Skip to content
This repository
Fetching contributors…

Octocat-spinner-32-eaf2f5

Cannot retrieve contributors at this time

file 1519 lines (1287 sloc) 64.37 kb
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 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518
# -*- coding: utf-8 -*-
"""
flask.app
~~~~~~~~~

This module implements the central WSGI application object.

:copyright: (c) 2011 by Armin Ronacher.
:license: BSD, see LICENSE for more details.
"""

from __future__ import with_statement

import os
import sys
from threading import Lock
from datetime import timedelta
from itertools import chain
from functools import update_wrapper

from werkzeug.datastructures import ImmutableDict
from werkzeug.routing import Map, Rule, RequestRedirect
from werkzeug.exceptions import HTTPException, InternalServerError, \
     MethodNotAllowed, BadRequest

from .helpers import _PackageBoundObject, url_for, get_flashed_messages, \
    locked_cached_property, _tojson_filter, _endpoint_from_view_func, \
    find_package
from .wrappers import Request, Response
from .config import ConfigAttribute, Config
from .ctx import RequestContext
from .globals import _request_ctx_stack, request
from .sessions import SecureCookieSessionInterface
from .module import blueprint_is_module
from .templating import DispatchingJinjaLoader, Environment, \
    _default_template_ctx_processor
from .signals import request_started, request_finished, got_request_exception, \
    request_tearing_down

# a lock used for logger initialization
_logger_lock = Lock()


def _make_timedelta(value):
    if not isinstance(value, timedelta):
        return timedelta(seconds=value)
    return value


def setupmethod(f):
    """Wraps a method so that it performs a check in debug mode if the
first request was already handled.
"""
    def wrapper_func(self, *args, **kwargs):
        if self.debug and self._got_first_request:
            raise AssertionError('A setup function was called after the '
                'first request was handled. This usually indicates a bug '
                'in the application where a module was not imported '
                'and decorators or other functionality was called too late.\n'
                'To fix this make sure to import all your view modules, '
                'database models and everything related at a central place '
                'before the application starts serving requests.')
        return f(self, *args, **kwargs)
    return update_wrapper(wrapper_func, f)


class Flask(_PackageBoundObject):
    """The flask object implements a WSGI application and acts as the central
object. It is passed the name of the module or package of the
application. Once it is created it will act as a central registry for
the view functions, the URL rules, template configuration and much more.

The name of the package is used to resolve resources from inside the
package or the folder the module is contained in depending on if the
package parameter resolves to an actual python package (a folder with
an `__init__.py` file inside) or a standard module (just a `.py` file).

For more information about resource loading, see :func:`open_resource`.

Usually you create a :class:`Flask` instance in your main module or
in the `__init__.py` file of your package like this::

from flask import Flask
app = Flask(__name__)

.. admonition:: About the First Parameter

The idea of the first parameter is to give Flask an idea what
belongs to your application. This name is used to find resources
on the file system, can be used by extensions to improve debugging
information and a lot more.

So it's important what you provide there. If you are using a single
module, `__name__` is always the correct value. If you however are
using a package, it's usually recommended to hardcode the name of
your package there.

For example if your application is defined in `yourapplication/app.py`
you should create it with one of the two versions below::

app = Flask('yourapplication')
app = Flask(__name__.split('.')[0])

Why is that? The application will work even with `__name__`, thanks
to how resources are looked up. However it will make debugging more
painful. Certain extensions can make assumptions based on the
import name of your application. For example the Flask-SQLAlchemy
extension will look for the code in your application that triggered
an SQL query in debug mode. If the import name is not properly set
up, that debugging information is lost. (For example it would only
pick up SQL queries in `yourapplication.app` and not
`yourapplication.views.frontend`)

.. versionadded:: 0.7
The `static_url_path`, `static_folder`, and `template_folder`
parameters were added.

.. versionadded:: 0.8
The `instance_path` and `instance_relative_config` parameters were
added.

:param import_name: the name of the application package
:param static_url_path: can be used to specify a different path for the
static files on the web. Defaults to the name
of the `static_folder` folder.
:param static_folder: the folder with static files that should be served
at `static_url_path`. Defaults to the ``'static'``
folder in the root path of the application.
:param template_folder: the folder that contains the templates that should
be used by the application. Defaults to
``'templates'`` folder in the root path of the
application.
:param instance_path: An alternative instance path for the application.
By default the folder ``'instance'`` next to the
package or module is assumed to be the instance
path.
:param instance_relative_config: if set to `True` relative filenames
for loading the config are assumed to
be relative to the instance path instead
of the application root.
"""

    #: The class that is used for request objects. See :class:`~flask.Request`
    #: for more information.
    request_class = Request

    #: The class that is used for response objects. See
    #: :class:`~flask.Response` for more information.
    response_class = Response

    #: The debug flag. Set this to `True` to enable debugging of the
    #: application. In debug mode the debugger will kick in when an unhandled
    #: exception ocurrs and the integrated server will automatically reload
    #: the application if changes in the code are detected.
    #:
    #: This attribute can also be configured from the config with the `DEBUG`
    #: configuration key. Defaults to `False`.
    debug = ConfigAttribute('DEBUG')

    #: The testing flag. Set this to `True` to enable the test mode of
    #: Flask extensions (and in the future probably also Flask itself).
    #: For example this might activate unittest helpers that have an
    #: additional runtime cost which should not be enabled by default.
    #:
    #: If this is enabled and PROPAGATE_EXCEPTIONS is not changed from the
    #: default it's implicitly enabled.
    #:
    #: This attribute can also be configured from the config with the
    #: `TESTING` configuration key. Defaults to `False`.
    testing = ConfigAttribute('TESTING')

    #: If a secret key is set, cryptographic components can use this to
    #: sign cookies and other things. Set this to a complex random value
    #: when you want to use the secure cookie for instance.
    #:
    #: This attribute can also be configured from the config with the
    #: `SECRET_KEY` configuration key. Defaults to `None`.
    secret_key = ConfigAttribute('SECRET_KEY')

    #: The secure cookie uses this for the name of the session cookie.
