Client Reference¶
Client Session¶
Client session is the recommended interface for making HTTP requests.
Session encapsulates a connection pool (connector instance) and supports keepalives by default. Unless you are connecting to a large, unknown number of different servers over the lifetime of your application, it is suggested you use a single session for the lifetime of your application to benefit from connection pooling.
Usage example:
import aiohttp
import asyncio
async def fetch(client):
async with client.get('http://python.org') as resp:
assert resp.status == 200
return await resp.text()
async def main():
async with aiohttp.ClientSession() as client:
html = await fetch(client)
print(html)
asyncio.run(main())
The client session supports the context manager protocol for self closing.
- class aiohttp.ClientSession(base_url=None, *, connector=None, cookies=None, headers=None, skip_auto_headers=None, auth=None, json_serialize=json.dumps, version=aiohttp.HttpVersion11, cookie_jar=None, read_timeout=None, conn_timeout=None, timeout=sentinel, raise_for_status=False, connector_owner=True, auto_decompress=True, read_bufsize=2**16, requote_redirect_url=False, trust_env=False, trace_configs=None)¶
The class for creating client sessions and making requests.
- Parameters:
base_url –
Base part of the URL (optional) If set it allows to skip the base part in request calls.
New in version 3.8.
connector (aiohttp.BaseConnector) – BaseConnector sub-class instance to support connection pooling.
loop –
event loop used for processing HTTP requests.
If loop is
None
the constructor borrows it from connector if specified.asyncio.get_event_loop()
is used for getting default event loop otherwise.Deprecated since version 2.0.
cookies (dict) – Cookies to send with the request (optional)
headers –
HTTP Headers to send with every request (optional).
May be either iterable of key-value pairs or
Mapping
(e.g.dict
,CIMultiDict
).skip_auto_headers –
set of headers for which autogeneration should be skipped.
aiohttp autogenerates headers like
User-Agent
orContent-Type
if these headers are not explicitly passed. Usingskip_auto_headers
parameter allows to skip that generation. Note thatContent-Length
autogeneration can’t be skipped.auth (aiohttp.BasicAuth) – an object that represents HTTP Basic Authorization (optional)
version – supported HTTP version,
HTTP 1.1
by default.cookie_jar –
Cookie Jar,
AbstractCookieJar
instance.By default every session instance has own private cookie jar for automatic cookies processing but user may redefine this behavior by providing own jar implementation.
One example is not processing cookies at all when working in proxy mode.
If no cookie processing is needed, a
aiohttp.DummyCookieJar
instance can be provided.json_serialize (collections.abc.Callable) –
Json serializer callable.
By default
json.dumps()
function.raise_for_status (bool) –
Automatically call
ClientResponse.raise_for_status()
for each response,False
by default.This parameter can be overridden when you making a request, e.g.:
client_session = aiohttp.ClientSession(raise_for_status=True) resp = await client_session.get(url, raise_for_status=False) async with resp: assert resp.status == 200
Set the parameter to
True
if you needraise_for_status
for most of cases but overrideraise_for_status
for those requests where you need to handle responses with status 400 or higher.timeout –
- a
ClientTimeout
settings structure, 300 seconds (5min) total timeout by default.
New in version 3.3.
- a
read_timeout (float) –
Request operations timeout.
read_timeout
is cumulative for all request operations (request, redirects, responses, data consuming). By default, the read timeout is 5*60 seconds. UseNone
or0
to disable timeout checks.Deprecated since version 3.3: Use
timeout
parameter instead.conn_timeout (float) –
timeout for connection establishing (optional). Values
0
orNone
mean no timeout.Deprecated since version 3.3: Use
timeout
parameter instead.connector_owner (bool) –
Close connector instance on session closing.
Setting the parameter to
False
allows to share connection pool between sessions without sharing session state: cookies etc.auto_decompress (bool) –
- Automatically decompress response body,
True
by default
New in version 2.3.
read_bufsize (int) –
- Size of the read buffer (
ClientResponse.content
). 64 KiB by default.
New in version 3.7.
