quart.app module#

class quart.app.Quart(import_name: str, static_url_path: Optional[str] = None, static_folder: Optional[str] = 'static', static_host: Optional[str] = None, host_matching: bool = False, subdomain_matching: bool = False, template_folder: Optional[str] = 'templates', instance_path: Optional[str] = None, instance_relative_config: bool = False, root_path: Optional[str] = None)#

Bases: Scaffold

The web framework class, handles requests and returns responses.

The primary method from a serving viewpoint is handle_request(), from an application viewpoint all the other methods are vital.

This can be extended in many ways, with most methods designed with this in mind. Additionally any of the classes listed as attributes can be replaced.

aborter_class#

The class to use to raise HTTP error via the abort helper function.

app_ctx_globals_class#

The class to use for the g object

asgi_http_class#

The class to use to handle the ASGI HTTP protocol.

Type:

Type[quart.typing.ASGIHTTPProtocol]

asgi_lifespan_class#

The class to use to handle the ASGI lifespan protocol.

Type:

Type[quart.typing.ASGILifespanProtocol]

asgi_websocket_class#

The class to use to handle the ASGI websocket protocol.

Type:

Type[quart.typing.ASGIWebsocketProtocol]

config_class#

The class to use for the configuration.

env#

The name of the environment the app is running on.

debug#

Wrapper around configuration DEBUG value, in many places this will result in more output if True. If unset, debug mode will be activated if environ is set to ‘development’.

jinja_environment#

The class to use for the jinja environment.

jinja_options#

The default options to set when creating the jinja environment.

Type:

dict

permanent_session_lifetime#

Wrapper around configuration PERMANENT_SESSION_LIFETIME value. Specifies how long the session data should survive.

request_class#

The class to use for requests.

response_class#

The class to user for responses.

secret_key#

Warpper around configuration SECRET_KEY value. The app secret for signing sessions.

Wrapper around configuration SESSION_COOKIE_NAME, use to specify the cookie name for session data.

session_interface#

The class to use as the session interface.

url_map_class#

The class to map rules to endpoints.

url_rule_class#

The class to use for URL rules.

websocket_class#

The class to use for websockets.

aborter_class#

alias of Aborter

add_background_task(func: Callable, *args: Any, **kwargs: Any) None#
add_template_filter(func: Callable[[Any], Any], name: Optional[str] = None) None#

Add a template filter.

This is designed to be used on the application directly. An example usage,

def to_upper(value):
    return value.upper()

app.add_template_filter(to_upper)
Parameters:
  • func – The function that is the filter.

  • name – The filter name (defaults to function name).

add_template_global(func: Callable[[Any], Any], name: Optional[str] = None) None#

Add a template global.

This is designed to be used on the application directly. An example usage,

def five():
    return 5

app.add_template_global(five)
Parameters:
  • func – The function that is the global.

  • name – The global name (defaults to function name).

add_template_test(func: Callable[[Any], bool], name: Optional[str] = None) None#

Add a template test.

This is designed to be used on the application directly. An example usage,

def is_upper(value):
    return value.isupper()

app.add_template_test(is_upper)
Parameters:
  • func – The function that is the test.

  • name – The test name (defaults to function name).

add_url_rule(rule: str, endpoint: Optional[str] = None, view_func: Optional[Callable] = None, provide_automatic_options: Optional[bool] = None, *, methods: Optional[Iterable[str]] = None, defaults: Optional[dict] = None, host: Optional[str] = None, subdomain: Optional[str] = None, is_websocket: bool = False, strict_slashes: Optional[bool] = None, merge_slashes: Optional[bool] = None) None#

Add a route/url rule to the application.

This is designed to be used on the application directly. An example usage,

def route():
    ...

app.add_url_rule('/', route)
Parameters:
  • rule – The path to route on, should start with a /.

  • endpoint – Optional endpoint name, if not present the function name is used.

  • view_func – Callable that returns a response.

  • provide_automatic_options – Optionally False to prevent OPTION handling.

  • methods – List of HTTP verbs the function routes.

