/
web.py
1591 lines (1362 loc) · 60.5 KB
/
web.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
#!/usr/bin/env python
#
# Copyright 2009 Facebook
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
"""The Tornado web framework.
The Tornado web framework looks a bit like web.py (http://webpy.org/) or
Google's webapp (http://code.google.com/appengine/docs/python/tools/webapp/),
but with additional tools and optimizations to take advantage of the
Tornado non-blocking web server and tools.
Here is the canonical "Hello, world" example app:
import tornado.ioloop
import tornado.web
class MainHandler(tornado.web.RequestHandler):
def get(self):
self.write("Hello, world")
if __name__ == "__main__":
application = tornado.web.Application([
(r"/", MainHandler),
])
application.listen(8888)
tornado.ioloop.IOLoop.instance().start()
See the Tornado walkthrough on http://tornadoweb.org for more details
and a good getting started guide.
"""
from __future__ import with_statement
import Cookie
import base64
import binascii
import cStringIO
import calendar
import contextlib
import datetime
import email.utils
import functools
import gzip
import hashlib
import hmac
import httplib
import logging
import mimetypes
import os.path
import re
import stat
import sys
import time
import tornado
import types
import urllib
import urlparse
import uuid
from tornado import escape
from tornado import locale
from tornado import stack_context
from tornado import template
class RequestHandler(object):
"""Subclass this class and define get() or post() to make a handler.
If you want to support more methods than the standard GET/HEAD/POST, you
should override the class variable SUPPORTED_METHODS in your
RequestHandler class.
"""
SUPPORTED_METHODS = ("GET", "HEAD", "POST", "DELETE", "PUT", "OPTIONS")
def __init__(self, application, request, **kwargs):
self.application = application
self.request = request
self._headers_written = False
self._finished = False
self._auto_finish = True
self._transforms = None # will be set in _execute
self.ui = _O((n, self._ui_method(m)) for n, m in
application.ui_methods.iteritems())
self.ui["modules"] = _O((n, self._ui_module(n, m)) for n, m in
application.ui_modules.iteritems())
self.clear()
# Check since connection is not available in WSGI
if hasattr(self.request, "connection"):
self.request.connection.stream.set_close_callback(
self.on_connection_close)
self.initialize(**kwargs)
def initialize(self):
"""Hook for subclass initialization.
A dictionary passed as the third argument of a url spec will be
supplied as keyword arguments to initialize().
Example:
class ProfileHandler(RequestHandler):
def initialize(self, database):
self.database = database
def get(self, username):
...
app = Application([
(r'/user/(.*)', ProfileHandler, dict(database=database)),
])
"""
pass
@property
def settings(self):
return self.application.settings
def head(self, *args, **kwargs):
raise HTTPError(405)
def get(self, *args, **kwargs):
raise HTTPError(405)
def post(self, *args, **kwargs):
raise HTTPError(405)
def delete(self, *args, **kwargs):
raise HTTPError(405)
def put(self, *args, **kwargs):
raise HTTPError(405)
def options(self, *args, **kwargs):
raise HTTPError(405)
def prepare(self):
"""Called before the actual handler method.
Useful to override in a handler if you want a common bottleneck for
all of your requests.
"""
pass
def on_connection_close(self):
"""Called in async handlers if the client closed the connection.
You may override this to clean up resources associated with
long-lived connections.
Proxies may keep a connection open for a time (perhaps
indefinitely) after the client has gone away, so this method
may not be called promptly after the end user closes their
connection.
"""
pass
def clear(self):
"""Resets all headers and content for this response."""
self._headers = {
"Server": "TornadoServer/%s" % tornado.version,
"Content-Type": "text/html; charset=UTF-8",
}
if not self.request.supports_http_1_1():
if self.request.headers.get("Connection") == "Keep-Alive":
self.set_header("Connection", "Keep-Alive")
self._write_buffer = []
self._status_code = 200
def set_status(self, status_code):
"""Sets the status code for our response."""
assert status_code in httplib.responses
self._status_code = status_code
def set_header(self, name, value):
"""Sets the given response header name and value.
If a datetime is given, we automatically format it according to the
HTTP specification. If the value is not a string, we convert it to
a string. All header values are then encoded as UTF-8.
