Motivation:
An intermediary like a load balancer might require that a Cross Origin
Resource Sharing (CORS) preflight request have certain headers set.
As a concrete example the Elastic Load Balancer (ELB) requires the
'Date' and 'Content-Length' header to be set or it will fail with a 502
error code.
This works is an enhancement of https://github.com/netty/netty/pull/2290
Modifications:
CorsConfig has been extended to make additional HTTP response headers
configurable for preflight responses. Since some headers, like the
'Date' header need to be generated each time, m0wfo suggested using a
Callable.
Result:
By default, the 'Date' and 'Content-Lenght' headers will be sent in a
preflight response. This can be overriden and users can specify
any headers that might be required by different intermediaries.
Motivation:
If the last item analyzed in a previous received HttpChunk/HttpContent was a part of an attribute's name, the read index was not set to the new right place and therefore raizing an exception in some case (since the "new" name analyzed is empty, which is not allowed so the exception).
What appears there is that the read index should be reset to the last valid position encountered whatever the case. Currently it was set when only when there is an attribute not already finished (name is ok, but content is possibly not).
Therefore the issue is that elements could be rescanned multiple times (including completed elements) and moreover some bad decoding can occur such as when in a middle of an attribute's name.
Modifications:
To fix this issue, since "firstpos" contains the last "valid" read index of the decoding (when finding a '&', '=', 'CR/LF'), we should add the setting of the read index for the following cases:
'lastchunk' encountered, therefore finishing the current buffer
any other cases than current attribute is not finished (name not found yet in particular)
So adding for this 2 cases:
undecodedChunk.readerIndex(firstpos);
Result:
Now the decoding is done once, content is added from chunk/content to chunk/content, name is decoded correctly even if in the middle of 2 chunks/contents.
A Junit test code was added: testChunkCorrect that should not raized any exception.
Motivation:
When an HttpResponseDecoder decodes an invalid chunk, a LastHttpContent instance is produced and the decoder enters the 'BAD_MESSAGE' state, which is not supposed to produce a message any further. However, because HttpObjectDecoder.invalidChunk() did not clear this.message out to null, decodeLast() will produce another LastHttpContent message on a certain situation.
Modification:
Do not forget to null out HttpObjectDecoder.message in invalidChunk(), and add a test case for it.
Result:
No more consecutive LastHttpContent messages produced by HttpObjectDecoder.
Motivation:
Currently, it is impossible to give a user the full control over what to do in response to the request with 'Expect: 100-continue' header. Currently, a user have to do one of the following:
- Accept the request and respond with 100 Continue, or
- Send the reject response and close the connection.
.. which means it is impossible to send the reject response and keep the connection alive so that the client sends additional requests.
Modification:
Added a public method called 'reset()' to HttpObjectDecoder so that a user can reset the state of the decoder easily. Once called, the decoder will assume the next input will be the beginning of a new request.
HttpObjectAggregator now calls `reset()`right after calling 'handleOversizedMessage()' so that the decoder can continue to decode the subsequent request even after the request with 'Expect: 100-continue' header is rejected.
Added relevant unit tests / Minor clean-up
Result:
This commit completes the fix of #2211
Exposing the constant as a public static final field is usually not a
good idea because it gives less flexibility to us when we happen to
change our internal implementation.
- Related: #2163
- Add ResourceLeakHint to allow a user to provide a meaningful information about the leak when touching it
- DefaultChannelHandlerContext now implements ResourceLeakHint to tell where the message is going.
- Cleaner resource leak report by excluding noisy stack trace elements
