404) or a `filter()` method (for get_list_or_404) might do
+    the job.
+    """
+    # If it is a model class or anything else with ._default_manager
+    if hasattr(klass, '_default_manager'):
+        return klass._default_manager.all()
+    return klass
+
+
+def get_object_or_404(klass, *args, **kwargs):
+    """
+    Use get() to return an object, or raise a Http404 exception if the object
+    does not exist.
+
+    klass may be a Model, Manager, or QuerySet object. All other passed
+    arguments and keyword arguments are used in the get() query.
+
+    Like with QuerySet.get(), MultipleObjectsReturned is raised if more than
+    one object is found.
+    """
+    queryset = _get_queryset(klass)
+    if not hasattr(queryset, 'get'):
+        klass__name = klass.__name__ if isinstance(klass, type) else klass.__class__.__name__
+        raise ValueError(
+            "First argument to get_object_or_404() must be a Model, Manager, "
+            "or QuerySet, not '%s'." % klass__name
+        )
+    try:
+        return queryset.get(*args, **kwargs)
+    except queryset.model.DoesNotExist:
+        raise Http404('No %s matches the given query.' % queryset.model._meta.object_name)
+
+
+def get_list_or_404(klass, *args, **kwargs):
+    """
+    Use filter() to return a list of objects, or raise a Http404 exception if
+    the list is empty.
+
+    klass may be a Model, Manager, or QuerySet object. All other passed
+    arguments and keyword arguments are used in the filter() query.
+    """
+    queryset = _get_queryset(klass)
+    if not hasattr(queryset, 'filter'):
+        klass__name = klass.__name__ if isinstance(klass, type) else klass.__class__.__name__
+        raise ValueError(
+            "First argument to get_list_or_404() must be a Model, Manager, or "
+            "QuerySet, not '%s'." % klass__name
+        )
+    obj_list = list(queryset.filter(*args, **kwargs))
+    if not obj_list:
+        raise Http404('No %s matches the given query.' % queryset.model._meta.object_name)
+    return obj_list
+
+
+def resolve_url(to, *args, **kwargs):
+    """
+    Return a URL appropriate for the arguments passed.
+
+    The arguments could be:
+
+        * A model: the model's `get_absolute_url()` function will be called.
+
+        * A view name, possibly with arguments: `urls.reverse()` will be used
+          to reverse-resolve the name.
+
+        * A URL, which will be returned as-is.
+    """
+    # If it's a model, use get_absolute_url()
+    if hasattr(to, 'get_absolute_url'):
+        return to.get_absolute_url()
+
+    if isinstance(to, Promise):
+        # Expand the lazy instance, as it can cause issues when it is passed
+        # further to some Python functions like urlparse.
+        to = str(to)
+
+    if isinstance(to, str):
+        # Handle relative URLs
+        if to.startswith(('./', '../')):
+            return to
+
+    # Next try a reverse URL resolution.
+    try:
+        return reverse(to, args=args, kwargs=kwargs)
+    except NoReverseMatch:
+        # If this is a callable, re-raise.
+        if callable(to):
+            raise
+        # If this doesn't "feel" like a URL, re-raise.
+        if '/' not in to and '.' not in to:
+            raise
+
+    # Finally, fall back and assume it's a URL
+    return to