.. _aiohttp-web-reference: Server Reference ================ .. currentmodule:: aiohttp.web .. _aiohttp-web-request: Request and Base Request ------------------------ The Request object contains all the information about an incoming HTTP request. :class:`BaseRequest` is used for :ref:`Low-Level Servers` (which have no applications, routers, signals and middlewares). :class:`Request` has an :attr:`Request.app` and :attr:`Request.match_info` attributes. A :class:`BaseRequest` / :class:`Request` are :obj:`dict` like objects, allowing them to be used for :ref:`sharing data` among :ref:`aiohttp-web-middlewares` and :ref:`aiohttp-web-signals` handlers. .. class:: BaseRequest .. attribute:: version *HTTP version* of request, Read-only property. Returns :class:`aiohttp.protocol.HttpVersion` instance. .. attribute:: method *HTTP method*, read-only property. The value is upper-cased :class:`str` like ``"GET"``, ``"POST"``, ``"PUT"`` etc. .. attribute:: url A :class:`~yarl.URL` instance with absolute URL to resource (*scheme*, *host* and *port* are included). .. note:: In case of malformed request (e.g. without ``"HOST"`` HTTP header) the absolute url may be unavailable. .. attribute:: rel_url A :class:`~yarl.URL` instance with relative URL to resource (contains *path*, *query* and *fragment* parts only, *scheme*, *host* and *port* are excluded). The property is equal to ``.url.relative()`` but is always present. .. seealso:: A note from :attr:`url`. .. attribute:: scheme A string representing the scheme of the request. The scheme is ``'https'`` if transport for request handling is *SSL*, ``'http'`` otherwise. The value could be overridden by :meth:`~BaseRequest.clone`. Read-only :class:`str` property. .. versionchanged:: 2.3 *Forwarded* and *X-Forwarded-Proto* are not used anymore. Call ``.clone(scheme=new_scheme)`` for setting up the value explicitly. .. seealso:: :ref:`aiohttp-web-forwarded-support` .. attribute:: secure Shorthand for ``request.url.scheme == 'https'`` Read-only :class:`bool` property. .. seealso:: :attr:`scheme` .. attribute:: forwarded A tuple containing all parsed Forwarded header(s). Makes an effort to parse Forwarded headers as specified by :rfc:`7239`: - It adds one (immutable) dictionary per Forwarded ``field-value``, i.e. per proxy. The element corresponds to the data in the Forwarded ``field-value`` added by the first proxy encountered by the client. Each subsequent item corresponds to those added by later proxies. - It checks that every value has valid syntax in general as specified in :rfc:`7239#section-4`: either a ``token`` or a ``quoted-string``. - It un-escapes ``quoted-pairs``. - It does NOT validate 'by' and 'for' contents as specified in :rfc:`7239#section-6`. - It does NOT validate ``host`` contents (Host ABNF). - It does NOT validate ``proto`` contents for valid URI scheme names. Returns a tuple containing one or more ``MappingProxy`` objects .. seealso:: :attr:`scheme` .. seealso:: :attr:`host` .. attribute:: host Host name of the request, resolved in this order: - Overridden value by :meth:`~BaseRequest.clone` call. - *Host* HTTP header - :func:`socket.getfqdn` Read-only :class:`str` property. .. versionchanged:: 2.3 *Forwarded* and *X-Forwarded-Host* are not used anymore. Call ``.clone(host=new_host)`` for setting up the value explicitly. .. seealso:: :ref:`aiohttp-web-forwarded-support` .. attribute:: remote Originating IP address of a client initiated HTTP request. The IP is resolved through the following headers, in this order: - Overridden value by :meth:`~BaseRequest.clone` call. - Peer name of opened socket. Read-only :class:`str` property. Call ``.clone(remote=new_remote)`` for setting up the value explicitly. .. versionadded:: 2.3 .. seealso:: :ref:`aiohttp-web-forwarded-support` .. attribute:: client_max_size The maximum size of the request body. The value could be overridden by :meth:`~BaseRequest.clone`. Read-only :class:`int` property. .. attribute:: path_qs The URL including PATH_INFO and the query string. e.g., ``/app/blog?id=10`` Read-only :class:`str` property. .. attribute:: path The URL including *PATH INFO* without the host or scheme. e.g., ``/app/blog``. The path is URL-decoded. For raw path info see :attr:`raw_path`. Read-only :class:`str` property. .. attribute:: raw_path The URL including raw *PATH INFO* without the host or scheme. Warning, the path may be URL-encoded and may contain invalid URL characters, e.g. ``/my%2Fpath%7Cwith%21some%25strange%24characters``. For URL-decoded version please take a look on :attr:`path`. Read-only :class:`str` property. .. attribute:: query A multidict with all the variables in the query string. Read-only :class:`~multidict.MultiDictProxy` lazy property. .. attribute:: query_string The query string in the URL, e.g., ``id=10`` Read-only :class:`str` property. .. attribute:: headers A case-insensitive multidict proxy with all headers. Read-only :class:`~multidict.CIMultiDictProxy` property. .. attribute:: raw_headers HTTP headers of response as unconverted bytes, a sequence of ``(key, value)`` pairs. .. attribute:: keep_alive ``True`` if keep-alive connection enabled by HTTP client and protocol version supports it, otherwise ``False``. Read-only :class:`bool` property. .. attribute:: transport A :ref:`transport` used to process request. Read-only property. The property can be used, for example, for getting IP address of client's peer:: peername = request.transport.get_extra_info('peername') if peername is not None: host, port = peername .. attribute:: loop An event loop instance used by HTTP request handling. Read-only :class:`asyncio.AbstractEventLoop` property. .. deprecated:: 3.5 .. attribute:: cookies A read-only dictionary-like object containing the request's cookies. Read-only :class:`~types.MappingProxyType` property. .. attribute:: content A :class:`~aiohttp.StreamReader` instance, input stream for reading request's *BODY*. Read-only property. .. attribute:: body_exists Return ``True`` if request has *HTTP BODY*, ``False`` otherwise. Read-only :class:`bool` property. .. versionadded:: 2.3 .. attribute:: can_read_body Return ``True`` if request's *HTTP BODY* can be read, ``False`` otherwise. Read-only :class:`bool` property. .. versionadded:: 2.3 .. attribute:: has_body Return ``True`` if request's *HTTP BODY* can be read, ``False`` otherwise. Read-only :class:`bool` property. .. deprecated:: 2.3 Use :meth:`can_read_body` instead. .. attribute:: content_type Read-only property with *content* part of *Content-Type* header. Returns :class:`str` like ``'text/html'`` .. note:: Returns value is ``'application/octet-stream'`` if no Content-Type header present in HTTP headers according to :rfc:`2616` .. attribute:: charset Read-only property that specifies the *encoding* for the request's BODY. The value is parsed from the *Content-Type* HTTP header. Returns :class:`str` like ``'utf-8'`` or ``None`` if *Content-Type* has no charset information. .. attribute:: content_length Read-only property that returns length of the request's BODY. The value is parsed from the *Content-Length* HTTP header. Returns :class:`int` or ``None`` if *Content-Length* is absent. .. attribute:: http_range Read-only property that returns information about *Range* HTTP header. Returns a :class:`slice` where ``.start`` is *left inclusive bound*, ``.stop`` is *right exclusive bound* and ``.step`` is ``1``. The property might be used in two manners: 1. Attribute-access style (example assumes that both left and right borders are set, the real logic for case of open bounds is more complex):: rng = request.http_range with open(filename, 'rb') as f: f.seek(rng.start) return f.read(rng.stop-rng.start) 2. Slice-style:: return buffer[request.http_range] .. attribute:: if_modified_since Read-only property that returns the date specified in the *If-Modified-Since* header. Returns :class:`datetime.datetime` or ``None`` if *If-Modified-Since* header is absent or is not a valid HTTP date. .. attribute:: if_unmodified_since Read-only property that returns the date specified in the *If-Unmodified-Since* header. Returns :class:`datetime.datetime` or ``None`` if *If-Unmodified-Since* header is absent or is not a valid HTTP date. .. versionadded:: 3.1 .. attribute:: if_match Read-only property that returns :class:`~aiohttp.ETag` objects specified in the *If-Match* header. Returns :class:`tuple` of :class:`~aiohttp.ETag` or ``None`` if *If-Match* header is absent. .. versionadded:: 3.8 .. attribute:: if_none_match Read-only property that returns :class:`~aiohttp.ETag` objects specified *If-None-Match* header. Returns :class:`tuple` of :class:`~aiohttp.ETag` or ``None`` if *If-None-Match* header is absent. .. versionadded:: 3.8 .. attribute:: if_range Read-only property that returns the date specified in the *If-Range* header. Returns :class:`datetime.datetime` or ``None`` if *If-Range* header is absent or is not a valid HTTP date. .. versionadded:: 3.1 .. method:: clone(*, method=..., rel_url=..., headers=...) Clone itself with replacement some attributes. Creates and returns a new instance of Request object. If no parameters are given, an exact copy is returned. If a parameter is not passed, it will reuse the one from the current request object. :param str method: http method :param rel_url: url to use, :class:`str` or :class:`~yarl.URL` :param headers: :class:`~multidict.CIMultiDict` or compatible headers container. :return: a cloned :class:`Request` instance. .. method:: get_extra_info(name, default=None) Reads extra information from the protocol's transport. If no value associated with ``name`` is found, ``default`` is returned. See :meth:`asyncio.BaseTransport.get_extra_info` :param str name: The key to look up in the transport extra information. :param default: Default value to be used when no value for ``name`` is found (default is ``None``). .. versionadded:: 3.7 .. method:: read() :async: Read request body, returns :class:`bytes` object with body content. .. note:: The method **does** store read data internally, subsequent :meth:`~aiohttp.web.BaseRequest.read` call will return the same value. .. method:: text() :async: Read request body, decode it using :attr:`charset` encoding or ``UTF-8`` if no encoding was specified in *MIME-type*. Returns :class:`str` with body content. .. note:: The method **does** store