quart package¶

Subpackages¶

Module contents¶

class quart.Blueprint(name: str, import_name: str, static_folder: Optional[str] = None, static_url_path: Optional[str] = None, template_folder: Optional[str] = None, url_prefix: Optional[str] = None, subdomain: Optional[str] = None, url_defaults: Optional[dict] = None, root_path: Optional[str] = None, **kwargs: Any)¶

Bases: quart.static.PackageStatic

A blueprint is a collection of application properties.

The application properties include routes, error handlers, and before and after request functions. It is useful to produce modular code as it allows the properties to be defined in a blueprint thereby deferring the addition of these properties to the app.

json_decoder¶: The decoder to use for routes in this blueprint, the default, None, indicates that the app encoder should be used.

json_encoder¶: The encoder to use for routes in this blueprint, the default, None, indicates that the app encoder should be used.

url_prefix¶: An additional prefix to every route rule in the blueprint.

add_app_template_filter(func: Callable, name: Optional[str] = None) → None¶

Add an application wide template filter.

This is designed to be used on the blueprint directly, and has the same arguments as add_template_filter(). An example usage,

def filter():
    ...

blueprint = Blueprint(__name__)
blueprint.add_app_template_filter(filter)

add_app_template_global(func: Callable, name: Optional[str] = None) → None¶

Add an application wide template global.

This is designed to be used on the blueprint directly, and has the same arguments as add_template_global(). An example usage,

def global():
    ...

blueprint = Blueprint(__name__)
blueprint.add_app_template_global(global)

add_app_template_test(func: Callable, name: Optional[str] = None) → None¶

Add an application wide template test.

This is designed to be used on the blueprint directly, and has the same arguments as add_template_test(). An example usage,

def test():
    ...

blueprint = Blueprint(__name__)
blueprint.add_app_template_test(test)

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

Add a route/url rule to the blueprint.

This is designed to be used on the blueprint directly, and has the same arguments as add_url_rule(). An example usage,

def route():
    ...

blueprint = Blueprint(__name__)
blueprint.add_url_rule('/', route)

add_websocket(rule: str, endpoint: Optional[str] = None, view_func: Optional[Callable] = None, defaults: Optional[dict] = None, host: Optional[str] = None, subdomain: Optional[str] = None, *, strict_slashes: Optional[bool] = None) → None¶

Add a websocket rule to the blueprint.

This is designed to be used on the blueprint directly, and has the same arguments as add_websocket(). An example usage,

def route():
    ...

blueprint = Blueprint(__name__)
blueprint.add_websocket('/', route)

after_app_request(func: Callable) → Callable¶

Add a after request function to the app.

This is designed to be used as a decorator, and has the same arguments as after_request(). It applies to all requests to the app this blueprint is registered on. An example usage,

blueprint = Blueprint(__name__)
@blueprint.after_app_request
def after():
    ...

after_app_websocket(func: Callable) → Callable¶

Add an after websocket function to the App.

This is designed to be used as a decorator, and has the same arguments as after_websocket(). It applies to all requests to the ppe this blueprint is registerd on. An example usage,

blueprint = Blueprint(__name__)
@blueprint.after_app_websocket
def after():
    ...

after_request(func: Callable) → Callable¶

Add an after request function to the Blueprint.

This is designed to be used as a decorator, and has the same arguments as after_request(). It applies only to requests that are routed to an endpoint in this blueprint. An example usage,

blueprint = Blueprint(__name__)
@blueprint.after_request
def after():
    ...

after_websocket(func: Callable) → Callable¶

Add an after websocket function to the Blueprint.

This is designed to be used as a decorator, and has the same arguments as after_websocket(). It applies only to requests that are routed to an endpoint in this blueprint. An example usage,

blueprint = Blueprint(__name__)
@blueprint.after_websocket
def after():
    ...

app_context_processor(func: Callable) → Callable¶

Add a context processor function to the app.

This is designed to be used as a decorator, and has the same arguments as context_processor(). This will add context to all templates rendered. An example usage,

blueprint = Blueprint(__name__)
@blueprint.app_context_processor
def processor():
    ...

app_errorhandler(error: Union[Type[Exception], int]) → Callable¶

Add an error handler function to the App.

This is designed to be used as a decorator, and has the same arguments as errorhandler(). It applies only to all errors. An example usage,

blueprint = Blueprint(__name__)
@blueprint.app_errorhandler(404)
def not_found():
    ...

app_template_filter(name: Optional[str] = None) → Callable¶

Add an application wide template filter.

This is designed to be used as a decorator, and has the same arguments as template_filter(). An example usage,

blueprint = Blueprint(__name__)
@blueprint.app_template_filter()
def filter(value):
    ...

app_template_global(name: Optional[str] = None) → Callable¶

Add an application wide template global.

This is designed to be used as a decorator, and has the same arguments as template_global(). An example usage,

blueprint = Blueprint(__name__)
@blueprint.app_template_global()
def global(value):
    ...

app_template_test(name: Optional[str] = None) → Callable¶

Add an application wide template test.

This is designed to be used as a decorator, and has the same arguments as template_test(). An example usage,

blueprint = Blueprint(__name__)
@blueprint.app_template_test()
def test(value):
    ...

app_url_defaults(func: Callable) → Callable¶

Add a url default preprocessor.

This is designed to be used as a decorator, and has the same arguments as url_defaults(). This will apply to all urls. An example usage,

blueprint = Blueprint(__name__)
@blueprint.app_url_defaults
def default(endpoint, values):
    ...

app_url_value_preprocessor(func: Callable) → Callable¶

Add a url value preprocessor.