- Size of the read buffer (
trust_env (bool) –
Get proxies information from HTTP_PROXY / HTTPS_PROXY environment variables if the parameter is
True
(False
by default).Get proxy credentials from
~/.netrc
file if present.See also
.netrc
documentation: https://www.gnu.org/software/inetutils/manual/html_node/The-_002enetrc-file.htmlNew in version 2.3.
Changed in version 3.0: Added support for
~/.netrc
file.requote_redirect_url (bool) –
- Apply URL requoting for redirection URLs if
automatic redirection is enabled (
True
by default).
New in version 3.5.
trace_configs – A list of
TraceConfig
instances used for client tracing.None
(default) is used for request tracing disabling. See Tracing Reference for more information.
- closed¶
True
if the session has been closed,False
otherwise.A read-only property.
- connector¶
aiohttp.BaseConnector
derived instance used for the session.A read-only property.
- cookie_jar¶
The session cookies,
AbstractCookieJar
instance.Gives access to cookie jar’s content and modifiers.
A read-only property.
- requote_redirect_url¶
aiohttp re quote’s redirect urls by default, but some servers require exact url from location header. To disable re-quote system set
requote_redirect_url
attribute toFalse
.New in version 2.1.
Note
This parameter affects all subsequent requests.
Deprecated since version 3.5: The attribute modification is deprecated.
- loop¶
A loop instance used for session creation.
A read-only property.
Deprecated since version 3.5.
- timeout¶
Default client timeouts,
ClientTimeout
instance. The value can be tuned by passing timeout parameter toClientSession
constructor.New in version 3.7.
- headers¶
HTTP Headers that sent with every request
May be either iterable of key-value pairs or
Mapping
(e.g.dict
,CIMultiDict
).New in version 3.7.
- skip_auto_headers¶
Set of headers for which autogeneration skipped.
frozenset
ofstr
oristr
(optional)New in version 3.7.
- json_serialize¶
Json serializer callable.
By default
json.dumps()
function.New in version 3.7.
- raise_for_status¶
Should
ClientResponse.raise_for_status()
be called for each responseEither
bool
orcollections.abc.Callable
New in version 3.7.
- auto_decompress¶
Should the body response be automatically decompressed
bool
default isTrue
New in version 3.7.
- trust_env¶
Should get proxies information from HTTP_PROXY / HTTPS_PROXY environment variables or ~/.netrc file if present
bool
default isFalse
New in version 3.7.
- trace_config¶
A list of
TraceConfig
instances used for client tracing.None
(default) is used for request tracing disabling. See Tracing Reference for more information.New in version 3.7.
- detach()¶
Detach connector from session without closing the former.
Session is switched to closed state anyway.
Basic API¶
While we encourage ClientSession
usage we also provide simple
coroutines for making HTTP requests.
Basic API is good for performing simple HTTP requests without keepaliving, cookies and complex connection stuff like properly configured SSL certification chaining.
Connectors¶
Connectors are transports for aiohttp client API.
There are standard connectors:
TCPConnector
for regular TCP sockets (both HTTP and HTTPS schemes supported).UnixConnector
for connecting via UNIX socket (it’s used mostly for testing purposes).
All connector classes should be derived from BaseConnector
.
By default all connectors support keep-alive connections (behavior is controlled by force_close constructor’s parameter).
BaseConnector¶
- class aiohttp.BaseConnector(*, keepalive_timeout=15, force_close=False, limit=100, limit_per_host=0, enable_cleanup_closed=False, loop=None)¶
Base class for all connectors.
- Parameters:
keepalive_timeout (float) – timeout for connection reusing after releasing (optional). Values
0
. For disabling keep-alive feature useforce_close=True
flag.limit (int) – total number simultaneous connections. If limit is
None
the connector has no limit (default: 100).limit_per_host (int) – limit simultaneous connections to the same endpoint. Endpoints are the same if they are have equal
(host, port, is_ssl)
triple. If limit is0
the connector has no limit (default: 0).force_close (bool) – close underlying sockets after connection releasing (optional).
enable_cleanup_closed (bool) – some SSL servers do not properly complete SSL shutdown process, in that case asyncio leaks ssl connections. If this parameter is set to True, aiohttp additionally aborts underlining transport after 2 seconds. It is off by default.
loop –
event loop used for handling connections. If param is
None
,asyncio.get_event_loop()
is used for getting default event loop.Deprecated since version 2.0.