    #:
    #: This attribute can also be configured from the config with the
    #: `SESSION_COOKIE_NAME` configuration key. Defaults to ``'session'``
    session_cookie_name = ConfigAttribute('SESSION_COOKIE_NAME')

    #: A :class:`~datetime.timedelta` which is used to set the expiration
    #: date of a permanent session. The default is 31 days which makes a
    #: permanent session survive for roughly one month.
    #:
    #: This attribute can also be configured from the config with the
    #: `PERMANENT_SESSION_LIFETIME` configuration key. Defaults to
    #: ``timedelta(days=31)``
    permanent_session_lifetime = ConfigAttribute('PERMANENT_SESSION_LIFETIME',
        get_converter=_make_timedelta)

    #: Enable this if you want to use the X-Sendfile feature. Keep in
    #: mind that the server has to support this. This only affects files
    #: sent with the :func:`send_file` method.
    #:
    #: .. versionadded:: 0.2
    #:
    #: This attribute can also be configured from the config with the
    #: `USE_X_SENDFILE` configuration key. Defaults to `False`.
    use_x_sendfile = ConfigAttribute('USE_X_SENDFILE')

    #: The name of the logger to use. By default the logger name is the
    #: package name passed to the constructor.
    #:
    #: .. versionadded:: 0.4
    logger_name = ConfigAttribute('LOGGER_NAME')

    #: Enable the deprecated module support? This is active by default
    #: in 0.7 but will be changed to False in 0.8. With Flask 1.0 modules
    #: will be removed in favor of Blueprints
    enable_modules = True

    #: The logging format used for the debug logger. This is only used when
    #: the application is in debug mode, otherwise the attached logging
    #: handler does the formatting.
    #:
    #: .. versionadded:: 0.3
    debug_log_format = (
        '-' * 80 + '\n' +
        '%(levelname)s in %(module)s [%(pathname)s:%(lineno)d]:\n' +
        '%(message)s\n' +
        '-' * 80
    )

    #: Options that are passed directly to the Jinja2 environment.
    jinja_options = ImmutableDict(
        extensions=['jinja2.ext.autoescape', 'jinja2.ext.with_']
    )

    #: Default configuration parameters.
    default_config = ImmutableDict({
        'DEBUG': False,
        'TESTING': False,
        'PROPAGATE_EXCEPTIONS': None,
        'PRESERVE_CONTEXT_ON_EXCEPTION': None,
        'SECRET_KEY': None,
        'PERMANENT_SESSION_LIFETIME': timedelta(days=31),
        'USE_X_SENDFILE': False,
        'LOGGER_NAME': None,
        'SERVER_NAME': None,
        'APPLICATION_ROOT': None,
        'SESSION_COOKIE_NAME': 'session',
        'SESSION_COOKIE_DOMAIN': None,
        'SESSION_COOKIE_PATH': None,
        'SESSION_COOKIE_HTTPONLY': True,
        'SESSION_COOKIE_SECURE': False,
        'MAX_CONTENT_LENGTH': None,
        'TRAP_BAD_REQUEST_ERRORS': False,
        'TRAP_HTTP_EXCEPTIONS': False
    })

    #: The rule object to use for URL rules created. This is used by
    #: :meth:`add_url_rule`. Defaults to :class:`werkzeug.routing.Rule`.
    #:
    #: .. versionadded:: 0.7
    url_rule_class = Rule

    #: the test client that is used with when `test_client` is used.
    #:
    #: .. versionadded:: 0.7
    test_client_class = None

    #: the session interface to use. By default an instance of
    #: :class:`~flask.sessions.SecureCookieSessionInterface` is used here.
    #:
    #: .. versionadded:: 0.8
    session_interface = SecureCookieSessionInterface()

    def __init__(self, import_name, static_path=None, static_url_path=None,
                 static_folder='static', template_folder='templates',
                 instance_path=None, instance_relative_config=False):
        _PackageBoundObject.__init__(self, import_name,
                                     template_folder=template_folder)
        if static_path is not None:
            from warnings import warn
            warn(DeprecationWarning('static_path is now called '
                                    'static_url_path'), stacklevel=2)
            static_url_path = static_path

        if static_url_path is not None:
            self.static_url_path = static_url_path
        if static_folder is not None:
            self.static_folder = static_folder
        if instance_path is None:
            instance_path = self.auto_find_instance_path()
        elif not os.path.isabs(instance_path):
            raise ValueError('If an instance path is provided it must be '
                             'absolute. A relative path was given instead.')

        #: Holds the path to the instance folder.
        #:
        #: .. versionadded:: 0.8
        self.instance_path = instance_path

        #: The configuration dictionary as :class:`Config`. This behaves
        #: exactly like a regular dictionary but supports additional methods
        #: to load a config from files.
        self.config = self.make_config(instance_relative_config)

        # Prepare the deferred setup of the logger.
        self._logger = None
        self.logger_name = self.import_name

        #: A dictionary of all view functions registered. The keys will
        #: be function names which are also used to generate URLs and
        #: the values are the function objects themselves.
        #: To register a view function, use the :meth:`route` decorator.
        self.view_functions = {}

        # support for the now deprecated `error_handlers` attribute. The
        # :attr:`error_handler_spec` shall be used now.
        self._error_handlers = {}

        #: A dictionary of all registered error handlers. The key is `None`
        #: for error handlers active on the application, otherwise the key is
        #: the name of the blueprint. Each key points to another dictionary
        #: where they key is the status code of the http exception. The
        #: special key `None` points to a list of tuples where the first item
        #: is the class for the instance check and the second the error handler
        #: function.
        #:
        #: To register a error handler, use the :meth:`errorhandler`
        #: decorator.
        self.error_handler_spec = {None: self._error_handlers}

        #: A dictionary with lists of functions that should be called at the
        #: beginning of the request. The key of the dictionary is the name of
        #: the blueprint this function is active for, `None` for all requests.
        #: This can for example be used to open database connections or
        #: getting hold of the currently logged in user. To register a
        #: function here, use the :meth:`before_request` decorator.
        self.before_request_funcs = {}

        #: A lists of functions that should be called at the beginning of the
        #: first request to this instance. To register a function here, use
        #: the :meth:`before_first_request` decorator.