This is designed to be used as a decorator, and has the same arguments as app_url_value_preprocessor(). This will apply to all URLs. An example usage,

blueprint = Blueprint(__name__)
@blueprint.app_url_value_preprocessor
def processor(endpoint, view_args):
    ...

before_app_first_request(func: Callable) → Callable¶

Add a before request first function to the app.

This is designed to be used as a decorator, and has the same arguments as before_first_request(). It is triggered before the first request to the app this blueprint is registered on. An example usage,

blueprint = Blueprint(__name__)
@blueprint.before_app_first_request
def before_first():
    ...

before_app_request(func: Callable) → Callable¶

Add a before request function to the app.

This is designed to be used as a decorator, and has the same arguments as before_request(). It applies to all requests to the app this blueprint is registered on. An example usage,

blueprint = Blueprint(__name__)
@blueprint.before_app_request
def before():
    ...

before_app_websocket(func: Callable) → Callable¶

Add a before request websocket to the App.

This is designed to be used as a decorator, and has the same arguments as before_websocket(). It applies to all requests to the app this blueprint is registered on. An example usage,

blueprint = Blueprint(__name__)
@blueprint.before_app_websocket
def before():
    ...

before_request(func: Callable) → Callable¶

Add a before request function to the Blueprint.

This is designed to be used as a decorator, and has the same arguments as before_request(). It applies only to requests that are routed to an endpoint in this blueprint. An example usage,

blueprint = Blueprint(__name__)
@blueprint.before_request
def before():
    ...

before_websocket(func: Callable) → Callable¶

Add a before request websocket to the Blueprint.

This is designed to be used as a decorator, and has the same arguments as before_websocket(). It applies only to requests that are routed to an endpoint in this blueprint. An example usage,

blueprint = Blueprint(__name__)
@blueprint.before_websocket
def before():
    ...

context_processor(func: Callable) → Callable¶

Add a context processor function to this blueprint.

This is designed to be used as a decorator, and has the same arguments as context_processor(). This will add context to all templates rendered in this blueprint’s routes. An example usage,

blueprint = Blueprint(__name__)
@blueprint.context_processor
def processor():
    ...

endpoint(endpoint: str) → Callable¶

Add an endpoint to the blueprint.

This is designed to be used as a decorator, and has the same arguments as endpoint(). An example usage,

blueprint = Blueprint(__name__)
@blueprint.endpoint('index')
def index():
    ...

errorhandler(error: Union[Type[Exception], int]) → Callable¶

Add an error handler function to the Blueprint.

This is designed to be used as a decorator, and has the same arguments as errorhandler(). It applies only to errors that originate in routes in this blueprint. An example usage,

blueprint = Blueprint(__name__)
@blueprint.errorhandler(404)
def not_found():
    ...

json_decoder: Optional[Type[json.decoder.JSONDecoder]] = None¶

json_encoder: Optional[Type[json.encoder.JSONEncoder]] = None¶

make_setup_state(app: Quart, options: dict, first_registration: bool = False) → BlueprintSetupState¶

Return a blueprint setup state instance.

Parameters

first_registration – True if this is the first registration of this blueprint on the app.
options – Keyword arguments forwarded from register_blueprint().
first_registration – Whether this is the first time this blueprint has been registered on the application.

record(func: Callable[[BlueprintSetupState], Callable]) → None¶: Used to register a deferred action.

record_once(func: Callable[[BlueprintSetupState], Callable]) → None¶: Used to register a deferred action that happens only once.

register(app: Quart, options: dict, first_registration: bool = False) → None¶

Parameters

app – The application this blueprint is being registered with.
options – Keyword arguments forwarded from register_blueprint().
first_registration – Whether this is the first time this blueprint has been registered on the application.

register_error_handler(error: Union[Type[Exception], int], func: Callable) → None¶

Add an error handler function to the blueprint.

This is designed to be used on the blueprint directly, and has the same arguments as register_error_handler(). An example usage,

def not_found():
    ...

blueprint = Blueprint(__name__)
blueprint.register_error_handler(404, not_found)

route(rule: str, methods: Optional[List[str]] = None, endpoint: Optional[str] = None, defaults: Optional[dict] = None, host: Optional[str] = None, subdomain: Optional[str] = None, *, provide_automatic_options: Optional[bool] = None, strict_slashes: Optional[bool] = None) → Callable¶

Add a route to the blueprint.

This is designed to be used as a decorator, and has the same arguments as route(). An example usage,

blueprint = Blueprint(__name__)
@blueprint.route('/')
def route():
    ...

teardown_app_request(func: Callable) → Callable¶

Add a teardown request function to the app.

This is designed to be used as a decorator, and has the same arguments as teardown_request(). It applies to all requests to the app this blueprint is registered on. An example usage,

blueprint = Blueprint(__name__)
@blueprint.teardown_app_request
def teardown():
    ...

teardown_request(func: Callable) → Callable¶

Add a teardown request function to the Blueprint.

This is designed to be used as a decorator, and has the same arguments as teardown_request(). It applies only to requests that are routed to an endpoint in this blueprint. An example usage,

blueprint = Blueprint(__name__)
@blueprint.teardown_request
def teardown():
    ...

teardown_websocket(func: Callable) → Callable¶

Add a teardown websocket function to the Blueprint.

