3.10.6rc0

Bug fixes

• Implemented binding to IPv6 addresses in the pytest server fixture.

  Related issues and pull requests on GitHub:
  #4650.

• Fixed StreamResponse.prepared to return True after EOF is sent -- by :user:arthurdarcet.

  Related issues and pull requests on GitHub:
  #5343.

• Fixed Response.text when body is a Payload -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #6485.

• Added support for URL credentials with empty (zero-length) username, e.g. https://:password@host -- by :user:shuckc

  Related issues and pull requests on GitHub:
  #6494.

• Fixed handling of some file-like objects (e.g. tarfile.extractfile()) which raise AttributeError instead of OSError when fileno fails for streaming payload data -- by :user:ReallyReivax.

  Related issues and pull requests on GitHub:
  #6732.

• Stopped logging exceptions from web.run_app() that would be raised regardless -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #6807.

• Changed make_mocked_request() to use empty payload by default -- by :user:rahulnht.

  Related issues and pull requests on GitHub:
  #7167.

• Used more precise type for ClientResponseError.headers, fixing some type errors when using them -- by :user:Dreamorcerer.

  Related issues and pull requests on GitHub:
  #8768.

• Fixed Python parser chunked handling with multiple Transfer-Encoding values -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #8823.

• Changed behavior when returning an invalid response to send a 500 response -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #8845.

• Stopped adding a default Content-Type header when response has no content -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #8858.

• Fixed an unclosed transport ResourceWarning on web handlers -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #8875.

• Fixed error handling after 100-continue so server sends 500 response instead of disconnecting -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #8876.

• Fixed response reading from closed session to throw an error immediately instead of timing out -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #8878.

• Fixed web router not matching pre-encoded URLs (requires yarl 1.9.6+) -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #8898.

• Fixed CancelledError from one cleanup context stopping other contexts from completing -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #8908.

• Fixed Site.name when host is an empty string -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #8929.

• Fixed resolve_host() 'Task was destroyed but is pending' errors -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #8967.

• Fixed changing scheme/host in Response.clone() for absolute URLs -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #8990.

• Fixed client incorrectly reusing a connection when the previous message had not been fully sent -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #8992.

• Fixed an error when trying to add a route for multiple methods with a path containing a regex pattern -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #8998.

• Updated Python parser to reject messages after a close message, matching C parser behaviour -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #9018.

• Fixed creation of SSLContext inside of :py:class:aiohttp.TCPConnector with multiple event loops in different threads -- by :user:bdraco.

  Related issues and pull requests on GitHub:
  #9029.

• Fixed (on Python 3.11+) some edge cases where a task cancellation may get incorrectly suppressed -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #9030.

• Fixed the incorrect use of flags for getnameinfo() in the Resolver --by :user:GitNMLee

  Link-Local IPv6 addresses can now be handled by the Resolver correctly.

  Related issues and pull requests on GitHub:
  #9032.

• Fixed exception information getting lost on HttpProcessingError -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #9052.

• Fixed If-None-Match not using weak comparison -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #9063.

• Fixed compressed requests failing when no body was provided -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #9108.

• Added :exc:aiohttp.ClientConnectionResetError. Client code that previously threw :exc:ConnectionResetError
  will now throw this -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #9137.

• Fixed race condition that could cause server to close connection incorrectly at keepalive timeout -- by :user:Dreamosorcerer.

  Related issues and pull requests on GitHub:
  #9140.

• Fixed badly encoded charset crashing when getting response text instead of falling back to charset detector.

  Related issues and pull requests on GitHub:
  #9160.

• Rejected \n in reason values to avoid sending broken HTTP messages -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #9167.

• Changed :py:meth:ClientResponse.raise_for_status() <aiohttp.ClientResponse.raise_for_status> to only release the connection when invoked outside an async with context -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #9239.

Features

• Improved type on params to match the underlying type allowed by yarl -- by :user:lpetre.

  Related issues and pull requests on GitHub:
  #8564.

Removals and backward incompatible breaking changes

• Improved middleware performance -- by :user:bdraco.

  The set_current_app method was removed from UrlMappingMatchInfo because it is no longer used, and it was unlikely external caller would ever use it.

