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reformat config from table to linkable sections

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David Lord 8 years ago
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      docs/config.rst

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docs/config.rst
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@ -3,8 +3,6 @@
Configuration Handling
======================
.. versionadded:: 0.3
Applications need some kind of configuration. There are different settings
you might want to change depending on the application environment like
toggling the debug mode, setting the secret key, and other such
@ -64,172 +62,242 @@ Builtin Configuration Values
The following configuration values are used internally by Flask:
.. tabularcolumns:: |p{6.5cm}|p{8.5cm}|
================================= =========================================
``DEBUG`` enable/disable debug mode when using
``Flask.run()`` method to start server
``TESTING`` enable/disable testing mode
``PROPAGATE_EXCEPTIONS`` explicitly enable or disable the
propagation of exceptions. If not set or
explicitly set to ``None`` this is
implicitly true if either ``TESTING`` or
``DEBUG`` is true.
``PRESERVE_CONTEXT_ON_EXCEPTION`` By default if the application is in
debug mode the request context is not
popped on exceptions to enable debuggers
to introspect the data. This can be
disabled by this key. You can also use
this setting to force-enable it for non
debug execution which might be useful to
debug production applications (but also
very risky).
``SECRET_KEY`` the secret key
``SESSION_COOKIE_NAME`` the name of the session cookie
``SESSION_COOKIE_DOMAIN`` the domain for the session cookie. If
this is not set, the cookie will be
valid for all subdomains of
``SERVER_NAME``.
``SESSION_COOKIE_PATH`` the path for the session cookie. If
this is not set the cookie will be valid
for all of ``APPLICATION_ROOT`` or if
that is not set for ``'/'``.
``SESSION_COOKIE_HTTPONLY`` controls if the cookie should be set
with the httponly flag. Defaults to
``True``.
``SESSION_COOKIE_SECURE`` controls if the cookie should be set
with the secure flag. Defaults to
``False``.
``PERMANENT_SESSION_LIFETIME`` the lifetime of a permanent session as
:class:`datetime.timedelta` object.
Starting with Flask 0.8 this can also be
an integer representing seconds.
``SESSION_REFRESH_EACH_REQUEST`` this flag controls how permanent
sessions are refreshed. If set to ``True``
(which is the default) then the cookie
is refreshed each request which
automatically bumps the lifetime. If
set to ``False`` a `set-cookie` header is
only sent if the session is modified.
Non permanent sessions are not affected
by this.
``USE_X_SENDFILE`` enable/disable x-sendfile
``LOGGER_NAME`` the name of the logger
``LOGGER_HANDLER_POLICY`` the policy of the default logging
handler. The default is ``'always'``
which means that the default logging
handler is always active. ``'debug'``
will only activate logging in debug
mode, ``'production'`` will only log in
production and ``'never'`` disables it
entirely.
``SERVER_NAME`` the name and port number of the server.
Required for subdomain support (e.g.:
``'myapp.dev:5000'``) Note that
localhost does not support subdomains so
setting this to “localhost” does not
help. Setting a ``SERVER_NAME`` also
by default enables URL generation
without a request context but with an
application context.
``APPLICATION_ROOT`` The path value used for the session
cookie if ``SESSION_COOKIE_PATH`` isn't
set. If it's also ``None`` ``'/'`` is used.
Note that to actually serve your Flask
app under a subpath you need to tell
your WSGI container the ``SCRIPT_NAME``
WSGI environment variable.
``MAX_CONTENT_LENGTH`` If set to a value in bytes, Flask will
reject incoming requests with a
content length greater than this by
returning a 413 status code.
``SEND_FILE_MAX_AGE_DEFAULT`` Default cache control max age to use with
:meth:`~flask.Flask.send_static_file` (the
default static file handler) and
:func:`~flask.send_file`, as
:class:`datetime.timedelta` or as seconds.
Override this value on a per-file
basis using the
:meth:`~flask.Flask.get_send_file_max_age`
hook on :class:`~flask.Flask` or
:class:`~flask.Blueprint`,
respectively. Defaults to 43200 (12 hours).
``TRAP_HTTP_EXCEPTIONS`` If this is set to ``True`` Flask will
not execute the error handlers of HTTP
exceptions but instead treat the
exception like any other and bubble it
through the exception stack. This is
helpful for hairy debugging situations
where you have to find out where an HTTP
exception is coming from.
``TRAP_BAD_REQUEST_ERRORS`` Werkzeug's internal data structures that
deal with request specific data will
raise special key errors that are also
bad request exceptions. Likewise many
operations can implicitly fail with a
BadRequest exception for consistency.
Since it's nice for debugging to know
why exactly it failed this flag can be
used to debug those situations. If this
config is set to ``True`` you will get
a regular traceback instead.