This is designed to be used as a decorator, and has the same arguments as teardown_websocket(). It applies only to requests that are routed to an endpoint in this blueprint. An example usage,

blueprint = Blueprint(__name__)
@blueprint.teardown_websocket
def teardown():
    ...

url_defaults(func: Callable) → Callable¶

Add a url default preprocessor.

This is designed to be used as a decorator, and has the same arguments as url_defaults(). This will apply to urls in this blueprint. An example usage,

blueprint = Blueprint(__name__)
@blueprint.url_defaults
def default(endpoint, values):
    ...

url_value_preprocessor(func: Callable) → Callable¶

Add a url value preprocessor.

This is designed to be used as a decorator, and has the same arguments as url_value_preprocessor(). This will apply to urls in this blueprint. An example usage,

blueprint = Blueprint(__name__)
@blueprint.url_value_preprocessor
def processor(endpoint, view_args):
    ...

websocket(rule: str, endpoint: Optional[str] = None, defaults: Optional[dict] = None, host: Optional[str] = None, subdomain: Optional[str] = None, *, strict_slashes: Optional[bool] = None) → Callable¶

Add a websocket to the blueprint.

This is designed to be used as a decorator, and has the same arguments as websocket(). An example usage,

blueprint = Blueprint(__name__)
@blueprint.websocket('/')
async def route():
    ...

class quart.Config(root_path: Union[bytes, str, os.PathLike], defaults: Optional[dict] = None)¶

Bases: dict

Extends a standard Python dictionary with additional load (from) methods.

Note that the convention (as enforced when loading) is that configuration keys are upper case. Whilst you can set lower case keys it is not recommended.

from_envvar(variable_name: str, silent: bool = False) → None¶

Load the configuration from a location specified in the environment.

This will load a cfg file using from_pyfile() from the location specified in the environment, for example the two blocks below are equivalent.

app.config.from_envvar('CONFIG')

filename = os.environ['CONFIG']
app.config.from_pyfile(filename)

from_file(filename: str, load: Callable[[IO[Any]], Mapping], silent: bool = False) → None¶

Load the configuration from a data file.

This allows configuration to be loaded as so

app.config.from_file('config.toml', toml.load)
app.config.from_file('config.json', json.load)

Parameters

filename – The filename which when appended to root_path gives the path to the file.
load – Callable that takes a file descriptor and returns a mapping loaded from the file.
silent – If True any errors will fail silently.

from_json(filename: str, silent: bool = False) → None¶

Load the configuration values from a JSON formatted file.

This allows configuration to be loaded as so

app.config.from_json('config.json')

Parameters

filename – The filename which when appended to root_path gives the path to the file.
silent – If True any errors will fail silently.

from_mapping(mapping: Optional[Mapping[str, Any]] = None, **kwargs: Any) → None¶

Load the configuration values from a mapping.

This allows either a mapping to be directly passed or as keyword arguments, for example,

config = {'FOO': 'bar'}
app.config.from_mapping(config)
app.config.form_mapping(FOO='bar')

Parameters

mapping – Optionally a mapping object.
kwargs – Optionally a collection of keyword arguments to form a mapping.

from_object(instance: Union[object, str]) → None¶

Load the configuration from a Python object.

This can be used to reference modules or objects within modules for example,

app.config.from_object('module')
app.config.from_object('module.instance')
from module import instance
app.config.from_object(instance)

are valid.

Parameters: instance – Either a str referencing a python object or the object itself.

from_pyfile(filename: str, silent: bool = False) → None¶

Load the configuration from a Python cfg or py file.

See Python’s ConfigParser docs for details on the cfg format. It is a common practice to load the defaults from the source using the from_object() and then override with a cfg or py file, for example

app.config.from_object('config_module')
app.config.from_pyfile('production.cfg')

Parameters: filename – The filename which when appended to root_path gives the path to the file

get_namespace(namespace: str, lowercase: bool = True, trim_namespace: bool = True) → Dict[str, Any]¶

Return a dictionary of keys within a namespace.

A namespace is considered to be a key prefix, for example the keys FOO_A, FOO_BAR, FOO_B are all within the FOO namespace. This method would return a dictionary with these keys and values present.

config = {'FOO_A': 'a', 'FOO_BAR': 'bar', 'BAR': False}
app.config.from_mapping(config)
assert app.config.get_namespace('FOO_') == {'a': 'a', 'bar': 'bar'}

Parameters

namespace – The namespace itself (should be uppercase).
lowercase – Lowercase the keys in the returned dictionary.
trim_namespace – Remove the namespace from the returned keys.

class quart.Markup(base='', encoding=None, errors='strict')¶

Bases: str

A string that is ready to be safely inserted into an HTML or XML document, either because it was escaped or because it was marked safe.

Passing an object to the constructor converts it to text and wraps it to mark it safe without escaping. To escape the text, use the escape() class method instead.

>>> Markup('Hello, <em>World</em>!')
Markup('Hello, <em>World</em>!')
>>> Markup(42)
Markup('42')
>>> Markup.escape('Hello, <em>World</em>!')
Markup('Hello &lt;em&gt;World&lt;/em&gt;!')

This implements the __html__() interface that some frameworks use. Passing an object that implements __html__() will wrap the output of that method, marking it safe.

>>> class Foo:
...     def __html__(self):
...         return '<a href="/foo">foo</a>'
...
>>> Markup(Foo())
Markup('<a href="/foo">foo</a>')

This is a subclass of the text type (str in Python 3, unicode in Python 2). It has the same methods as that type, but all methods escape their arguments and return a Markup instance.

