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HTTP/2 framing layer for Python

Project description

This library contains the HTTP/2 framing code used in the hyper project. It provides a pure-Python codebase that is capable of decoding a binary stream into HTTP/2 frames.

This library is used directly by hyper and a number of other projects to provide HTTP/2 frame decoding logic.


hyperframe welcomes contributions from anyone! Unlike many other projects we are happy to accept cosmetic contributions and small contributions, in addition to large feature requests and changes.

Before you contribute (either by opening an issue or filing a pull request), please read the contribution guidelines.


hyperframe is made available under the MIT License. For more details, see the LICENSE file in the repository.


hyperframe is maintained by Cory Benfield, with contributions from others. For more details about the contributors, please see CONTRIBUTORS.rst.

Release History


5.2.0 (2019-01-18)

API Changes (Backward-compatible)

  • Add a new ENABLE_CONNECT_PROTOCOL settings paramter.

Other Changes

  • Fix deprecation.

  • Drop support for Python 3.3 and support 3.7.

5.1.0 (2017-04-24)

API Changes (Backward-compatible)

  • Added support for being a memoryview object.

5.0.0 (2017-03-07)

Backwards Incompatible API Changes

  • Added support for unknown extension frames. These will be returned in the new ExtensionFrame object. The flag information for these frames is persisted in flag_byte if needed.

4.0.2 (2017-02-20)


  • Fixed AltSvc stream association, which was incorrectly set to 'both': should have been 'either'.

  • Fixed a bug where stream IDs on received frames were allowed to be 32-bit, instead of 31-bit.

  • Fixed a bug with frames that had the PADDING flag set but zero-length padding, whose flow-controlled length was calculated wrongly.

  • Miscellaneous performance improvements to serialization and parsing logic.

4.0.1 (2016-03-13)


  • Fixed bug with the repr of AltSvcFrame, where building it could throw exceptions if the frame had been received from the network.

4.0.0 (2016-03-13)

Backwards Incompatible API Changes

  • Updated old ALTSVC frame definition to match the newly specified RFC 7838.

  • Remove BLOCKED frame, which was never actually specified.

  • Removed previously deprecated SettingsFrame.SETTINGS_MAX_FRAME_SIZE and SettingsFrame.SETTINGS_MAX_HEADER_LIST_SIZE.

3.2.0 (2016-02-02)

API Changes (Backward-compatible)

  • Invalid PING frame bodies now raise InvalidFrameError, not ValueError. Note that InvalidFrameError is a ValueError subclass.

  • Invalid RST_STREAM frame bodies now raise InvalidFramError, not ValueError. Note that InvalidFrameError is a ValueError subclass.

  • Canonicalized the names of SettingsFrame.SETTINGS_MAX_FRAME_SIZE and SettingsFrame.SETTINGS_MAX_HEADER_LIST_SIZE to match their peers, by adding new properties SettingsFrame.MAX_FRAME_SIZE and SettingsFrame.SETTINGS_MAX_HEADER_LIST_SIZE. The old names are still present, but will be deprecated in 4.0.0.


  • The change in 3.1.0 that ensured that InvalidFrameError would be thrown did not affect certain invalid values in ALT_SVC frames. This has been fixed: ValueError will no longer be thrown from invalid ALT_SVC bodies.

3.1.1 (2016-01-18)


  • Correctly error when receiving Ping frames that have insufficient data.

3.1.0 (2016-01-13)

API Changes

  • Added new InvalidFrameError that is thrown instead of struct.error when parsing a frame.


  • Fixed error when trying to serialize frames that use Priority information with the defaults for that information.

  • Fixed errors when displaying the repr of frames with non-printable bodies.

3.0.1 (2016-01-08)


  • Fix issue where unpadded DATA, PUSH_PROMISE and HEADERS frames that had empty bodies would raise InvalidPaddingError exceptions when parsed.

3.0.0 (2016-01-08)

Backwards Incompatible API Changes

  • Parsing padded frames that have invalid padding sizes now throws an InvalidPaddingError.

2.2.0 (2015-10-15)

API Changes

  • When an unknown frame is encountered, parse_frame_header now throws a ValueError subclass: UnknownFrameError. This subclass contains the frame type and the length of the frame body.

2.1.0 (2015-10-06)

API Changes

  • Frames parsed from binary data now carry a body_len attribute that matches the frame length (minus the frame header).

2.0.0 (2015-09-21)

API Changes

  • Attempting to parse unrecognised frames now throws ValueError instead of KeyError. Thanks to @Kriechi!

  • Flags are now validated for correctness, preventing setting flags that hyperframe does not recognise and that would not serialize. Thanks to @mhils!

  • Frame properties can now be initialized in the constructors. Thanks to @mhils and @Kriechi!

  • Frames that cannot be sent on a stream now have their stream ID defaulted to 0. Thanks to @Kriechi!

Other Changes

  • Frames have a more useful repr. Thanks to @mhils!

1.1.1 (2015-07-20)

  • Fix a bug where FRAME_MAX_LEN was one byte too small.

1.1.0 (2015-06-28)

  • Add body_len property to frames to enable introspection of the actual frame length. Thanks to @jdecuyper!

1.0.1 (2015-06-27)

  • Fix bug where the frame header would have an incorrect length added to it.

1.0.0 (2015-04-12)

  • Initial extraction from hyper.

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