- closed¶
Read-only property,
True
if connector is closed.
- force_close¶
Read-only property,
True
if connector should ultimately close connections on releasing.
- limit¶
The total number for simultaneous connections. If limit is 0 the connector has no limit. The default limit size is 100.
- limit_per_host¶
The limit for simultaneous connections to the same endpoint.
Endpoints are the same if they are have equal
(host, port, is_ssl)
triple.If limit_per_host is
None
the connector has no limit per host.Read-only property.
TCPConnector¶
- class aiohttp.TCPConnector(*, ssl=None, verify_ssl=True, fingerprint=None, use_dns_cache=True, ttl_dns_cache=10, family=0, ssl_context=None, local_addr=None, resolver=None, keepalive_timeout=sentinel, force_close=False, limit=100, limit_per_host=0, enable_cleanup_closed=False, loop=None)¶
Connector for working with HTTP and HTTPS via TCP sockets.
The most common transport. When you don’t know what connector type to use, use a
TCPConnector
instance.TCPConnector
inherits fromBaseConnector
.Constructor accepts all parameters suitable for
BaseConnector
plus several TCP-specific ones:- param ssl:
- SSL validation mode.
None
for default SSL check (
ssl.create_default_context()
is used),False
for skip SSL certificate validation,aiohttp.Fingerprint
for fingerprint validation,ssl.SSLContext
for custom SSL certificate validation.Supersedes verify_ssl, ssl_context and fingerprint parameters.
New in version 3.0.
- SSL validation mode.
- Parameters:
verify_ssl (bool) –
perform SSL certificate validation for HTTPS requests (enabled by default). May be disabled to skip validation for sites with invalid certificates.
Deprecated since version 2.3: Pass verify_ssl to
ClientSession.get()
etc.fingerprint (bytes) –
pass the SHA256 digest of the expected certificate in DER format to verify that the certificate the server presents matches. Useful for certificate pinning.
Note: use of MD5 or SHA1 digests is insecure and deprecated.
Deprecated since version 2.3: Pass verify_ssl to
ClientSession.get()
etc.use_dns_cache (bool) –
use internal cache for DNS lookups,
True
by default.Enabling an option may speedup connection establishing a bit but may introduce some side effects also.
ttl_dns_cache (int) –
expire after some seconds the DNS entries,
None
means cached forever. By default 10 seconds (optional).In some environments the IP addresses related to a specific HOST can change after a specific time. Use this option to keep the DNS cache updated refreshing each entry after N seconds.
limit (int) – total number simultaneous connections. If limit is
None
the connector has no limit (default: 100).limit_per_host (int) – limit simultaneous connections to the same endpoint. Endpoints are the same if they are have equal
(host, port, is_ssl)
triple. If limit is0
the connector has no limit (default: 0).resolver (aiohttp.abc.AbstractResolver) –
custom resolver instance to use.
aiohttp.DefaultResolver
by default (asynchronous ifaiodns>=1.1
is installed).Custom resolvers allow to resolve hostnames differently than the way the host is configured.
The resolver is
aiohttp.ThreadedResolver
by default, asynchronous version is pretty robust but might fail in very rare cases.family (int) –
TCP socket family, both IPv4 and IPv6 by default. For IPv4 only use
socket.AF_INET
, for IPv6 only –socket.AF_INET6
.family is
0
by default, that means both IPv4 and IPv6 are accepted. To specify only concrete version please passsocket.AF_INET
orsocket.AF_INET6
explicitly.ssl_context (ssl.SSLContext) –
SSL context used for processing HTTPS requests (optional).
ssl_context may be used for configuring certification authority channel, supported SSL options etc.
local_addr (tuple) – tuple of
(local_host, local_port)
used to bind socket locally if specified.force_close (bool) – close underlying sockets after connection releasing (optional).
enable_cleanup_closed (bool) – Some ssl servers do not properly complete SSL shutdown process, in that case asyncio leaks SSL connections. If this parameter is set to True, aiohttp additionally aborts underlining transport after 2 seconds. It is off by default.
- family¶
TCP socket family e.g.
socket.AF_INET
orsocket.AF_INET6
Read-only property.