``PREFERRED_URL_SCHEME`` The URL scheme that should be used for
URL generation if no URL scheme is
available. This defaults to ``http``.
``JSON_AS_ASCII`` By default Flask serialize object to
ascii-encoded JSON. If this is set to
``False`` Flask will not encode to ASCII
and output strings as-is and return
unicode strings. ``jsonify`` will
automatically encode it in ``utf-8``
then for transport for instance.
``JSON_SORT_KEYS`` By default Flask will serialize JSON
objects in a way that the keys are
ordered. This is done in order to
ensure that independent of the hash seed
of the dictionary the return value will
be consistent to not trash external HTTP
caches. You can override the default
behavior by changing this variable.
This is not recommended but might give
you a performance improvement on the
cost of cacheability.
``JSONIFY_PRETTYPRINT_REGULAR`` If this is set to ``True`` or the Flask app
is running in debug mode, jsonify responses
will be pretty printed.
``JSONIFY_MIMETYPE`` MIME type used for jsonify responses.
``TEMPLATES_AUTO_RELOAD`` Whether to check for modifications of
the template source and reload it
automatically. By default the value is
``None`` which means that Flask checks
original file only in debug mode.
``EXPLAIN_TEMPLATE_LOADING`` If this is enabled then every attempt to
load a template will write an info
message to the logger explaining the
attempts to locate the template. This
can be useful to figure out why
templates cannot be found or wrong
templates appear to be loaded.
================================= =========================================
.. admonition:: More on ``SERVER_NAME``
The ``SERVER_NAME`` key is used for the subdomain support. Because
Flask cannot guess the subdomain part without the knowledge of the
actual server name, this is required if you want to work with
subdomains. This is also used for the session cookie.
Please keep in mind that not only Flask has the problem of not knowing
what subdomains are, your web browser does as well. Most modern web
browsers will not allow cross-subdomain cookies to be set on a
server name without dots in it. So if your server name is
``'localhost'`` you will not be able to set a cookie for
``'localhost'`` and every subdomain of it. Please choose a different
server name in that case, like ``'myapplication.local'`` and add
this name + the subdomains you want to use into your host config
or setup a local `bind`_.
.. _bind: https://www.isc.org/downloads/bind/
.. py:data:: DEBUG
Enable debug mode. When using the development server with ``flask run`` or
``app.run``, an interactive debugger will be shown for unhanlded
exceptions, and the server will be reloaded when code changes.
**Do not enable debug mode in production.**
Default: ``False``
.. py:data:: TESTING
Enable testing mode. Exceptions are propagated rather than handled by the
the app's error handlers. Extensions may also change their behavior to
facilitate easier testing. You should enable this in your own tests.
Default: ``False``
.. py:data:: PROPAGATE_EXCEPTIONS
Exceptions are re-raised rather than being handled by the app's error
handlers. If not set, this is implicitly true if ``TESTING`` or ``DEBUG``
is enabled.
Default: ``None``
.. py:data:: PRESERVE_CONTEXT_ON_EXCEPTION
Don't pop the request context when an exception occurs. If not set, this
is true if ``DEBUG`` is true. This allows debuggers to introspect the
request data on errors, and should normally not need to be set directly.
Default: ``None``
.. py:data:: TRAP_HTTP_EXCEPTIONS
If there is no handler for an ``HTTPException``-type exception, re-raise it
to be handled by the interactive debugger instead of returning it as a
simple error response.
Default: ``False``
.. py:data:: TRAP_BAD_REQUEST_ERRORS``
Trying to access a key that doesn't exist from request dicts like ``args``
and ``form`` will return a 400 Bad Request error page. Enable this to treat
the error as an unhandled exception instead so that you get the interactive
debugger. This is a more specific version of ``TRAP_HTTP_EXCEPTIONS``.
Default: ``False``
.. py:data:: SECRET_KEY
A secret key that will be used for securely signing the session cookie
and can be used for any other security related needs by extensions or your
application. It should be a long random string of bytes, although unicode
is accepted too. For example, copy the output of this to your config::
python -c 'import os; print(os.urandom(32))'
**Do not reveal the secret key when posting questions or committing code.**
Default: ``None``
.. py:data:: SESSION_COOKIE_NAME
The name of the session cookie. Can be changed in case you already have a
cookie with the same name.
Default: ``'session'``
.. py:data:: SESSION_COOKIE_DOMAIN
The domain match rule that the session cookie will be valid for. If not
set, the cookie will be valid for all subdomains of ``SERVER_NAME``. If
``False``, the cookie's domain will not be set.
Default: ``None``
.. py:data:: SESSION_COOKIE_PATH
The path that the session cookie will be valid for. If not set, the cookie
will be valid underneath ``APPLICATION_ROOT`` or ``/`` if that is not set.
