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1 # -*- coding: utf-8 -*- | |
2 """ | |
3 jinja2.loaders | |
4 ~~~~~~~~~~~~~~ | |
5 | |
6 Jinja loader classes. | |
7 | |
8 :copyright: (c) 2010 by the Jinja Team. | |
9 :license: BSD, see LICENSE for more details. | |
10 """ | |
11 import os | |
12 import sys | |
13 import weakref | |
14 from types import ModuleType | |
15 from os import path | |
16 from hashlib import sha1 | |
17 from jinja2.exceptions import TemplateNotFound | |
18 from jinja2.utils import open_if_exists, internalcode | |
19 from jinja2._compat import string_types, iteritems | |
20 | |
21 | |
22 def split_template_path(template): | |
23 """Split a path into segments and perform a sanity check. If it detects | |
24 '..' in the path it will raise a `TemplateNotFound` error. | |
25 """ | |
26 pieces = [] | |
27 for piece in template.split('/'): | |
28 if path.sep in piece \ | |
29 or (path.altsep and path.altsep in piece) or \ | |
30 piece == path.pardir: | |
31 raise TemplateNotFound(template) | |
32 elif piece and piece != '.': | |
33 pieces.append(piece) | |
34 return pieces | |
35 | |
36 | |
37 class BaseLoader(object): | |
38 """Baseclass for all loaders. Subclass this and override `get_source` to | |
39 implement a custom loading mechanism. The environment provides a | |
40 `get_template` method that calls the loader's `load` method to get the | |
41 :class:`Template` object. | |
42 | |
43 A very basic example for a loader that looks up templates on the file | |
44 system could look like this:: | |
45 | |
46 from jinja2 import BaseLoader, TemplateNotFound | |
47 from os.path import join, exists, getmtime | |
48 | |
49 class MyLoader(BaseLoader): | |
50 | |
51 def __init__(self, path): | |
52 self.path = path | |
53 | |
54 def get_source(self, environment, template): | |
55 path = join(self.path, template) | |
56 if not exists(path): | |
57 raise TemplateNotFound(template) | |
58 mtime = getmtime(path) | |
59 with file(path) as f: | |
60 source = f.read().decode('utf-8') | |
61 return source, path, lambda: mtime == getmtime(path) | |
62 """ | |
63 | |
64 #: if set to `False` it indicates that the loader cannot provide access | |
65 #: to the source of templates. | |
66 #: | |
67 #: .. versionadded:: 2.4 | |
68 has_source_access = True | |
69 | |
70 def get_source(self, environment, template): | |
71 """Get the template source, filename and reload helper for a template. | |
72 It's passed the environment and template name and has to return a | |
73 tuple in the form ``(source, filename, uptodate)`` or raise a | |
74 `TemplateNotFound` error if it can't locate the template. | |
75 | |
76 The source part of the returned tuple must be the source of the | |
77 template as unicode string or a ASCII bytestring. The filename should | |
78 be the name of the file on the filesystem if it was loaded from there, | |
79 otherwise `None`. The filename is used by python for the tracebacks | |
80 if no loader extension is used. | |
81 | |
82 The last item in the tuple is the `uptodate` function. If auto | |
83 reloading is enabled it's always called to check if the template | |
84 changed. No arguments are passed so the function must store the | |
85 old state somewhere (for example in a closure). If it returns `False` | |
86 the template will be reloaded. | |
87 """ | |
88 if not self.has_source_access: | |
89 raise RuntimeError('%s cannot provide access to the source' % | |
90 self.__class__.__name__) | |
91 raise TemplateNotFound(template) | |
92 | |
93 def list_templates(self): | |
94 """Iterates over all templates. If the loader does not support that | |
95 it should raise a :exc:`TypeError` which is the default behavior. | |
96 """ | |
97 raise TypeError('this loader cannot iterate over all templates') | |
98 | |
99 @internalcode | |
100 def load(self, environment, name, globals=None): | |
101 """Loads a template. This method looks up the template in the cache | |
102 or loads one by calling :meth:`get_source`. Subclasses should not | |
103 override this method as loaders working on collections of other | |
104 loaders (such as :class:`PrefixLoader` or :class:`ChoiceLoader`) | |
105 will not call this method but `get_source` directly. | |
106 """ | |
107 code = None | |
108 if globals is None: | |
109 globals = {} | |
110 | |
111 # first we try to get the source for this template together | |