"""
if isinstance(value, datetime.datetime):
t = calendar.timegm(value.utctimetuple())
value = email.utils.formatdate(t, localtime=False, usegmt=True)
elif isinstance(value, int) or isinstance(value, long):
value = str(value)
else:
value = _utf8(value)
# If \n is allowed into the header, it is possible to inject
# additional headers or split the request. Also cap length to
# prevent obviously erroneous values.
safe_value = re.sub(r"[\x00-\x1f]", " ", value)[:4000]
if safe_value != value:
raise ValueError("Unsafe header value %r", value)
self._headers[name] = value
_ARG_DEFAULT = []
def get_argument(self, name, default=_ARG_DEFAULT, strip=True):
"""Returns the value of the argument with the given name.
If default is not provided, the argument is considered to be
required, and we throw an HTTP 404 exception if it is missing.
If the argument appears in the url more than once, we return the
last value.
The returned value is always unicode.
"""
args = self.get_arguments(name, strip=strip)
if not args:
if default is self._ARG_DEFAULT:
raise HTTPError(404, "Missing argument %s" % name)
return default
return args[-1]
def get_arguments(self, name, strip=True):
"""Returns a list of the arguments with the given name.
If the argument is not present, returns an empty list.
The returned values are always unicode.
"""
values = self.request.arguments.get(name, [])
# Get rid of any weird control chars
values = [re.sub(r"[\x00-\x08\x0e-\x1f]", " ", x) for x in values]
values = [_unicode(x) for x in values]
if strip:
values = [x.strip() for x in values]
return values
@property
def cookies(self):
"""A dictionary of Cookie.Morsel objects."""
if not hasattr(self, "_cookies"):
self._cookies = Cookie.BaseCookie()
if "Cookie" in self.request.headers:
try:
self._cookies.load(self.request.headers["Cookie"])
except:
self.clear_all_cookies()
return self._cookies
def get_cookie(self, name, default=None):
"""Gets the value of the cookie with the given name, else default."""
if name in self.cookies:
return self.cookies[name].value
return default
def set_cookie(self, name, value, domain=None, expires=None, path="/",
expires_days=None, **kwargs):
"""Sets the given cookie name/value with the given options.
Additional keyword arguments are set on the Cookie.Morsel
directly.
See http://docs.python.org/library/cookie.html#morsel-objects
for available attributes.
"""
name = _utf8(name)
value = _utf8(value)
if re.search(r"[\x00-\x20]", name + value):
# Don't let us accidentally inject bad stuff
raise ValueError("Invalid cookie %r: %r" % (name, value))
if not hasattr(self, "_new_cookies"):
self._new_cookies = []
new_cookie = Cookie.BaseCookie()
self._new_cookies.append(new_cookie)
new_cookie[name] = value
if domain:
new_cookie[name]["domain"] = domain
if expires_days is not None and not expires:
expires = datetime.datetime.utcnow() + datetime.timedelta(
days=expires_days)
if expires:
timestamp = calendar.timegm(expires.utctimetuple())
new_cookie[name]["expires"] = email.utils.formatdate(
timestamp, localtime=False, usegmt=True)
if path:
new_cookie[name]["path"] = path
for k, v in kwargs.iteritems():
new_cookie[name][k] = v
def clear_cookie(self, name, path="/", domain=None):
"""Deletes the cookie with the given name."""
expires = datetime.datetime.utcnow() - datetime.timedelta(days=365)
self.set_cookie(name, value="", path=path, expires=expires,
domain=domain)
def clear_all_cookies(self):
"""Deletes all the cookies the user sent with this request."""
for name in self.cookies.iterkeys():
self.clear_cookie(name)
def set_secure_cookie(self, name, value, expires_days=30, **kwargs):
"""Signs and timestamps a cookie so it cannot be forged.
You must specify the 'cookie_secret' setting in your Application
to use this method. It should be a long, random sequence of bytes
to be used as the HMAC secret for the signature.
To read a cookie set with this method, use get_secure_cookie().
"""
self.set_cookie(name, self.create_signed_value(name, value),
expires_days=expires_days, **kwargs)
def create_signed_value(self, name, value):
"""Signs and timestamps a string so it cannot be forged.
Normally used via set_secure_cookie, but provided as a separate
method for non-cookie uses. To decode a value not stored
as a cookie use the optional value argument to get_secure_cookie.