  Related issues and pull requests on GitHub:
  #9200.

Improved documentation

• Clarified that GracefulExit needs to be handled in AppRunner and ServerRunner when using handle_signals=True. -- by :user:Daste745

  Related issues and pull requests on GitHub:
  #4414.

• Clarified that auth parameter in ClientSession will persist and be included with any request to any origin, even during redirects to different origins. -- by :user:MaximZemskov.

  Related issues and pull requests on GitHub:
  #6764.

• Clarified which timeout exceptions happen on which timeouts -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #8968.

• Updated ClientSession parameters to match current code -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #8991.

Packaging updates and notes for downstreams

• Fixed test_client_session_timeout_zero to not require internet access -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #9004.

Miscellaneous internal changes

• Improved performance of making requests when there are no auto headers to skip -- by :user:bdraco.

  Related issues and pull requests on GitHub:
  #8847.

• Exported aiohttp.TraceRequestHeadersSentParams -- by :user:Hadock-is-ok.

  Related issues and pull requests on GitHub:
  #8947.

• Avoided tracing overhead in the http writer when there are no active traces -- by user:bdraco.

  Related issues and pull requests on GitHub:
  #9031.

• Improved performance of reify Cython implementation -- by :user:bdraco.

  Related issues and pull requests on GitHub:
  #9054.

• Use :meth:URL.extend_query() <yarl.URL.extend_query> to extend query params (requires yarl 1.11.0+) -- by :user:bdraco.

  If yarl is older than 1.11.0, the previous slower hand rolled version will be used.

  Related issues and pull requests on GitHub:
  #9068.

• Improved performance of checking if a host is an IP Address -- by :user:bdraco.

  Related issues and pull requests on GitHub:
  #9095.

• Significantly improved performance of middlewares -- by :user:bdraco.

  The construction of the middleware wrappers is now cached and is built once per handler instead of on every request.

  Related issues and pull requests on GitHub:
  #9158, #9170.

• Improved performance of web requests -- by :user:bdraco.

  Related issues and pull requests on GitHub:
  #9168, #9169, #9172, #9174, #9175, #9241.

• Improved performance of starting web requests when there is no response prepare hook -- by :user:bdraco.

  Related issues and pull requests on GitHub:
  #9173.

• Significantly improved performance of expiring cookies -- by :user:bdraco.

  Expiring cookies has been redesigned to use :mod:heapq instead of a linear search, to better scale.

  Related issues and pull requests on GitHub:
  #9203.

• Significantly sped up filtering cookies -- by :user:bdraco.

  Related issues and pull requests on GitHub:
  #9204.

---

3.10.5

Bug fixes

• Fixed :meth:aiohttp.ClientResponse.json() not setting status when :exc:aiohttp.ContentTypeError is raised -- by :user:bdraco.

  Related issues and pull requests on GitHub:
  #8742.

Miscellaneous internal changes

• Improved performance of the WebSocket reader -- by :user:bdraco.

  Related issues and pull requests on GitHub:
  #8736, #8747.

---

3.10.4

Bug fixes

• Fixed decoding base64 chunk in BodyPartReader -- by :user:hyzyla.

  Related issues and pull requests on GitHub:
  #3867.

• Fixed a race closing the server-side WebSocket where the close code would not reach the client -- by :user:bdraco.

  Related issues and pull requests on GitHub:
  #8680.

• Fixed unconsumed exceptions raised by the WebSocket heartbeat -- by :user:bdraco.

  If the heartbeat ping raised an exception, it would not be consumed and would be logged as an warning.

  Related issues and pull requests on GitHub:
  #8685.

• Fixed an edge case in the Python parser when chunk separators happen to align with network chunks -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #8720.

Improved documentation

• Added aiohttp-apischema to supported libraries -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #8700.

Miscellaneous internal changes

• Improved performance of starting request handlers with Python 3.12+ -- by :user:bdraco.

  This change is a followup to #8661 to make the same optimization for Python 3.12+ where the request is connected.

  Related issues and pull requests on GitHub:
  #8681.

---

3.10.3

Bug fixes

• Fixed multipart reading when stream buffer splits the boundary over several read() calls -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #8653.