read data internally, subsequent :meth:`~aiohttp.web.BaseRequest.text` call will return the same value. .. method:: json(*, loads=json.loads) :async: Read request body decoded as *json*. The method is just a boilerplate :ref:`coroutine ` implemented as:: async def json(self, *, loads=json.loads): body = await self.text() return loads(body) :param collections.abc.Callable loads: any :term:`callable` that accepts :class:`str` and returns :class:`dict` with parsed JSON (:func:`json.loads` by default). .. note:: The method **does** store read data internally, subsequent :meth:`~aiohttp.web.BaseRequest.json` call will return the same value. .. method:: multipart() :async: Returns :class:`aiohttp.MultipartReader` which processes incoming *multipart* request. The method is just a boilerplate :ref:`coroutine ` implemented as:: async def multipart(self, *, reader=aiohttp.multipart.MultipartReader): return reader(self.headers, self._payload) This method is a coroutine for consistency with the else reader methods. .. warning:: The method **does not** store read data internally. That means once you exhausts multipart reader, you cannot get the request payload one more time. .. seealso:: :ref:`aiohttp-multipart` .. versionchanged:: 3.4 Dropped *reader* parameter. .. method:: post() :async: A :ref:`coroutine ` that reads POST parameters from request body. Returns :class:`~multidict.MultiDictProxy` instance filled with parsed data. If :attr:`method` is not *POST*, *PUT*, *PATCH*, *TRACE* or *DELETE* or :attr:`content_type` is not empty or *application/x-www-form-urlencoded* or *multipart/form-data* returns empty multidict. .. note:: The method **does** store read data internally, subsequent :meth:`~aiohttp.web.BaseRequest.post` call will return the same value. .. method:: release() :async: Release request. Eat unread part of HTTP BODY if present. .. note:: User code may never call :meth:`~aiohttp.web.BaseRequest.release`, all required work will be processed by :mod:`aiohttp.web` internal machinery. .. class:: Request A request used for receiving request's information by *web handler*. Every :ref:`handler` accepts a request instance as the first positional parameter. The class in derived from :class:`BaseRequest`, shares all parent's attributes and methods but has a couple of additional properties: .. attribute:: match_info Read-only property with :class:`~aiohttp.abc.AbstractMatchInfo` instance for result of route resolving. .. note:: Exact type of property depends on used router. If ``app.router`` is :class:`UrlDispatcher` the property contains :class:`UrlMappingMatchInfo` instance. .. attribute:: app An :class:`Application` instance used to call :ref:`request handler `, Read-only property. .. attribute:: config_dict A :class:`aiohttp.ChainMapProxy` instance for mapping all properties from the current application returned by :attr:`app` property and all its parents. .. seealso:: :ref:`aiohttp-web-data-sharing-app-config` .. versionadded:: 3.2 .. note:: You should never create the :class:`Request` instance manually -- :mod:`aiohttp.web` does it for you. But :meth:`~BaseRequest.clone` may be used for cloning *modified* request copy with changed *path*, *method* etc. .. _aiohttp-web-response: Response classes ---------------- For now, :mod:`aiohttp.web` has three classes for the *HTTP response*: :class:`StreamResponse`, :class:`Response` and :class:`FileResponse`. Usually you need to use the second one. :class:`StreamResponse` is intended for streaming data, while :class:`Response` contains *HTTP BODY* as an attribute and sends own content as single piece with the correct *Content-Length HTTP header*. For sake of design decisions :class:`Response` is derived from :class:`StreamResponse` parent class. The response supports *keep-alive* handling out-of-the-box if *request* supports it. You can disable *keep-alive* by :meth:`~StreamResponse.force_close` though. The common case for sending an answer from :ref:`web-handler` is returning a :class:`Response` instance:: async def handler(request): return Response(text="All right!") Response classes are :obj:`dict` like objects, allowing them to be used for :ref:`sharing data` among :ref:`aiohttp-web-middlewares` and :ref:`aiohttp-web-signals` handlers:: resp['key'] = value .. versionadded:: 3.0 Dict-like interface support. .. class:: StreamResponse(*, status=200, reason=None) The base class for the *HTTP response* handling. Contains methods for setting *HTTP response headers*, *cookies*, *response status code*, writing *HTTP response BODY* and so on. The most important thing you should know about *response* --- it is *Finite State Machine*. That means you can do any manipulations with *headers*, *cookies* and *status code* only before :meth:`prepare` coroutine is called. Once you call :meth:`prepare` any change of the *HTTP header* part will raise :exc:`RuntimeError` exception. Any :meth:`write` call after :meth:`write_eof` is also forbidden. :param int status: HTTP status code, ``200`` by default. :param str reason: HTTP reason. If param is ``None`` reason will be calculated basing on *status* parameter. Otherwise pass :class:`str` with arbitrary *status* explanation.. .. attribute:: prepared Read-only :class:`bool` property, ``True`` if :meth:`prepare` has been called, ``False`` otherwise. .. attribute:: task A task that serves HTTP request handling. May be useful for graceful shutdown of long-running requests (streaming, long polling or web-socket). .. attribute:: status Read-only property for *HTTP response status code*, :class:`int`. ``200`` (OK) by default. .. attribute:: reason Read-only property for *HTTP response reason*, :class:`str`. .. method:: set_status(status, reason=None) Set :attr:`status` and :attr:`reason`. *reason* value is auto calculated if not specified (``None``). .. attribute:: keep_alive Read-only property, copy of :attr:`aiohttp.web.BaseRequest.keep_alive` by default. Can be switched to ``False`` by :meth:`force_close` call. .. method:: force_close Disable :attr:`keep_alive` for connection. There are no ways to enable it back. .. attribute:: compression Read-only :class:`bool` property, ``True`` if compression is enabled. ``False`` by default. .. seealso:: :meth:`enable_compression` .. method:: enable_compression(force=None) Enable compression. When *force* is unset compression encoding is selected based on the request's *Accept-Encoding* header. *Accept-Encoding* is not checked if *force* is set to a :class:`ContentCoding`. .. seealso:: :attr:`compression` .. attribute:: chunked Read-only property, indicates if chunked encoding is on. Can be enabled by :meth:`enable_chunked_encoding` call. .. seealso:: :attr:`enable_chunked_encoding` .. method:: enable_chunked_encoding Enables :attr:`chunked` encoding for response. There are no ways to disable it back. With enabled :attr:`chunked` encoding each :meth:`write` operation encoded in separate chunk. .. warning:: chunked encoding can be enabled for ``HTTP/1.1`` only. Setting up both :attr:`content_length` and chunked encoding is mutually exclusive. .. seealso:: :attr:`chunked` .. attribute:: headers :class:`~multidict.CIMultiDict` instance for *outgoing* *HTTP headers*. .. attribute:: cookies An instance of :class:`http.cookies.SimpleCookie` for *outgoing* cookies. .. warning:: Direct setting up *Set-Cookie* header may be overwritten by explicit calls to cookie manipulation. We are encourage using of :attr:`cookies` and :meth:`set_cookie`, :meth:`del_cookie` for cookie manipulations. .. method:: set_cookie(name, value, *, path='/', expires=None, \ domain=None, max_age=None, \ secure=None, httponly=None, version=None, \ samesite=None) Convenient way for setting :attr:`cookies`, allows to specify some additional properties like *max_age* in a single call. :param str name: cookie name :param str value: cookie value (will be converted to :class:`str` if value has another type). :param expires: expiration date (optional) :param str domain: cookie domain (optional) :param int max_age: defines the lifetime of the cookie, in seconds. The delta-seconds value is a decimal non- negative integer. After delta-seconds seconds elapse, the client should discard the cookie. A value of zero means the cookie should be discarded immediately. (optional) :param str path: specifies the subset of URLs to which this cookie applies. (optional, ``'/'`` by default) :param bool secure: attribute (with no value) directs the user agent to use only (unspecified) secure means to contact the origin server whenever it sends back this cookie. The user agent (possibly under the user's control) may determine what level of security it considers appropriate for "secure" cookies. The *secure* should be considered security advice from the server to the user agent, indicating that it is in the session's interest to protect the cookie contents. (optional) :param bool httponly: ``True`` if the cookie HTTP only (optional) :param int version: a decimal integer, identifies to which version of the state management specification the cookie conforms. (optional) :param str samesite: Asserts that a cookie must not be sent with cross-origin requests, providing some protection against cross-site request forgery attacks. Generally the value should be one of: ``None``, ``Lax`` or ``Strict``. (optional) .. versionadded:: 3.7 .. warning:: In HTTP version 1.1, ``expires`` was deprecated and replaced with the easier-to-use ``max-age``, but Internet Explorer (IE6, IE7, and IE8) **does not** support ``max-age``. .. method:: del_cookie(name, *, path='/', domain=None) Deletes cookie. :param str name: cookie name :param str domain: optional cookie domain :param str path: optional cookie path, ``'/'`` by default .. attribute:: content_length *Content-Length* for outgoing response. .. attribute:: content_type *Content* part of *Content-Type* for outgoing response. .. attribute:: charset *Charset* aka *encoding* part of *Content-Type* for outgoing response. The value converted to lower-case on attribute assigning. .. attribute:: last_modified *Last-Modified* header for outgoing response. This property accepts raw :class:`str` values, :class:`datetime.datetime` objects, Unix timestamps specified as an :class:`int` or a :class:`float` object, and the value ``None`` to unset the header. .. attribute:: etag *ETag* header for outgoing