Baseclass for all loaders. Subclass this and override `get_source` to
implement a custom loading mechanism. The environment provides a
`get_template` method that calls the loader's `load` method to get the
:class:`Template` object.
A very basic example for a loader that looks up templates on the file
system could look like this::
from jinja2 import BaseLoader, TemplateNotFound
from os.path import join, exists, getmtime
class MyLoader(BaseLoader):
def __init__(self, path):
self.path = path
def get_source(self, environment, template):
path = join(self.path, template)
if not exists(path):
raise TemplateNotFound(template)
mtime = getmtime(path)
with file(path) as f:
source = f.read().decode('utf-8')
return source, path, lambda: mtime == getmtime(path)
def get_source |
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self, |
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environment, |
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template |
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Get the template source, filename and reload helper for a template.
It's passed the environment and template name and has to return a
tuple in the form ``(source, filename, uptodate)`` or raise a
`TemplateNotFound` error if it can't locate the template.
The source part of the returned tuple must be the source of the
template as unicode string or a ASCII bytestring. The filename should
be the name of the file on the filesystem if it was loaded from there,
otherwise `None`. The filename is used by python for the tracebacks
if no loader extension is used.
The last item in the tuple is the `uptodate` function. If auto
reloading is enabled it's always called to check if the template
changed. No arguments are passed so the function must store the
old state somewhere (for example in a closure). If it returns `False`
the template will be reloaded.
Reimplemented in ChoiceLoader, PrefixLoader, FunctionLoader, DictLoader, PackageLoader, and FileSystemLoader.