  • defaults

    A dictionary of variables to provide automatically, use to provide a simpler default path for a route, e.g. to allow for /book rather than /book/0,

    @app.route('/book', defaults={'page': 0})
    @app.route('/book/<int:page>')
    def book(page):
        ...
    

  • host – The full host name for this route (should include subdomain if needed) - cannot be used with subdomain.

  • subdomain – A subdomain for this specific route.

  • strict_slashes – Strictly match the trailing slash present in the path. Will redirect a leaf (no slash) to a branch (with slash).

  • is_websocket – Whether or not the view_func is a websocket.

  • merge_slashes – Merge consecutive slashes to a single slash (unless as part of the path variable).

after_serving(func: T_after_serving) T_after_serving#

Add a after serving function.

This will allow the function provided to be called once after anything is served (after last byte is sent).

This is designed to be used as a decorator, if used to decorate a synchronous function, the function will be wrapped in run_sync() and run in a thread executor (with the wrapped function returned). An example usage,

@app.after_serving
async def func():
    ...
Parameters:

func – The function itself.

app_context() AppContext#

Create and return an app context.

This is best used within a context, i.e.

async with app.app_context():
    ...
app_ctx_globals_class#

alias of _AppCtxGlobals

async asgi_app(scope: Union[HTTPScope, WebsocketScope, LifespanScope], receive: Callable[[], Awaitable[Union[HTTPRequestEvent, HTTPDisconnectEvent, WebsocketConnectEvent, WebsocketReceiveEvent, WebsocketDisconnectEvent, LifespanStartupEvent, LifespanShutdownEvent]]], send: Callable[[Union[HTTPResponseStartEvent, HTTPResponseBodyEvent, HTTPServerPushEvent, HTTPEarlyHintEvent, HTTPDisconnectEvent, WebsocketAcceptEvent, WebsocketSendEvent, WebsocketResponseStartEvent, WebsocketResponseBodyEvent, WebsocketCloseEvent, LifespanStartupCompleteEvent, LifespanStartupFailedEvent, LifespanShutdownCompleteEvent, LifespanShutdownFailedEvent]], Awaitable[None]]) None#

This handles ASGI calls, it can be wrapped in middleware.

When using middleware with Quart it is preferable to wrap this method rather than the app itself. This is to ensure that the app is an instance of this class - which allows the quart cli to work correctly. To use this feature simply do,

app.asgi_app = middleware(app.asgi_app)
asgi_http_class#

alias of ASGIHTTPConnection

asgi_lifespan_class#

alias of ASGILifespan

asgi_websocket_class#

alias of ASGIWebsocketConnection

auto_find_instance_path() Path#

Locates the instance_path if it was not provided

before_first_request(func: T_before_first_request) T_before_first_request#

Add a before first request function.

This is designed to be used as a decorator, if used to decorate a synchronous function, the function will be wrapped in run_sync() and run in a thread executor (with the wrapped function returned). An example usage,

@app.before_first_request
async def func():
    ...
Parameters:

func – The before first request function itself.

before_serving(func: T_before_serving) T_before_serving#

Add a before serving function.

This will allow the function provided to be called once before anything is served (before any byte is received).

This is designed to be used as a decorator, if used to decorate a synchronous function, the function will be wrapped in run_sync() and run in a thread executor (with the wrapped function returned). An example usage,

@app.before_serving
async def func():
    ...
Parameters:

func – The function itself.

config_class#

alias of Config

create_global_jinja_loader() DispatchingJinjaLoader#

Create and return a global (not blueprint specific) Jinja loader.

create_jinja_environment() Environment#

Create and return the jinja environment.

This will create the environment based on the jinja_options and configuration settings. The environment will include the Quart globals by default.

create_url_adapter(request: Optional[BaseRequestWebsocket]) Optional[MapAdapter]#

Create and return a URL adapter.

This will create the adapter based on the request if present otherwise the app configuration.

property debug: bool#

Activate debug mode (extra checks, logging and reloading).