response. This property accepts raw :class:`str` values, :class:`~aiohttp.ETag` objects and the value ``None`` to unset the header. In case of :class:`str` input, etag is considered as strong by default. **Do not** use double quotes ``"`` in the etag value, they will be added automatically. .. versionadded:: 3.8 .. method:: prepare(request) :async: :param aiohttp.web.Request request: HTTP request object, that the response answers. Send *HTTP header*. You should not change any header data after calling this method. The coroutine calls :attr:`~aiohttp.web.Application.on_response_prepare` signal handlers after default headers have been computed and directly before headers are sent. .. method:: write(data) :async: Send byte-ish data as the part of *response BODY*:: await resp.write(data) :meth:`prepare` must be invoked before the call. Raises :exc:`TypeError` if data is not :class:`bytes`, :class:`bytearray` or :class:`memoryview` instance. Raises :exc:`RuntimeError` if :meth:`prepare` has not been called. Raises :exc:`RuntimeError` if :meth:`write_eof` has been called. .. method:: write_eof() :async: A :ref:`coroutine` *may* be called as a mark of the *HTTP response* processing finish. *Internal machinery* will call this method at the end of the request processing if needed. After :meth:`write_eof` call any manipulations with the *response* object are forbidden. .. class:: Response(*, body=None, status=200, reason=None, text=None, \ headers=None, content_type=None, charset=None, \ zlib_executor_size=sentinel, zlib_executor=None) The most usable response class, inherited from :class:`StreamResponse`. Accepts *body* argument for setting the *HTTP response BODY*. The actual :attr:`body` sending happens in overridden :meth:`~StreamResponse.write_eof`. :param bytes body: response's BODY :param int status: HTTP status code, 200 OK by default. :param collections.abc.Mapping headers: HTTP headers that should be added to response's ones. :param str text: response's BODY :param str content_type: response's content type. ``'text/plain'`` if *text* is passed also, ``'application/octet-stream'`` otherwise. :param str charset: response's charset. ``'utf-8'`` if *text* is passed also, ``None`` otherwise. :param int zlib_executor_size: length in bytes which will trigger zlib compression of body to happen in an executor .. versionadded:: 3.5 :param int zlib_executor: executor to use for zlib compression .. versionadded:: 3.5 .. attribute:: body Read-write attribute for storing response's content aka BODY, :class:`bytes`. Assigning :class:`str` to :attr:`body` will make the :attr:`body` type of :class:`aiohttp.payload.StringPayload`, which tries to encode the given data based on *Content-Type* HTTP header, while defaulting to ``UTF-8``. .. attribute:: text Read-write attribute for storing response's :attr:`~aiohttp.StreamResponse.body`, represented as :class:`str`. .. class:: WebSocketResponse(*, timeout=10.0, receive_timeout=None, \ autoclose=True, autoping=True, heartbeat=None, \ protocols=(), compress=True, max_msg_size=4194304) Class for handling server-side websockets, inherited from :class:`StreamResponse`. After starting (by :meth:`prepare` call) the response you cannot use :meth:`~StreamResponse.write` method but should to communicate with websocket client by :meth:`send_str`, :meth:`receive` and others. To enable back-pressure from slow websocket clients treat methods :meth:`ping()`, :meth:`pong()`, :meth:`send_str()`, :meth:`send_bytes()`, :meth:`send_json()` as coroutines. By default write buffer size is set to 64k. :param bool autoping: Automatically send :const:`~aiohttp.WSMsgType.PONG` on :const:`~aiohttp.WSMsgType.PING` message from client, and handle :const:`~aiohttp.WSMsgType.PONG` responses from client. Note that server does not send :const:`~aiohttp.WSMsgType.PING` requests, you need to do this explicitly using :meth:`ping` method. :param float heartbeat: Send `ping` message every `heartbeat` seconds and wait `pong` response, close connection if `pong` response is not received. The timer is reset on any data reception. :param float receive_timeout: Timeout value for `receive` operations. Default value is None (no timeout for receive operation) :param bool compress: Enable per-message deflate extension support. False for disabled, default value is True. :param int max_msg_size: maximum size of read websocket message, 4 MB by default. To disable the size limit use ``0``. .. versionadded:: 3.3 :param bool autoclose: Close connection when the client sends a :const:`~aiohttp.WSMsgType.CLOSE` message, ``True`` by default. If set to ``False``, the connection is not closed and the caller is responsible for calling ``request.transport.close()`` to avoid leaking resources. The class supports ``async for`` statement for iterating over incoming messages:: ws = web.WebSocketResponse() await ws.prepare(request) async for msg in ws: print(msg.data) .. method:: prepare(request) :async: Starts websocket. After the call you can use websocket methods. :param aiohttp.web.Request request: HTTP request object, that the response answers. :raises HTTPException: if websocket handshake has failed. .. method:: can_prepare(request) Performs checks for *request* data to figure out if websocket can be started on the request. If :meth:`can_prepare` call is success then :meth:`prepare` will success too. :param aiohttp.web.Request request: HTTP request object, that the response answers. :return: :class:`WebSocketReady` instance. :attr:`WebSocketReady.ok` is ``True`` on success, :attr:`WebSocketReady.protocol` is websocket subprotocol which is passed by client and accepted by server (one of *protocols* sequence from :class:`WebSocketResponse` ctor). :attr:`WebSocketReady.protocol` may be ``None`` if client and server subprotocols are not overlapping. .. note:: The method never raises exception. .. attribute:: closed Read-only property, ``True`` if connection has been closed or in process of closing. :const:`~aiohttp.WSMsgType.CLOSE` message has been received from peer. .. attribute:: close_code Read-only property, close code from peer. It is set to ``None`` on opened connection. .. attribute:: ws_protocol Websocket *subprotocol* chosen after :meth:`start` call. May be ``None`` if server and client protocols are not overlapping. .. method:: get_extra_info(name, default=None) Reads optional extra information from the writer's transport. If no value associated with ``name`` is found, ``default`` is returned. See :meth:`asyncio.BaseTransport.get_extra_info` :param str name: The key to look up in the transport extra information. :param default: Default value to be used when no value for ``name`` is found (default is ``None``). .. method:: exception() Returns last occurred exception or None. .. method:: ping(message=b'') :async: Send :const:`~aiohttp.WSMsgType.PING` to peer. :param message: optional payload of *ping* message, :class:`str` (converted to *UTF-8* encoded bytes) or :class:`bytes`. :raise RuntimeError: if connections is not started or closing. .. versionchanged:: 3.0 The method is converted into :term:`coroutine` .. method:: pong(message=b'') :async: Send *unsolicited* :const:`~aiohttp.WSMsgType.PONG` to peer. :param message: optional payload of *pong* message, :class:`str` (converted to *UTF-8* encoded bytes) or :class:`bytes`. :raise RuntimeError: if connections is not started or closing. .. versionchanged:: 3.0 The method is converted into :term:`coroutine` .. method:: send_str(data, compress=None) :async: Send *data* to peer as :const:`~aiohttp.WSMsgType.TEXT` message. :param str data: data to send. :param int compress: sets specific level of compression for single message, ``None`` for not overriding per-socket setting. :raise RuntimeError: if connection is not started or closing :raise TypeError: if data is not :class:`str` .. versionchanged:: 3.0 The method is converted into :term:`coroutine`, *compress* parameter added. .. method:: send_bytes(data, compress=None) :async: Send *data* to peer as :const:`~aiohttp.WSMsgType.BINARY` message. :param data: data to send. :param int compress: sets specific level of compression for single message, ``None`` for not overriding per-socket setting. :raise RuntimeError: if connection is not started or closing :raise TypeError: if data is not :class:`bytes`, :class:`bytearray` or :class:`memoryview`. .. versionchanged:: 3.0 The method is converted into :term:`coroutine`, *compress* parameter added. .. method:: send_json(data, compress=None, *, dumps=json.dumps) :async: Send *data* to peer as JSON string. :param data: data to send. :param int compress: sets specific level of compression for single message, ``None`` for not overriding per-socket setting. :param collections.abc.Callable dumps: any :term:`callable` that accepts an object and returns a JSON string (:func:`json.dumps` by default). :raise RuntimeError: if connection is not started or closing :raise ValueError: if data is not serializable object :raise TypeError: if value returned by ``dumps`` param is not :class:`str` .. versionchanged:: 3.0 The method is converted into :term:`coroutine`, *compress* parameter added. .. method:: close(*, code=WSCloseCode.OK, message=b'', drain=True) :async: A :ref:`coroutine` that initiates closing handshake by sending :const:`~aiohttp.WSMsgType.CLOSE` message. It is safe to call `close()` from different task. :param int code: closing code. See also :class:`~aiohttp.WSCloseCode`. :param message: optional payload of *close* message, :class:`str` (converted to *UTF-8* encoded bytes) or :class:`bytes`. :param bool drain: drain outgoing buffer before closing connection. :raise RuntimeError: if connection is not started .. method:: receive(timeout=None) :async: A :ref:`coroutine` that waits upcoming *data* message from peer and returns it. The coroutine implicitly handles :const:`~aiohttp.WSMsgType.PING`, :const:`~aiohttp.WSMsgType.PONG` and :const:`~aiohttp.WSMsgType.CLOSE` without returning the message. It process *ping-pong game* and performs *closing handshake* internally. .. note:: Can only be called by the request handling task. :param timeout: timeout for `receive` operation. timeout value overrides response`s receive_timeout attribute. :return: :class:`~aiohttp.WSMessage` :raise RuntimeError: if connection is not started .. method:: receive_str(*, timeout=None) :async: A :ref:`coroutine` that calls :meth:`receive` but also asserts the message type is :const:`~aiohttp.WSMsgType.TEXT`. .. note:: Can only be called by the request handling task. :param timeout: timeout for `receive` operation. timeout value overrides response`s receive_timeout attribute. :return str: peer's message content. :raise TypeError: if message is :const:`~aiohttp.WSMsgType.BINARY`. .. method:: receive_bytes(*, timeout=None) :async: A :ref:`coroutine` that calls :meth:`receive` but also asserts the message type is :const:`~aiohttp.WSMsgType.BINARY`. .. note:: Can only be called by the request handling task. :param timeout: timeout for `receive` operation. timeout value overrides response`s receive_timeout attribute. :return bytes: peer's message content. :raise TypeError: if message is :const:`~aiohttp.WSMsgType.TEXT`. .. method:: receive_json(*, loads=json.loads, timeout=None) :async: A :ref:`coroutine` that calls :meth:`receive_str` and loads the JSON string to a Python dict. .. note:: Can only be called by the request handling task. :param collections.abc.Callable loads: any :term:`callable` that accepts :class:`str` and returns :class:`dict` with parsed JSON (:func:`json.loads` by default). :param timeout: timeout for `receive` operation. timeout value overrides response`s receive_timeout attribute. :return dict: loaded JSON content :raise TypeError: if message is :const:`~aiohttp.WSMsgType.BINARY`. :raise ValueError: if message is not valid JSON. .. seealso:: :ref:`WebSockets handling` .. class:: WebSocketReady A named tuple for returning result from :meth:`WebSocketResponse.can_prepare`. Has :class:`bool` check implemented, e.g.:: if not await ws.can_prepare(...): cannot_start_websocket() .. attribute:: ok ``True`` if websocket connection can be established, ``False`` otherwise. .. attribute:: protocol :class:`str` represented selected websocket sub-protocol. .. seealso:: :meth:`WebSocketResponse.can_prepare` .. function:: json_response([data], *, text=None, body=None, \ status=200, reason=None, headers=None, \ content_type='application/json', \ dumps=json.dumps) Return :class:`Response` with predefined ``'application/json'`` content type and *data* encoded by ``dumps`` parameter (:func:`json.dumps` by default). HTTP Exceptions ^^^^^^^^^^^^^^^ Errors can also be returned by raising a HTTP exception instance from within the handler. .. class:: HTTPException(*, headers=None, reason=None, text=None, content_type=None) Low-level HTTP failure. :param headers: headers for the response :type headers: dict or multidict.CIMultiDict :param str reason: reason included in the response :param str text: response's body :param str content_type: response's content type. This is passed through to the :class:`Response` initializer. Sub-classes of ``HTTPException`` exist for the standard HTTP response codes as described in :ref:`aiohttp-web-exceptions` and the expected usage is to simply raise the appropriate exception type to respond with a specific HTTP response code. Since ``HTTPException`` is a sub-class of :class:`Response`, it contains the methods and properties that allow you to directly manipulate details of the response. .. attribute:: status_code HTTP status code for this exception class. This attribute is usually defined at the class level. ``self.status_code`` is passed to the :class:`Response` initializer. .. _aiohttp-web-app-and-router: Application and Router ---------------------- .. class:: Application(*, logger=, router=None, middlewares=(), \ handler_args=None, client_max_size=1024**2, \ loop=None, debug=...) Application is a synonym for web-server. To get a fully working example, you have to make an *application*, register supported urls in the *router* and pass it to :func:`aiohttp.web.run_app` or :class:`aiohttp.web.AppRunner`. *Application* contains a *router* instance and a list of callbacks that will be called during application finishing. This class is a :obj:`dict`-like object, so you can use it for :ref:`sharing data` globally by storing arbitrary properties for later access from a :ref:`handler` via the :attr:`Request.app` property:: app = Application() database = AppKey("database", AsyncEngine) app[database] = await create_async_engine(db_url) async def handler(request): async with request.app[database].begin() as conn: await conn.execute("DELETE * FROM table") Although it` is a :obj:`dict`-like object, it can't be duplicated like one using :meth:`~aiohttp.web.Application.copy`. The class inherits :class:`dict`. :param logger: :class:`logging.Logger` instance for storing application logs. By default the value is ``logging.getLogger("aiohttp.web")`` :param router: :class:`aiohttp.abc.AbstractRouter` instance, the system creates :class:`UrlDispatcher` by default if *router* is ``None``. .. deprecated:: 3.3 The custom routers support is deprecated, the parameter will be removed in 4.0. :param middlewares: :class:`list` of middleware factories, see :ref:`aiohttp-web-middlewares` for details. :param handler_args: dict-like object that overrides keyword arguments of :meth:`Application.make_handler` :param client_max_size: client's maximum size in a request, in bytes. If a POST request exceeds this value, it raises an `HTTPRequestEntityTooLarge` exception. :param loop: event loop .. deprecated:: 2.0 The parameter is deprecated. Loop is get set during freeze stage. :param debug: Switches debug mode. .. deprecated:: 3.5 Use asyncio :ref:`asyncio-debug-mode` instead. .. attribute:: router Read-only property that returns *router instance*. .. attribute:: logger :class:`logging.Logger` instance for storing application logs. .. attribute:: loop :ref:`event loop` used for processing HTTP requests. .. deprecated:: 3.5 .. attribute:: debug Boolean value indicating whether the debug mode is turned on or off. .. deprecated:: 3.5 Use asyncio :ref:`asyncio-debug-mode` instead. .. attribute:: on_response_prepare A :class:`~aiosignal.Signal` that is fired near the end of :meth:`StreamResponse.prepare` with parameters *request* and *response*. It can be used, for example, to add custom headers to each response, or to modify the default headers computed by the application, directly before sending the headers to the client. Signal handlers should have the following signature:: async def on_prepare(request, response): pass .. note:: The headers are written immediately after these callbacks are run. Therefore, if you modify the content of the response, you may need to adjust the `Content-Length` header or similar to match. Aiohttp will not make any updates to the headers from this point. .. attribute:: on_startup A :class:`~aiosignal.Signal` that is fired on application start-up. Subscribers may use the signal to run background tasks in the event loop along with the application's request handler just after the application start-up. Signal handlers should have the following signature:: async def on_startup(app): pass .. seealso:: :ref:`aiohttp-web-signals`. .. attribute:: on_shutdown A :class:`~aiosignal.Signal` that is fired on application shutdown. Subscribers may use the signal for gracefully closing long running connections, e.g. websockets and data streaming. Signal handlers should have the following signature:: async def on_shutdown(app): pass It's up to end user to figure out which :term:`web-handler`\s are still alive and how to finish them properly. We suggest keeping a list of long running handlers in :class:`Application` dictionary. .. seealso:: :ref:`aiohttp-web-graceful-shutdown` and :attr:`on_cleanup`. .. attribute:: on_cleanup A :class:`~aiosignal.Signal` that is fired on application cleanup. Subscribers may use the signal for gracefully closing connections to database server etc. Signal handlers should have the following signature:: async def on_cleanup(app): pass .. seealso:: :ref:`aiohttp-web-signals` and :attr:`on_shutdown`. .. attribute:: cleanup_ctx A list of *context generators* for *startup*/*cleanup* handling. Signal handlers should have the following signature:: async def context(app): # do startup stuff yield # do cleanup .. versionadded:: 3.1 .. seealso:: :ref:`aiohttp-web-cleanup-ctx`. .. method:: add_subapp(prefix, subapp) Register nested sub-application under given path *prefix*. In resolving process if request's path starts with *prefix* then further resolving is passed to *subapp*. :param str prefix: path's prefix for the resource. :param Application subapp: nested application attached under *prefix*. :returns: a :class:`PrefixedSubAppResource` instance. .. method:: add_domain(domain, subapp) Register nested sub-application that serves the domain name or domain name mask. In resolving process if request.headers['host'] matches the pattern *domain* then further resolving is passed to *subapp*. :param str domain: domain or mask of domain for the resource. :param Application subapp: nested application. :returns: a :class:`~aiohttp.web.MatchedSubAppResource` instance. .. method:: add_routes(routes_table) Register route definitions from *routes_table*. The table is a :class:`list` of :class:`RouteDef` items or :class:`RouteTableDef`. :returns: :class:`list` of registered :class:`AbstractRoute` instances. The method is a shortcut for ``app.router.add_routes(routes_table)``, see also :meth:`UrlDispatcher.add_routes`. .. versionadded:: 3.1 .. versionchanged:: 3.7 Return value updated from ``None`` to :class:`list` of :class:`AbstractRoute` instances. .. method:: make_handler(loop=None, **kwargs) Creates HTTP protocol factory for handling requests. :param loop: :ref:`event loop` used for processing HTTP requests. If param is ``None`` :func:`asyncio.get_event_loop` used for getting default event loop. .. deprecated:: 2.0 :param bool tcp_keepalive: Enable TCP Keep-Alive. Default: ``True``. :param int keepalive_timeout: Number of seconds before closing Keep-Alive connection. Default: ``75`` seconds (NGINX's default value). :param logger: Custom logger object. Default: :data:`aiohttp.log.server_logger`. :param access_log: Custom logging object. Default: :data:`aiohttp.log.access_logger`. :param access_log_class: Class for `access_logger`. Default: :data:`aiohttp.helpers.AccessLogger`. Must to be a subclass of :class:`aiohttp.abc.AbstractAccessLogger`. :param str access_log_format: Access log format string. Default: :attr:`helpers.AccessLogger.LOG_FORMAT`. :param int max_line_size: Optional maximum header line size. Default: ``8190``. :param int max_headers: Optional maximum header size. Default: ``32768``. :param int max_field_size: Optional maximum header field size. Default: ``8190``. :param float lingering_time: Maximum time during which the server reads and ignores additional data coming from the client when lingering close is on. Use ``0`` to disable lingering on server channel closing. You should pass result of the method as *protocol_factory* to :meth:`~asyncio.AbstractEventLoop.create_server`, e.g.:: loop = asyncio.get_event_loop() app = Application() # setup route table # app.router.add_route(...) await loop.create_server(app.make_handler(), '0.0.0.0', 8080) .. deprecated:: 3.2 The method is deprecated and will be removed in future aiohttp versions. Please use :ref:`aiohttp-web-app-runners` instead. .. method:: startup() :async: A :ref:`coroutine` that will be called along with the application's request handler. The purpose of the method is calling :attr:`on_startup` signal handlers. .. method:: shutdown() :async: A :ref:`coroutine` that should be called on server stopping but before :meth:`cleanup()`. The purpose of the method is calling :attr:`on_shutdown` signal handlers. .. method:: cleanup() :async: A :ref:`coroutine` that should be called on server stopping but after :meth:`shutdown`. The purpose of the method is calling :attr:`on_cleanup` signal handlers. .. note:: Application object has :attr:`router` attribute but has no ``add_route()`` method. The reason is: we want to support different router implementations (even maybe not url-matching based but traversal ones). For sake of that fact we have very trivial ABC for :class:`~aiohttp.abc.AbstractRouter`: it should have only :meth:`aiohttp.abc.AbstractRouter.resolve` coroutine. No methods for adding routes or route reversing (getting URL by route name). All those are router implementation details (but, sure, you need to deal with that methods after choosing the router for your application). .. class:: AppKey(name, t) This class should be used for the keys in :class:`Application`. They provide a type-safe alternative to `str` keys when checking your code with a type checker (e.g. mypy). They also avoid name clashes with keys from different libraries etc. :param name: A name to help with debugging. This should be the same as the variable name (much like how :class:`typing.TypeVar` is used). :param t: The type that should be used for the value in the dict (e.g. `str`, `Iterator[int]` etc.) .. class:: Server A protocol factory compatible with :meth:`~asyncio.AbstractEventLoop.create_server`. The class is responsible for creating HTTP protocol objects that can handle HTTP connections. .. attribute:: connections List of all currently opened connections. .. attribute:: requests_count Amount of processed requests. .. method:: Server.shutdown(timeout) :async: A :ref:`coroutine` that should be called to close all opened connections. .. class:: UrlDispatcher() For dispatching URLs to :ref:`handlers` :mod:`aiohttp.web` uses *routers*, which is any object that implements :class:`~aiohttp.abc.AbstractRouter` interface. This class is a straightforward url-matching router, implementing :class:`collections.abc.Mapping` for access to *named routes*. :class:`Application` uses this class as :meth:`~aiohttp.web.Application.router` by default. Before running an :class:`Application` you should fill *route table* first by calling :meth:`add_route` and :meth:`add_static`. :ref:`Handler` lookup is performed by iterating on added *routes* in FIFO order. The first matching *route* will be used to call the corresponding *handler*. If during route creation you specify *name* parameter the result is a *named route*. A *named route* can be retrieved by a ``app.router[name]`` call, checking for existence can be done with ``name in app.router`` etc. .. seealso:: :ref:`Route classes ` .. method:: add_resource(path, *, name=None) Append a :term:`resource` to the end of route table. *path* may be either *constant* string like ``'/a/b/c'`` or *variable rule* like ``'/a/{var}'`` (see :ref:`handling variable paths `) :param str path: resource path spec. :param str name: optional resource name. :return: created resource instance (:class:`PlainResource` or :class:`DynamicResource`). .. method:: add_route(method, path, handler, *, \ name=None, expect_handler=None) Append :ref:`handler` to the end of route table. *path* may be either *constant* string like ``'/a/b/c'`` or *variable rule* like ``'/a/{var}'`` (see :ref:`handling variable paths `) Pay attention please: *handler* is converted to coroutine internally when it is a regular function. :param str method: HTTP method for route. Should be one of ``'GET'``, ``'POST'``, ``'PUT'``, ``'DELETE'``, ``'PATCH'``, ``'HEAD'``, ``'OPTIONS'`` or ``'*'`` for any method. The parameter is case-insensitive, e.g. you can push ``'get'`` as well as ``'GET'``. :param str path: route path. Should be started with slash (``'/'``). :param collections.abc.Callable handler: route handler. :param str name: optional route name. :param collections.abc.Coroutine expect_handler: optional *expect* header handler. :returns: new :class:`AbstractRoute` instance. .. method:: add_routes(routes_table) Register route definitions from *routes_table*. The table is a :class:`list` of :class:`RouteDef` items or :class:`RouteTableDef`. :returns: :class:`list` of registered :class:`AbstractRoute` instances. .. versionadded:: 2.3 .. versionchanged:: 3.7 Return value updated from ``None`` to :class:`list` of :class:`AbstractRoute` instances. .. method:: add_get(path, handler, *, name=None, allow_head=True, **kwargs) Shortcut for adding a GET handler. Calls the :meth:`add_route` with \ ``method`` equals to ``'GET'``. If *allow_head* is ``True`` (default) the route for method HEAD is added with the same handler as for GET. If *name* is provided the name for HEAD route is suffixed with ``'-head'``. For example ``router.add_get(path, handler, name='route')`` call adds two routes: first for GET with name ``'route'`` and second for HEAD with name ``'route-head'``. .. method:: add_post(path, handler, **kwargs) Shortcut for adding a POST handler. Calls the :meth:`add_route` with \ ``method`` equals to ``'POST'``. .. method:: add_head(path, handler, **kwargs) Shortcut for adding a HEAD handler. Calls the :meth:`add_route` with \ ``method`` equals to ``'HEAD'``. .. method:: add_put(path, handler, **kwargs) Shortcut for adding a PUT handler. Calls the :meth:`add_route` with \ ``method`` equals to ``'PUT'``. .. method:: add_patch(path, handler, **kwargs) Shortcut for adding a PATCH handler. Calls the :meth:`add_route` with \ ``method`` equals to ``'PATCH'``. .. method:: add_delete(path, handler, **kwargs) Shortcut for adding a DELETE handler. Calls the :meth:`add_route` with \ ``method`` equals to ``'DELETE'``. .. method:: add_view(path, handler, **kwargs) Shortcut for adding a class-based view handler. Calls the \ :meth:`add_route` with ``method`` equals to ``'*'``. .. versionadded:: 3.0 .. method:: add_static(prefix, path, *, name=None, expect_handler=None, \ chunk_size=256*1024, \ response_factory=StreamResponse, \ show_index=False, \ follow_symlinks=False, \ append_version=False) Adds a router and a handler for returning static files. Useful for serving static content like images, javascript and css files. On platforms that support it, the handler will transfer files more efficiently using the ``sendfile`` system call. In some situations it might be necessary to avoid using the ``sendfile`` system call even if the platform supports it. This can be accomplished by by setting environment variable ``AIOHTTP_NOSENDFILE=1``. If a gzip version of the static content exists at file path + ``.gz``, it will be used for the response. .. warning:: Use :meth:`add_static` for development only. In production, static content should be processed by web servers like *nginx* or *apache*. :param str prefix: URL path prefix for handled static files :param path: path to the folder in file system that contains handled static files, :class:`str` or :class:`pathlib.Path`. :param str name: optional route name. :param collections.abc.Coroutine expect_handler: optional *expect* header handler. :param int chunk_size: size of single chunk for file downloading, 256Kb by default. Increasing *chunk_size* parameter to, say, 1Mb may increase file downloading speed but consumes more memory. :param bool show_index: flag for allowing to show indexes of a directory, by default it's not allowed and HTTP/403 will be returned on directory access. :param bool follow_symlinks: flag for allowing to follow symlinks that lead outside the static root directory, by default it's not allowed and HTTP/404 will be returned on access. Enabling ``follow_symlinks`` can be a security risk, and may lead to a directory transversal attack. You do NOT need this option to follow symlinks which point to somewhere else within the static directory, this option is only used to break out of the security sandbox. Enabling this option is highly discouraged, and only expected to be used for edge cases in a local development setting where remote users do not have access to the server. :param bool append_version: flag for adding file version (hash) to the url query string, this value will be used as default when you call to :meth:`~aiohttp.web.AbstractRoute.url` and :meth:`~aiohttp.web.AbstractRoute.url_for` methods. :returns: new :class:`~aiohttp.web.AbstractRoute` instance. .. method:: resolve(request) :async: A :ref:`coroutine` that returns :class:`~aiohttp.abc.AbstractMatchInfo` for *request*. The method never raises exception, but returns :class:`~aiohttp.abc.AbstractMatchInfo` instance with: 1. :attr:`~aiohttp.abc.AbstractMatchInfo.http_exception` assigned to :exc:`HTTPException` instance. 