>>> Markup('<em>%s</em>') % 'foo & bar'
Markup('<em>foo &amp; bar</em>')
>>> Markup('<em>Hello</em> ') + '<foo>'
Markup('<em>Hello</em> &lt;foo&gt;')

capitalize(*args, **kwargs)¶

Return a capitalized version of the string.

More specifically, make the first character have upper case and the rest lower case.

center(*args, **kwargs)¶

Return a centered string of length width.

Padding is done using the specified fill character (default is a space).

classmethod escape(s)¶: Escape a string. Calls escape() and ensures that for subclasses the correct type is returned.

expandtabs(*args, **kwargs)¶

Return a copy where all tab characters are expanded using spaces.

If tabsize is not given, a tab size of 8 characters is assumed.

format(*args, **kwargs) → str¶: Return a formatted version of S, using substitutions from args and kwargs. The substitutions are identified by braces (‘{‘ and ‘}’).

join(seq)¶

Concatenate any number of strings.

The string whose method is called is inserted in between each given string. The result is returned as a new string.

Example: ‘.’.join([‘ab’, ‘pq’, ‘rs’]) -> ‘ab.pq.rs’

ljust(*args, **kwargs)¶

Return a left-justified string of length width.

Padding is done using the specified fill character (default is a space).

lower(*args, **kwargs)¶: Return a copy of the string converted to lowercase.

lstrip(*args, **kwargs)¶

Return a copy of the string with leading whitespace removed.

If chars is given and not None, remove characters in chars instead.

partition(sep)¶

Partition the string into three parts using the given separator.

This will search for the separator in the string. If the separator is found, returns a 3-tuple containing the part before the separator, the separator itself, and the part after it.

If the separator is not found, returns a 3-tuple containing the original string and two empty strings.

replace(*args, **kwargs)¶

Return a copy with all occurrences of substring old replaced by new.

count
Maximum number of occurrences to replace. -1 (the default value) means replace all occurrences.

If the optional argument count is given, only the first count occurrences are replaced.

rjust(*args, **kwargs)¶

Return a right-justified string of length width.

Padding is done using the specified fill character (default is a space).

rpartition(sep)¶

Partition the string into three parts using the given separator.

This will search for the separator in the string, starting at the end. If the separator is found, returns a 3-tuple containing the part before the separator, the separator itself, and the part after it.

If the separator is not found, returns a 3-tuple containing two empty strings and the original string.

rsplit(*args, **kwargs)¶

Return a list of the words in the string, using sep as the delimiter string.

sep
The delimiter according which to split the string. None (the default value) means split according to any whitespace, and discard empty strings from the result.

maxsplit
Maximum number of splits to do. -1 (the default value) means no limit.

Splits are done starting at the end of the string and working to the front.

rstrip(*args, **kwargs)¶

Return a copy of the string with trailing whitespace removed.

If chars is given and not None, remove characters in chars instead.

split(*args, **kwargs)¶

Return a list of the words in the string, using sep as the delimiter string.

sep: The delimiter according which to split the string. None (the default value) means split according to any whitespace, and discard empty strings from the result.
maxsplit: Maximum number of splits to do. -1 (the default value) means no limit.

splitlines(*args, **kwargs)¶

Return a list of the lines in the string, breaking at line boundaries.

Line breaks are not included in the resulting list unless keepends is given and true.

strip(*args, **kwargs)¶

Return a copy of the string with leading and trailing whitespace removed.

If chars is given and not None, remove characters in chars instead.

striptags()¶

unescape() the markup, remove tags, and normalize whitespace to single spaces.

>>> Markup('Main &raquo;        <em>About</em>').striptags()
'Main » About'

swapcase(*args, **kwargs)¶: Convert uppercase characters to lowercase and lowercase characters to uppercase.

title(*args, **kwargs)¶

Return a version of the string where each word is titlecased.

More specifically, words start with uppercased characters and all remaining cased characters have lower case.

translate(*args, **kwargs)¶

Replace each character in the string using the given translation table.

table
Translation table, which must be a mapping of Unicode ordinals to Unicode ordinals, strings, or None.

The table must implement lookup/indexing via __getitem__, for instance a dictionary or list. If this operation raises LookupError, the character is left untouched. Characters mapped to None are deleted.

unescape()¶

Convert escaped markup back into a text string. This replaces HTML entities with the characters they represent.

>>> Markup('Main &raquo; <em>About</em>').unescape()
'Main » <em>About</em>'

upper(*args, **kwargs)¶: Return a copy of the string converted to uppercase.

zfill(*args, **kwargs)¶

Pad a numeric string with zeros on the left, to fill a field of the given width.

The string is never truncated.

class quart.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', root_path: Optional[str] = None, instance_path: Optional[str] = None, instance_relative_config: bool = False)¶

Bases: quart.static.PackageStatic

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.

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.

asgi_lifespan_class¶: The class to use to handle the ASGI lifespan protocol.

asgi_websocket_class¶: The class to use to handle the ASGI websocket protocol.

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.

json_decoder¶: The decoder for JSON data.

json_encoder¶: The encoder for JSON data.

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.

session_cookie_name¶: 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.

add_template_filter(func: Callable, 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, 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, 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).

Add a websocket url rule to the application.

