# mako/lookup.py
# Copyright 2006-2025 the Mako authors and contributors <see AUTHORS file>
#
# This module is part of Mako and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
import os
import posixpath
import re
import stat
import threading
from mako import exceptions
from mako import util
from mako.template import Template
class TemplateCollection:
"""Represent a collection of :class:`.Template` objects,
identifiable via URI.
A :class:`.TemplateCollection` is linked to the usage of
all template tags that address other templates, such
as ``<%include>``, ``<%namespace>``, and ``<%inherit>``.
The ``file`` attribute of each of those tags refers
to a string URI that is passed to that :class:`.Template`
object's :class:`.TemplateCollection` for resolution.
:class:`.TemplateCollection` is an abstract class,
with the usual default implementation being :class:`.TemplateLookup`.
"""
def has_template(self, uri):
"""Return ``True`` if this :class:`.TemplateLookup` is
capable of returning a :class:`.Template` object for the
given ``uri``.
:param uri: String URI of the template to be resolved.
"""
try:
self.get_template(uri)
return True
except exceptions.TemplateLookupException:
return False
def get_template(self, uri, relativeto=None):
"""Return a :class:`.Template` object corresponding to the given
``uri``.
The default implementation raises
:class:`.NotImplementedError`. Implementations should
raise :class:`.TemplateLookupException` if the given ``uri``
cannot be resolved.
:param uri: String URI of the template to be resolved.
:param relativeto: if present, the given ``uri`` is assumed to
be relative to this URI.
"""
raise NotImplementedError()
def filename_to_uri(self, uri, filename):
"""Convert the given ``filename`` to a URI relative to
this :class:`.TemplateCollection`."""
return uri
def adjust_uri(self, uri, filename):
"""Adjust the given ``uri`` based on the calling ``filename``.
When this method is called from the runtime, the
``filename`` parameter is taken directly to the ``filename``
attribute of the calling template. Therefore a custom
:class:`.TemplateCollection` subclass can place any string
identifier desired in the ``filename`` parameter of the
:class:`.Template` objects it constructs and have them come back
here.
"""
return uri
class TemplateLookup(TemplateCollection):
"""Represent a collection of templates that locates template source files
from the local filesystem.
The primary argument is the ``directories`` argument, the list of
directories to search:
.. sourcecode:: python
lookup = TemplateLookup(["/path/to/templates"])
some_template = lookup.get_template("/index.html")
The :class:`.TemplateLookup` can also be given :class:`.Template` objects
programatically using :meth:`.put_string` or :meth:`.put_template`:
.. sourcecode:: python
lookup = TemplateLookup()
lookup.put_string("base.html", '''
<html><body>${self.next()}</body></html>
''')
lookup.put_string("hello.html", '''
<%include file='base.html'/>
Hello, world !
''')
:param directories: A list of directory names which will be
searched for a particular template URI. The URI is appended
to each directory and the filesystem checked.
:param collection_size: Approximate size of the collection used
to store templates. If left at its default of ``-1``, the size
is unbounded, and a plain Python dictionary is used to
relate URI strings to :class:`.Template` instances.
Otherwise, a least-recently-used cache object is used which
will maintain the size of the collection approximately to
the number given.
:param filesystem_checks: When at its default value of ``True``,
each call to :meth:`.TemplateLookup.get_template()` will
compare the filesystem last modified time to the time in
which an existing :class:`.Template` object was created.
This allows the :class:`.TemplateLookup` to regenerate a
new :class:`.Template` whenever the original source has
been updated. Set this to ``False`` for a very minor
performance increase.
:param modulename_callable: A callable which, when present,
is passed the path of the source file as well as the
requested URI, and then returns the full path of the
generated Python module file. This is used to inject
alternate schemes for Python module location. If left at
its default of ``None``, the built in system of generation
based on ``module_directory`` plus ``uri`` is used.
All other keyword parameters available for
:class:`.Template` are mirrored here. When new
:class:`.Template` objects are created, the keywords
established with this :class:`.TemplateLookup` are passed on
to each new :class:`.Template`.
