The top-level `httpcore.request()` function is provided for convenience. In practice whenever you're working with `httpcore` you'll want to use the connection pooling functionality that it provides.
Once you're ready to get going, [head over to the documentation](https://www.encode.io/httpcore/).
## Motivation
You *probably* don't want to be using HTTP Core directly. It might make sense if
you're writing something like a proxy service in Python, and you just want
something at the lowest possible level, but more typically you'll want to use
a higher level client library, such as `httpx`.
The motivation for `httpcore` is:
* To provide a reusable low-level client library, that other packages can then build on top of.
* To provide a *really clear interface split* between the networking code and client logic,
so that each is easier to understand and reason about in isolation.
# Changelog
All notable changes to this project will be documented in this file.
The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
## 0.17.3 (5th July 2023)
- Support async cancellations, ensuring that the connection pool is left in a clean state when cancellations occur. (#726)
- The networking backend interface has [been added to the public API](https://www.encode.io/httpcore/network-backends). Some classes which were previously private implementation detail are now part of the top-level public API. (#699)
- Graceful handling of HTTP/2 GoAway frames, with requests being transparently retried on a new connection. (#730)
- Add exceptions when a synchronous `trace callback` is passed to an asynchronous request or an asynchronous `trace callback` is passed to a synchronous request. (#717)
## 0.17.2 (May 23th, 2023)
- Add `socket_options` argument to `ConnectionPool` and `HTTProxy` classes. (#668)
- Improve logging with per-module logger names. (#690)
- Add `sni_hostname` request extension. (#696)
- Resolve race condition during import of `anyio` package. (#692)
- Enable TCP_NODELAY for all synchronous sockets. (#651)
## 0.17.1 (May 17th, 2023)
- If 'retries' is set, then allow retries if an SSL handshake error occurs. (#669)
- Improve correctness of tracebacks on network exceptions, by raising properly chained exceptions. (#678)
- Prevent connection-hanging behaviour when HTTP/2 connections are closed by a server-sent 'GoAway' frame. (#679)
- Fix edge-case exception when removing requests from the connection pool. (#680)
- Fix pool timeout edge-case. (#688)
## 0.17.0 (March 16th, 2023)
- Add DEBUG level logging. (#648)
- Respect HTTP/2 max concurrent streams when settings updates are sent by server. (#652)
- Increase the allowable HTTP header size to 100kB. (#647)
- Add `retries` option to SOCKS proxy classes. (#643)
## 0.16.3 (December 20th, 2022)
- Allow `ws` and `wss` schemes. Allows us to properly support websocket upgrade connections. (#625)
- Forwarding HTTP proxies use a connection-per-remote-host. Required by some proxy implementations. (#637)
- Don't raise `RuntimeError` when closing a connection pool with active connections. Removes some error cases when cancellations are used. (#631)
- Lazy import `anyio`, so that it's no longer a hard dependancy, and isn't imported if unused. (#639)
- Raise `RuntimeError` if attempting to us UNIX domain sockets on Windows. (#619)
## 0.16.1 (November 17th, 2022)
- Fix HTTP/1.1 interim informational responses, such as "100 Continue". (#605)
## 0.16.0 (October 11th, 2022)
- Support HTTP/1.1 informational responses. (#581)
- Fix async cancellation behaviour. (#580)
- Support `h11` 0.14. (#579)
## 0.15.0 (May 17th, 2022)
- Drop Python 3.6 support (#535)
- Ensure HTTP proxy CONNECT requests include `timeout` configuration. (#506)
- Switch to explicit `typing.Optional` for type hints. (#513)
- For `trio` map OSError exceptions to `ConnectError`. (#543)
## 0.14.7 (February 4th, 2022)
- Requests which raise a PoolTimeout need to be removed from the pool queue. (#502)
- Fix AttributeError that happened when Socks5Connection were terminated. (#501)
## 0.14.6 (February 1st, 2022)
- Fix SOCKS support for `http://` URLs. (#492)
- Resolve race condition around exceptions during streaming a response. (#491)
## 0.14.5 (January 18th, 2022)
- SOCKS proxy support. (#478)
- Add proxy_auth argument to HTTPProxy. (#481)
- Improve error message on 'RemoteProtocolError' exception when server disconnects without sending a response. (#479)
## 0.14.4 (January 5th, 2022)
- Support HTTP/2 on HTTPS tunnelling proxies. (#468)
- Fix proxy headers missing on HTTP forwarding. (#456)
- Only instantiate SSL context if required. (#457)
- More robust HTTP/2 handling. (#253, #439, #440, #441)
## 0.14.3 (November 17th, 2021)
- Fix race condition when removing closed connections from the pool. (#437)
## 0.14.2 (November 16th, 2021)
- Failed connections no longer remain in the pool. (Pull #433)
## 0.14.1 (November 12th, 2021)
- `max_connections` becomes optional. (Pull #429)
- `certifi` is now included in the install dependancies. (Pull #428)
- `h2` is now strictly optional. (Pull #428)
## 0.14.0 (November 11th, 2021)
The 0.14 release is a complete reworking of `httpcore`, comprehensively addressing some underlying issues in the connection pooling, as well as substantially redesigning the API to be more user friendly.