Should/must be False in production.

async dispatch_request(request_context: Optional[RequestContext] = None) Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None], Tuple[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None]], Union[Headers, Dict[str, Union[str, List[str], Tuple[str, ...]]], List[Tuple[str, Union[str, List[str], Tuple[str, ...]]]]]], Tuple[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None]], int], Tuple[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None]], int, Union[Headers, Dict[str, Union[str, List[str], Tuple[str, ...]]], List[Tuple[str, Union[str, List[str], Tuple[str, ...]]]]]]]#

Dispatch the request to the view function.

Parameters:

request_context – The request context, optional as Flask omits this argument.

async dispatch_websocket(websocket_context: Optional[WebsocketContext] = None) Optional[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None], Tuple[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None]], Union[Headers, Dict[str, Union[str, List[str], Tuple[str, ...]]], List[Tuple[str, Union[str, List[str], Tuple[str, ...]]]]]], Tuple[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None]], int], Tuple[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None]], int, Union[Headers, Dict[str, Union[str, List[str], Tuple[str, ...]]], List[Tuple[str, Union[str, List[str], Tuple[str, ...]]]]]]]]#

Dispatch the websocket to the view function.

Parameters:

websocket_context – The websocket context, optional to match the Flask convention.

async do_teardown_appcontext(exc: Optional[BaseException]) None#

Teardown the app (context), calling the teardown functions.

async do_teardown_request(exc: Optional[BaseException], request_context: Optional[RequestContext] = None) None#

Teardown the request, calling the teardown functions.

Parameters:
  • exc – Any exception not handled that has caused the request to teardown.

  • request_context – The request context, optional as Flask omits this argument.

async do_teardown_websocket(exc: Optional[BaseException], websocket_context: Optional[WebsocketContext] = None) None#

Teardown the websocket, calling the teardown functions.

Parameters:
  • exc – Any exception not handled that has caused the websocket to teardown.

  • websocket_context – The websocket context, optional as Flask omits this argument.

ensure_async(func: Callable[[...], Any]) Callable[[...], Awaitable[Any]]#

Ensure that the returned func is async and calls the func.

New in version 0.11.

Override if you wish to change how synchronous functions are run. Before Quart 0.11 this did not run the synchronous code in an executor.

env#

Implements a property descriptor for objects with a config attribute.

When used as a class instance it will look up the key on the class config object, for example:

class Object:
    config = {}
    foo = ConfigAttribute('foo')

obj = Object()
obj.foo = 'bob'
assert obj.foo == obj.config['foo']
async finalize_request(result: Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None], Tuple[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None]], Union[Headers, Dict[str, Union[str, List[str], Tuple[str, ...]]], List[Tuple[str, Union[str, List[str], Tuple[str, ...]]]]]], Tuple[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None]], int], Tuple[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None]], int, Union[Headers, Dict[str, Union[str, List[str], Tuple[str, ...]]], List[Tuple[str, Union[str, List[str], Tuple[str, ...]]]]]], HTTPException], request_context: Optional[RequestContext] = None, from_error_handler: bool = False) Union[Response, Response]#

Turns the view response return value into a response.

Parameters:
  • result – The result of the request to finalize into a response.

  • request_context – The request context, optional as Flask omits this argument.

async finalize_websocket(result: Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None], Tuple[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None]], Union[Headers, Dict[str, Union[str, List[str], Tuple[str, ...]]], List[Tuple[str, Union[str, List[str], Tuple[str, ...]]]]]], Tuple[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None]], int], Tuple[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None]], int, Union[Headers, Dict[str, Union[str, List[str], Tuple[str, ...]]], List[Tuple[str, Union[str, List[str], Tuple[str, ...]]]]]]], websocket_context: Optional[WebsocketContext] = None, from_error_handler: bool = False) Optional[Union[Response, Response]]#

Turns the view response return value into a response.

Parameters:
  • result – The result of the websocket to finalize into a response.

  • websocket_context – The websocket context, optional as Flask omits this argument.

async full_dispatch_request(request_context: Optional[RequestContext] = None) Union[Response, Response]#

Adds pre and post processing to the request dispatching.