"""
def __init__(
self,
directories=None,
module_directory=None,
filesystem_checks=True,
collection_size=-1,
format_exceptions=False,
error_handler=None,
output_encoding=None,
encoding_errors="strict",
cache_args=None,
cache_impl="beaker",
cache_enabled=True,
cache_type=None,
cache_dir=None,
cache_url=None,
modulename_callable=None,
module_writer=None,
default_filters=None,
buffer_filters=(),
strict_undefined=False,
imports=None,
future_imports=None,
enable_loop=True,
input_encoding=None,
preprocessor=None,
lexer_cls=None,
include_error_handler=None,
):
self.directories = [
posixpath.normpath(d) for d in util.to_list(directories, ())
]
self.module_directory = module_directory
self.modulename_callable = modulename_callable
self.filesystem_checks = filesystem_checks
self.collection_size = collection_size
if cache_args is None:
cache_args = {}
# transfer deprecated cache_* args
if cache_dir:
cache_args.setdefault("dir", cache_dir)
if cache_url:
cache_args.setdefault("url", cache_url)
if cache_type:
cache_args.setdefault("type", cache_type)
self.template_args = {
"format_exceptions": format_exceptions,
"error_handler": error_handler,
"include_error_handler": include_error_handler,
"output_encoding": output_encoding,
"cache_impl": cache_impl,
"encoding_errors": encoding_errors,
"input_encoding": input_encoding,
"module_directory": module_directory,
"module_writer": module_writer,
"cache_args": cache_args,
"cache_enabled": cache_enabled,
"default_filters": default_filters,
"buffer_filters": buffer_filters,
"strict_undefined": strict_undefined,
"imports": imports,
"future_imports": future_imports,
"enable_loop": enable_loop,
"preprocessor": preprocessor,
"lexer_cls": lexer_cls,
}
if collection_size == -1:
self._collection = {}
self._uri_cache = {}
else:
self._collection = util.LRUCache(collection_size)
self._uri_cache = util.LRUCache(collection_size)
self._mutex = threading.Lock()
def get_template(self, uri):
"""Return a :class:`.Template` object corresponding to the given
``uri``.
.. note:: The ``relativeto`` argument is not supported here at
the moment.
"""
try:
if self.filesystem_checks:
return self._check(uri, self._collection[uri])
else:
return self._collection[uri]
except KeyError as e:
u = re.sub(r"^\/+", "", uri)
for dir_ in self.directories:
# make sure the path seperators are posix - os.altsep is empty
# on POSIX and cannot be used.
dir_ = dir_.replace(os.path.sep, posixpath.sep)
srcfile = posixpath.normpath(posixpath.join(dir_, u))
if os.path.isfile(srcfile):
return self._load(srcfile, uri)
else:
raise exceptions.TopLevelLookupException(
"Can't locate template for uri %r" % uri
) from e
def adjust_uri(self, uri, relativeto):
"""Adjust the given ``uri`` based on the given relative URI."""
key = (uri, relativeto)
if key in self._uri_cache:
return self._uri_cache[key]
if uri[0] == "/":
v = self._uri_cache[key] = uri
elif relativeto is not None:
v = self._uri_cache[key] = posixpath.join(
posixpath.dirname(relativeto), uri
)
else:
v = self._uri_cache[key] = "/" + uri
return v
def filename_to_uri(self, filename):
"""Convert the given ``filename`` to a URI relative to
this :class:`.TemplateCollection`."""
try:
return self._uri_cache[filename]
except KeyError:
value = self._relativeize(filename)
self._uri_cache[filename] = value
return value
def _relativeize(self, filename):
"""Return the portion of a filename that is 'relative'
to the directories in this lookup.
"""
filename = posixpath.normpath(filename)
for dir_ in self.directories:
if filename[0 : len(dir_)] == dir_:
return filename[len(dir_) :]
else:
return None
def _load(self, filename, uri):
self._mutex.acquire()
try:
try:
# try returning from collection one
# more time in case concurrent thread already loaded
return self._collection[uri]
except KeyError:
pass
try:
if self.modulename_callable is not None:
module_filename = self.modulename_callable(filename, uri)
else:
module_filename = None
self._collection[uri] = template = Template(
uri=uri,
filename=posixpath.normpath(filename),
lookup=self,
module_filename=module_filename,
**self.template_args,
)
return template
except:
# if compilation fails etc, ensure
# template is removed from collection,
# re-raise
self._collection.pop(uri, None)
raise
finally:
self._mutex.release()
def _check(self, uri, template):
if template.filename is None:
return template
try:
template_stat = os.stat(template.filename)
if template.module._modified_time >= template_stat[stat.ST_MTIME]:
return template
self._collection.pop(uri, None)
return self._load(template.filename, uri)
except OSError as e:
self._collection.pop(uri, None)
raise exceptions.TemplateLookupException(
"Can't locate template for uri %r" % uri
) from e
def put_string(self, uri, text):
"""Place a new :class:`.Template` object into this
:class:`.TemplateLookup`, based on the given string of
``text``.
"""
self._collection[uri] = Template(
text, lookup=self, uri=uri, **self.template_args
)
def put_template(self, uri, template):
"""Place a new :class:`.Template` object into this
:class:`.TemplateLookup`, based on the given
:class:`.Template` object.
"""
self._collection[uri] = template
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