- cached_hosts¶
The cache of resolved hosts if
dns_cache
is enabled.Read-only
types.MappingProxyType
property.
- clear_dns_cache(self, host=None, port=None)¶
Clear internal DNS cache.
Remove specific entry if both host and port are specified, clear all cache otherwise.
UnixConnector¶
- class aiohttp.UnixConnector(path, *, conn_timeout=None, keepalive_timeout=30, limit=100, force_close=False, loop=None)¶
Unix socket connector.
Use
UnixConnector
for sending HTTP/HTTPS requests through UNIX Sockets as underlying transport.UNIX sockets are handy for writing tests and making very fast connections between processes on the same host.
UnixConnector
is inherited fromBaseConnector
.Usage:
conn = UnixConnector(path='/path/to/socket') session = ClientSession(connector=conn) async with session.get('http://python.org') as resp: ...
Constructor accepts all parameters suitable for
BaseConnector
plus UNIX-specific one:- Parameters:
path (str) – Unix socket path
Connection¶
- class aiohttp.Connection¶
Encapsulates single connection in connector object.
End user should never create
Connection
instances manually but get it byBaseConnector.connect()
coroutine.- loop¶
Event loop used for connection
Deprecated since version 3.5.
- transport¶
Connection transport
- close()¶
Close connection with forcibly closing underlying socket.
- release()¶
Release connection back to connector.
Underlying socket is not closed, the connection may be reused later if timeout (30 seconds by default) for connection was not expired.
Response object¶
- class aiohttp.ClientResponse¶
Client response returned by
aiohttp.ClientSession.request()
and family.User never creates the instance of ClientResponse class but gets it from API calls.
ClientResponse
supports async context manager protocol, e.g.:resp = await client_session.get(url) async with resp: assert resp.status == 200
After exiting from
async with
block response object will be released (seerelease()
coroutine).- version¶
Response’s version,
HttpVersion
instance.
- ok¶
Boolean representation of HTTP status code (
bool
).True
ifstatus
is less than400
; otherwise,False
.
- connection¶
Connection
used for handling response.
- content¶
Payload stream, which contains response’s BODY (
StreamReader
). It supports various reading methods depending on the expected format. When chunked transfer encoding is used by the server, allows retrieving the actual http chunks.Reading from the stream may raise
aiohttp.ClientPayloadError
if the response object is closed before response receives all data or in case if any transfer encoding related errors like misformed chunked encoding of broken compression data.
- cookies¶
HTTP cookies of response (Set-Cookie HTTP header,
SimpleCookie
).
- headers¶
A case-insensitive multidict proxy with HTTP headers of response,
CIMultiDictProxy
.
- raw_headers¶
Unmodified HTTP headers of response as unconverted bytes, a sequence of
(key, value)
pairs.
- links¶
Link HTTP header parsed into a
MultiDictProxy
.For each link, key is link param rel when it exists, or link url as
str
otherwise, and value isMultiDictProxy
of link params and url at key url asURL
instance.New in version 3.2.
- content_type¶
Read-only property with content part of Content-Type header.
Note
Returns value is
'application/octet-stream'
if no Content-Type header present in HTTP headers according to RFC 2616. To make sure Content-Type header is not present in the server reply, useheaders
orraw_headers
, e.g.'CONTENT-TYPE' not in resp.headers
.
- charset¶
Read-only property that specifies the encoding for the request’s BODY.
The value is parsed from the Content-Type HTTP header.
Returns
str
like'utf-8'
orNone
if no Content-Type header present in HTTP headers or it has no charset information.
- content_disposition¶
Read-only property that specified the Content-Disposition HTTP header.
Instance of
ContentDisposition
orNone
if no Content-Disposition header present in HTTP headers.
- history¶
A
Sequence
ofClientResponse
objects of preceding requests (earliest request first) if there were redirects, an empty sequence otherwise.
- close()¶
Close response and underlying connection.
For keep-alive support see
release()
.
- raise_for_status()¶
Raise an
aiohttp.ClientResponseError
if the response status is 400 or higher.Do nothing for success responses (less than 400).
- request_info¶
A namedtuple with request URL and headers from
ClientRequest
object,aiohttp.RequestInfo
instance.
