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439cb4047f
improvement and forward-compatible with future Python releases. Patch from Gary Wilson. git-svn-id: http://code.djangoproject.com/svn/django/trunk@5091 bcc190cf-cafb-0310-a4f2-bffc1f526a37
101 lines
3.2 KiB
Python
101 lines
3.2 KiB
Python
from django.conf import settings
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from django.core.exceptions import ImproperlyConfigured
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_standard_context_processors = None
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class ContextPopException(Exception):
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"pop() has been called more times than push()"
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pass
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class Context(object):
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"A stack container for variable context"
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def __init__(self, dict_=None):
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dict_ = dict_ or {}
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self.dicts = [dict_]
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def __repr__(self):
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return repr(self.dicts)
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def __iter__(self):
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for d in self.dicts:
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yield d
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def push(self):
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self.dicts = [{}] + self.dicts
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def pop(self):
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if len(self.dicts) == 1:
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raise ContextPopException
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del self.dicts[0]
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def __setitem__(self, key, value):
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"Set a variable in the current context"
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self.dicts[0][key] = value
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def __getitem__(self, key):
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"Get a variable's value, starting at the current context and going upward"
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for d in self.dicts:
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if key in d:
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return d[key]
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raise KeyError(key)
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def __delitem__(self, key):
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"Delete a variable from the current context"
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del self.dicts[0][key]
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def has_key(self, key):
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for d in self.dicts:
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if key in d:
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return True
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return False
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def __contains__(self, key):
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return self.has_key(key)
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def get(self, key, otherwise=None):
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for d in self.dicts:
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if key in d:
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return d[key]
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return otherwise
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def update(self, other_dict):
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"Like dict.update(). Pushes an entire dictionary's keys and values onto the context."
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self.dicts = [other_dict] + self.dicts
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# This is a function rather than module-level procedural code because we only
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# want it to execute if somebody uses RequestContext.
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def get_standard_processors():
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global _standard_context_processors
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if _standard_context_processors is None:
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processors = []
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for path in settings.TEMPLATE_CONTEXT_PROCESSORS:
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i = path.rfind('.')
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module, attr = path[:i], path[i+1:]
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try:
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mod = __import__(module, {}, {}, [attr])
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except ImportError, e:
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raise ImproperlyConfigured, 'Error importing request processor module %s: "%s"' % (module, e)
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try:
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func = getattr(mod, attr)
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except AttributeError:
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raise ImproperlyConfigured, 'Module "%s" does not define a "%s" callable request processor' % (module, attr)
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processors.append(func)
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_standard_context_processors = tuple(processors)
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return _standard_context_processors
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class RequestContext(Context):
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"""
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This subclass of template.Context automatically populates itself using
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the processors defined in TEMPLATE_CONTEXT_PROCESSORS.
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Additional processors can be specified as a list of callables
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using the "processors" keyword argument.
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"""
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def __init__(self, request, dict=None, processors=None):
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Context.__init__(self, dict)
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if processors is None:
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processors = ()
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else:
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processors = tuple(processors)
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for processor in get_standard_processors() + processors:
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self.update(processor(request))
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