"""
timestamp = str(int(time.time()))
value = base64.b64encode(value)
signature = self._cookie_signature(name, value, timestamp)
value = "|".join([value, timestamp, signature])
return value
def get_secure_cookie(self, name, include_name=True, value=None):
"""Returns the given signed cookie if it validates, or None.
In older versions of Tornado (0.1 and 0.2), we did not include the
name of the cookie in the cookie signature. To read these old-style
cookies, pass include_name=False to this method. Otherwise, all
attempts to read old-style cookies will fail (and you may log all
your users out whose cookies were written with a previous Tornado
version).
"""
if value is None: value = self.get_cookie(name)
if not value: return None
parts = value.split("|")
if len(parts) != 3: return None
if include_name:
signature = self._cookie_signature(name, parts[0], parts[1])
else:
signature = self._cookie_signature(parts[0], parts[1])
if not _time_independent_equals(parts[2], signature):
logging.warning("Invalid cookie signature %r", value)
return None
timestamp = int(parts[1])
if timestamp < time.time() - 31 * 86400:
logging.warning("Expired cookie %r", value)
return None
if timestamp > time.time() + 31 * 86400:
# _cookie_signature does not hash a delimiter between the
# parts of the cookie, so an attacker could transfer trailing
# digits from the payload to the timestamp without altering the
# signature. For backwards compatibility, sanity-check timestamp
# here instead of modifying _cookie_signature.
logging.warning("Cookie timestamp in future; possible tampering %r", value)
return None
if parts[1].startswith("0"):
logging.warning("Tampered cookie %r", value)
try:
return base64.b64decode(parts[0])
except:
return None
def _cookie_signature(self, *parts):
self.require_setting("cookie_secret", "secure cookies")
hash = hmac.new(self.application.settings["cookie_secret"],
digestmod=hashlib.sha1)
for part in parts: hash.update(part)
return hash.hexdigest()
def redirect(self, url, permanent=False):
"""Sends a redirect to the given (optionally relative) URL."""
if self._headers_written:
raise Exception("Cannot redirect after headers have been written")
self.set_status(301 if permanent else 302)
# Remove whitespace
url = re.sub(r"[\x00-\x20]+", "", _utf8(url))
self.set_header("Location", urlparse.urljoin(self.request.uri, url))
self.finish()
def write(self, chunk):
"""Writes the given chunk to the output buffer.
To write the output to the network, use the flush() method below.
If the given chunk is a dictionary, we write it as JSON and set
the Content-Type of the response to be text/javascript.
Note that lists are not converted to JSON because of a potential
cross-site security vulnerability. All JSON output should be
wrapped in a dictionary. More details at
http://haacked.com/archive/2008/11/20/anatomy-of-a-subtle-json-vulnerability.aspx
"""
assert not self._finished
if isinstance(chunk, dict):
chunk = escape.json_encode(chunk)
self.set_header("Content-Type", "text/javascript; charset=UTF-8")
chunk = _utf8(chunk)
self._write_buffer.append(chunk)
def render(self, template_name, **kwargs):
"""Renders the template with the given arguments as the response."""