- get_encoding()¶
Automatically detect content encoding using
charset
info inContent-Type
HTTP header. If this info is not exists or there are no appropriate codecs for encoding then cchardet / charset-normalizer is used.Beware that it is not always safe to use the result of this function to decode a response. Some encodings detected by cchardet are not known by Python (e.g. VISCII). charset-normalizer is not concerned by that issue.
- Raises:
RuntimeError – if called before the body has been read, for cchardet usage
New in version 3.0.
ClientWebSocketResponse¶
To connect to a websocket server aiohttp.ws_connect()
or
aiohttp.ClientSession.ws_connect()
coroutines should be used, do
not create an instance of class ClientWebSocketResponse
manually.
- class aiohttp.ClientWebSocketResponse¶
Class for handling client-side websockets.
- closed¶
Read-only property,
True
ifclose()
has been called orCLOSE
message has been received from peer.
- protocol¶
Websocket subprotocol chosen after
start()
call.May be
None
if server and client protocols are not overlapping.
- get_extra_info(name, default=None)¶
Reads extra info from connection’s transport
- exception()¶
Returns exception if any occurs or returns None.
Utilities¶
ClientTimeout¶
- class aiohttp.ClientTimeout(*, total=None, connect=None, sock_connect=None, sock_read=None)¶
A data class for client timeout settings.
See Timeouts for usage examples.
- connect¶
Maximal number of seconds for acquiring a connection from pool. The time consists connection establishment for a new connection or waiting for a free connection from a pool if pool connection limits are exceeded.
For pure socket connection establishment time use
sock_connect
.float
,None
by default.
- sock_connect¶
Maximal number of seconds for connecting to a peer for a new connection, not given from a pool. See also
connect
.float
,None
by default.
- sock_read¶
Maximal number of seconds for reading a portion of data from a peer.
float
,None
by default.
New in version 3.3.
Note
Timeouts of 5 seconds or more are rounded for scheduling on the next second boundary (an absolute time where microseconds part is zero) for the sake of performance.
E.g., assume a timeout is
10
, absolute time when timeout should expire isloop.time() + 5
, and it points to12345.67 + 10
which is equal to12355.67
.The absolute time for the timeout cancellation is
12356
.It leads to grouping all close scheduled timeout expirations to exactly the same time to reduce amount of loop wakeups.
Changed in version 3.7: Rounding to the next seconds boundary is disabled for timeouts smaller than 5 seconds for the sake of easy debugging.
In turn, tiny timeouts can lead to significant performance degradation on production environment.
ETag¶
RequestInfo¶
- class aiohttp.RequestInfo¶
A data class with request URL and headers from
ClientRequest
object, available asClientResponse.request_info
attribute.- headers¶
HTTP headers for request,
multidict.CIMultiDict
instance.
BasicAuth¶
- class aiohttp.BasicAuth(login, password='', encoding='latin1')¶
HTTP basic authentication helper.
- Parameters:
Should be used for specifying authorization data in client API, e.g. auth parameter for
ClientSession.request()
.- classmethod decode(auth_header, encoding='latin1')¶
Decode HTTP basic authentication credentials.
FormData¶
A FormData
object contains the form data and also handles
encoding it into a body that is either multipart/form-data
or
application/x-www-form-urlencoded
. multipart/form-data
is
used if at least one field is an io.IOBase
object or was
added with at least one optional argument to add_field
(content_type
, filename
, or content_transfer_encoding
).
Otherwise, application/x-www-form-urlencoded
is used.
FormData
instances are callable and return a aiohttp.payload.Payload
on being called.
- class aiohttp.FormData(fields, quote_fields=True, charset=None)¶
Helper class for multipart/form-data and application/x-www-form-urlencoded body generation.
- Parameters:
fields –
A container for the key/value pairs of this form.
Possible types are:
io.IOBase
, e.g. a file-like object
If it is a
tuple
orlist
, it must be a valid argument foradd_fields
.For
dict
,multidict.MultiDict
, andmultidict.MultiDictProxy
, the keys and values must be valid name and value arguments toadd_field
, respectively.
- add_field(name, value, content_type=None, filename=None, content_transfer_encoding=None)¶
Add a field to the form.
