Edit File: lookup.py
# mako/lookup.py # Copyright 2006-2022 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