Parameters:

request_context – The request context, optional as Flask omits this argument.

async full_dispatch_websocket(websocket_context: Optional[WebsocketContext] = None) Optional[Union[Response, Response]]#

Adds pre and post processing to the websocket dispatching.

Parameters:

websocket_context – The websocket context, optional to match the Flask convention.

property got_first_request: bool#

Return if the app has received a request.

async handle_background_exception(error: Exception) None#
async handle_exception(error: Exception) Union[Response, Response]#

Handle an uncaught exception.

By default this switches the error response to a 500 internal server error.

async handle_http_exception(error: HTTPException) Union[HTTPException, Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None], Tuple[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None]], Union[Headers, Dict[str, Union[str, List[str], Tuple[str, ...]]], List[Tuple[str, Union[str, List[str], Tuple[str, ...]]]]]], Tuple[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None]], int], Tuple[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None]], int, Union[Headers, Dict[str, Union[str, List[str], Tuple[str, ...]]], List[Tuple[str, Union[str, List[str], Tuple[str, ...]]]]]]]#

Handle a HTTPException subclass error.

This will attempt to find a handler for the error and if fails will fall back to the error response.

async handle_request(request: Request) Union[Response, Response]#
handle_url_build_error(error: Exception, endpoint: str, values: dict) str#

Handle a build error.

Ideally this will return a valid url given the error endpoint and values.

async handle_user_exception(error: Exception) Union[HTTPException, Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None], Tuple[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None]], Union[Headers, Dict[str, Union[str, List[str], Tuple[str, ...]]], List[Tuple[str, Union[str, List[str], Tuple[str, ...]]]]]], Tuple[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None]], int], Tuple[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None]], int, Union[Headers, Dict[str, Union[str, List[str], Tuple[str, ...]]], List[Tuple[str, Union[str, List[str], Tuple[str, ...]]]]]]]#

Handle an exception that has been raised.

This should forward HTTPException to handle_http_exception(), then attempt to handle the error. If it cannot it should reraise the error.

async handle_websocket(websocket: Websocket) Optional[Union[Response, Response]]#
async handle_websocket_exception(error: Exception) Optional[Union[Response, Response]]#

Handle an uncaught exception.

By default this logs the exception and then re-raises it.

inject_url_defaults(endpoint: str, values: dict) None#

Injects default URL values into the passed values dict.

This is used to assist when building urls, see url_for.

iter_blueprints() ValuesView[Blueprint]#

Return a iterator over the blueprints.

property jinja_env: Environment#

The jinja environment used to load templates.

jinja_environment#

alias of Environment

jinja_options: dict = {}#
json_provider_class#

alias of DefaultJSONProvider

lock_class#

alias of Lock

log_exception(exception_info: Union[Tuple[type, BaseException, TracebackType], Tuple[None, None, None]]) None#

Log a exception to the logger.

By default this is only invoked for unhandled exceptions.

property logger: Logger#

A logging.Logger logger for the app.

This can be used to log messages in a format as defined in the app configuration, for example,

app.logger.debug("Request method %s", request.method)
app.logger.error("Error, of some kind")
make_aborter() Aborter#

Create and return the aborter instance.

make_config(instance_relative: bool = False) Config#

Create and return the configuration with appropriate defaults.

async make_default_options_response() Response#

This is the default route function for OPTIONS requests.

async make_response(result: Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None], Tuple[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None]], Union[Headers, Dict[str, Union[str, List[str], Tuple[str, ...]]], List[Tuple[str, Union[str, List[str], Tuple[str, ...]]]]]], Tuple[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None]], int], Tuple[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None]], int, Union[Headers, Dict[str, Union[str, List[str], Tuple[str, ...]]], List[Tuple[str, Union[str, List[str], Tuple[str, ...]]]]]], HTTPException]) Union[Response, Response]#

Make a Response from the result of the route handler.

The result itself can either be:
  • A Response object (or subclass).

  • A tuple of a ResponseValue and a header dictionary.

  • A tuple of a ResponseValue, status code and a header dictionary.