2. :meth:`~aiohttp.abc.AbstractMatchInfo.handler` which raises :exc:`HTTPNotFound` or :exc:`HTTPMethodNotAllowed` on handler's execution if there is no registered route for *request*. *Middlewares* can process that exceptions to render pretty-looking error page for example. Used by internal machinery, end user unlikely need to call the method. .. note:: The method uses :attr:`aiohttp.web.BaseRequest.raw_path` for pattern matching against registered routes. .. method:: resources() The method returns a *view* for *all* registered resources. The view is an object that allows to: 1. Get size of the router table:: len(app.router.resources()) 2. Iterate over registered resources:: for resource in app.router.resources(): print(resource) 3. Make a check if the resources is registered in the router table:: route in app.router.resources() .. method:: routes() The method returns a *view* for *all* registered routes. .. method:: named_resources() Returns a :obj:`dict`-like :class:`types.MappingProxyType` *view* over *all* named **resources**. The view maps every named resource's **name** to the :class:`AbstractResource` instance. It supports the usual :obj:`dict`-like operations, except for any mutable operations (i.e. it's **read-only**):: len(app.router.named_resources()) for name, resource in app.router.named_resources().items(): print(name, resource) "name" in app.router.named_resources() app.router.named_resources()["name"] .. _aiohttp-web-resource: Resource ^^^^^^^^ Default router :class:`UrlDispatcher` operates with :term:`resource`\s. Resource is an item in *routing table* which has a *path*, an optional unique *name* and at least one :term:`route`. :term:`web-handler` lookup is performed in the following way: 1. Router iterates over *resources* one-by-one. 2. If *resource* matches to requested URL the resource iterates over own *routes*. 3. If route matches to requested HTTP method (or ``'*'`` wildcard) the route's handler is used as found :term:`web-handler`. The lookup is finished. 4. Otherwise router tries next resource from the *routing table*. 5. If the end of *routing table* is reached and no *resource* / *route* pair found the *router* returns special :class:`~aiohttp.abc.AbstractMatchInfo` instance with :attr:`aiohttp.abc.AbstractMatchInfo.http_exception` is not ``None`` but :exc:`HTTPException` with either *HTTP 404 Not Found* or *HTTP 405 Method Not Allowed* status code. Registered :meth:`~aiohttp.abc.AbstractMatchInfo.handler` raises this exception on call. User should never instantiate resource classes but give it by :meth:`UrlDispatcher.add_resource` call. After that he may add a :term:`route` by calling :meth:`Resource.add_route`. :meth:`UrlDispatcher.add_route` is just shortcut for:: router.add_resource(path).add_route(method, handler) Resource with a *name* is called *named resource*. The main purpose of *named resource* is constructing URL by route name for passing it into *template engine* for example:: url = app.router['resource_name'].url_for().with_query({'a': 1, 'b': 2}) Resource classes hierarchy:: AbstractResource Resource PlainResource DynamicResource StaticResource .. class:: AbstractResource A base class for all resources. Inherited from :class:`collections.abc.Sized` and :class:`collections.abc.Iterable`. ``len(resource)`` returns amount of :term:`route`\s belongs to the resource, ``for route in resource`` allows to iterate over these routes. .. attribute:: name Read-only *name* of resource or ``None``. .. attribute:: canonical Read-only *canonical path* associate with the resource. For example ``/path/to`` or ``/path/{to}`` .. versionadded:: 3.3 .. method:: resolve(request) :async: Resolve resource by finding appropriate :term:`web-handler` for ``(method, path)`` combination. :return: (*match_info*, *allowed_methods*) pair. *allowed_methods* is a :class:`set` or HTTP methods accepted by resource. *match_info* is either :class:`UrlMappingMatchInfo` if request is resolved or ``None`` if no :term:`route` is found. .. method:: get_info() A resource description, e.g. ``{'path': '/path/to'}`` or ``{'formatter': '/path/{to}', 'pattern': re.compile(r'^/path/(?P[a-zA-Z][_a-zA-Z0-9]+)$`` .. method:: url_for(*args, **kwargs) Construct an URL for route with additional params. *args* and **kwargs** depend on a parameters list accepted by inherited resource class. :return: :class:`~yarl.URL` -- resulting URL instance. .. class:: Resource A base class for new-style resources, inherits :class:`AbstractResource`. .. method:: add_route(method, handler, *, expect_handler=None) Add a :term:`web-handler` to resource. :param str method: HTTP method for route. Should be one of ``'GET'``, ``'POST'``, ``'PUT'``, ``'DELETE'``, ``'PATCH'``, ``'HEAD'``, ``'OPTIONS'`` or ``'*'`` for any method. The parameter is case-insensitive, e.g. you can push ``'get'`` as well as ``'GET'``. The method should be unique for resource. :param collections.abc.Callable handler: route handler. :param collections.abc.Coroutine expect_handler: optional *expect* header handler. :returns: new :class:`ResourceRoute` instance. .. class:: PlainResource A resource, inherited from :class:`Resource`. The class corresponds to resources with plain-text matching, ``'/path/to'`` for example. .. attribute:: canonical Read-only *canonical path* associate with the resource. Returns the path used to create the PlainResource. For example ``/path/to`` .. versionadded:: 3.3 .. method:: url_for() Returns a :class:`~yarl.URL` for the resource. .. class:: DynamicResource A resource, inherited from :class:`Resource`. The class corresponds to resources with :ref:`variable ` matching, e.g. ``'/path/{to}/{param}'`` etc. .. attribute:: canonical Read-only *canonical path* associate with the resource. Returns the formatter obtained from the path used to create the DynamicResource. For example, from a path ``/get/{num:^\d+}``, it returns ``/get/{num}`` .. versionadded:: 3.3 .. method:: url_for(**params) Returns a :class:`~yarl.URL` for the resource. :param params: -- a variable substitutions for dynamic resource. E.g. for ``'/path/{to}/{param}'`` pattern the method should be called as ``resource.url_for(to='val1', param='val2')`` .. class:: StaticResource A resource, inherited from :class:`Resource`. The class corresponds to resources for :ref:`static file serving `. .. attribute:: canonical Read-only *canonical path* associate with the resource. Returns the prefix used to create the StaticResource. For example ``/prefix`` .. versionadded:: 3.3 .. method:: url_for(filename, append_version=None) Returns a :class:`~yarl.URL` for file path under resource prefix. :param filename: -- a file name substitution for static file handler. Accepts both :class:`str` and :class:`pathlib.Path`. E.g. an URL for ``'/prefix/dir/file.txt'`` should be generated as ``resource.url_for(filename='dir/file.txt')`` :param bool append_version: -- a flag for adding file version (hash) to the url query string for cache boosting By default has value from a constructor (``False`` by default) When set to ``True`` - ``v=FILE_HASH`` query string param will be added When set to ``False`` has no impact if file not found has no impact .. class:: PrefixedSubAppResource A resource for serving nested applications. The class instance is returned by :class:`~aiohttp.web.Application.add_subapp` call. .. attribute:: canonical Read-only *canonical path* associate with the resource. Returns the prefix used to create the PrefixedSubAppResource. For example ``/prefix`` .. versionadded:: 3.3 .. method:: url_for(**kwargs) The call is not allowed, it raises :exc:`RuntimeError`. .. _aiohttp-web-route: Route ^^^^^ Route has *HTTP method* (wildcard ``'*'`` is an option), :term:`web-handler` and optional *expect handler*. Every route belong to some resource. Route classes hierarchy:: AbstractRoute ResourceRoute SystemRoute :class:`ResourceRoute` is the route used for resources, :class:`SystemRoute` serves URL resolving errors like *404 Not Found* and *405 Method Not Allowed*. .. class:: AbstractRoute Base class for routes served by :class:`UrlDispatcher`. .. attribute:: method HTTP method handled by the route, e.g. *GET*, *POST* etc. .. attribute:: handler :ref:`handler` that processes the route. .. attribute:: name Name of the route, always equals to name of resource which owns the route. .. attribute:: resource Resource instance which holds the route, ``None`` for :class:`SystemRoute`. .. method:: url_for(*args, **kwargs) Abstract method for constructing url handled by the route. Actually it's a shortcut for ``route.resource.url_for(...)``. .. method:: handle_expect_header(request) :async: ``100-continue`` handler. .. class:: ResourceRoute The route class for handling different HTTP methods for :class:`Resource`. .. class:: SystemRoute The route class for handling URL resolution errors like like *404 Not Found* and *405 Method Not Allowed*. .. attribute:: status HTTP status code .. attribute:: reason HTTP status reason .. _aiohttp-web-route-def: RouteDef and StaticDef ^^^^^^^^^^^^^^^^^^^^^^ Route definition, a description for not registered yet route. Could be used for filing route table by providing a list of route definitions (Django style). The definition is created by functions like :func:`get` or :func:`post`, list of definitions could be added to router by :meth:`UrlDispatcher.add_routes` call:: from aiohttp import web async def handle_get(request): ... async def handle_post(request): ... app.router.add_routes([web.get('/get', handle_get), web.post('/post', handle_post), .. class:: AbstractRouteDef A base class for route definitions. Inherited from :class:`abc.ABC`. .. versionadded:: 3.1 .. method:: register(router) Register itself into :class:`UrlDispatcher`. Abstract method, should be overridden by subclasses. :returns: :class:`list` of registered :class:`AbstractRoute` objects. .. versionchanged:: 3.7 Return value updated from ``None`` to :class:`list` of :class:`AbstractRoute` instances. .. class:: RouteDef A definition of not registered yet route. Implements :class:`AbstractRouteDef`. .. versionadded:: 2.3 .. versionchanged:: 3.1 The class implements :class:`AbstractRouteDef` interface. .. attribute:: method HTTP method (``GET``, ``POST`` etc.) (:class:`str`). .. attribute:: path Path to resource, e.g. ``/path/to``. Could contain ``{}`` brackets for :ref:`variable resources ` (:class:`str`). .. attribute:: handler An async function to handle HTTP request. .. attribute:: kwargs A :class:`dict` of additional arguments. .. class:: StaticDef A definition of static file resource. Implements :class:`AbstractRouteDef`. .. versionadded:: 3.1 .. attribute:: prefix A prefix used for static file handling, e.g. ``/static``. .. attribute:: path File system directory to serve, :class:`str` or :class:`pathlib.Path` (e.g. ``'/home/web-service/path/to/static'``. .. attribute:: kwargs A :class:`dict` of additional arguments, see :meth:`UrlDispatcher.add_static` for a list of supported options. .. function:: get(path, handler, *, name=None, allow_head=True, \ expect_handler=None) Return :class:`RouteDef` for processing ``GET`` requests. See :meth:`UrlDispatcher.add_get` for information about parameters. .. versionadded:: 2.3 .. function:: post(path, handler, *, name=None, expect_handler=None) Return :class:`RouteDef` for processing ``POST`` requests. See :meth:`UrlDispatcher.add_post` for information about parameters. .. versionadded:: 2.3 .. function:: head(path, handler, *, name=None, expect_handler=None) Return :class:`RouteDef` for processing ``HEAD`` requests. See :meth:`UrlDispatcher.add_head` for information about parameters. .. versionadded:: 2.3 .. function:: put(path, handler, *, name=None, expect_handler=None) Return :class:`RouteDef` for processing ``PUT`` requests. See :meth:`UrlDispatcher.add_put` for information about parameters. .. versionadded:: 2.3 .. function:: patch(path, handler, *, name=None, expect_handler=None) Return :class:`RouteDef` for processing ``PATCH`` requests. See :meth:`UrlDispatcher.add_patch` for information about parameters. .. versionadded:: 2.3 .. function:: delete(path, handler, *, name=None, expect_handler=None) Return :class:`RouteDef` for processing ``DELETE`` requests. See :meth:`UrlDispatcher.add_delete` for information about parameters. .. versionadded:: 2.3 .. function:: view(path, handler, *, name=None, expect_handler=None) Return :class:`RouteDef` for processing ``ANY`` requests. See :meth:`UrlDispatcher.add_view` for information about parameters. .. versionadded:: 3.0 .. function:: static(prefix, path, *, name=None, expect_handler=None, \ chunk_size=256*1024, \ show_index=False, follow_symlinks=False, \ append_version=False) Return :class:`StaticDef` for processing static files. See :meth:`UrlDispatcher.add_static` for information about supported parameters. .. versionadded:: 3.1 .. function:: route(method, path, handler, *, name=None, expect_handler=None) Return :class:`RouteDef` for processing requests that decided by ``method``. See :meth:`UrlDispatcher.add_route` for information about parameters. .. versionadded:: 2.3 .. _aiohttp-web-route-table-def: RouteTableDef ^^^^^^^^^^^^^ A routes table definition used for describing routes by decorators (Flask style):: from aiohttp import web routes = web.RouteTableDef() @routes.get('/get') async def handle_get(request): ... @routes.post('/post') async def handle_post(request): ... app.router.add_routes(routes) @routes.view("/view") class MyView(web.View): async def get(self): ... async def post(self): ... .. class:: RouteTableDef() A sequence of :class:`RouteDef` instances (implements :class:`collections.abc.Sequence` protocol). In addition to all standard :class:`list` methods the class provides also methods like ``get()`` and ``post()`` for adding new route definition. .. versionadded:: 2.3 .. decoratormethod:: get(path, *, allow_head=True, \ name=None, expect_handler=None) Add a new :class:`RouteDef` item for registering ``GET`` web-handler. See :meth:`UrlDispatcher.add_get` for information about parameters. .. decoratormethod:: post(path, *, name=None, expect_handler=None) Add a new :class:`RouteDef` item for registering ``POST`` web-handler. See :meth:`UrlDispatcher.add_post` for information about parameters. .. decoratormethod:: head(path, *, name=None, expect_handler=None) Add a new :class:`RouteDef` item for registering ``HEAD`` web-handler. See :meth:`UrlDispatcher.add_head` for information about parameters. .. decoratormethod:: put(path, *, name=None, expect_handler=None) Add a new :class:`RouteDef` item for registering ``PUT`` web-handler. See :meth:`UrlDispatcher.add_put` for information about parameters. .. decoratormethod:: patch(path, *, name=None, expect_handler=None) Add a new :class:`RouteDef` item for registering ``PATCH`` web-handler. See :meth:`UrlDispatcher.add_patch` for information about parameters. .. decoratormethod:: delete(path, *, name=None, expect_handler=None) Add a new :class:`RouteDef` item for registering ``DELETE`` web-handler. See :meth:`UrlDispatcher.add_delete` for information about parameters. .. decoratormethod:: view(path, *, name=None, expect_handler=None) Add a new :class:`RouteDef` item for registering ``ANY`` methods against a class-based view. See :meth:`UrlDispatcher.add_view` for information about parameters. .. versionadded:: 3.0 .. method:: static(prefix, path, *, name=None, expect_handler=None, \ chunk_size=256*1024, \ show_index=False, follow_symlinks=False, \ append_version=False) Add a new :class:`StaticDef` item for registering static files processor. See :meth:`UrlDispatcher.add_static` for information about supported parameters. .. versionadded:: 3.1 .. decoratormethod:: route(method, path, *, name=None, expect_handler=None) Add a new :class:`RouteDef` item for registering a web-handler for arbitrary HTTP method. See :meth:`UrlDispatcher.add_route` for information about parameters. MatchInfo ^^^^^^^^^ After route matching web application calls found handler if any. Matching result can be accessible from handler as :attr:`Request.match_info` attribute. In general the result may be any object derived from :class:`~aiohttp.abc.AbstractMatchInfo` (:class:`UrlMappingMatchInfo` for default :class:`UrlDispatcher` router). .. class:: UrlMappingMatchInfo Inherited from :class:`dict` and :class:`~aiohttp.abc.AbstractMatchInfo`. Dict items are filled by matching info and is :term:`resource`\-specific. .. attribute:: expect_handler A coroutine for handling ``100-continue``. .. attribute:: handler A coroutine for handling request. .. attribute:: route :class:`AbstractRoute` instance for url matching. View ^^^^ .. class:: View(request) Inherited from :class:`~aiohttp.abc.AbstractView`. Base class for class based views. Implementations should derive from :class:`View` and override methods for handling HTTP verbs like ``get()`` or ``post()``:: class MyView(View): async def get(self): resp = await get_response(self.request) return resp async def post(self): resp = await post_response(self.request) return resp app.router.add_view('/view', MyView) The view raises *405 Method Not allowed* (:class:`HTTPMethodNotAllowed`) if requested web verb is not supported. :param request: instance of :class:`Request` that has initiated a view processing. .. attribute:: request Request sent to view's constructor, read-only property. Overridable coroutine methods: ``connect()``, ``delete()``, ``get()``, ``head()``, ``options()``, ``patch()``, ``post()``, ``put()``, ``trace()``. .. seealso:: :ref:`aiohttp-web-class-based-views` .. _aiohttp-web-app-runners-reference: Running Applications -------------------- To start web application there is ``AppRunner`` and site classes. Runner is a storage for running application, sites are for running application on specific TCP or Unix socket, e.g.:: runner = web.AppRunner(app) await runner.setup() site = web.TCPSite(runner, 'localhost', 8080) await site.start() # wait for finish signal await runner.cleanup() .. versionadded:: 3.0 :class:`AppRunner` / :class:`ServerRunner` and :class:`TCPSite` / :class:`UnixSite` / :class:`SockSite` are added in aiohttp 3.0 .. class:: BaseRunner A base class for runners. Use :class:`AppRunner` for serving :class:`Application`, :class:`ServerRunner` for low-level :class:`Server`. .. attribute:: server Low-level web :class:`Server` for handling HTTP requests, read-only attribute. .. attribute:: addresses A :class:`list` of served sockets addresses. See :meth:`socket.getsockname() ` for items type. .. versionadded:: 3.3 .. attribute:: sites A read-only :class:`set` of served sites (:class:`TCPSite` / :class:`UnixSite` / :class:`NamedPipeSite` / :class:`SockSite` instances). .. method:: setup() :async: Initialize the server. Should be called before adding sites. .. method:: cleanup() :async: Stop handling all registered sites and cleanup used resources. .. class:: AppRunner(app, *, handle_signals=False, **kwargs) A runner for :class:`Application`. Used with conjunction with sites to serve on specific port. Inherited from :class:`BaseRunner`. :param Application app: web application instance to serve. :param bool handle_signals: add signal handlers for :data:`signal.SIGINT` and :data:`signal.SIGTERM` (``False`` by default). :param kwargs: named parameters to pass into web protocol. Supported *kwargs*: :param bool tcp_keepalive: Enable TCP Keep-Alive. Default: ``True``. :param int keepalive_timeout: Number of seconds before closing Keep-Alive connection. Default: ``75`` seconds (NGINX's default value). :param logger: Custom logger object. Default: :data:`aiohttp.log.server_logger`. :param access_log: Custom logging object. Default: :data:`aiohttp.log.access_logger`. :param access_log_class: Class for `access_logger`. Default: :data:`aiohttp.helpers.AccessLogger`. Must to be a subclass of :class:`aiohttp.abc.AbstractAccessLogger`. :param str access_log_format: Access log format string. Default: :attr:`helpers.AccessLogger.LOG_FORMAT`. :param int max_line_size: Optional maximum header line size. Default: ``8190``. :param int max_headers: Optional maximum header size. Default: ``32768``. :param int max_field_size: Optional maximum header field size. Default: ``8190``. :param float lingering_time: Maximum time during which the server reads and ignores additional data coming from the client when lingering close is on. Use ``0`` to disable lingering on server channel closing. :param int read_bufsize: Size of the read buffer (:attr:`BaseRequest.content`). ``None`` by default, it means that the session global value is used. .. versionadded:: 3.7 :param bool auto_decompress: Automatically decompress request body, ``True`` by default. .. versionadded:: 3.8 .. attribute:: app Read-only attribute for accessing to :class:`Application` served instance. .. method:: setup() :async: Initialize application. Should be called before adding sites. The method calls :attr:`Application.on_startup` registered signals. .. method:: cleanup() :async: Stop handling all registered sites and cleanup used resources. :attr:`Application.on_shutdown` and :attr:`Application.on_cleanup` signals are called