Some of the lower-level API design also makes the components more easily testable in isolation, and the package now has 100% test coverage.
See [discussion #419](https://github.com/encode/httpcore/discussions/419) for a little more background.
There's some other neat bits in there too, such as the "trace" extension, which gives a hook into inspecting the internal events that occur during the request/response cycle. This extension is needed for the HTTPX cli, in order to...
* Log the point at which the connection is established, and the IP/port on which it is made.
* Determine if the outgoing request should log as HTTP/1.1 or HTTP/2, rather than having to assume it's HTTP/2 if the --http2 flag was passed. (Which may not actually be true.)
* Log SSL version info / certificate info.
Note that `curio` support is not currently available in 0.14.0. If you're using `httpcore` with `curio` please get in touch, so we can assess if we ought to prioritize it as a feature or not.
## 0.13.7 (September 13th, 2021)
- Fix broken error messaging when URL scheme is missing, or a non HTTP(S) scheme is used. (Pull #403)
## 0.13.6 (June 15th, 2021)
### Fixed
- Close sockets when read or write timeouts occur. (Pull #365)
## 0.13.5 (June 14th, 2021)
### Fixed
- Resolved niggles with AnyIO EOF behaviours. (Pull #358, #362)
## 0.13.4 (June 9th, 2021)
### Added
- Improved error messaging when URL scheme is missing, or a non HTTP(S) scheme is used. (Pull #354)
### Fixed
- Switched to `anyio` as the default backend implementation when running with `asyncio`. Resolves some awkward [TLS timeout issues](https://github.com/encode/httpx/discussions/1511).
## 0.13.3 (May 6th, 2021)
### Added
- Support HTTP/2 prior knowledge, using `httpcore.SyncConnectionPool(http1=False)`. (Pull #333)
### Fixed
- Handle cases where environment does not provide `select.poll` support. (Pull #331)
## 0.13.2 (April 29th, 2021)
### Added
- Improve error message for specific case of `RemoteProtocolError` where server disconnects without sending a response. (Pull #313)
## 0.13.1 (April 28th, 2021)
### Fixed
- More resiliant testing for closed connections. (Pull #311)
- Don't raise exceptions on ungraceful connection closes. (Pull #310)
## 0.13.0 (April 21st, 2021)
The 0.13 release updates the core API in order to match the HTTPX Transport API,
introduced in HTTPX 0.18 onwards.
An example of making requests with the new interface is:
To instead including an optional dictionary of extensions on the request and response:
```python
def request(method, url, headers, stream, ext):
return (status_code, headers, stream, ext)
```
Having an open-ended extensions point will allow us to add later support for various optional features, that wouldn't otherwise be supported without these API changes.
In particular:
* Trailing headers support.
* HTTP/2 Server Push
* sendfile.
* Exposing raw connection on CONNECT, Upgrade, HTTP/2 bi-di streaming.
* Exposing debug information out of the API, including template name, template context.
- Add `PlainByteStream`, `IteratorByteStream`, `AsyncIteratorByteStream`. The `AsyncByteSteam` and `SyncByteStream` classes are now pure interface classes. (#133)
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Iliyan Angelov