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

def websocket_route():
    ...

app.add_websocket('/', websocket_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.
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.websocket('/book', defaults={'page': 0})
@app.websocket('/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).

after_request(func: Union[Callable[[quart.wrappers.response.Response], quart.wrappers.response.Response], Callable[[quart.wrappers.response.Response], Awaitable[quart.wrappers.response.Response]]], name: Optional[str] = None) → Callable[[quart.wrappers.response.Response], Awaitable[None]]¶

Add an after 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.after_request
async def func(response):
    return response

Parameters

func – The after request function itself.
name – Optional blueprint key name.

after_serving(func: Union[Callable[], None], Callable[], Awaitable[None]]]) → Callable[], Awaitable[None]]¶

Add a after serving function.

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

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

Parameters: func – The function itself.

after_websocket(func: Union[Callable[[quart.wrappers.response.Response], Optional[quart.wrappers.response.Response]], Callable[[quart.wrappers.response.Response], Awaitable[Optional[quart.wrappers.response.Response]]]], name: Optional[str] = None) → Callable[[quart.wrappers.response.Response], Awaitable[None]]¶

Add an after websocket function.

@app.after_websocket
async def func(response):
    return response

Parameters

func – The after websocket function itself.
name – Optional blueprint key name.

app_context() → quart.ctx.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 quart.ctx._AppCtxGlobals

async asgi_app(scope: dict, receive: Callable, send: Callable) → 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 quart.asgi.ASGIHTTPConnection

asgi_lifespan_class¶: alias of quart.asgi.ASGILifespan

asgi_websocket_class¶: alias of quart.asgi.ASGIWebsocketConnection

auto_find_instance_path() → pathlib.Path¶: Locates the instance_path if it was not provided

before_first_request(func: Union[Callable[], None], Callable[], Awaitable[None]]]) → Callable[], Awaitable[None]]¶

Add a before first request function.

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

Parameters: func – The before first request function itself.

before_request(func: Union[Callable[], None], Callable[], Awaitable[None]]], name: Optional[str] = None) → Callable[], Awaitable[None]]¶

Add a before request function.

@app.before_request
async def func():
    ...

Parameters

func – The before request function itself.
name – Optional blueprint key name.

before_serving(func: Union[Callable[], None], Callable[], Awaitable[None]]]) → Callable[], Awaitable[None]]¶

Add a before serving function.

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

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

Parameters: func – The function itself.

before_websocket(func: Union[Callable[], None], Callable[], Awaitable[None]]], name: Optional[str] = None) → Callable[], Awaitable[None]]¶

Add a before websocket function.

@app.before_websocket
async def func():
    ...

Parameters

func – The before websocket function itself.
name – Optional blueprint key name.

config_class¶: alias of quart.config.Config

context_processor(func: Union[Callable[], Dict[str, Any]], Callable[], Awaitable[Dict[str, Any]]]], name: Optional[str] = None) → Callable[], Awaitable[Dict[str, Any]]]¶

Add a template context processor.

@app.context_processor
async def update_context(context):
    return context

create_global_jinja_loader() → quart.templating.DispatchingJinjaLoader ¶: Create and return a global (not blueprint specific) Jinja loader.

create_jinja_environment() → quart.templating.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[quart.wrappers.base.BaseRequestWebsocket]) → Optional[werkzeug.routing.MapAdapter]¶

Create and return a URL adapter.

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

debug¶

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 dispatch_request(request_context: Optional[quart.ctx.RequestContext] = None) → Union[Response, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, None, None], Tuple[Union[Response, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, None, None]], Union[Headers, Dict[str, Union[str, List[str], Tuple[str, …]]], List[Tuple[str, Union[str, List[str], Tuple[str, …]]]]]], Tuple[Union[Response, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, None, None]], int], Tuple[Union[Response, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, 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[quart.ctx.WebsocketContext] = None) → None¶

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[quart.ctx.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[quart.ctx.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.

endpoint(endpoint: str) → Callable¶

@app.endpoint('name')
async def endpoint():
    ...

Parameters: endpoint – The endpoint name to use.

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']

errorhandler(error: Union[Type[Exception], int]) → Callable¶

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

@app.errorhandler(500)
def error_handler():
    return "Error", 500

Parameters: error – The error code or Exception to handle.

async finalize_request(result: Union[Response, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, None, None], Tuple[Union[Response, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, None, None]], Union[Headers, Dict[str, Union[str, List[str], Tuple[str, …]]], List[Tuple[str, Union[str, List[str], Tuple[str, …]]]]]], Tuple[Union[Response, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, None, None]], int], Tuple[Union[Response, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, None, None]], int, Union[Headers, Dict[str, Union[str, List[str], Tuple[str, …]]], List[Tuple[str, Union[str, List[str], Tuple[str, …]]]]]]], request_context: Optional[quart.ctx.RequestContext] = None, from_error_handler: bool = False) → quart.wrappers.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, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, None, None], Tuple[Union[Response, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, None, None]], Union[Headers, Dict[str, Union[str, List[str], Tuple[str, …]]], List[Tuple[str, Union[str, List[str], Tuple[str, …]]]]]], Tuple[Union[Response, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, None, None]], int], Tuple[Union[Response, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, 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[quart.ctx.WebsocketContext] = None, from_error_handler: bool = False) → Optional[quart.wrappers.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[quart.ctx.RequestContext] = None) → quart.wrappers.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[quart.ctx.WebsocketContext] = None) → Optional[quart.wrappers.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¶: Return if the app has received a request.

async handle_exception(error: Exception) → quart.wrappers.response.Response ¶

Handle an uncaught exception.

