# mako/lookup.py # Copyright (C) 2006-2011 the Mako authors and contributors # # This module is part of Mako and is released under # the MIT License: http://www.opensource.org/licenses/mit-license.php import os, stat, posixpath, re from mako import exceptions, util from mako.template import Template try: import threading except: import dummy_threading as threading class TemplateCollection(object): """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 URL. :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 URL. 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 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 TemplateCollection subclass can place any string identifier desired in the "filename" parameter of the 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:: 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`:: lookup = TemplateLookup() lookup.put_string("base.html", ''' ${self.next()} ''') 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 Pyhton 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, disable_unicode=False, bytestring_passthrough=False, output_encoding=None, encoding_errors='strict', cache_type=None, cache_dir=None, cache_url=None, cache_enabled=True, modulename_callable=None, default_filters=None, buffer_filters=(), strict_undefined=False, imports=None, input_encoding=None, preprocessor=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 self.template_args = { 'format_exceptions':format_exceptions, 'error_handler':error_handler, 'disable_unicode':disable_unicode, 'bytestring_passthrough':bytestring_passthrough, 'output_encoding':output_encoding, 'encoding_errors':encoding_errors, 'input_encoding':input_encoding, 'module_directory':module_directory, 'cache_type':cache_type, 'cache_dir':cache_dir or module_directory, 'cache_url':cache_url, 'cache_enabled':cache_enabled, 'default_filters':default_filters, 'buffer_filters':buffer_filters, 'strict_undefined':strict_undefined, 'imports':imports, 'preprocessor':preprocessor} 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 URL. 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: u = re.sub(r'^\/+', '', uri) for dir in self.directories: srcfile = posixpath.normpath(posixpath.join(dir, u)) if os.path.isfile(srcfile): return self._load(srcfile, uri) else: raise exceptions.TopLevelLookupException( "Cant locate template for uri %r" % uri) 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] != '/': if relativeto is not None: v = self._uri_cache[key] = posixpath.join(posixpath.dirname(relativeto), uri) else: v = self._uri_cache[key] = '/' + 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 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]: self._collection.pop(uri, None) return self._load(template.filename, uri) else: return template except OSError: self._collection.pop(uri, None) raise exceptions.TemplateLookupException( "Cant locate template for uri %r" % uri) 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