112 # with the filename and the uptodate function. | |
113 source, filename, uptodate = self.get_source(environment, name) | |
114 | |
115 # try to load the code from the bytecode cache if there is a | |
116 # bytecode cache configured. | |
117 bcc = environment.bytecode_cache | |
118 if bcc is not None: | |
119 bucket = bcc.get_bucket(environment, name, filename, source) | |
120 code = bucket.code | |
121 | |
122 # if we don't have code so far (not cached, no longer up to | |
123 # date) etc. we compile the template | |
124 if code is None: | |
125 code = environment.compile(source, name, filename) | |
126 | |
127 # if the bytecode cache is available and the bucket doesn't | |
128 # have a code so far, we give the bucket the new code and put | |
129 # it back to the bytecode cache. | |
130 if bcc is not None and bucket.code is None: | |
131 bucket.code = code | |
132 bcc.set_bucket(bucket) | |
133 | |
134 return environment.template_class.from_code(environment, code, | |
135 globals, uptodate) | |
136 | |
137 | |
138 class FileSystemLoader(BaseLoader): | |
139 """Loads templates from the file system. This loader can find templates | |
140 in folders on the file system and is the preferred way to load them. | |
141 | |
142 The loader takes the path to the templates as string, or if multiple | |
143 locations are wanted a list of them which is then looked up in the | |
144 given order: | |
145 | |
146 >>> loader = FileSystemLoader('/path/to/templates') | |
147 >>> loader = FileSystemLoader(['/path/to/templates', '/other/path']) | |
148 | |
149 Per default the template encoding is ``'utf-8'`` which can be changed | |
150 by setting the `encoding` parameter to something else. | |
151 """ | |
152 | |
153 def __init__(self, searchpath, encoding='utf-8'): | |
154 if isinstance(searchpath, string_types): | |
155 searchpath = [searchpath] | |
156 self.searchpath = list(searchpath) | |
157 self.encoding = encoding | |
158 | |
159 def get_source(self, environment, template): | |
160 pieces = split_template_path(template) | |
161 for searchpath in self.searchpath: | |
162 filename = path.join(searchpath, *pieces) | |
163 f = open_if_exists(filename) | |
164 if f is None: | |
165 continue | |
166 try: | |
167 contents = f.read().decode(self.encoding) | |
168 finally: | |
169 f.close() | |
170 | |
171 mtime = path.getmtime(filename) | |
172 def uptodate(): | |
173 try: | |
174 return path.getmtime(filename) == mtime | |
175 except OSError: | |
176 return False | |
177 return contents, filename, uptodate | |
178 raise TemplateNotFound(template) | |
179 | |
180 def list_templates(self): | |
181 found = set() | |
182 for searchpath in self.searchpath: | |
183 for dirpath, dirnames, filenames in os.walk(searchpath): | |
184 for filename in filenames: | |
185 template = os.path.join(dirpath, filename) \ | |
186 [len(searchpath):].strip(os.path.sep) \ | |
187 .replace(os.path.sep, '/') | |
188 if template[:2] == './': | |
189 template = template[2:] | |
190 if template not in found: | |
191 found.add(template) | |
192 return sorted(found) | |
193 | |
194 | |
195 class PackageLoader(BaseLoader): | |
196 """Load templates from python eggs or packages. It is constructed with | |
197 the name of the python package and the path to the templates in that | |
198 package:: | |
199 | |
200 loader = PackageLoader('mypackage', 'views') | |
201 | |
202 If the package path is not given, ``'templates'`` is assumed. | |
203 | |
204 Per default the template encoding is ``'utf-8'`` which can be changed | |
205 by setting the `encoding` parameter to something else. Due to the nature | |
206 of eggs it's only possible to reload templates if the package was loaded | |
207 from the file system and not a zip file. | |
208 """ | |
209 | |
210 def __init__(self, package_name, package_path='templates', | |
211 encoding='utf-8'): | |
212 from pkg_resources import DefaultProvider, ResourceManager, \ | |
213 get_provider | |
214 provider = get_provider(package_name) | |
215 self.encoding = encoding | |
216 self.manager = ResourceManager() | |
217 self.filesystem_bound = isinstance(provider, DefaultProvider) | |
218 self.provider = provider | |
219 self.package_path = package_path | |
220 | |
221 def get_source(self, environment, template): | |
222 pieces = split_template_path(template) | |
223 p = '/'.join((self.package_path,) + tuple(pieces)) | |