html = self.render_string(template_name, **kwargs)
# Insert the additional JS and CSS added by the modules on the page
js_embed = []
js_files = []
css_embed = []
css_files = []
html_heads = []
html_bodies = []
for module in getattr(self, "_active_modules", {}).itervalues():
embed_part = module.embedded_javascript()
if embed_part: js_embed.append(_utf8(embed_part))
file_part = module.javascript_files()
if file_part:
if isinstance(file_part, basestring):
js_files.append(file_part)
else:
js_files.extend(file_part)
embed_part = module.embedded_css()
if embed_part: css_embed.append(_utf8(embed_part))
file_part = module.css_files()
if file_part:
if isinstance(file_part, basestring):
css_files.append(file_part)
else:
css_files.extend(file_part)
head_part = module.html_head()
if head_part: html_heads.append(_utf8(head_part))
body_part = module.html_body()
if body_part: html_bodies.append(_utf8(body_part))
if js_files:
# Maintain order of JavaScript files given by modules
paths = []
unique_paths = set()
for path in js_files:
if not path.startswith("/") and not path.startswith("http:"):
path = self.static_url(path)
if path not in unique_paths:
paths.append(path)
unique_paths.add(path)
js = ''.join('<script src="' + escape.xhtml_escape(p) +
'" type="text/javascript"></script>'
for p in paths)
sloc = html.rindex('</body>')
html = html[:sloc] + js + '\n' + html[sloc:]
if js_embed:
js = '<script type="text/javascript">\n//<![CDATA[\n' + \
'\n'.join(js_embed) + '\n//]]>\n</script>'
sloc = html.rindex('</body>')
html = html[:sloc] + js + '\n' + html[sloc:]
if css_files:
paths = set()
for path in css_files:
if not path.startswith("/") and not path.startswith("http:"):
paths.add(self.static_url(path))
else:
paths.add(path)
css = ''.join('<link href="' + escape.xhtml_escape(p) + '" '
'type="text/css" rel="stylesheet"/>'
for p in paths)
hloc = html.index('</head>')
html = html[:hloc] + css + '\n' + html[hloc:]
if css_embed:
css = '<style type="text/css">\n' + '\n'.join(css_embed) + \
'\n</style>'
hloc = html.index('</head>')
html = html[:hloc] + css + '\n' + html[hloc:]
if html_heads:
hloc = html.index('</head>')
html = html[:hloc] + ''.join(html_heads) + '\n' + html[hloc:]
if html_bodies:
hloc = html.index('</body>')
html = html[:hloc] + ''.join(html_bodies) + '\n' + html[hloc:]
self.finish(html)
def render_string(self, template_name, **kwargs):
"""Generate the given template with the given arguments.
We return the generated string. To generate and write a template
as a response, use render() above.
"""
# If no template_path is specified, use the path of the calling file
template_path = self.get_template_path()
if not template_path:
frame = sys._getframe(0)
web_file = frame.f_code.co_filename
while frame.f_code.co_filename == web_file:
frame = frame.f_back
template_path = os.path.dirname(frame.f_code.co_filename)
if not getattr(RequestHandler, "_templates", None):
RequestHandler._templates = {}
if template_path not in RequestHandler._templates:
loader = self.application.settings.get("template_loader") or\
template.Loader(template_path)
RequestHandler._templates[template_path] = loader
t = RequestHandler._templates[template_path].load(template_name)
args = dict(
handler=self,
request=self.request,
current_user=self.current_user,
locale=self.locale,
_=self.locale.translate,
static_url=self.static_url,
xsrf_form_html=self.xsrf_form_html,
reverse_url=self.application.reverse_url
)
args.update(self.ui)
args.update(kwargs)
return t.generate(**args)
def flush(self, include_footers=False):
"""Flushes the current output buffer to the network."""
if self.application._wsgi:
raise Exception("WSGI applications do not support flush()")
chunk = "".join(self._write_buffer)
self._write_buffer = []
if not self._headers_written:
self._headers_written = True
for transform in self._transforms:
self._headers, chunk = transform.transform_first_chunk(
self._headers, chunk, include_footers)
headers = self._generate_headers()
else:
for transform in self._transforms:
chunk = transform.transform_chunk(chunk, include_footers)
headers = ""
# Ignore the chunk and only write the headers for HEAD requests
if self.request.method == "HEAD":
if headers: self.request.write(headers)
return
if headers or chunk:
self.request.write(headers + chunk)
def finish(self, chunk=None):
"""Finishes this response, ending the HTTP request."""
assert not self._finished
if chunk is not None: self.write(chunk)
# Automatically support ETags and add the Content-Length header if
# we have not flushed any content yet.
if not self._headers_written:
if (self._status_code == 200 and self.request.method == "GET" and
"Etag" not in self._headers):
hasher = hashlib.sha1()
for part in self._write_buffer:
hasher.update(part)
etag = '"%s"' % hasher.hexdigest()
inm = self.request.headers.get("If-None-Match")
if inm and inm.find(etag) != -1:
self._write_buffer = []
self.set_status(304)
else:
self.set_header("Etag", etag)
if "Content-Length" not in self._headers:
content_length = sum(len(part) for part in self._write_buffer)
self.set_header("Content-Length", content_length)
if hasattr(self.request, "connection"):
# Now that the request is finished, clear the callback we
# set on the IOStream (which would otherwise prevent the
# garbage collection of the RequestHandler when there
# are keepalive connections)
self.request.connection.stream.set_close_callback(None)
if not self.application._wsgi:
self.flush(include_footers=True)
self.request.finish()
self._log()
self._finished = True
def send_error(self, status_code=500, **kwargs):
"""Sends the given HTTP error code to the browser.
