netty5/codec-http2
Trustin Lee 4d6ab1d30d Fix missing trailing data on HTTP client upgrade
Motivation:

When HttpClientUpgradeHandler upgrades from HTTP/1 to another protocol,
it performs a two-step opertion:

1. Remove the SourceCodec (HttpClientCodec)
2. Add the UpgradeCodec

When HttpClientCodec is removed from the pipeline, the decoder being
removed triggers channelRead() event with the data left in its
cumulation buffer. However, this is not received by the UpgradeCodec
becuase it's not added yet. e.g. HTTP/2 SETTINGS frame sent by the
server can be missed out.

To fix the problem, we need to reverse the steps:

1. Add the UpgradeCodec
2. Remove the SourceCodec

However, this does not work as expected either, because UpgradeCodec can
send a greeting message such as HTTP/2 Preface. Such a greeting message
will be handled by the SourceCodec and will trigger an 'unsupported
message type' exception.

To fix the problem really, we need to make the upgrade process 3-step:

1. Remove/disable the encoder of SourceCodec
2. Add the UpgradeCodec
3. Remove the SourceCodec

Modifications:

- Add SourceCodec.prepareUpgradeFrom() so that SourceCodec can remove or
  disable its encoder
- Implement HttpClientCodec.prepareUpgradeFrom() properly
- Miscellaneous:
  - Log the related channel as well When logging the failure to send a
    GOAWAY

Result:

Cleartext HTTP/1-to-HTTP/2 upgrade works again.
2016-02-01 15:52:37 +01:00
..
src Fix missing trailing data on HTTP client upgrade 2016-02-01 15:52:37 +01:00
pom.xml [maven-release-plugin] prepare for next development iteration 2016-01-21 15:35:55 +01:00