A ResponseValue is either a Response object (or subclass) or a str.

make_shell_context() dict#

Create a context for interactive shell usage.

The shell_context_processors can be used to add additional context.

property name: str#

The name of this application.

This is taken from the import_name and is used for debugging purposes.

async open_instance_resource(path: Union[bytes, str, PathLike], mode: str = 'rb') AiofilesContextManager[None, None, AsyncBufferedReader]#

Open a file for reading.

Use as

async with await app.open_instance_resource(path) as file_:
    await file_.read()
permanent_session_lifetime#

Implements a property descriptor for objects with a config attribute.

When used as a class instance it will look up the key on the class config object, for example:

class Object:
    config = {}
    foo = ConfigAttribute('foo')

obj = Object()
obj.foo = 'bob'
assert obj.foo == obj.config['foo']
async postprocess_websocket(response: Optional[Union[Response, Response]], websocket_context: Optional[WebsocketContext] = None) Union[Response, Response]#

Postprocess the websocket acting on the response.

Parameters:
  • response – The response after the websocket is finalized.

  • websocket_context – The websocket context, optional as Flask omits this argument.

async preprocess_request(request_context: Optional[RequestContext] = None) Optional[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None], Tuple[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None]], Union[Headers, Dict[str, Union[str, List[str], Tuple[str, ...]]], List[Tuple[str, Union[str, List[str], Tuple[str, ...]]]]]], Tuple[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None]], int], Tuple[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None]], int, Union[Headers, Dict[str, Union[str, List[str], Tuple[str, ...]]], List[Tuple[str, Union[str, List[str], Tuple[str, ...]]]]]]]]#

Preprocess the request i.e. call before_request functions.

Parameters:

request_context – The request context, optional as Flask omits this argument.

async preprocess_websocket(websocket_context: Optional[WebsocketContext] = None) Optional[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None], Tuple[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None]], Union[Headers, Dict[str, Union[str, List[str], Tuple[str, ...]]], List[Tuple[str, Union[str, List[str], Tuple[str, ...]]]]]], Tuple[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None]], int], Tuple[Union[Response, Response, AnyStr, Mapping[str, Any], List[Any], AsyncGenerator[AnyStr, None], Generator[AnyStr, None, None]], int, Union[Headers, Dict[str, Union[str, List[str], Tuple[str, ...]]], List[Tuple[str, Union[str, List[str], Tuple[str, ...]]]]]]]]#

Preprocess the websocket i.e. call before_websocket functions.

Parameters:

websocket_context – The websocket context, optional as Flask omits this argument.

property preserve_context_on_exception: bool#
async process_response(response: Union[Response, Response], request_context: Optional[RequestContext] = None) Union[Response, Response]#

Postprocess the request acting on the response.

Parameters:
  • response – The response after the request is finalized.

  • request_context – The request context, optional as Flask omits this argument.

property propagate_exceptions: bool#

Return true if exceptions should be propagated into debug pages.

If false the exception will be handled. See the PROPAGATE_EXCEPTIONS config setting.

raise_routing_exception(request: BaseRequestWebsocket) NoReturn#
redirect(location: str, code: int = 302) Response#

Create a redirect response object.

register_blueprint(blueprint: Blueprint, **options: Any) None#

Register a blueprint on the app.

This results in the blueprint’s routes, error handlers etc… being added to the app.

Parameters:
  • blueprint – The blueprint to register.

  • url_prefix – Optional prefix to apply to all paths.

  • url_defaults – Blueprint routes will use these default values for view arguments.

  • subdomain – Blueprint routes will match on this subdomain.

request_class#

alias of Request

request_context(request: Request) RequestContext#

Create and return a request context.

Use the test_request_context() whilst testing. This is best used within a context, i.e.

async with app.request_context(request):
    ...
Parameters:

request – A request to build a context around.

response_class#

alias of Response

run(host: Optional[str] = None, port: Optional[int] = None, debug: Optional[bool] = None, use_reloader: bool = True, loop: Optional[AbstractEventLoop] = None, ca_certs: Optional[str] = None, certfile: Optional[str] = None, keyfile: Optional[str] = None, **kwargs: Any) None#

Run this application.