        #:
        #: .. versionadded:: 0.8
        self.before_first_request_funcs = []

        #: A dictionary with lists of functions that should be called after
        #: each request. The key of the dictionary is the name of the blueprint
        #: this function is active for, `None` for all requests. This can for
        #: example be used to open database connections or getting hold of the
        #: currently logged in user. To register a function here, use the
        #: :meth:`after_request` decorator.
        self.after_request_funcs = {}

        #: A dictionary with lists of functions that are called after
        #: each request, even if an exception has occurred. The key of the
        #: dictionary is the name of the blueprint this function is active for,
        #: `None` for all requests. These functions are not allowed to modify
        #: the request, and their return values are ignored. If an exception
        #: occurred while processing the request, it gets passed to each
        #: teardown_request function. To register a function here, use the
        #: :meth:`teardown_request` decorator.
        #:
        #: .. versionadded:: 0.7
        self.teardown_request_funcs = {}

        #: A dictionary with lists of functions that can be used as URL
        #: value processor functions. Whenever a URL is built these functions
        #: are called to modify the dictionary of values in place. The key
        #: `None` here is used for application wide
        #: callbacks, otherwise the key is the name of the blueprint.
        #: Each of these functions has the chance to modify the dictionary
        #:
        #: .. versionadded:: 0.7
        self.url_value_preprocessors = {}

        #: A dictionary with lists of functions that can be used as URL value
        #: preprocessors. The key `None` here is used for application wide
        #: callbacks, otherwise the key is the name of the blueprint.
        #: Each of these functions has the chance to modify the dictionary
        #: of URL values before they are used as the keyword arguments of the
        #: view function. For each function registered this one should also
        #: provide a :meth:`url_defaults` function that adds the parameters
        #: automatically again that were removed that way.
        #:
        #: .. versionadded:: 0.7
        self.url_default_functions = {}

        #: A dictionary with list of functions that are called without argument
        #: to populate the template context. The key of the dictionary is the
        #: name of the blueprint this function is active for, `None` for all
        #: requests. Each returns a dictionary that the template context is
        #: updated with. To register a function here, use the
        #: :meth:`context_processor` decorator.
        self.template_context_processors = {
            None: [_default_template_ctx_processor]
        }

        #: all the attached blueprints in a directory by name. Blueprints
        #: can be attached multiple times so this dictionary does not tell
        #: you how often they got attached.
        #:
        #: .. versionadded:: 0.7
        self.blueprints = {}

        #: a place where extensions can store application specific state. For
        #: example this is where an extension could store database engines and
        #: similar things. For backwards compatibility extensions should register
        #: themselves like this::
        #:
        #: if not hasattr(app, 'extensions'):
        #: app.extensions = {}
        #: app.extensions['extensionname'] = SomeObject()
        #:
        #: The key must match the name of the `flaskext` module. For example in
        #: case of a "Flask-Foo" extension in `flaskext.foo`, the key would be
        #: ``'foo'``.
        #:
        #: .. versionadded:: 0.7
        self.extensions = {}

        #: The :class:`~werkzeug.routing.Map` for this instance. You can use
        #: this to change the routing converters after the class was created
        #: but before any routes are connected. Example::
        #:
        #: from werkzeug.routing import BaseConverter
        #:
        #: class ListConverter(BaseConverter):
        #: def to_python(self, value):
        #: return value.split(',')
        #: def to_url(self, values):
        #: return ','.join(BaseConverter.to_url(value)
        #: for value in values)
        #:
        #: app = Flask(__name__)
        #: app.url_map.converters['list'] = ListConverter
        self.url_map = Map()

        # tracks internally if the application already handled at least one
        # request.
        self._got_first_request = False
        self._before_request_lock = Lock()

        # register the static folder for the application. Do that even
        # if the folder does not exist. First of all it might be created
        # while the server is running (usually happens during development)
        # but also because google appengine stores static files somewhere
        # else when mapped with the .yml file.
        if self.has_static_folder:
            self.add_url_rule(self.static_url_path + '/<path:filename>',
                              endpoint='static',
                              view_func=self.send_static_file)

    def _get_error_handlers(self):
        from warnings import warn
        warn(DeprecationWarning('error_handlers is deprecated, use the '
            'new error_handler_spec attribute instead.'), stacklevel=1)
        return self._error_handlers
    def _set_error_handlers(self, value):
        self._error_handlers = value
        self.error_handler_spec[None] = value
    error_handlers = property(_get_error_handlers, _set_error_handlers)
    del _get_error_handlers, _set_error_handlers

    @locked_cached_property
    def name(self):
        """The name of the application. This is usually the import name
with the difference that it's guessed from the run file if the
import name is main. This name is used as a display name when
Flask needs the name of the application. It can be set and overriden
to change the value.

.. versionadded:: 0.8
"""
        if self.import_name == '__main__':
            fn = getattr(sys.modules['__main__'], '__file__', None)
            if fn is None:
                return '__main__'
            return os.path.splitext(os.path.basename(fn))[0]
        return self.import_name

    @property
    def propagate_exceptions(self):
        """Returns the value of the `PROPAGATE_EXCEPTIONS` configuration
value in case it's set, otherwise a sensible default is returned.

.. versionadded:: 0.7
"""
        rv = self.config['PROPAGATE_EXCEPTIONS']
        if rv is not None:
            return rv
        return self.testing or self.debug

    @property
    def preserve_context_on_exception(self):
        """Returns the value of the `PRESERVE_CONTEXT_ON_EXCEPTION`
configuration value in case it's set, otherwise a sensible default
is returned.

.. versionadded:: 0.7
"""
        rv = self.config['PRESERVE_CONTEXT_ON_EXCEPTION']
        if rv is not None:
            return rv
        return self.debug

    @property
    def logger(self):
        """A :class:`logging.Logger` object for this application. The
default configuration is to log to stderr if the application is
in debug mode. This logger can be used to (surprise) log messages.