• Fixed :py:class:aiohttp.TCPConnector doing blocking I/O in the event loop to create the SSLContext -- by :user:bdraco.

  The blocking I/O would only happen once per verify mode. However, it could cause the event loop to block for a long time if the SSLContext creation is slow, which is more likely during startup when the disk cache is not yet present.

  Related issues and pull requests on GitHub:
  #8672.

Miscellaneous internal changes

• Improved performance of :py:meth:~aiohttp.ClientWebSocketResponse.receive and :py:meth:~aiohttp.web.WebSocketResponse.receive when there is no timeout. -- by :user:bdraco.

  The timeout context manager is now avoided when there is no timeout as it accounted for up to 50% of the time spent in the :py:meth:~aiohttp.ClientWebSocketResponse.receive and :py:meth:~aiohttp.web.WebSocketResponse.receive methods.

  Related issues and pull requests on GitHub:
  #8660.

• Improved performance of starting request handlers with Python 3.12+ -- by :user:bdraco.

  Related issues and pull requests on GitHub:
  #8661.

• Improved performance of HTTP keep-alive checks -- by :user:bdraco.

  Previously, when processing a request for a keep-alive connection, the keep-alive check would happen every second; the check is now rescheduled if it fires too early instead.

  Related issues and pull requests on GitHub:
  #8662.

• Improved performance of generating random WebSocket mask -- by :user:bdraco.

  Related issues and pull requests on GitHub:
  #8667.

---

3.10.2

Bug fixes

• Fixed server checks for circular symbolic links to be compatible with Python 3.13 -- by :user:steverep.

  Related issues and pull requests on GitHub:
  #8565.

• Fixed request body not being read when ignoring an Upgrade request -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #8597.

• Fixed an edge case where shutdown would wait for timeout when the handler was already completed -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #8611.

• Fixed connecting to npipe://, tcp://, and unix:// urls -- by :user:bdraco.

  Related issues and pull requests on GitHub:
  #8632.

• Fixed WebSocket ping tasks being prematurely garbage collected -- by :user:bdraco.

  There was a small risk that WebSocket ping tasks would be prematurely garbage collected because the event loop only holds a weak reference to the task. The garbage collection risk has been fixed by holding a strong reference to the task. Additionally, the task is now scheduled eagerly with Python 3.12+ to increase the chance it can be completed immediately and avoid having to hold any references to the task.

  Related issues and pull requests on GitHub:
  #8641.

• Fixed incorrectly following symlinks for compressed file variants -- by :user:steverep.

  Related issues and pull requests on GitHub:
  #8652.

Removals and backward incompatible breaking changes

• Removed Request.wait_for_disconnection(), which was mistakenly added briefly in 3.10.0 -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #8636.

Contributor-facing changes

• Fixed monkey patches for Path.stat() and Path.is_dir() for Python 3.13 compatibility -- by :user:steverep.

  Related issues and pull requests on GitHub:
  #8551.

Miscellaneous internal changes

• Improved WebSocket performance when messages are sent or received frequently -- by :user:bdraco.

  The WebSocket heartbeat scheduling algorithm was improved to reduce the asyncio scheduling overhead by decreasing the number of asyncio.TimerHandle creations and cancellations.

  Related issues and pull requests on GitHub:
  #8608.

• Minor improvements to various type annotations -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #8634.

---

3.10.1

Bug fixes

• Fixed WebSocket server heartbeat timeout logic to terminate :py:meth:~aiohttp.ClientWebSocketResponse.receive and return :py:class:~aiohttp.ServerTimeoutError -- by :user:arcivanov.

  When a WebSocket pong message was not received, the :py:meth:~aiohttp.ClientWebSocketResponse.receive operation did not terminate. This change causes _pong_not_received to feed the reader an error message, causing pending :py:meth:~aiohttp.ClientWebSocketResponse.receive to terminate and return the error message. The error message contains the exception :py:class:~aiohttp.ServerTimeoutError.

  Related issues and pull requests on GitHub:
  #8540.

• Fixed url dispatcher index not matching when a variable is preceded by a fixed string after a slash -- by :user:bdraco.

  Related issues and pull requests on GitHub:
  #8566.