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

async handle_http_exception(error: quart.exceptions.HTTPException) → quart.wrappers.response.Response ¶

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: quart.wrappers.request.Request, *, _preserve: bool = False) → quart.wrappers.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) → quart.wrappers.response.Response ¶

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: quart.wrappers.request.Websocket, *, _preserve: bool = False) → Optional[quart.wrappers.response.Response]¶

async handle_websocket_exception(error: Exception) → Optional[quart.wrappers.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[quart.blueprints.Blueprint]¶: Return a iterator over the blueprints.

property jinja_env¶: The jinja environment used to load templates.

jinja_environment¶: alias of quart.templating.Environment

jinja_options = {'autoescape': True, 'extensions': ['jinja2.ext.autoescape', 'jinja2.ext.with_']}¶

json_decoder¶: alias of quart.json.JSONDecoder

json_encoder¶: alias of quart.json.JSONEncoder

lock_class¶: alias of asyncio.locks.Lock

log_exception(exception_info: Tuple[type, BaseException, traceback]) → None¶

Log a exception to the logger.

By default this is only invoked for unhandled exceptions.

property 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_config(instance_relative: bool = False) → quart.config.Config ¶: Create and return the configuration with appropriate defaults.

async make_default_options_response() → quart.wrappers.response.Response ¶: This is the default route function for OPTIONS requests.

async make_null_session() → quart.sessions.Session ¶: Create and return a null session.

async make_response(result: Union[Response, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, None, None], Tuple[Union[Response, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, None, None]], Union[Headers, Dict[str, Union[str, List[str], Tuple[str, …]]], List[Tuple[str, Union[str, List[str], Tuple[str, …]]]]]], Tuple[Union[Response, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, None, None]], int], Tuple[Union[Response, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, None, None]], int, Union[Headers, Dict[str, Union[str, List[str], Tuple[str, …]]], List[Tuple[str, Union[str, List[str], Tuple[str, …]]]]]]]) → quart.wrappers.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¶

The name of this application.

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

open_instance_resource(path: Union[bytes, str, os.PathLike], mode: str = 'rb') → IO¶

Open a file for reading.

Use as

with app.open_instance_resource(path) as file_:
    file_.read()

async open_session(request: quart.wrappers.base.BaseRequestWebsocket) → quart.sessions.Session ¶: Open and return a Session using the request.

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[quart.wrappers.response.Response], websocket_context: Optional[quart.ctx.WebsocketContext] = None) → quart.wrappers.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[quart.ctx.RequestContext] = None) → Optional[Union[Response, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, None, None], Tuple[Union[Response, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, None, None]], Union[Headers, Dict[str, Union[str, List[str], Tuple[str, …]]], List[Tuple[str, Union[str, List[str], Tuple[str, …]]]]]], Tuple[Union[Response, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, None, None]], int], Tuple[Union[Response, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, 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[quart.ctx.WebsocketContext] = None) → Optional[Union[Response, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, None, None], Tuple[Union[Response, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, None, None]], Union[Headers, Dict[str, Union[str, List[str], Tuple[str, …]]], List[Tuple[str, Union[str, List[str], Tuple[str, …]]]]]], Tuple[Union[Response, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, None, None]], int], Tuple[Union[Response, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, 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.

async process_response(response: quart.wrappers.response.Response, request_context: Optional[quart.ctx.RequestContext] = None) → quart.wrappers.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¶

Return true if exceptions should be propagated into debug pages.

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

register_blueprint(blueprint: quart.blueprints.Blueprint, *, url_prefix: Optional[str] = None, url_defaults: Optional[Dict[str, Any]] = None, subdomain: Optional[str] = None, **options: Any) → None¶

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.

register_error_handler(error: Union[Type[Exception], int], func: Union[Callable[[Exception], None], Callable[[Exception], Awaitable[None]]], name: Optional[str] = None) → None¶

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

def error_handler():
    return "Error", 500

app.register_error_handler(500, error_handler)

Parameters

error – The error code or Exception to handle.
func – The function to handle the error.
name – Optional blueprint key name.

request_class¶: alias of quart.wrappers.request.Request

request_context(request: quart.wrappers.request.Request, *, _preserve: bool = False) → quart.ctx.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 quart.wrappers.response.Response

Add a route to the application.

@app.route('/')
async def route():
    ...

Parameters

rule – The path to route on, should start with a /.
methods – List of HTTP verbs the function routes.
endpoint – Optional endpoint name, if not present the function name is used.
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.
provide_automatic_options – Optionally False to prevent OPTION handling.
strict_slashes – Strictly match the trailing slash present in the path. Will redirect a leaf (no slash) to a branch (with slash).

run(host: str = '127.0.0.1', port: int = 5000, debug: Optional[bool] = None, use_reloader: bool = True, loop: Optional[asyncio.events.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, use_reloader: bool = True, 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.
use_reloader – Automatically reload on code changes.
ca_certs – Path to the SSL CA certificate file.
certfile – Path to the SSL certificate file.
keyfile – Path to the SSL key file.

async save_session(session: quart.sessions.Session, response: quart.wrappers.response.Response) → None¶: Saves the session to the response.

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: Callable[], None]) → Callable¶

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¶

teardown_appcontext(func: Union[Callable[[Optional[BaseException]], None], Callable[[Optional[BaseException]], Awaitable[None]]]) → Callable[[Optional[BaseException]], Awaitable[None]]¶

Add a teardown app (context) function.