internally. .. class:: ServerRunner(web_server, *, handle_signals=False, **kwargs) A runner for low-level :class:`Server`. Used with conjunction with sites to serve on specific port. Inherited from :class:`BaseRunner`. :param Server web_server: low-level web server instance to serve. :param bool handle_signals: add signal handlers for :data:`signal.SIGINT` and :data:`signal.SIGTERM` (``False`` by default). :param kwargs: named parameters to pass into web protocol. .. seealso:: :ref:`aiohttp-web-lowlevel` demonstrates low-level server usage .. class:: BaseSite An abstract class for handled sites. .. attribute:: name An identifier for site, read-only :class:`str` property. Could be a handled URL or UNIX socket path. .. method:: start() :async: Start handling a site. .. method:: stop() :async: Stop handling a site. .. class:: TCPSite(runner, host=None, port=None, *, \ shutdown_timeout=60.0, ssl_context=None, \ backlog=128, reuse_address=None, \ reuse_port=None) Serve a runner on TCP socket. :param runner: a runner to serve. :param str host: HOST to listen on, all interfaces if ``None`` (default). :param int port: PORT to listed on, ``8080`` if ``None`` (default). :param float shutdown_timeout: a timeout used for both waiting on pending tasks before application shutdown and for closing opened connections on :meth:`BaseSite.stop` call. :param ssl_context: a :class:`ssl.SSLContext` instance for serving SSL/TLS secure server, ``None`` for plain HTTP server (default). :param int backlog: a number of unaccepted connections that the system will allow before refusing new connections, see :meth:`socket.socket.listen` for details. ``128`` by default. :param bool reuse_address: tells the kernel to reuse a local socket in TIME_WAIT state, without waiting for its natural timeout to expire. If not specified will automatically be set to True on UNIX. :param bool reuse_port: tells the kernel to allow this endpoint to be bound to the same port as other existing endpoints are bound to, so long as they all set this flag when being created. This option is not supported on Windows. .. class:: UnixSite(runner, path, *, \ shutdown_timeout=60.0, ssl_context=None, \ backlog=128) Serve a runner on UNIX socket. :param runner: a runner to serve. :param str path: PATH to UNIX socket to listen. :param float shutdown_timeout: a timeout used for both waiting on pending tasks before application shutdown and for closing opened connections on :meth:`BaseSite.stop` call. :param ssl_context: a :class:`ssl.SSLContext` instance for serving SSL/TLS secure server, ``None`` for plain HTTP server (default). :param int backlog: a number of unaccepted connections that the system will allow before refusing new connections, see :meth:`socket.socket.listen` for details. ``128`` by default. .. class:: NamedPipeSite(runner, path, *, shutdown_timeout=60.0) Serve a runner on Named Pipe in Windows. :param runner: a runner to serve. :param str path: PATH of named pipe to listen. :param float shutdown_timeout: a timeout used for both waiting on pending tasks before application shutdown and for closing opened connections on :meth:`BaseSite.stop` call. .. class:: SockSite(runner, sock, *, \ shutdown_timeout=60.0, ssl_context=None, \ backlog=128) Serve a runner on UNIX socket. :param runner: a runner to serve. :param sock: A :ref:`socket instance ` to listen to. :param float shutdown_timeout: a timeout used for both waiting on pending tasks before application shutdown and for closing opened connections on :meth:`BaseSite.stop` call. :param ssl_context: a :class:`ssl.SSLContext` instance for serving SSL/TLS secure server, ``None`` for plain HTTP server (default). :param int backlog: a number of unaccepted connections that the system will allow before refusing new connections, see :meth:`socket.socket.listen` for details. ``128`` by default. Utilities --------- .. class:: FileField A :mod:`dataclass ` instance that is returned as multidict value by :meth:`aiohttp.web.BaseRequest.post` if field is uploaded file. .. attribute:: name Field name .. attribute:: filename File name as specified by uploading (client) side. .. attribute:: file An :class:`io.IOBase` instance with content of uploaded file. .. attribute:: content_type *MIME type* of uploaded file, ``'text/plain'`` by default. .. seealso:: :ref:`aiohttp-web-file-upload` .. function:: run_app(app, *, host=None, port=None, path=None, \ sock=None, shutdown_timeout=60.0, \ keepalive_timeout=75.0, \ ssl_context=None, print=print, backlog=128, \ access_log_class=aiohttp.helpers.AccessLogger, \ access_log_format=aiohttp.helpers.AccessLogger.LOG_FORMAT, \ access_log=aiohttp.log.access_logger, \ handle_signals=True, \ reuse_address=None, \ reuse_port=None, \ handler_cancellation=False) A high-level function for running an application, serving it until keyboard interrupt and performing a :ref:`aiohttp-web-graceful-shutdown`. This is a high-level function very similar to :func:`asyncio.run` and should be used as the main entry point for an application. The :class:`Application` object essentially becomes our `main()` function. If additional tasks need to be run in parallel, see :ref:`aiohttp-web-complex-applications`. The server will listen on any host or Unix domain socket path you supply. If no hosts or paths are supplied, or only a port is supplied, a TCP server listening on 0.0.0.0 (all hosts) will be launched. Distributing HTTP traffic to multiple hosts or paths on the same application process provides no performance benefit as the requests are handled on the same event loop. See :doc:`deployment` for ways of distributing work for increased performance. :param app: :class:`Application` instance to run or a *coroutine* that returns an application. :param str host: TCP/IP host or a sequence of hosts for HTTP server. Default is ``'0.0.0.0'`` if *port* has been specified or if *path* is not supplied. :param int port: TCP/IP port for HTTP server. Default is ``8080`` for plain text HTTP and ``8443`` for HTTP via SSL (when *ssl_context* parameter is specified). :param path: file system path for HTTP server Unix domain socket. A sequence of file system paths can be used to bind multiple domain sockets. Listening on Unix domain sockets is not supported by all operating systems, :class:`str`, :class:`pathlib.Path` or an iterable of these. :param socket.socket sock: a preexisting socket object to accept connections on. A sequence of socket objects can be passed. :param int shutdown_timeout: a delay to wait for graceful server shutdown before disconnecting all open client sockets hard way. This is used as a delay to wait for pending tasks to complete and then again to close any pending connections. A system with properly :ref:`aiohttp-web-graceful-shutdown` implemented never waits for the second timeout but closes a server in a few milliseconds. :param float keepalive_timeout: a delay before a TCP connection is closed after a HTTP request. The delay allows for reuse of a TCP connection. .. versionadded:: 3.8 :param ssl_context: :class:`ssl.SSLContext` for HTTPS server, ``None`` for HTTP connection. :param print: a callable compatible with :func:`print`. May be used to override STDOUT output or suppress it. Passing `None` disables output. :param int backlog: the number of unaccepted connections that the system will allow before refusing new connections (``128`` by default). :param access_log_class: class for `access_logger`. Default: :data:`aiohttp.helpers.AccessLogger`. Must to be a subclass of :class:`aiohttp.abc.AbstractAccessLogger`. :param access_log: :class:`logging.Logger` instance used for saving access logs. Use ``None`` for disabling logs for sake of speedup. :param access_log_format: access log format, see :ref:`aiohttp-logging-access-log-format-spec` for details. :param bool handle_signals: override signal TERM handling to gracefully exit the application. :param bool reuse_address: tells the kernel to reuse a local socket in TIME_WAIT state, without waiting for its natural timeout to expire. If not specified will automatically be set to True on UNIX. :param bool reuse_port: tells the kernel to allow this endpoint to be bound to the same port as other existing endpoints are bound to, so long as they all set this flag when being created. This option is not supported on Windows. :param bool handler_cancellation: cancels the web handler task if the client drops the connection. This is recommended if familiar with asyncio behavior or scalability is a concern. :ref:`aiohttp-web-peer-disconnection` .. versionadded:: 3.0 Support *access_log_class* parameter. Support *reuse_address*, *reuse_port* parameter. .. versionadded:: 3.1 Accept a coroutine as *app* parameter. .. versionadded:: 3.9 Support handler_cancellation parameter (this was the default behavior in aiohttp <3.7). Constants --------- .. class:: ContentCoding An :class:`enum.Enum` class of available Content Codings. .. attribute:: deflate *DEFLATE compression* .. attribute:: gzip *GZIP compression* .. attribute:: identity *no compression* Middlewares ----------- .. function:: normalize_path_middleware(*, \ append_slash=True, \ remove_slash=False, \ merge_slashes=True, \ redirect_class=HTTPPermanentRedirect) Middleware factory which produces a middleware that normalizes the path of a request. By normalizing it means: - Add or remove a trailing slash to the path. - Double slashes are replaced by one. The middleware returns as soon as it finds a path that resolves correctly. The order if both merge and append/remove are enabled is: 1. *merge_slashes* 2. *append_slash* or *remove_slash* 3. both *merge_slashes* and *append_slash* or *remove_slash* If the path resolves with at least one of those conditions, it will redirect to the new path. Only one of *append_slash* and *remove_slash* can be enabled. If both are ``True`` the factory will raise an ``AssertionError`` If *append_slash* is ``True`` the middleware will append a slash when needed. If a resource is defined with trailing slash and the request comes without it, it will append it automatically. If *remove_slash* is ``True``, *append_slash* must be ``False``. When enabled the middleware will remove trailing slashes and redirect if the resource is defined. If *merge_slashes* is ``True``, merge multiple consecutive slashes in the path into one. .. versionadded:: 3.4 Support for *remove_slash*