Removals and backward incompatible breaking changes

• Creating :py:class:aiohttp.TCPConnector, :py:class:aiohttp.ClientSession, :py:class:~aiohttp.resolver.ThreadedResolver :py:class:aiohttp.web.Server, or :py:class:aiohttp.CookieJar instances without a running event loop now raises a :exc:RuntimeError -- by :user:asvetlov.

  Creating these objects without a running event loop was deprecated in #3372 which was released in version 3.5.0.

  This change first appeared in version 3.10.0 as #6378.

  Related issues and pull requests on GitHub:
  #8555, #8583.

---

3.10.0

Bug fixes

• Fixed server response headers for Content-Type and Content-Encoding for
  static compressed files -- by :user:steverep.

  Server will now respond with a Content-Type appropriate for the compressed
  file (e.g. "application/gzip"), and omit the Content-Encoding header.
  Users should expect that most clients will no longer decompress such responses
  by default.

  Related issues and pull requests on GitHub:
  #4462.

• Fixed duplicate cookie expiration calls in the CookieJar implementation

  Related issues and pull requests on GitHub:
  #7784.

• Adjusted FileResponse to check file existence and access when preparing the response -- by :user:steverep.

  The :py:class:~aiohttp.web.FileResponse class was modified to respond with
  403 Forbidden or 404 Not Found as appropriate. Previously, it would cause a
  server error if the path did not exist or could not be accessed. Checks for
  existence, non-regular files, and permissions were expected to be done in the
  route handler. For static routes, this now permits a compressed file to exist
  without its uncompressed variant and still be served. In addition, this
  changes the response status for files without read permission to 403, and for
  non-regular files from 404 to 403 for consistency.

  Related issues and pull requests on GitHub:
  #8182.

• Fixed AsyncResolver to match ThreadedResolver behavior
  -- by :user:bdraco.

  On system with IPv6 support, the :py:class:~aiohttp.resolver.AsyncResolver would not fallback
  to providing A records when AAAA records were not available.
  Additionally, unlike the :py:class:~aiohttp.resolver.ThreadedResolver, the :py:class:~aiohttp.resolver.AsyncResolver
  did not handle link-local addresses correctly.

  This change makes the behavior consistent with the :py:class:~aiohttp.resolver.ThreadedResolver.

  Related issues and pull requests on GitHub:
  #8270.

• Fixed ws_connect not respecting receive_timeout`` on WS(S) connection. -- by :user:arcivanov`.

  Related issues and pull requests on GitHub:
  #8444.

• Removed blocking I/O in the event loop for static resources and refactored
  exception handling -- by :user:steverep.

  File system calls when handling requests for static routes were moved to a
  separate thread to potentially improve performance. Exception handling
  was tightened in order to only return 403 Forbidden or 404 Not Found responses
  for expected scenarios; 500 Internal Server Error would be returned for any
  unknown errors.

  Related issues and pull requests on GitHub:
  #8507.

Features

• Added a Request.wait_for_disconnection() method, as means of allowing request handlers to be notified of premature client disconnections.

  Related issues and pull requests on GitHub:
  #2492.

• Added 5 new exceptions: :py:exc:~aiohttp.InvalidUrlClientError, :py:exc:~aiohttp.RedirectClientError,
  :py:exc:~aiohttp.NonHttpUrlClientError, :py:exc:~aiohttp.InvalidUrlRedirectClientError,
  :py:exc:~aiohttp.NonHttpUrlRedirectClientError

  :py:exc:~aiohttp.InvalidUrlRedirectClientError, :py:exc:~aiohttp.NonHttpUrlRedirectClientError
  are raised instead of :py:exc:ValueError or :py:exc:~aiohttp.InvalidURL when the redirect URL is invalid. Classes
  :py:exc:~aiohttp.InvalidUrlClientError, :py:exc:~aiohttp.RedirectClientError,
  :py:exc:~aiohttp.NonHttpUrlClientError are base for them.

  The :py:exc:~aiohttp.InvalidURL now exposes a description property with the text explanation of the error details.

  -- by :user:setla, :user:AraHaan, and :user:bdraco

  Related issues and pull requests on GitHub:
  #2507, #3315, #6722, #8481, #8482.