Here some examples::

app.logger.debug('A value for debugging')
app.logger.warning('A warning ocurred (%d apples)', 42)
app.logger.error('An error occoured')

.. versionadded:: 0.3
"""
        if self._logger and self._logger.name == self.logger_name:
            return self._logger
        with _logger_lock:
            if self._logger and self._logger.name == self.logger_name:
                return self._logger
            from flask.logging import create_logger
            self._logger = rv = create_logger(self)
            return rv

    @locked_cached_property
    def jinja_env(self):
        """The Jinja2 environment used to load templates."""
        rv = self.create_jinja_environment()

        # Hack to support the init_jinja_globals method which is supported
        # until 1.0 but has an API deficiency.
        if getattr(self.init_jinja_globals, 'im_func', None) is not \
           Flask.init_jinja_globals.im_func:
            from warnings import warn
            warn(DeprecationWarning('This flask class uses a customized '
                'init_jinja_globals() method which is deprecated. '
                'Move the code from that method into the '
                'create_jinja_environment() method instead.'))
            self.__dict__['jinja_env'] = rv
            self.init_jinja_globals()

        return rv

    @property
    def got_first_request(self):
        """This attribute is set to `True` if the application started
handling the first request.

.. versionadded:: 0.8
"""
        return self._got_first_request

    def make_config(self, instance_relative=False):
        """Used to create the config attribute by the Flask constructor.
The `instance_relative` parameter is passed in from the constructor
of Flask (there named `instance_relative_config`) and indicates if
the config should be relative to the instance path or the root path
of the application.

.. versionadded:: 0.8
"""
        root_path = self.root_path
        if instance_relative:
            root_path = self.instance_path
        return Config(root_path, self.default_config)

    def auto_find_instance_path(self):
        """Tries to locate the instance path if it was not provided to the
constructor of the application class. It will basically calculate
the path to a folder named ``instance`` next to your main file or
the package.

.. versionadded:: 0.8
"""
        prefix, package_path = find_package(self.import_name)
        if prefix is None:
            return os.path.join(package_path, 'instance')
        return os.path.join(prefix, 'var', self.name + '-instance')

    def open_instance_resource(self, resource, mode='rb'):
        """Opens a resource from the application's instance folder
(:attr:`instance_path`). Otherwise works like
:meth:`open_resource`. Instance resources can also be opened for
writing.

:param resource: the name of the resource. To access resources within
subfolders use forward slashes as separator.
"""
        return open(os.path.join(self.instance_path, resource), mode)

    def create_jinja_environment(self):
        """Creates the Jinja2 environment based on :attr:`jinja_options`
and :meth:`select_jinja_autoescape`. Since 0.7 this also adds
the Jinja2 globals and filters after initialization. Override
this function to customize the behavior.

.. versionadded:: 0.5
"""
        options = dict(self.jinja_options)
        if 'autoescape' not in options:
            options['autoescape'] = self.select_jinja_autoescape
        rv = Environment(self, **options)
        rv.globals.update(
            url_for=url_for,
            get_flashed_messages=get_flashed_messages
        )
        rv.filters['tojson'] = _tojson_filter
        return rv

    def create_global_jinja_loader(self):
        """Creates the loader for the Jinja2 environment. Can be used to
override just the loader and keeping the rest unchanged. It's
discouraged to override this function. Instead one should override
the :meth:`jinja_loader` function instead.

The global loader dispatches between the loaders of the application
and the individual blueprints.

.. versionadded:: 0.7
"""
        return DispatchingJinjaLoader(self)

    def init_jinja_globals(self):
        """Deprecated. Used to initialize the Jinja2 globals.

.. versionadded:: 0.5
.. versionchanged:: 0.7
This method is deprecated with 0.7. Override
:meth:`create_jinja_environment` instead.
"""

    def select_jinja_autoescape(self, filename):
        """Returns `True` if autoescaping should be active for the given
template name.

.. versionadded:: 0.5
"""
        if filename is None:
            return False
        return filename.endswith(('.html', '.htm', '.xml', '.xhtml'))

    def update_template_context(self, context):
        """Update the template context with some commonly used variables.
This injects request, session, config and g into the template
context as well as everything template context processors want
to inject. Note that the as of Flask 0.6, the original values
in the context will not be overriden if a context processor
decides to return a value with the same key.

:param context: the context as a dictionary that is updated in place
to add extra variables.
"""
        funcs = self.template_context_processors[None]
        bp = _request_ctx_stack.top.request.blueprint
        if bp is not None and bp in self.template_context_processors:
            funcs = chain(funcs, self.template_context_processors[bp])
        orig_ctx = context.copy()
        for func in funcs:
            context.update(func())
        # make sure the original values win. This makes it possible to
        # easier add new variables in context processors without breaking
        # existing views.
        context.update(orig_ctx)

    def run(self, host='127.0.0.1', port=5000, debug=None, **options):
        """Runs the application on a local development server. If the
:attr:`debug` flag is set the server will automatically reload
for code changes and show a debugger in case an exception happened.

If you want to run the application in debug mode, but disable the
code execution on the interactive debugger, you can pass
``use_evalex=False`` as parameter. This will keep the debugger's
traceback screen active, but disable code execution.

.. admonition:: Keep in Mind

Flask will suppress any server error with a generic error page
unless it is in debug mode. As such to enable just the
interactive debugger without the code reloading, you have to
invoke :meth:`run` with ``debug=True`` and ``use_reloader=False``.
Setting ``use_debugger`` to `True` without being in debug mode
won't catch any exceptions because there won't be any to
catch.

:param host: the hostname to listen on. set this to ``'0.0.0.0'``
to have the server available externally as well.
:param port: the port of the webserver
:param debug: if given, enable or disable debug mode.
See :attr:`debug`.
:param options: the options to be forwarded to the underlying
Werkzeug server. See
:func:`werkzeug.serving.run_simple` for more
information.
"""
        from werkzeug.serving import run_simple
        if debug is not None:
            self.debug = bool(debug)
        options.setdefault('use_reloader', self.debug)
        options.setdefault('use_debugger', self.debug)
        try:
            run_simple(host, port, self, **options)
        finally:
            # reset the first request information if the development server
            # resetted normally. This makes it possible to restart the server
            # without reloader and that stuff from an interactive shell.
            self._got_first_request = False

    def test_client(self, use_cookies=True):
        """Creates a test client for this application. For information
about unit testing head over to :ref:`testing`.