224 if not self.provider.has_resource(p): | |
225 raise TemplateNotFound(template) | |
226 | |
227 filename = uptodate = None | |
228 if self.filesystem_bound: | |
229 filename = self.provider.get_resource_filename(self.manager, p) | |
230 mtime = path.getmtime(filename) | |
231 def uptodate(): | |
232 try: | |
233 return path.getmtime(filename) == mtime | |
234 except OSError: | |
235 return False | |
236 | |
237 source = self.provider.get_resource_string(self.manager, p) | |
238 return source.decode(self.encoding), filename, uptodate | |
239 | |
240 def list_templates(self): | |
241 path = self.package_path | |
242 if path[:2] == './': | |
243 path = path[2:] | |
244 elif path == '.': | |
245 path = '' | |
246 offset = len(path) | |
247 results = [] | |
248 def _walk(path): | |
249 for filename in self.provider.resource_listdir(path): | |
250 fullname = path + '/' + filename | |
251 if self.provider.resource_isdir(fullname): | |
252 _walk(fullname) | |
253 else: | |
254 results.append(fullname[offset:].lstrip('/')) | |
255 _walk(path) | |
256 results.sort() | |
257 return results | |
258 | |
259 | |
260 class DictLoader(BaseLoader): | |
261 """Loads a template from a python dict. It's passed a dict of unicode | |
262 strings bound to template names. This loader is useful for unittesting: | |
263 | |
264 >>> loader = DictLoader({'index.html': 'source here'}) | |
265 | |
266 Because auto reloading is rarely useful this is disabled per default. | |
267 """ | |
268 | |
269 def __init__(self, mapping): | |
270 self.mapping = mapping | |
271 | |
272 def get_source(self, environment, template): | |
273 if template in self.mapping: | |
274 source = self.mapping[template] | |
275 return source, None, lambda: source == self.mapping.get(template) | |
276 raise TemplateNotFound(template) | |
277 | |
278 def list_templates(self): | |
279 return sorted(self.mapping) | |
280 | |
281 | |
282 class FunctionLoader(BaseLoader): | |
283 """A loader that is passed a function which does the loading. The | |
284 function becomes the name of the template passed and has to return either | |
285 an unicode string with the template source, a tuple in the form ``(source, | |
286 filename, uptodatefunc)`` or `None` if the template does not exist. | |
287 | |
288 >>> def load_template(name): | |
289 ... if name == 'index.html': | |
290 ... return '...' | |
291 ... | |
292 >>> loader = FunctionLoader(load_template) | |
293 | |
294 The `uptodatefunc` is a function that is called if autoreload is enabled | |
295 and has to return `True` if the template is still up to date. For more | |
296 details have a look at :meth:`BaseLoader.get_source` which has the same | |
297 return value. | |
298 """ | |
299 | |
300 def __init__(self, load_func): | |
301 self.load_func = load_func | |
302 | |
303 def get_source(self, environment, template): | |
304 rv = self.load_func(template) | |
305 if rv is None: | |
306 raise TemplateNotFound(template) | |
307 elif isinstance(rv, string_types): | |
308 return rv, None, None | |
309 return rv | |
310 | |
311 | |
312 class PrefixLoader(BaseLoader): | |
313 """A loader that is passed a dict of loaders where each loader is bound | |
314 to a prefix. The prefix is delimited from the template by a slash per | |
315 default, which can be changed by setting the `delimiter` argument to | |
316 something else:: | |
317 | |
318 loader = PrefixLoader({ | |
319 'app1': PackageLoader('mypackage.app1'), | |
320 'app2': PackageLoader('mypackage.app2') | |
321 }) | |
322 | |
323 By loading ``'app1/index.html'`` the file from the app1 package is loaded, | |
324 by loading ``'app2/index.html'`` the file from the second. | |
325 """ | |
326 | |
327 def __init__(self, mapping, delimiter='/'): | |
328 self.mapping = mapping | |
329 self.delimiter = delimiter | |
330 | |
331 def get_loader(self, template): | |
332 try: | |
333 prefix, name = template.split(self.delimiter, 1) | |
334 loader = self.mapping[prefix] | |
335 except (ValueError, KeyError): | |
336 raise TemplateNotFound(template) | |
337 return loader, name | |
338 | |
339 def get_source(self, environment, template): | |
340 loader, name = self.get_loader(template) | |
341 try: | |
342 return loader.get_source(environment, name) | |
343 except TemplateNotFound: | |
344 # re-raise the exception with the correct fileame here. | |
