PEP 0287 -- reStructuredText Docstring Format



# -*- coding: utf-8 -*-

    Implements various helpers.

    :copyright: (c) 2015 by Armin Ronacher.
    :license: BSD, see LICENSE for more details.


1. 类里面的属性注释

#: the salt that should be applied on top of the secret key for the
#: signing of cookie based sessions.
salt = 'cookie-session'
#: the hash function to use for the signature.  The default is sha1
digest_method = staticmethod(hashlib.sha1)
#: the name of the itsdangerous supported key derivation.  The default
#: is hmac.
key_derivation = 'hmac'

2. 普通注释

# Delete case.  If there is no session we bail early.
# If the session was modified to be empty we remove the
# whole cookie.
if not session:
    if session.modified:
                               domain=domain, path=path)

# Modification case.  There are upsides and downsides to
# emitting a set-cookie header each request.  The behavior
# is controlled by the :meth:`should_set_cookie` method
# which performs a quick check to figure out if the cookie
# should be set or not.  This is controlled by the
# SESSION_REFRESH_EACH_REQUEST config flag as well as
# the permanent flag on the session itself.
if not self.should_set_cookie(app, session):


# If request specific information is available we have some extra
# features that support "relative" URLs.
if reqctx is not None:

# Otherwise go with the url adapter from the appctx and make
# the URLs external by default.


# TODO: get rid of this deprecated functionality in 1.0


Please never pass filenames to this function from user sources;
you should use :func:`send_from_directory` instead.

.. versionadded:: 0.2

.. versionadded:: 0.5
   The `add_etags`, `cache_timeout` and `conditional` parameters were
   added.  The default behavior is now to attach etags.

.. versionchanged:: 0.7
   mimetype guessing and etag support for file objects was
   deprecated because it was unreliable.  Pass a filename if you are
   able to, otherwise attach an etag yourself.  This functionality
   will be removed in Flask 1.0

:param mimetype: the mimetype of the file if provided. If a file path is
                 given, auto detection happens as fallback, otherwise an
                 error will be raised.