@app.teardown_appcontext
async def func():
    ...

Parameters

func – The teardown function itself.
name – Optional blueprint key name.

teardown_request(func: Union[Callable[[Optional[BaseException]], None], Callable[[Optional[BaseException]], Awaitable[None]]], name: Optional[str] = None) → Callable[[Optional[BaseException]], Awaitable[None]]¶

Add a teardown request function.

@app.teardown_request
async def func():
    ...

Parameters

func – The teardown request function itself.
name – Optional blueprint key name.

teardown_websocket(func: Union[Callable[[Optional[BaseException]], None], Callable[[Optional[BaseException]], Awaitable[None]]], name: Optional[str] = None) → Callable[[Optional[BaseException]], Awaitable[None]]¶

Add a teardown websocket function.

@app.teardown_websocket
async def func():
    ...

Parameters

func – The teardown websocket function itself.
name – Optional blueprint key name.

template_filter(name: Optional[str] = None) → Callable¶

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¶

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¶

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).

test_client() → quart.testing.QuartClient ¶: Creates and returns a test client.

test_client_class¶: alias of quart.testing.QuartClient

test_request_context(path: str, *, method: str = 'GET', headers: Optional[Union[dict, werkzeug.datastructures.Headers]] = None, query_string: Optional[dict] = None, scheme: str = 'http', send_push_promise: Callable[[str, werkzeug.datastructures.Headers], Awaitable[None]] = <function no_op_push>, data: Optional[AnyStr] = None, form: Optional[dict] = None, json: Any = <object object>, root_path: str = '', http_version: str = '1.1') → quart.ctx.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_defaults(func: Callable, name: Optional[str] = None) → Callable¶

Add a url default preprocessor.

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

@app.url_defaults
def default(endpoint, values):
    ...

url_map_class¶: alias of quart.routing.QuartMap

url_rule_class¶: alias of quart.routing.QuartRule

url_value_preprocessor(func: Callable[[str, dict], None], name: Optional[str] = None) → Callable¶

Add a url value preprocessor.

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

@app.url_value_preprocessor
def value_preprocessor(endpoint, view_args):
    ...

Add a websocket to the application.

@app.websocket('/')
async def websocket_route():
    ...

Parameters

rule – The path to route on, should start with a /.
endpoint – Optional endpoint name, if not present the function name is used.
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.websocket('/book', defaults={'page': 0})
@app.websocket('/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).

websocket_class¶: alias of quart.wrappers.request.Websocket

websocket_context(websocket: quart.wrappers.request.Websocket, *, _preserve: bool = False) → quart.ctx.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.

class quart.Request(method: str, scheme: str, path: str, query_string: bytes, headers: werkzeug.datastructures.Headers, root_path: str, http_version: str, *, max_content_length: Optional[int] = None, body_timeout: Optional[int] = None, send_push_promise: Callable[[str, werkzeug.datastructures.Headers], Awaitable[None]], scope: Optional[dict] = None)¶

Bases: quart.wrappers.base.BaseRequestWebsocket, quart.wrappers.base.JSONMixin

This class represents a request.

It can be subclassed and the subclassed used in preference by replacing the request_class with your subclass.

body_class¶: The class to store the body data within.

body_class¶: alias of Body

property content_encoding¶

property content_length¶

property content_md5¶

property content_type¶

property data¶

property files¶

The parsed files.

This will return an empty multidict unless the request mimetype was enctype="multipart/form-data" and the method POST, PUT, or PATCH.

property form¶

The parsed form encoded data.

Note file data is present in the files.

async get_data(raw: bool = True) → AnyStr¶: The request body data.

async send_push_promise(path: str) → None¶

property values¶

class quart.Response(response: Union[quart.wrappers.response.ResponseBody, AnyStr, Iterable], status: Optional[int] = None, headers: Optional[Union[dict, werkzeug.datastructures.Headers]] = None, mimetype: Optional[str] = None, content_type: Optional[str] = None)¶

Bases: quart.wrappers.base._BaseRequestResponse, quart.wrappers.base.JSONMixin

This class represents a response.

It can be subclassed and the subclassed used in preference by replacing the response_class with your subclass.

automatically_set_content_length¶: If False the content length header must be provided.

default_status¶: The status code to use if not provided.

default_mimetype¶: The mimetype to use if not provided.

implicit_sequence_conversion¶: Implicitly convert the response to a iterable in the get_data method, to allow multiple iterations.

property accept_ranges¶

property access_control_allow_credentials¶: Whether credentials can be shared by the browser to JavaScript code. As part of the preflight request it indicates whether credentials can be used on the cross origin request.

property access_control_allow_headers¶

property access_control_allow_methods¶

property access_control_allow_origin¶

property access_control_expose_headers¶

property access_control_max_age¶

async add_etag(overwrite: bool = False, weak: bool = False) → None¶

property age¶

property allow¶

automatically_set_content_length = True¶

property cache_control¶

property content_encoding¶

property content_language¶

property content_length¶

property content_location¶

property content_md5¶

property content_range¶

property content_security_policy¶

property content_security_policy_report_only¶

property content_type¶

data_body_class¶: alias of DataBody

property date¶

default_mimetype = 'text/html'¶

default_status = 200¶

delete_cookie(key: str, path: str = '/', domain: Optional[str] = None, secure: bool = False, httponly: bool = False, samesite: Optional[str] = None) → None¶: Delete a cookie (set to expire immediately).