We also send the error HTML for the given error code as returned by
get_error_html. Override that method if you want custom error pages
for your application.
"""
if self._headers_written:
logging.error("Cannot send error response after headers written")
if not self._finished:
self.finish()
return
self.clear()
self.set_status(status_code)
message = self.get_error_html(status_code, **kwargs)
self.finish(message)
def get_error_html(self, status_code, **kwargs):
"""Override to implement custom error pages.
If this error was caused by an uncaught exception, the
exception object can be found in kwargs e.g. kwargs['exception']
"""
return "<html><title>%(code)d: %(message)s</title>" \
"<body>%(code)d: %(message)s</body></html>" % {
"code": status_code,
"message": httplib.responses[status_code],
}
@property
def locale(self):
"""The local for the current session.
Determined by either get_user_locale, which you can override to
set the locale based on, e.g., a user preference stored in a
database, or get_browser_locale, which uses the Accept-Language
header.
"""
if not hasattr(self, "_locale"):
self._locale = self.get_user_locale()
if not self._locale:
self._locale = self.get_browser_locale()
assert self._locale
return self._locale
def get_user_locale(self):
"""Override to determine the locale from the authenticated user.
If None is returned, we use the Accept-Language header.
"""
return None
def get_browser_locale(self, default="en_US"):
"""Determines the user's locale from Accept-Language header.
See http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.4
"""
if "Accept-Language" in self.request.headers:
languages = self.request.headers["Accept-Language"].split(",")
locales = []
for language in languages:
parts = language.strip().split(";")
if len(parts) > 1 and parts[1].startswith("q="):
try:
score = float(parts[1][2:])
except (ValueError, TypeError):
score = 0.0
else:
score = 1.0
locales.append((parts[0], score))
if locales:
locales.sort(key=lambda (l, s): s, reverse=True)
codes = [l[0] for l in locales]
return locale.get(*codes)
return locale.get(default)
@property
def current_user(self):
"""The authenticated user for this request.
Determined by either get_current_user, which you can override to
set the user based on, e.g., a cookie. If that method is not
overridden, this method always returns None.
We lazy-load the current user the first time this method is called
and cache the result after that.
"""
if not hasattr(self, "_current_user"):
self._current_user = self.get_current_user()
return self._current_user
def get_current_user(self):
"""Override to determine the current user from, e.g., a cookie."""
return None
def get_login_url(self):
"""Override to customize the login URL based on the request.
By default, we use the 'login_url' application setting.
"""
self.require_setting("login_url", "@tornado.web.authenticated")
return self.application.settings["login_url"]
def get_template_path(self):
"""Override to customize template path for each handler.
By default, we use the 'template_path' application setting.
Return None to load templates relative to the calling file.
"""
return self.application.settings.get("template_path")
@property
def xsrf_token(self):
"""The XSRF-prevention token for the current user/session.
To prevent cross-site request forgery, we set an '_xsrf' cookie
and include the same '_xsrf' value as an argument with all POST
requests. If the two do not match, we reject the form submission
as a potential forgery.
See http://en.wikipedia.org/wiki/Cross-site_request_forgery
"""
if not hasattr(self, "_xsrf_token"):
token = self.get_cookie("_xsrf")
if not token:
token = binascii.b2a_hex(uuid.uuid4().bytes)
expires_days = 30 if self.current_user else None
self.set_cookie("_xsrf", token, expires_days=expires_days)
self._xsrf_token = token
return self._xsrf_token
def check_xsrf_cookie(self):
"""Verifies that the '_xsrf' cookie matches the '_xsrf' argument.
To prevent cross-site request forgery, we set an '_xsrf' cookie
and include the same '_xsrf' value as an argument with all POST
requests. If the two do not match, we reject the form submission
as a potential forgery.
See http://en.wikipedia.org/wiki/Cross-site_request_forgery
"""
if self.request.headers.get("X-Requested-With") == "XMLHttpRequest":
return
token = self.get_argument("_xsrf", None)
if not token:
raise HTTPError(403, "'_xsrf' argument missing from POST")
if self.xsrf_token != token:
raise HTTPError(403, "XSRF cookie does not match POST argument")
def xsrf_form_html(self):
"""An HTML <input/> element to be included with all POST forms.