• Added a feature to retry closed connections automatically for idempotent methods. -- by :user:Dreamsorcerer

  Related issues and pull requests on GitHub:
  #7297.

• Implemented filter_cookies() with domain-matching and path-matching on the keys, instead of testing every single cookie.
  This may break existing cookies that have been saved with CookieJar.save(). Cookies can be migrated with this script::

  import pickle
  with file_path.open("rb") as f:
      cookies = pickle.load(f)
  
  morsels = [(name, m) for c in cookies.values() for name, m in c.items()]
  cookies.clear()
  for name, m in morsels:
      cookies[(m["domain"], m["path"].rstrip("/"))][name] = m
  
  with file_path.open("wb") as f:
      pickle.dump(cookies, f, pickle.HIGHEST_PROTOCOL)
  

  Related issues and pull requests on GitHub:
  #7583, #8535.

• Separated connection and socket timeout errors, from ServerTimeoutError.

  Related issues and pull requests on GitHub:
  #7801.

• Implemented happy eyeballs

  Related issues and pull requests on GitHub:
  #7954.

• Added server capability to check for static files with Brotli compression via a .br extension -- by :user:steverep.

  Related issues and pull requests on GitHub:
  #8062.

Removals and backward incompatible breaking changes

• The shutdown logic in 3.9 waited on all tasks, which caused issues with some libraries.
  In 3.10 we've changed this logic to only wait on request handlers. This means that it's
  important for developers to correctly handle the lifecycle of background tasks using a
  library such as aiojobs. If an application is using handler_cancellation=True then
  it is also a good idea to ensure that any :func:asyncio.shield calls are replaced with
  :func:aiojobs.aiohttp.shield.

  Please read the updated documentation on these points:
  https://docs.aiohttp.org/en/stable/web_advanced.html#graceful-shutdown
  https://docs.aiohttp.org/en/stable/web_advanced.html#web-handler-cancellation

  -- by :user:Dreamsorcerer

  Related issues and pull requests on GitHub:
  #8495.

Improved documentation

• Added documentation for aiohttp.web.FileResponse.

  Related issues and pull requests on GitHub:
  #3958.

• Improved the docs for the ssl params.

  Related issues and pull requests on GitHub:
  #8403.

Contributor-facing changes

• Enabled HTTP parser tests originally intended for 3.9.2 release -- by :user:pajod.

  Related issues and pull requests on GitHub:
  #8088.

Miscellaneous internal changes

• Improved URL handler resolution time by indexing resources in the UrlDispatcher.
  For applications with a large number of handlers, this should increase performance significantly.
  -- by :user:bdraco

  Related issues and pull requests on GitHub:
  #7829.

• Added nacl_middleware <https://github.com/CosmicDNA/nacl_middleware>_ to the list of middlewares in the third party section of the documentation.

  Related issues and pull requests on GitHub:
  #8346.

• Minor improvements to static typing -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #8364.

• Added a 3.11-specific overloads to ClientSession -- by :user:max-muoto.

  Related issues and pull requests on GitHub:
  #8463.

• Simplified path checks for UrlDispatcher.add_static() method -- by :user:steverep.

  Related issues and pull requests on GitHub:
  #8491.

• Avoided creating a future on every websocket receive -- by :user:bdraco.

  Related issues and pull requests on GitHub:
  #8498.

• Updated identity checks for all WSMsgType type compares -- by :user:bdraco.

  Related issues and pull requests on GitHub:
  #8501.

• When using Python 3.12 or later, the writer is no longer scheduled on the event loop if it can finish synchronously. Avoiding event loop scheduling reduces latency and improves performance. -- by :user:bdraco.

  Related issues and pull requests on GitHub:
  #8510.

• Restored :py:class:~aiohttp.resolver.AsyncResolver to be the default resolver. -- by :user:bdraco.

  :py:class:~aiohttp.resolver.AsyncResolver was disabled by default because
  of IPv6 compatibility issues. These issues have been resolved and
  :py:class:~aiohttp.resolver.AsyncResolver is again now the default resolver.

  Related issues and pull requests on GitHub:
  #8522.

---

3.10.0rc0

Bug fixes

• Adjusted FileResponse to check file existence and access when preparing the response -- by :user:steverep.