property expires¶

file_body_class¶: alias of FileBody

async freeze() → None¶: Freeze this object ready for pickling.

async get_data(raw: bool = True) → AnyStr¶: Return the body data.

get_etag() → Tuple[Optional[str], Optional[bool]]¶

implicit_sequence_conversion = True¶

io_body_class¶: alias of IOBody

iterable_body_class¶: alias of IterableBody

property last_modified¶

property location¶

async make_conditional(request_range: Optional[werkzeug.datastructures.Range], max_partial_size: Optional[int] = None) → None¶

Make the response conditional to the

Parameters

request_range – The range as requested by the request.
max_partial_size – The maximum length the server is willing to serve in a single response. Defaults to unlimited.

max_cookie_size = 4093¶

property referrer¶

property retry_after¶

set_cookie(key: str, value: AnyStr = '', max_age: Optional[Union[int, datetime.timedelta]] = None, expires: Optional[Union[int, float, datetime.datetime]] = None, path: str = '/', domain: Optional[str] = None, secure: bool = False, httponly: bool = False, samesite: Optional[str] = None) → None¶

Set a cookie in the response headers.

The arguments are the standard cookie morsels and this is a wrapper around the stdlib SimpleCookie code.

set_data(data: AnyStr) → None¶

Set the response data.

This will encode using the charset.

set_etag(etag: str, weak: bool = False) → None¶

property vary¶

quart.ResponseReturnValue¶

The central part of internal API.

This represents a generic version of type ‘origin’ with type arguments ‘params’. There are two kind of these aliases: user defined and special. The special ones are wrappers around builtin collections and ABCs in collections.abc. These must have ‘name’ always set. If ‘inst’ is False, then the alias can’t be instantiated, this is used by e.g. typing.List and typing.Dict.

alias of Union[Response, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, None, None], Tuple[Union[Response, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, None, None]], Union[Headers, Dict[str, Union[str, List[str], Tuple[str, …]]], List[Tuple[str, Union[str, List[str], Tuple[str, …]]]]]], Tuple[Union[Response, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, None, None]], int], Tuple[Union[Response, AnyStr, Dict[str, Any], AsyncGenerator[bytes, None], Generator[bytes, None, None]], int, Union[Headers, Dict[str, Union[str, List[str], Tuple[str, …]]], List[Tuple[str, Union[str, List[str], Tuple[str, …]]]]]]]

quart.abort(status_or_response: Union[int, quart.wrappers.response.Response], description: Optional[str] = None, name: Optional[str] = None) → NoReturn¶

Raises a HTTPException with the status code or response given.

This can be used either with a status code (with optional description and name) or with a Response object. The latter allows for an abort (after response functions etc aren’t called) with a custom response.

abort(403)
abort(Response("Message"))

quart.after_this_request(func: Callable) → Callable¶

Schedule the func to be called after the current request.

This is useful in situations whereby you want an after request function for a specific route or circumstance only, for example,

def index():
    @after_this_request
    def set_cookie(response):
        response.set_cookie('special', 'value')
        return response

    ...

quart.copy_current_app_context(func: Callable) → Callable¶

Share the current app context with the function decorated.

The app context is local per task and hence will not be available in any other task. This decorator can be used to make the context available,

@copy_current_app_context
async def within_context() -> None:
    name = current_app.name
    ...

quart.copy_current_request_context(func: Callable) → Callable¶

Share the current request context with the function decorated.

The request context is local per task and hence will not be available in any other task. This decorator can be used to make the context available,

@copy_current_request_context
async def within_context() -> None:
    method = request.method
    ...

quart.copy_current_websocket_context(func: Callable) → Callable¶

Share the current websocket context with the function decorated.

The websocket context is local per task and hence will not be available in any other task. This decorator can be used to make the context available,

@copy_current_websocket_context
async def within_context() -> None:
    method = websocket.method
    ...

quart.escape(s) → markup¶: Convert the characters &, <, >, ‘, and ” in string s to HTML-safe sequences. Use this if you need to display text that might contain such characters in HTML. Marks return value as markup string.

async quart.flash(message: str, category: str = 'message') → None¶

Add a message (with optional category) to the session store.

This is typically used to flash a message to a user that will be stored in the session and shown during some other request. For example,

@app.route('/login', methods=['POST'])
async def login():
    ...
    await flash('Login successful')
    return redirect(url_for('index'))

allows the index route to show the flashed messages, without having to accept the message as an argument or otherwise. See get_flashed_messages() for message retrieval.

quart.get_flashed_messages(with_categories: bool = False, category_filter: List[str] = []) → Union[List[str], List[Tuple[str, str]]]¶

Retrieve the flashed messages stored in the session.

This is mostly useful in templates where it is exposed as a global function, for example

<ul>
{% for message in get_flashed_messages() %}
  <li>{{ message }}</li>
{% endfor %}
</ul>

Note that caution is required for usage of category_filter as all messages will be popped, but only those matching the filter returned. See flash() for message creation.

quart.get_template_attribute(template_name: str, attribute: str) → Any¶

Load a attribute from a template.

This is useful in Python code in order to use attributes in templates.

Parameters

template_name – To load the attribute from.
attribute – The attribute name to load

quart.has_app_context() → bool¶

Check if execution is within an app context.

This allows a controlled way to act if there is an app context available, or silently not act if not. For example,

if has_app_context():
    log.info("Executing in %s context", current_app.name)

quart package¶

Subpackages¶

Submodules¶

Module contents¶