It defines the _xsrf input value, which we check on all POST
requests to prevent cross-site request forgery. If you have set
the 'xsrf_cookies' application setting, you must include this
HTML within all of your HTML forms.
See check_xsrf_cookie() above for more information.
"""
return '<input type="hidden" name="_xsrf" value="' + \
escape.xhtml_escape(self.xsrf_token) + '"/>'
def static_url(self, path):
"""Returns a static URL for the given relative static file path.
This method requires you set the 'static_path' setting in your
application (which specifies the root directory of your static
files).
We append ?v=<signature> to the returned URL, which makes our
static file handler set an infinite expiration header on the
returned content. The signature is based on the content of the
file.
If this handler has a "include_host" attribute, we include the
full host for every static URL, including the "http://". Set
this attribute for handlers whose output needs non-relative static
path names.
"""
self.require_setting("static_path", "static_url")
if not hasattr(RequestHandler, "_static_hashes"):
RequestHandler._static_hashes = {}
hashes = RequestHandler._static_hashes
if path not in hashes:
try:
f = open(os.path.join(
self.application.settings["static_path"], path))
hashes[path] = hashlib.md5(f.read()).hexdigest()
f.close()
except:
logging.error("Could not open static file %r", path)
hashes[path] = None
base = self.request.protocol + "://" + self.request.host \
if getattr(self, "include_host", False) else ""
static_url_prefix = self.settings.get('static_url_prefix', '/static/')
if hashes.get(path):
return base + static_url_prefix + path + "?v=" + hashes[path][:5]
else:
return base + static_url_prefix + path
def async_callback(self, callback, *args, **kwargs):
"""Obsolete - catches exceptions from the wrapped function.
This function is unnecessary since Tornado 1.1.
"""
if callback is None:
return None
if args or kwargs:
callback = functools.partial(callback, *args, **kwargs)
def wrapper(*args, **kwargs):
try:
return callback(*args, **kwargs)
except Exception, e:
if self._headers_written:
logging.error("Exception after headers written",
exc_info=True)
else:
self._handle_request_exception(e)
return wrapper
def require_setting(self, name, feature="this feature"):
"""Raises an exception if the given app setting is not defined."""
if not self.application.settings.get(name):
raise Exception("You must define the '%s' setting in your "
"application to use %s" % (name, feature))
def reverse_url(self, name, *args):
return self.application.reverse_url(name, *args)
@contextlib.contextmanager
def _stack_context(self):
try:
yield
except Exception, e:
self._handle_request_exception(e)
def _execute(self, transforms, *args, **kwargs):
"""Executes this request with the given output transforms."""
self._transforms = transforms
with stack_context.StackContext(self._stack_context):
if self.request.method not in self.SUPPORTED_METHODS:
raise HTTPError(405)
# If XSRF cookies are turned on, reject form submissions without
# the proper cookie
if self.request.method == "POST" and \
self.application.settings.get("xsrf_cookies"):
self.check_xsrf_cookie()
self.prepare()
if not self._finished:
getattr(self, self.request.method.lower())(*args, **kwargs)
if self._auto_finish and not self._finished:
self.finish()
def _generate_headers(self):
lines = [self.request.version + " " + str(self._status_code) + " " +
httplib.responses[self._status_code]]
lines.extend(["%s: %s" % (n, v) for n, v in self._headers.iteritems()])
for cookie_dict in getattr(self, "_new_cookies", []):
for cookie in cookie_dict.values():
lines.append("Set-Cookie: " + cookie.OutputString(None))
return "\r\n".join(lines) + "\r\n\r\n"
def _log(self):
if self._status_code < 400:
log_method = logging.info
elif self._status_code < 500:
log_method = logging.warning
else:
log_method = logging.error
request_time = 1000.0 * self.request.request_time()
log_method("%d %s %.2fms", self._status_code,
self._request_summary(), request_time)
def _request_summary(self):
return self.request.method + " " + self.request.uri + " (" + \
self.request.remote_ip + ")"
def _handle_request_exception(self, e):
if isinstance(e, HTTPError):
if e.log_message:
format = "%d %s: " + e.log_message
args = [e.status_code, self._request_summary()] + list(e.args)
logging.warning(format, *args)
if e.status_code not in httplib.responses:
logging.error("Bad HTTP status code: %d", e.status_code)
self.send_error(500, exception=e)
else:
self.send_error(e.status_code, exception=e)
else:
logging.error("Uncaught exception %s\n%r", self._request_summary(),
self.request, exc_info=e)
self.send_error(500, exception=e)
def _ui_module(self, name, module):
def render(*args, **kwargs):
if not hasattr(self, "_active_modules"):
self._active_modules = {}
if name not in self._active_modules:
self._active_modules[name] = module(self)
rendered = self._active_modules[name].render(*args, **kwargs)
return rendered
return render
def _ui_method(self, method):
return lambda *args, **kwargs: method(self, *args, **kwargs)
def asynchronous(method):
"""Wrap request handler methods with this if they are asynchronous.
