flask.scaffold.Scaffold

Undocumented

Undocumented

Undocumented

Undocumented

Register a rule for routing incoming requests and building URLs. The route decorator is a shortcut to call this with the view_func argument. These are equivalent:

@app.route("/")
def index():
    ...

def index():
    ...

app.add_url_rule("/", view_func=index)

See :ref:`url-route-registrations`.

The endpoint name for the route defaults to the name of the view function if the endpoint parameter isn't passed. An error will be raised if a function has already been registered for the endpoint.

The methods parameter defaults to ["GET"]. HEAD is always added automatically, and OPTIONS is added automatically by default.

view_func does not necessarily need to be passed, but if the rule should participate in routing an endpoint name must be associated with a view function at some point with the endpoint decorator.

app.add_url_rule("/", endpoint="index")

@app.endpoint("index")
def index():
    ...

If view_func has a required_methods attribute, those methods are added to the passed and automatic methods. If it has a provide_automatic_methods attribute, it is used as the default if the parameter is not passed.

Register a function to run after each request to this object.

The function is called with the response object, and must return a response object. This allows the functions to modify or replace the response before it is sent.

If a function raises an exception, any remaining after_request functions will not be called. Therefore, this should not be used for actions that must execute, such as to close resources. Use teardown_request for that.

Register a function to run before each request.

For example, this can be used to open a database connection, or to load the logged in user from the session.

@app.before_request
def load_user():
    if "user_id" in session:
        g.user = db.session.get(session["user_id"])

The function will be called without any arguments. If it returns a non-None value, the value is handled as if it was the return value from the view, and further request handling is stopped.

Shortcut for route with methods=["DELETE"].

Decorate a view function to register it for the given endpoint. Used if a rule is added without a view_func with add_url_rule.

app.add_url_rule("/ex", endpoint="example")

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

Register a function to handle errors by code or exception class.

A decorator that is used to register a function given an 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

Shortcut for route with methods=["GET"].

Used by send_file to determine the max_age cache value for a given file path if it wasn't passed.

By default, this returns SEND_FILE_MAX_AGE_DEFAULT from the configuration of ~flask.current_app. This defaults to None, which tells the browser to use conditional requests instead of a timed cache, which is usually preferable.

Open a resource file relative to root_path for reading.

For example, if the file schema.sql is next to the file app.py where the Flask app is defined, it can be opened with:

with app.open_resource("schema.sql") as f:
    conn.executescript(f.read())

Shortcut for route with methods=["PATCH"].

Shortcut for route with methods=["POST"].

Shortcut for route with methods=["PUT"].

Alternative error attach function to the errorhandler decorator that is more straightforward to use for non decorator usage.

Decorate a view function to register it with the given URL rule and options. Calls add_url_rule, which has more details about the implementation.

@app.route("/")
def index():
    return "Hello, World!"

See :ref:`url-route-registrations`.

The endpoint name for the route defaults to the name of the view function if the endpoint parameter isn't passed.

The methods parameter defaults to ["GET"]. HEAD and OPTIONS are added automatically.

The view function used to serve files from static_folder. A route is automatically registered for this view at static_url_path if static_folder is set.

Undocumented

Undocumented

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.

Teardown functions must avoid raising exceptions, since they . If they execute code that might fail they will have to surround the execution of these code by try/except statements and log occurring errors.

When a teardown function was called because of an exception it will be passed an error object.

The return values of teardown functions are ignored.

Register a URL value preprocessor function for all view functions in the application. These functions will be called before the before_request functions.

The function can modify the values captured from the matched url before they are passed to the view. For example, this can be used to pop a common language code value and place it in g rather than pass it to every view.

The function is passed the endpoint name and values dict. The return value is ignored.