The test client can be used in a `with` block to defer the closing down
of the context until the end of the `with` block. This is useful if
you want to access the context locals for testing::

with app.test_client() as c:
rv = c.get('/?vodka=42')
assert request.args['vodka'] == '42'

See :class:`~flask.testing.FlaskClient` for more information.

.. versionchanged:: 0.4
added support for `with` block usage for the client.

.. versionadded:: 0.7
The `use_cookies` parameter was added as well as the ability
to override the client to be used by setting the
:attr:`test_client_class` attribute.
"""
        cls = self.test_client_class
        if cls is None:
            from flask.testing import FlaskClient as cls
        return cls(self, self.response_class, use_cookies=use_cookies)

    def open_session(self, request):
        """Creates or opens a new session. Default implementation stores all
session data in a signed cookie. This requires that the
:attr:`secret_key` is set. Instead of overriding this method
we recommend replacing the :class:`session_interface`.

:param request: an instance of :attr:`request_class`.
"""
        return self.session_interface.open_session(self, request)

    def save_session(self, session, response):
        """Saves the session if it needs updates. For the default
implementation, check :meth:`open_session`. Instead of overriding this
method we recommend replacing the :class:`session_interface`.

:param session: the session to be saved (a
:class:`~werkzeug.contrib.securecookie.SecureCookie`
object)
:param response: an instance of :attr:`response_class`
"""
        return self.session_interface.save_session(self, session, response)

    def make_null_session(self):
        """Creates a new instance of a missing session. Instead of overriding
this method we recommend replacing the :class:`session_interface`.

.. versionadded:: 0.7
"""
        return self.session_interface.make_null_session(self)

    def register_module(self, module, **options):
        """Registers a module with this application. The keyword argument
of this function are the same as the ones for the constructor of the
:class:`Module` class and will override the values of the module if
provided.

.. versionchanged:: 0.7
The module system was deprecated in favor for the blueprint
system.
"""
        assert blueprint_is_module(module), 'register_module requires ' \
            'actual module objects. Please upgrade to blueprints though.'
        if not self.enable_modules:
            raise RuntimeError('Module support was disabled but code '
                'attempted to register a module named %r' % module)
        else:
            from warnings import warn
            warn(DeprecationWarning('Modules are deprecated. Upgrade to '
                'using blueprints. Have a look into the documentation for '
                'more information. If this module was registered by a '
                'Flask-Extension upgrade the extension or contact the author '
                'of that extension instead. (Registered %r)' % module),
                stacklevel=2)

        self.register_blueprint(module, **options)

    @setupmethod
    def register_blueprint(self, blueprint, **options):
        """Registers a blueprint on the application.

.. versionadded:: 0.7
"""
        first_registration = False
        if blueprint.name in self.blueprints:
            assert self.blueprints[blueprint.name] is blueprint, \
                'A blueprint\'s name collision ocurred between %r and ' \
                '%r. Both share the same name "%s". Blueprints that ' \
                'are created on the fly need unique names.' % \
                (blueprint, self.blueprints[blueprint.name], blueprint.name)
        else:
            self.blueprints[blueprint.name] = blueprint
            first_registration = True
        blueprint.register(self, options, first_registration)

    @setupmethod
    def add_url_rule(self, rule, endpoint=None, view_func=None, **options):
        """Connects a URL rule. Works exactly like the :meth:`route`
decorator. If a view_func is provided it will be registered with the
endpoint.

Basically this example::

@app.route('/')
def index():
pass

Is equivalent to the following::

def index():
pass
app.add_url_rule('/', 'index', index)

If the view_func is not provided you will need to connect the endpoint
to a view function like so::

app.view_functions['index'] = index

Internally :meth:`route` invokes :meth:`add_url_rule` so if you want
to customize the behavior via subclassing you only need to change
this method.

For more information refer to :ref:`url-route-registrations`.

.. versionchanged:: 0.2
`view_func` parameter added.

.. versionchanged:: 0.6
`OPTIONS` is added automatically as method.

:param rule: the URL rule as string
:param endpoint: the endpoint for the registered URL rule. Flask
itself assumes the name of the view function as
endpoint
:param view_func: the function to call when serving a request to the
provided endpoint
:param options: the options to be forwarded to the underlying
:class:`~werkzeug.routing.Rule` object. A change
to Werkzeug is handling of method options. methods
is a list of methods this rule should be limited
to (`GET`, `POST` etc.). By default a rule
just listens for `GET` (and implicitly `HEAD`).
Starting with Flask 0.6, `OPTIONS` is implicitly
added and handled by the standard request handling.
"""
        if endpoint is None:
            endpoint = _endpoint_from_view_func(view_func)
        options['endpoint'] = endpoint
        methods = options.pop('methods', None)

        # if the methods are not given and the view_func object knows its
        # methods we can use that instead. If neither exists, we go with
        # a tuple of only `GET` as default.
        if methods is None:
            methods = getattr(view_func, 'methods', None) or ('GET',)

        # starting with Flask 0.8 the view_func object can disable and
        # force-enable the automatic options handling.
        provide_automatic_options = getattr(view_func,
            'provide_automatic_options', None)

        if provide_automatic_options is None:
            if 'OPTIONS' not in methods:
                methods = tuple(methods) + ('OPTIONS',)
                provide_automatic_options = True
            else:
                provide_automatic_options = False

        # due to a werkzeug bug we need to make sure that the defaults are
        # None if they are an empty dictionary. This should not be necessary
        # with Werkzeug 0.7
        options['defaults'] = options.get('defaults') or None

        rule = self.url_rule_class(rule, methods=methods, **options)
        rule.provide_automatic_options = provide_automatic_options
        self.url_map.add(rule)
        if view_func is not None:
            self.view_functions[endpoint] = view_func

    def route(self, rule, **options):
        """A decorator that is used to register a view function for a
given URL rule. This does the same thing as :meth:`add_url_rule`
but is intended for decorator usage::

@app.route('/')
def index():
return 'Hello World'

For more information refer to :ref:`url-route-registrations`.