Default: ``None``
.. py:data:: SESSION_COOKIE_HTTPONLY
Browsers will not allow JavaScript access to cookies marked as "HTTP only"
for security.
Default: ``True``
.. py:data:: SESSION_COOKIE_SECURE
Browsers will only send cookies with requests over HTTPS if the cookie is
marked "secure". The application must be served over HTTPS for this to make
sense.
Default: ``False``
.. py:data:: SESSION_COOKIE_LIFETIME
If ``session.permanent`` is true, the cookie's max age will be set to this
number of seconds. Can either be a :class:`datetime.timedelta` or an
``int``.
Default: ``timedelta(days=31)`` (``2678400`` seconds)
.. py:data:: SESSION_REFRESH_EACH_REQUEST
Control whether the cookie is sent with every response when
``session.permanent`` is true. Sending the cookie every time (the default)
can more reliably keep the session from expiring, but uses more bandwidth.
Non-permanent sessions are not affected.
Default: ``True``
.. py:data:: USE_X_SENDFILE
When serving files, set the ``X-Sendfile`` header instead of serving the
data with Flask. Some web servers, such as Apache, recognize this and serve
the data more efficiently. This only makes sense when using such a server.
Default: ``False``
.. py:data:: SEND_FILE_MAX_AGE
When serving files, set the cache control max age to this number of
seconds. Can either be a :class:`datetime.timedelta` or an ``int``.
Override this value on a per-file basis using
:meth:`~flask.Flask.get_send_file_max_age` on the application or blueprint.
Default: ``timedelta(hours=12)`` (``43200`` seconds)
.. py:data:: LOGGER_NAME
The name of the logger that the Flask application sets up. If not set,
it will take the import name passed to ``Flask.__init__``.
Default: ``None``
.. py:data:: LOGGER_HANDLER_POLICY
When to activate the application's logger handler. ``'always'`` always
enables it, ``'debug'`` only activates it in debug mode, ``'production'``
only activates it when not in debug mode, and ``'never'`` never enables it.
Default: ``'always'``
.. py:data:: SERVER_NAME
Inform the application what host and port it is bound to. Required for
subdomain route matching support.
If set, will be used for the session cookie domain if
``SESSION_COOKIE_DOMAIN`` is not set. Modern web browsers will not allow
setting cookies for domains without a dot. To use a domain locally,
add any names that should route to the app to your ``hosts`` file. ::
127.0.0.1 localhost.dev
If set, ``url_for`` can generate external URLs with only an application
context instead of a request context.
Default: ``None``
.. py:data:: APPLICATION_ROOT
Inform the application what path it is mounted under by the application /
web server.
Will be used for the session cookie path if ``SESSION_COOKIE_PATH`` is not
set.
Default: ``'/'``
.. py:data:: PREFERRED_URL_SCHEME
Use this scheme for generating external URLs when not in a request context.
Default: ``'http'``
.. py:data:: MAX_CONTENT_LENGTH
Don't read more than this many bytes from the incoming request data. If not
set and the request does not specify a ``CONTENT_LENGTH``, no data will be
read for security.
Default: ``None``
.. py:data:: JSON_AS_ASCII
Serialize objects to ASCII-encoded JSON. If this is disabled, the JSON
will be returned as a Unicode string, or encoded as ``UTF-8`` by
``jsonify``. This has security implications when rendering the JSON in
to JavaScript in templates, and should typically remain enabled.
Default: ``True``
.. py:data:: JSON_SORT_KEYS
Sort the keys of JSON objects alphabetically. This is useful for caching
because it ensures the data is serialized the same way no matter what
Python's hash seed is. While not recommended, you can disable this for a
possible performance improvement at the cost of caching.
Default: ``True``
.. py:data:: JSONIFY_PRETTYPRINT_REGULAR
``jsonify`` responses will be output with newlines, spaces, and indentation
for easier reading by humans. Always enabled in debug mode.
Default: ``False``
.. py:data:: JSONIFY_MIMETYPE
The mimetype of ``jsonify`` responses.
Default: ``'application/json'``
.. py:data:: TEMPLATES_AUTO_RELOAD
Reload templates when they are changed. If not set, it will be enabled in
debug mode.
Default: ``None``
.. py:data:: EXPLAIN_TEMPLATE_LOADING
Log debugging information tracing how a template file was loaded. This can
be useful to figure out why a template was not loaded or the wrong file
appears to be loaded.
Default: ``False``
.. versionadded:: 0.4
``LOGGER_NAME``
@ -477,3 +545,4 @@ Example usage for both::
# or via open_instance_resource:
with app.open_instance_resource('application.cfg') as f:
config = f.read()

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