  The :py:class:~aiohttp.web.FileResponse class was modified to respond with
  403 Forbidden or 404 Not Found as appropriate. Previously, it would cause a
  server error if the path did not exist or could not be accessed. Checks for
  existence, non-regular files, and permissions were expected to be done in the
  route handler. For static routes, this now permits a compressed file to exist
  without its uncompressed variant and still be served. In addition, this
  changes the response status for files without read permission to 403, and for
  non-regular files from 404 to 403 for consistency.

  Related issues and pull requests on GitHub:
  #8182.

Removals and backward incompatible breaking changes

• The shutdown logic in 3.9 waited on all tasks, which caused issues with some libraries.
  In 3.10 we've changed this logic to only wait on request handlers. This means that it's
  important for developers to correctly handle the lifecycle of background tasks using a
  library such as aiojobs. If an application is using handler_cancellation=True then
  it is also a good idea to ensure that any :func:asyncio.shield calls are replaced with
  :func:aiojobs.aiohttp.shield.

  Please read the updated documentation on these points:
  https://docs.aiohttp.org/en/stable/web_advanced.html#graceful-shutdown
  https://docs.aiohttp.org/en/stable/web_advanced.html#web-handler-cancellation

  -- by :user:Dreamsorcerer

  Related issues and pull requests on GitHub:
  #8495.

Miscellaneous internal changes

• Improve performance of filtering cookies -- by :user:bdraco.

  This change is a followup to the improvements in #7583

  Related issues and pull requests on GitHub:
  #8535.

---

3.10.0b1

Bug fixes

• Fixed server response headers for Content-Type and Content-Encoding for
  static compressed files -- by :user:steverep.

  Server will now respond with a Content-Type appropriate for the compressed
  file (e.g. "application/gzip"), and omit the Content-Encoding header.
  Users should expect that most clients will no longer decompress such responses
  by default.

  Related issues and pull requests on GitHub:
  #4462.

• Fix duplicate cookie expiration calls in the CookieJar implementation

  Related issues and pull requests on GitHub:
  #7784.

• Fix AsyncResolver to match ThreadedResolver behavior
  -- by :user:bdraco.

  On system with IPv6 support, the :py:class:~aiohttp.resolver.AsyncResolver would not fallback
  to providing A records when AAAA records were not available.
  Additionally, unlike the :py:class:~aiohttp.resolver.ThreadedResolver, the :py:class:~aiohttp.resolver.AsyncResolver
  did not handle link-local addresses correctly.

  This change makes the behavior consistent with the :py:class:~aiohttp.resolver.ThreadedResolver.

  Related issues and pull requests on GitHub:
  #8270.

• Fix ws_connect not respecting receive_timeout`` on WS(S) connection. -- by :user:arcivanov`.

  Related issues and pull requests on GitHub:
  #8444.

• Removed blocking I/O in the event loop for static resources and refactored
  exception handling -- by :user:steverep.

  File system calls when handling requests for static routes were moved to a
  separate thread to potentially improve performance. Exception handling
  was tightened in order to only return 403 Forbidden or 404 Not Found responses
  for expected scenarios; 500 Internal Server Error would be returned for any
  unknown errors.

  Related issues and pull requests on GitHub:
  #8507.

Features

• Add a Request.wait_for_disconnection() method, as means of allowing request handlers to be notified of premature client disconnections.

  Related issues and pull requests on GitHub:
  #2492.

• Added 5 new exceptions: :py:exc:~aiohttp.InvalidUrlClientError, :py:exc:~aiohttp.RedirectClientError,
  :py:exc:~aiohttp.NonHttpUrlClientError, :py:exc:~aiohttp.InvalidUrlRedirectClientError,
  :py:exc:~aiohttp.NonHttpUrlRedirectClientError

  :py:exc:~aiohttp.InvalidUrlRedirectClientError, :py:exc:~aiohttp.NonHttpUrlRedirectClientError
  are raised instead of :py:exc:ValueError or :py:exc:~aiohttp.InvalidURL when the redirect URL is invalid. Classes
  :py:exc:~aiohttp.InvalidUrlClientError, :py:exc:~aiohttp.RedirectClientError,
  :py:exc:~aiohttp.NonHttpUrlClientError are base for them.