If this decorator is given, the response is not finished when the
method returns. It is up to the request handler to call self.finish()
to finish the HTTP request. Without this decorator, the request is
automatically finished when the get() or post() method returns.
class MyRequestHandler(web.RequestHandler):
@web.asynchronous
def get(self):
http = httpclient.AsyncHTTPClient()
http.fetch("http://friendfeed.com/", self._on_download)
def _on_download(self, response):
self.write("Downloaded!")
self.finish()
"""
@functools.wraps(method)
def wrapper(self, *args, **kwargs):
if self.application._wsgi:
raise Exception("@asynchronous is not supported for WSGI apps")
self._auto_finish = False
return method(self, *args, **kwargs)
return wrapper
def removeslash(method):
"""Use this decorator to remove trailing slashes from the request path.
For example, a request to '/foo/' would redirect to '/foo' with this
decorator. Your request handler mapping should use a regular expression
like r'/foo/*' in conjunction with using the decorator.
"""
@functools.wraps(method)
def wrapper(self, *args, **kwargs):
if self.request.path.endswith("/"):
if self.request.method == "GET":
uri = self.request.path.rstrip("/")
if self.request.query: uri += "?" + self.request.query
self.redirect(uri)
return
raise HTTPError(404)
return method(self, *args, **kwargs)
return wrapper
def addslash(method):
"""Use this decorator to add a missing trailing slash to the request path.
For example, a request to '/foo' would redirect to '/foo/' with this
decorator. Your request handler mapping should use a regular expression
like r'/foo/?' in conjunction with using the decorator.
"""
@functools.wraps(method)
def wrapper(self, *args, **kwargs):
if not self.request.path.endswith("/"):
if self.request.method == "GET":
uri = self.request.path + "/"
if self.request.query: uri += "?" + self.request.query
self.redirect(uri)
return
raise HTTPError(404)
return method(self, *args, **kwargs)
return wrapper
class Application(object):
"""A collection of request handlers that make up a web application.
Instances of this class are callable and can be passed directly to
HTTPServer to serve the application:
application = web.Application([
(r"/", MainPageHandler),
])
http_server = httpserver.HTTPServer(application)
http_server.listen(8080)
ioloop.IOLoop.instance().start()
The constructor for this class takes in a list of URLSpec objects
or (regexp, request_class) tuples. When we receive requests, we
iterate over the list in order and instantiate an instance of the
first request class whose regexp matches the request path.
Each tuple can contain an optional third element, which should be a
dictionary if it is present. That dictionary is passed as keyword
arguments to the contructor of the handler. This pattern is used
for the StaticFileHandler below:
application = web.Application([
(r"/static/(.*)", web.StaticFileHandler, {"path": "/var/www"}),
])
We support virtual hosts with the add_handlers method, which takes in
a host regular expression as the first argument:
application.add_handlers(r"www\.myhost\.com", [
(r"/article/([0-9]+)", ArticleHandler),
])
You can serve static files by sending the static_path setting as a
keyword argument. We will serve those files from the /static/ URI
(this is configurable with the static_url_prefix setting),
and we will serve /favicon.ico and /robots.txt from the same directory.
"""
def __init__(self, handlers=None, default_host="", transforms=None,
wsgi=False, **settings):
if transforms is None:
self.transforms = []
if settings.get("gzip"):
self.transforms.append(GZipContentEncoding)
self.transforms.append(ChunkedTransferEncoding)