:param rule: the URL rule as string
:param endpoint: the endpoint for the registered URL rule. Flask
itself assumes the name of the view function as
endpoint
:param view_func: the function to call when serving a request to the
provided endpoint
:param options: the options to be forwarded to the underlying
:class:`~werkzeug.routing.Rule` object. A change
to Werkzeug is handling of method options. methods
is a list of methods this rule should be limited
to (`GET`, `POST` etc.). By default a rule
just listens for `GET` (and implicitly `HEAD`).
Starting with Flask 0.6, `OPTIONS` is implicitly
added and handled by the standard request handling.
"""
        def decorator(f):
            endpoint = options.pop('endpoint', None)
            self.add_url_rule(rule, endpoint, f, **options)
            return f
        return decorator

    @setupmethod
    def endpoint(self, endpoint):
        """A decorator to register a function as an endpoint.
Example::

@app.endpoint('example.endpoint')
def example():
return "example"

:param endpoint: the name of the endpoint
"""
        def decorator(f):
            self.view_functions[endpoint] = f
            return f
        return decorator

    @setupmethod
    def errorhandler(self, code_or_exception):
        """A decorator that is used to register a function give a given
error code. Example::

@app.errorhandler(404)
def page_not_found(error):
return 'This page does not exist', 404

You can also register handlers for arbitrary exceptions::

@app.errorhandler(DatabaseError)
def special_exception_handler(error):
return 'Database connection failed', 500

You can also register a function as error handler without using
the :meth:`errorhandler` decorator. The following example is
equivalent to the one above::

def page_not_found(error):
return 'This page does not exist', 404
app.error_handler_spec[None][404] = page_not_found

Setting error handlers via assignments to :attr:`error_handler_spec`
however is discouraged as it requires fidling with nested dictionaries
and the special case for arbitrary exception types.

The first `None` refers to the active blueprint. If the error
handler should be application wide `None` shall be used.

.. versionadded:: 0.7
One can now additionally also register custom exception types
that do not necessarily have to be a subclass of the
:class:`~werkzeug.exceptions.HTTPException` class.

:param code: the code as integer for the handler
"""
        def decorator(f):
            self._register_error_handler(None, code_or_exception, f)
            return f
        return decorator

    def register_error_handler(self, code_or_exception, f):
        """Alternative error attach function to the :meth:`errorhandler`
decorator that is more straightforward to use for non decorator
usage.

.. versionadded:: 0.7
"""
        self._register_error_handler(None, code_or_exception, f)

    @setupmethod
    def _register_error_handler(self, key, code_or_exception, f):
        if isinstance(code_or_exception, HTTPException):
            code_or_exception = code_or_exception.code
        if isinstance(code_or_exception, (int, long)):
            assert code_or_exception != 500 or key is None, \
                'It is currently not possible to register a 500 internal ' \
                'server error on a per-blueprint level.'
            self.error_handler_spec.setdefault(key, {})[code_or_exception] = f
        else:
            self.error_handler_spec.setdefault(key, {}).setdefault(None, []) \
                .append((code_or_exception, f))

    @setupmethod
    def template_filter(self, name=None):
        """A decorator that is used to register custom template filter.
You can specify a name for the filter, otherwise the function
name will be used. Example::

@app.template_filter()
def reverse(s):
return s[::-1]

:param name: the optional name of the filter, otherwise the
function name will be used.
"""
        def decorator(f):
            self.jinja_env.filters[name or f.__name__] = f
            return f
        return decorator

    @setupmethod
    def before_request(self, f):
        """Registers a function to run before each request."""
        self.before_request_funcs.setdefault(None, []).append(f)
        return f

    @setupmethod
    def before_first_request(self, f):
        """Registers a function to be run before the first request to this
instance of the application.

.. versionadded:: 0.8
"""
        self.before_first_request_funcs.append(f)

    @setupmethod
    def after_request(self, f):
        """Register a function to be run after each request. Your function
must take one parameter, a :attr:`response_class` object and return
a new response object or the same (see :meth:`process_response`).

As of Flask 0.7 this function might not be executed at the end of the
request in case an unhandled exception ocurred.
"""
        self.after_request_funcs.setdefault(None, []).append(f)
        return f

    @setupmethod
    def teardown_request(self, f):
        """Register a function to be run at the end of each request,
regardless of whether there was an exception or not. These functions
are executed when the request context is popped, even if not an
actual request was performed.

Example::

ctx = app.test_request_context()
ctx.push()
...
ctx.pop()

When ``ctx.pop()`` is executed in the above example, the teardown
functions are called just before the request context moves from the
stack of active contexts. This becomes relevant if you are using
such constructs in tests.

Generally teardown functions must take every necesary step to avoid
that they will fail. If they do execute code that might fail they
will have to surround the execution of these code by try/except
statements and log ocurring errors.
"""
        self.teardown_request_funcs.setdefault(None, []).append(f)
        return f

    @setupmethod
    def context_processor(self, f):
        """Registers a template context processor function."""
        self.template_context_processors[None].append(f)
        return f

    @setupmethod
    def url_value_preprocessor(self, f):
        """Registers a function as URL value preprocessor for all view
functions of the application. It's called before the view functions
are called and can modify the url values provided.
"""
        self.url_value_preprocessors.setdefault(None, []).append(f)
        return f

    @setupmethod
    def url_defaults(self, f):
        """Callback function for URL defaults for all view functions of the
application. It's called with the endpoint and values and should
update the values passed in place.
"""
        self.url_default_functions.setdefault(None, []).append(f)
        return f

    def handle_http_exception(self, e):
        """Handles an HTTP exception. By default this will invoke the
registered error handlers and fall back to returning the
exception as response.

.. versionadded: 0.3
"""
        handlers = self.error_handler_spec.get(request.blueprint)
        if handlers and e.code in handlers:
            handler = handlers[e.code]
        else:
            handler = self.error_handler_spec[None].get(e.code)
        if handler is None:
            return e
        return handler(e)

    def trap_http_exception(self, e):
        """Checks if an HTTP exception should be trapped or not. By default
this will return `False` for all exceptions except for a bad request
key error if ``TRAP_BAD_REQUEST_ERRORS`` is set to `True`. It
also returns `True` if ``TRAP_HTTP_EXCEPTIONS`` is set to `True`.