  The :py:exc:~aiohttp.InvalidURL now exposes a description property with the text explanation of the error details.

  -- by :user:setla, :user:AraHaan, and :user:bdraco

  Related issues and pull requests on GitHub:
  #2507, #3315, #6722, #8481, #8482.

• Added a feature to retry closed connections automatically for idempotent methods. -- by :user:Dreamsorcerer

  Related issues and pull requests on GitHub:
  #7297.

• Implement filter_cookies() with domain-matching and path-matching on the keys, instead of testing every single cookie.
  This may break existing cookies that have been saved with CookieJar.save(). Cookies can be migrated with this script::

  import pickle
  with file_path.open("rb") as f:
      cookies = pickle.load(f)
  
  morsels = [(name, m) for c in cookies.values() for name, m in c.items()]
  cookies.clear()
  for name, m in morsels:
      cookies[(m["domain"], m["path"].rstrip("/"))][name] = m
  
  with file_path.open("wb") as f:
      pickle.dump(cookies, f, pickle.HIGHEST_PROTOCOL)
  

  Related issues and pull requests on GitHub:
  #7583.

• Separated connection and socket timeout errors, from ServerTimeoutError.

  Related issues and pull requests on GitHub:
  #7801.

• Implement happy eyeballs

  Related issues and pull requests on GitHub:
  #7954.

• Added server capability to check for static files with Brotli compression via a .br extension -- by :user:steverep.

  Related issues and pull requests on GitHub:
  #8062.

Improved documentation

• Add documentation for aiohttp.web.FileResponse.

  Related issues and pull requests on GitHub:
  #3958.

• Improve the docs for the ssl params.

  Related issues and pull requests on GitHub:
  #8403.

Contributor-facing changes

• Enabled HTTP parser tests originally intended for 3.9.2 release -- by :user:pajod.

  Related issues and pull requests on GitHub:
  #8088.

Miscellaneous internal changes

• Improved URL handler resolution time by indexing resources in the UrlDispatcher.
  For applications with a large number of handlers, this should increase performance significantly.
  -- by :user:bdraco

  Related issues and pull requests on GitHub:
  #7829.

• Add nacl_middleware <https://github.com/CosmicDNA/nacl_middleware>_ to the list of middlewares in the third party section of the documentation.

  Related issues and pull requests on GitHub:
  #8346.

• Minor improvements to static typing -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #8364.

• Added a 3.11-specific overloads to ClientSession -- by :user:max-muoto.

  Related issues and pull requests on GitHub:
  #8463.

• Simplified path checks for UrlDispatcher.add_static() method -- by :user:steverep.

  Related issues and pull requests on GitHub:
  #8491.

• Avoid creating a future on every websocket receive -- by :user:bdraco.

  Related issues and pull requests on GitHub:
  #8498.

• Use identity checks for all WSMsgType type compares -- by :user:bdraco.

  Related issues and pull requests on GitHub:
  #8501.

• When using Python 3.12 or later, the writer is no longer scheduled on the event loop if it can finish synchronously. Avoiding event loop scheduling reduces latency and improves performance. -- by :user:bdraco.

  Related issues and pull requests on GitHub:
  #8510.

• Restore :py:class:~aiohttp.resolver.AsyncResolver to be the default resolver. -- by :user:bdraco.

  :py:class:~aiohttp.resolver.AsyncResolver was disabled by default because
  of IPv6 compatibility issues. These issues have been resolved and
  :py:class:~aiohttp.resolver.AsyncResolver is again now the default resolver.

  Related issues and pull requests on GitHub:
  #8522.

3.9.5

Bug fixes

• Fixed "Unclosed client session" when initialization of
  :py:class:~aiohttp.ClientSession fails -- by :user:NewGlad.

  Related issues and pull requests on GitHub:
  #8253.

• Fixed regression (from :pr:8280) with adding Content-Disposition to the form-data
  part after appending to writer -- by :user:Dreamsorcerer/:user:Olegt0rr.

  Related issues and pull requests on GitHub:
  #8332.

• Added default Content-Disposition in multipart/form-data responses to avoid broken
  form-data responses -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #8335.

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