117 lines
4.8 KiB
Python
117 lines
4.8 KiB
Python
# Wrapper for loading templates from storage of some sort (e.g. filesystem, database).
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#
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# This uses the TEMPLATE_LOADERS setting, which is a list of loaders to use.
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# Each loader is expected to have this interface:
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#
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# callable(name, dirs=[])
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#
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# name is the template name.
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# dirs is an optional list of directories to search instead of TEMPLATE_DIRS.
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#
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# The loader should return a tuple of (template_source, path). The path returned
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# might be shown to the user for debugging purposes, so it should identify where
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# the template was loaded from.
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#
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# Each loader should have an "is_usable" attribute set. This is a boolean that
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# specifies whether the loader can be used in this Python installation. Each
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# loader is responsible for setting this when it's initialized.
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#
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# For example, the eggs loader (which is capable of loading templates from
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# Python eggs) sets is_usable to False if the "pkg_resources" module isn't
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# installed, because pkg_resources is necessary to read eggs.
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from django.core.exceptions import ImproperlyConfigured
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from django.core.template import Origin, StringOrigin, Template, Context, TemplateDoesNotExist, add_to_builtins
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from django.conf.settings import TEMPLATE_LOADERS, TEMPLATE_DEBUG
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template_source_loaders = None
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class LoaderOrigin(Origin):
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def __init__(self, display_name, loader, name, dirs):
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super(LoaderOrigin, self).__init__(display_name)
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self.loader, self.loadname, self.dirs = loader, name, dirs
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def reload(self):
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return self.loader(self.loadname, self.dirs)[0]
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def make_origin(display_name, loader, name, dirs):
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if TEMPLATE_DEBUG:
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return LoaderOrigin(display_name, loader, name, dirs)
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else:
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return None
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def find_template_source(name, dirs=None):
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# Calculate template_source_loaders the first time the function is executed
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# because putting this logic in the module-level namespace may cause
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# circular import errors. See Django ticket #1292.
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global template_source_loaders
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if template_source_loaders is None:
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template_source_loaders = []
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for path in TEMPLATE_LOADERS:
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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, globals(), locals(), [attr])
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except ImportError, e:
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raise ImproperlyConfigured, 'Error importing template source loader %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 template source loader' % (module, attr)
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if not func.is_usable:
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import warnings
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warnings.warn("Your TEMPLATE_LOADERS setting includes %r, but your Python installation doesn't support that type of template loading. Consider removing that line from TEMPLATE_LOADERS." % path)
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else:
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template_source_loaders.append(func)
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for loader in template_source_loaders:
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try:
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source, display_name = loader(name, dirs)
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return (source, make_origin(display_name, loader, name, dirs))
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except TemplateDoesNotExist:
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pass
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raise TemplateDoesNotExist, name
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def get_template(template_name):
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"""
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Returns a compiled Template object for the given template name,
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handling template inheritance recursively.
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"""
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return get_template_from_string(*find_template_source(template_name))
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def get_template_from_string(source, origin=None ):
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"""
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Returns a compiled Template object for the given template code,
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handling template inheritance recursively.
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"""
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return Template(source, origin)
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def render_to_string(template_name, dictionary=None, context_instance=None):
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"""
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Loads the given template_name and renders it with the given dictionary as
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context. The template_name may be a string to load a single template using
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get_template, or it may be a tuple to use select_template to find one of
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the templates in the list. Returns a string.
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"""
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dictionary = dictionary or {}
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if isinstance(template_name, (list, tuple)):
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t = select_template(template_name)
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else:
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t = get_template(template_name)
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if context_instance:
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context_instance.update(dictionary)
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else:
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context_instance = Context(dictionary)
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return t.render(context_instance)
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def select_template(template_name_list):
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"Given a list of template names, returns the first that can be loaded."
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for template_name in template_name_list:
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try:
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return get_template(template_name)
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except TemplateDoesNotExist:
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continue
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# If we get here, none of the templates could be loaded
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raise TemplateDoesNotExist, ', '.join(template_name_list)
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add_to_builtins('django.core.template.loader_tags')
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