This is called for all HTTP exceptions raised by a view function.
If it returns `True` for any exception the error handler for this
exception is not called and it shows up as regular exception in the
traceback. This is helpful for debugging implicitly raised HTTP
exceptions.

.. versionadded:: 0.8
"""
        if self.config['TRAP_HTTP_EXCEPTIONS']:
            return True
        if self.config['TRAP_BAD_REQUEST_ERRORS']:
            return isinstance(e, BadRequest)
        return False

    def handle_user_exception(self, e):
        """This method is called whenever an exception occurs that should be
handled. A special case are
:class:`~werkzeug.exception.HTTPException`\s which are forwarded by
this function to the :meth:`handle_http_exception` method. This
function will either return a response value or reraise the
exception with the same traceback.

.. versionadded:: 0.7
"""
        exc_type, exc_value, tb = sys.exc_info()
        assert exc_value is e

        # ensure not to trash sys.exc_info() at that point in case someone
        # wants the traceback preserved in handle_http_exception. Of course
        # we cannot prevent users from trashing it themselves in a custom
        # trap_http_exception method so that's their fault then.
        if isinstance(e, HTTPException) and not self.trap_http_exception(e):
            return self.handle_http_exception(e)

        blueprint_handlers = ()
        handlers = self.error_handler_spec.get(request.blueprint)
        if handlers is not None:
            blueprint_handlers = handlers.get(None, ())
        app_handlers = self.error_handler_spec[None].get(None, ())
        for typecheck, handler in chain(blueprint_handlers, app_handlers):
            if isinstance(e, typecheck):
                return handler(e)

        raise exc_type, exc_value, tb

    def handle_exception(self, e):
        """Default exception handling that kicks in when an exception
occours that is not caught. In debug mode the exception will
be re-raised immediately, otherwise it is logged and the handler
for a 500 internal server error is used. If no such handler
exists, a default 500 internal server error message is displayed.

.. versionadded: 0.3
"""
        exc_type, exc_value, tb = sys.exc_info()

        got_request_exception.send(self, exception=e)
        handler = self.error_handler_spec[None].get(500)

        if self.propagate_exceptions:
            # if we want to repropagate the exception, we can attempt to
            # raise it with the whole traceback in case we can do that
            # (the function was actually called from the except part)
            # otherwise, we just raise the error again
            if exc_value is e:
                raise exc_type, exc_value, tb
            else:
                raise e

        self.log_exception((exc_type, exc_value, tb))
        if handler is None:
            return InternalServerError()
        return handler(e)

    def log_exception(self, exc_info):
        """Logs an exception. This is called by :meth:`handle_exception`
if debugging is disabled and right before the handler is called.
The default implementation logs the exception as error on the
:attr:`logger`.

.. versionadded:: 0.8
"""
        self.logger.error('Exception on %s [%s]' % (
            request.path,
            request.method
        ), exc_info=exc_info)

    def raise_routing_exception(self, request):
        """Exceptions that are recording during routing are reraised with
this method. During debug we are not reraising redirect requests
for non ``GET``, ``HEAD``, or ``OPTIONS`` requests and we're raising
a different error instead to help debug situations.

:internal:
"""
        if not self.debug \
           or not isinstance(request.routing_exception, RequestRedirect) \
           or request.method in ('GET', 'HEAD', 'OPTIONS'):
            raise request.routing_exception

        from .debughelpers import FormDataRoutingRedirect
        raise FormDataRoutingRedirect(request)

    def dispatch_request(self):
        """Does the request dispatching. Matches the URL and returns the
return value of the view or error handler. This does not have to
be a response object. In order to convert the return value to a
proper response object, call :func:`make_response`.

.. versionchanged:: 0.7
This no longer does the exception handling, this code was
moved to the new :meth:`full_dispatch_request`.
"""
        req = _request_ctx_stack.top.request
        if req.routing_exception is not None:
            self.raise_routing_exception(req)
        rule = req.url_rule
        # if we provide automatic options for this URL and the
        # request came with the OPTIONS method, reply automatically
        if getattr(rule, 'provide_automatic_options', False) \
           and req.method == 'OPTIONS':
            return self.make_default_options_response()
        # otherwise dispatch to the handler for that endpoint
        return self.view_functions[rule.endpoint](**req.view_args)

    def full_dispatch_request(self):
        """Dispatches the request and on top of that performs request
pre and postprocessing as well as HTTP exception catching and
error handling.

.. versionadded:: 0.7
"""
        self.try_trigger_before_first_request_functions()
        try:
            request_started.send(self)
            rv = self.preprocess_request()
            if rv is None:
                rv = self.dispatch_request()
        except Exception, e:
            rv = self.handle_user_exception(e)
        response = self.make_response(rv)
        response = self.process_response(response)
        request_finished.send(self, response=response)
        return response

    def try_trigger_before_first_request_functions(self):
        """Called before each request and will ensure that it triggers
the :attr:`before_first_request_funcs` and only exactly once per
application instance (which means process usually).

:internal:
"""
        if self._got_first_request:
            return
        with self._before_request_lock:
            if self._got_first_request:
                return
            self._got_first_request = True
            for func in self.before_first_request_funcs:
                func()

    def make_default_options_response(self):
        """This method is called to create the default `OPTIONS` response.
This can be changed through subclassing to change the default
behaviour of `OPTIONS` responses.

.. versionadded:: 0.7
"""
        adapter = _request_ctx_stack.top.url_adapter
        if hasattr(adapter, 'allowed_methods'):
            methods = adapter.allowed_methods()
        else:
            # fallback for Werkzeug < 0.7
            methods = []
            try:
                adapter.match(method='--')
            except MethodNotAllowed, e:
                methods = e.valid_methods
            except HTTPException, e:
                pass
        rv = self.response_class()
        rv.allow.update(methods)
        return rv

    def make_response(self, rv):
        """Converts the return value from a view function to a real
response object that is an instance of :attr:`response_class`.