345 # (the one that includes the prefix) | |
346 raise TemplateNotFound(template) | |
347 | |
348 @internalcode | |
349 def load(self, environment, name, globals=None): | |
350 loader, local_name = self.get_loader(name) | |
351 try: | |
352 return loader.load(environment, local_name) | |
353 except TemplateNotFound: | |
354 # re-raise the exception with the correct fileame here. | |
355 # (the one that includes the prefix) | |
356 raise TemplateNotFound(name) | |
357 | |
358 def list_templates(self): | |
359 result = [] | |
360 for prefix, loader in iteritems(self.mapping): | |
361 for template in loader.list_templates(): | |
362 result.append(prefix + self.delimiter + template) | |
363 return result | |
364 | |
365 | |
366 class ChoiceLoader(BaseLoader): | |
367 """This loader works like the `PrefixLoader` just that no prefix is | |
368 specified. If a template could not be found by one loader the next one | |
369 is tried. | |
370 | |
371 >>> loader = ChoiceLoader([ | |
372 ... FileSystemLoader('/path/to/user/templates'), | |
373 ... FileSystemLoader('/path/to/system/templates') | |
374 ... ]) | |
375 | |
376 This is useful if you want to allow users to override builtin templates | |
377 from a different location. | |
378 """ | |
379 | |
380 def __init__(self, loaders): | |
381 self.loaders = loaders | |
382 | |
383 def get_source(self, environment, template): | |
384 for loader in self.loaders: | |
385 try: | |
386 return loader.get_source(environment, template) | |
387 except TemplateNotFound: | |
388 pass | |
389 raise TemplateNotFound(template) | |
390 | |
391 @internalcode | |
392 def load(self, environment, name, globals=None): | |
393 for loader in self.loaders: | |
394 try: | |
395 return loader.load(environment, name, globals) | |
396 except TemplateNotFound: | |
397 pass | |
398 raise TemplateNotFound(name) | |
399 | |
400 def list_templates(self): | |
401 found = set() | |
402 for loader in self.loaders: | |
403 found.update(loader.list_templates()) | |
404 return sorted(found) | |
405 | |
406 | |
407 class _TemplateModule(ModuleType): | |
408 """Like a normal module but with support for weak references""" | |
409 | |
410 | |
411 class ModuleLoader(BaseLoader): | |
412 """This loader loads templates from precompiled templates. | |
413 | |
414 Example usage: | |
415 | |
416 >>> loader = ChoiceLoader([ | |
417 ... ModuleLoader('/path/to/compiled/templates'), | |
418 ... FileSystemLoader('/path/to/templates') | |
419 ... ]) | |
420 | |
421 Templates can be precompiled with :meth:`Environment.compile_templates`. | |
422 """ | |
423 | |
424 has_source_access = False | |
425 | |
426 def __init__(self, path): | |
427 package_name = '_jinja2_module_templates_%x' % id(self) | |
428 | |
429 # create a fake module that looks for the templates in the | |
430 # path given. | |
431 mod = _TemplateModule(package_name) | |
432 if isinstance(path, string_types): | |
433 path = [path] | |
434 else: | |
435 path = list(path) | |
436 mod.__path__ = path | |
437 | |
438 sys.modules[package_name] = weakref.proxy(mod, | |
439 lambda x: sys.modules.pop(package_name, None)) | |
440 | |
441 # the only strong reference, the sys.modules entry is weak | |
442 # so that the garbage collector can remove it once the | |
443 # loader that created it goes out of business. | |
444 self.module = mod | |
445 self.package_name = package_name | |
446 | |
447 @staticmethod | |
448 def get_template_key(name): | |
449 return 'tmpl_' + sha1(name.encode('utf-8')).hexdigest() | |
450 | |
451 @staticmethod | |
452 def get_module_filename(name): | |
453 return ModuleLoader.get_template_key(name) + '.py' | |
454 | |
455 @internalcode | |
456 def load(self, environment, name, globals=None): | |
457 key = self.get_template_key(name) | |
458 module = '%s.%s' % (self.package_name, key) | |
459 mod = getattr(self.module, module, None) | |
460 if mod is None: | |
461 try: | |
462 mod = __import__(module, None, None, ['root']) | |
463 except ImportError: | |
464 raise TemplateNotFound(name) | |
465 | |
466 # remove the entry from sys.modules, we only want the attribute | |
467 # on the module object we have stored on the loader. | |
468 sys.modules.pop(module, None) | |
469 | |
470 return environment.template_class.from_module_dict( | |
471 environment, mod.__dict__, globals) | |
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