- Parameters:
name (str) – Name of the field
value –
Value of the field
Possible types are:
bytes
,bytearray
, ormemoryview
io.IOBase
, e.g. a file-like object
content_type (str) – The field’s content-type header (optional)
filename (str) –
The field’s filename (optional)
If this is not set and
value
is abytes
,bytearray
, ormemoryview
object, the name argument is used as the filename unlesscontent_transfer_encoding
is specified.If
filename
is not set andvalue
is anio.IOBase
object, the filename is extracted from the object if possible.content_transfer_encoding (str) – The field’s content-transfer-encoding header (optional)
Client exceptions¶
Exception hierarchy has been significantly modified in version
2.0. aiohttp defines only exceptions that covers connection handling
and server response misbehaviors. For developer specific mistakes,
aiohttp uses python standard exceptions like ValueError
or
TypeError
.
Reading a response content may raise a ClientPayloadError
exception. This exception indicates errors specific to the payload
encoding. Such as invalid compressed data, malformed chunked-encoded
chunks or not enough data that satisfy the content-length header.
All exceptions are available as members of aiohttp module.
- exception aiohttp.ClientError¶
Base class for all client specific exceptions.
Derived from
Exception
- class aiohttp.ClientPayloadError¶
This exception can only be raised while reading the response payload if one of these errors occurs:
invalid compression
malformed chunked encoding
not enough data that satisfy
Content-Length
HTTP header.
Derived from
ClientError
- exception aiohttp.InvalidURL¶
URL used for fetching is malformed, e.g. it does not contain host part.
Derived from
ClientError
andValueError
- class aiohttp.ContentDisposition¶
Represent Content-Disposition header
- type¶
A
str
instance. Value of Content-Disposition header itself, e.g.attachment
.- filename¶
A
str
instance. Content filename extracted from parameters. May beNone
.- parameters¶
Read-only mapping contains all parameters.
Response errors¶
- exception aiohttp.ClientResponseError¶
These exceptions could happen after we get response from server.
Derived from
ClientError
- request_info¶
Instance of
RequestInfo
object, contains information about request.
- headers¶
Headers in response, a list of pairs.
- history¶
History from failed response, if available, else empty tuple.
A
tuple
ofClientResponse
objects used for handle redirection responses.
- class aiohttp.WSServerHandshakeError¶
Web socket server response error.
Derived from
ClientResponseError
- class aiohttp.ContentTypeError¶
Invalid content type.
Derived from
ClientResponseError
New in version 2.3.
- class aiohttp.TooManyRedirects¶
Client was redirected too many times.
Maximum number of redirects can be configured by using parameter
max_redirects
inrequest
.Derived from
ClientResponseError
New in version 3.2.
Connection errors¶
- class aiohttp.ClientConnectionError¶
These exceptions related to low-level connection problems.
Derived from
ClientError
- class aiohttp.ClientOSError¶
Subset of connection errors that are initiated by an
OSError
exception.Derived from
ClientConnectionError
andOSError
- class aiohttp.ClientConnectorError¶
Connector related exceptions.
Derived from
ClientOSError
- class aiohttp.ClientProxyConnectionError¶
Derived from
ClientConnectorError
- class aiohttp.UnixClientConnectorError¶
Derived from
ClientConnectorError
- class aiohttp.ServerConnectionError¶
Derived from
ClientConnectionError
- class aiohttp.ClientSSLError¶
Derived from
ClientConnectorError
- class aiohttp.ClientConnectorSSLError¶
Response ssl error.
Derived from
ClientSSLError
andssl.SSLError
- class aiohttp.ClientConnectorCertificateError¶
Response certificate error.
Derived from
ClientSSLError
andssl.CertificateError
- class aiohttp.ServerDisconnectedError¶
Server disconnected.
Derived from
ServerConnectionError
- message¶
Partially parsed HTTP message (optional).
- class aiohttp.ServerTimeoutError¶
Server operation timeout: read timeout, etc.
Derived from
ServerConnectionError
andasyncio.TimeoutError
- class aiohttp.ServerFingerprintMismatch¶
Server fingerprint mismatch.
Derived from
ServerConnectionError