This is best used for development only, see Hypercorn for production servers.

Parameters:
  • host – Hostname to listen on. By default this is loopback only, use 0.0.0.0 to have the server listen externally.

  • port – Port number to listen on.

  • debug – If set enable (or disable) debug mode and debug output.

  • use_reloader – Automatically reload on code changes.

  • loop – Asyncio loop to create the server in, if None, take default one. If specified it is the caller’s responsibility to close and cleanup the loop.

  • ca_certs – Path to the SSL CA certificate file.

  • certfile – Path to the SSL certificate file.

  • keyfile – Path to the SSL key file.

run_task(host: str = '127.0.0.1', port: int = 5000, debug: Optional[bool] = None, ca_certs: Optional[str] = None, certfile: Optional[str] = None, keyfile: Optional[str] = None, shutdown_trigger: Optional[Callable[[...], Awaitable[None]]] = None) Coroutine[None, None, None]#

Return a task that when awaited runs this application.

This is best used for development only, see Hypercorn for production servers.

Parameters:
  • host – Hostname to listen on. By default this is loopback only, use 0.0.0.0 to have the server listen externally.

  • port – Port number to listen on.

  • debug – If set enable (or disable) debug mode and debug output.

  • ca_certs – Path to the SSL CA certificate file.

  • certfile – Path to the SSL certificate file.

  • keyfile – Path to the SSL key file.

secret_key#

Implements a property descriptor for objects with a config attribute.

When used as a class instance it will look up the key on the class config object, for example:

class Object:
    config = {}
    foo = ConfigAttribute('foo')

obj = Object()
obj.foo = 'bob'
assert obj.foo == obj.config['foo']
select_jinja_autoescape(filename: str) bool#

Returns True if the filename indicates that it should be escaped.

send_file_max_age_default#

Implements a property descriptor for objects with a config attribute.

When used as a class instance it will look up the key on the class config object, for example:

class Object:
    config = {}
    foo = ConfigAttribute('foo')

obj = Object()
obj.foo = 'bob'
assert obj.foo == obj.config['foo']
session_cookie_name#

Implements a property descriptor for objects with a config attribute.

When used as a class instance it will look up the key on the class config object, for example:

class Object:
    config = {}
    foo = ConfigAttribute('foo')

obj = Object()
obj.foo = 'bob'
assert obj.foo == obj.config['foo']
session_interface = <quart.sessions.SecureCookieSessionInterface object>#
shell_context_processor(func: T_shell_context_processor) T_shell_context_processor#

Add a shell context processor.

This is designed to be used as a decorator. An example usage,

@app.shell_context_processor
def additional_context():
    return context
async shutdown() None#
async startup() None#
sync_to_async(func: Callable[[...], Any]) Callable[[...], Awaitable[Any]]#

Return a async function that will run the synchronous function func.

This can be used as so,:

result = await app.sync_to_async(func)(*args, **kwargs)

Override this method to change how the app converts sync code to be asynchronously callable.

teardown_appcontext(func: T_teardown) T_teardown#

Add a teardown app (context) function.

This is designed to be used as a decorator, if used to decorate a synchronous function, the function will be wrapped in run_sync() and run in a thread executor (with the wrapped function returned). An example usage,

@app.teardown_appcontext
async def func():
    ...
Parameters:
  • func – The teardown function itself.

  • name – Optional blueprint key name.

template_filter(name: Optional[str] = None) Callable[[T_template_filter], T_template_filter]#

Add a template filter.

This is designed to be used as a decorator. An example usage,

@app.template_filter('name')
def to_upper(value):
    return value.upper()
Parameters:

name – The filter name (defaults to function name).

template_global(name: Optional[str] = None) Callable[[T_template_global], T_template_global]#

Add a template global.

This is designed to be used as a decorator. An example usage,

@app.template_global('name')
def five():
    return 5
Parameters:

name – The global name (defaults to function name).

template_test(name: Optional[str] = None) Callable[[T_template_test], T_template_test]#

Add a template test.