The following types are allowed for `rv`:

.. tabularcolumns:: |p{3.5cm}|p{9.5cm}|

======================= ===========================================
:attr:`response_class` the object is returned unchanged
:class:`str` a response object is created with the
string as body
:class:`unicode` a response object is created with the
string encoded to utf-8 as body
:class:`tuple` the response object is created with the
contents of the tuple as arguments
a WSGI function the function is called as WSGI application
and buffered as response object
======================= ===========================================

:param rv: the return value from the view function
"""
        if rv is None:
            raise ValueError('View function did not return a response')
        if isinstance(rv, self.response_class):
            return rv
        if isinstance(rv, basestring):
            return self.response_class(rv)
        if isinstance(rv, tuple):
            return self.response_class(*rv)
        return self.response_class.force_type(rv, request.environ)

    def create_url_adapter(self, request):
        """Creates a URL adapter for the given request. The URL adapter
is created at a point where the request context is not yet set up
so the request is passed explicitly.

.. versionadded:: 0.6
"""
        return self.url_map.bind_to_environ(request.environ,
            server_name=self.config['SERVER_NAME'])

    def inject_url_defaults(self, endpoint, values):
        """Injects the URL defaults for the given endpoint directly into
the values dictionary passed. This is used internally and
automatically called on URL building.

.. versionadded:: 0.7
"""
        funcs = self.url_default_functions.get(None, ())
        if '.' in endpoint:
            bp = endpoint.split('.', 1)[0]
            funcs = chain(funcs, self.url_default_functions.get(bp, ()))
        for func in funcs:
            func(endpoint, values)

    def preprocess_request(self):
        """Called before the actual request dispatching and will
call every as :meth:`before_request` decorated function.
If any of these function returns a value it's handled as
if it was the return value from the view and further
request handling is stopped.

This also triggers the :meth:`url_value_processor` functions before
the actualy :meth:`before_request` functions are called.
"""
        bp = _request_ctx_stack.top.request.blueprint

        funcs = self.url_value_preprocessors.get(None, ())
        if bp is not None and bp in self.url_value_preprocessors:
            funcs = chain(funcs, self.url_value_preprocessors[bp])
        for func in funcs:
            func(request.endpoint, request.view_args)

        funcs = self.before_request_funcs.get(None, ())
        if bp is not None and bp in self.before_request_funcs:
            funcs = chain(funcs, self.before_request_funcs[bp])
        for func in funcs:
            rv = func()
            if rv is not None:
                return rv

    def process_response(self, response):
        """Can be overridden in order to modify the response object
before it's sent to the WSGI server. By default this will
call all the :meth:`after_request` decorated functions.

.. versionchanged:: 0.5
As of Flask 0.5 the functions registered for after request
execution are called in reverse order of registration.

:param response: a :attr:`response_class` object.
:return: a new response object or the same, has to be an
instance of :attr:`response_class`.
"""
        ctx = _request_ctx_stack.top
        bp = ctx.request.blueprint
        if not self.session_interface.is_null_session(ctx.session):
            self.save_session(ctx.session, response)
        funcs = ()
        if bp is not None and bp in self.after_request_funcs:
            funcs = reversed(self.after_request_funcs[bp])
        if None in self.after_request_funcs:
            funcs = chain(funcs, reversed(self.after_request_funcs[None]))
        for handler in funcs:
            response = handler(response)
        return response

    def do_teardown_request(self):
        """Called after the actual request dispatching and will
call every as :meth:`teardown_request` decorated function. This is
not actually called by the :class:`Flask` object itself but is always
triggered when the request context is popped. That way we have a
tighter control over certain resources under testing environments.
"""
        funcs = reversed(self.teardown_request_funcs.get(None, ()))
        bp = _request_ctx_stack.top.request.blueprint
        if bp is not None and bp in self.teardown_request_funcs:
            funcs = chain(funcs, reversed(self.teardown_request_funcs[bp]))
        exc = sys.exc_info()[1]
        for func in funcs:
            rv = func(exc)
            if rv is not None:
                return rv
        request_tearing_down.send(self)

    def request_context(self, environ):
        """Creates a :class:`~flask.ctx.RequestContext` from the given
environment and binds it to the current context. This must be used in
combination with the `with` statement because the request is only bound
to the current context for the duration of the `with` block.

Example usage::

with app.request_context(environ):
do_something_with(request)

The object returned can also be used without the `with` statement
which is useful for working in the shell. The example above is
doing exactly the same as this code::

ctx = app.request_context(environ)
ctx.push()
try:
do_something_with(request)
finally:
ctx.pop()

.. versionchanged:: 0.3
Added support for non-with statement usage and `with` statement
is now passed the ctx object.

:param environ: a WSGI environment
"""
        return RequestContext(self, environ)

    def test_request_context(self, *args, **kwargs):
        """Creates a WSGI environment from the given values (see
:func:`werkzeug.test.EnvironBuilder` for more information, this
function accepts the same arguments).
"""
        from flask.testing import make_test_environ_builder
        builder = make_test_environ_builder(self, *args, **kwargs)
        try:
            return self.request_context(builder.get_environ())
        finally:
            builder.close()

    def wsgi_app(self, environ, start_response):
        """The actual WSGI application. This is not implemented in
`__call__` so that middlewares can be applied without losing a
reference to the class. So instead of doing this::

app = MyMiddleware(app)

It's a better idea to do this instead::

app.wsgi_app = MyMiddleware(app.wsgi_app)

Then you still have the original application object around and
can continue to call methods on it.

.. versionchanged:: 0.7
The behavior of the before and after request callbacks was changed
under error conditions and a new callback was added that will
always execute at the end of the request, independent on if an
error ocurred or not. See :ref:`callbacks-and-errors`.

:param environ: a WSGI environment
:param start_response: a callable accepting a status code,
a list of headers and an optional
exception context to start the response
"""
        with self.request_context(environ):
            try:
                response = self.full_dispatch_request()
            except Exception, e:
                response = self.make_response(self.handle_exception(e))
            return response(environ, start_response)

    @property
    def modules(self):
        from warnings import warn
        warn(DeprecationWarning('Flask.modules is deprecated, use '
                                'Flask.blueprints instead'), stacklevel=2)
        return self.blueprints

    def __call__(self, environ, start_response):
        """Shortcut for :attr:`wsgi_app`."""
        return self.wsgi_app(environ, start_response)
Something went wrong with that request. Please try again.