This is designed to be used as a decorator. An example usage,

@app.template_test('name')
def is_upper(value):
    return value.isupper()
Parameters:

name – The test name (defaults to function name).

property templates_auto_reload: bool#

Returns True if templates should auto reload.

test_app() TestAppProtocol#
test_app_class#

alias of TestApp

test_cli_runner(**kwargs: Any) QuartCliRunner#

Creates and returns a CLI test runner.

test_cli_runner_class#

alias of QuartCliRunner

test_client(use_cookies: bool = True) TestClientProtocol#

Creates and returns a test client.

test_client_class#

alias of QuartClient

test_request_context(path: str, *, method: str = 'GET', headers: ~typing.Optional[~typing.Union[dict, ~werkzeug.datastructures.Headers]] = None, query_string: ~typing.Optional[dict] = None, scheme: str = 'http', send_push_promise: ~typing.Callable[[str, ~werkzeug.datastructures.Headers], ~typing.Awaitable[None]] = <function no_op_push>, data: ~typing.Optional[AnyStr] = None, form: ~typing.Optional[dict] = None, json: ~typing.Any = <object object>, root_path: str = '', http_version: str = '1.1', scope_base: ~typing.Optional[dict] = None, auth: ~typing.Optional[~typing.Union[~werkzeug.datastructures.Authorization, ~typing.Tuple[str, str]]] = None) RequestContext#

Create a request context for testing purposes.

This is best used for testing code within request contexts. It is a simplified wrapper of request_context(). It is best used in a with block, i.e.

async with app.test_request_context("/", method="GET"):
    ...
Parameters:
  • path – Request path.

  • method – HTTP verb

  • headers – Headers to include in the request.

  • query_string – To send as a dictionary, alternatively the query_string can be determined from the path.

  • scheme – Scheme for the request, default http.

testing#

Implements a property descriptor for objects with a config attribute.

When used as a class instance it will look up the key on the class config object, for example:

class Object:
    config = {}
    foo = ConfigAttribute('foo')

obj = Object()
obj.foo = 'bob'
assert obj.foo == obj.config['foo']
trap_http_exception(error: Exception) bool#

Check it error is http and should be trapped.

Trapped errors are not handled by the handle_http_exception(), but instead trapped by the outer most (or user handlers). This can be useful when debugging to allow tracebacks to be viewed by the debug page.

async try_trigger_before_first_request_functions() None#

Trigger the before first request methods.

async update_template_context(context: dict) None#

Update the provided template context.

This adds additional context from the various template context processors.

Parameters:

context – The context to update (mutate).

url_for(endpoint: str, *, _anchor: Optional[str] = None, _external: Optional[bool] = None, _method: Optional[str] = None, _scheme: Optional[str] = None, **values: Any) str#

Return the url for a specific endpoint.

This is most useful in templates and redirects to create a URL that can be used in the browser.

Parameters:
  • endpoint – The endpoint to build a url for, if prefixed with . it targets endpoint’s in the current blueprint.

  • _anchor – Additional anchor text to append (i.e. #text).

  • _external – Return an absolute url for external (to app) usage.

  • _method – The method to consider alongside the endpoint.

  • _scheme – A specific scheme to use.

  • values – The values to build into the URL, as specified in the endpoint rule.

url_map_class#

alias of QuartMap

url_rule_class#

alias of QuartRule

websocket_class#

alias of Websocket

websocket_context(websocket: Websocket) WebsocketContext#

Create and return a websocket context.

Use the test_websocket_context() whilst testing. This is best used within a context, i.e.

async with app.websocket_context(websocket):
    ...
Parameters:

websocket – A websocket to build a context around.

while_serving(func: T_while_serving) T_while_serving#

Add a while serving generator function.

This will allow the generator provided to be invoked at startup and then again at shutdown.

This is designed to be used as a decorator. An example usage,

@app.while_serving
async def func():
    ...  # Startup
    yield
    ...  # Shutdown
Parameters:

func – The function itself.