Motivation:
For HTTP/2 messages with multiple cookies HttpConversionUtil.addHttp2ToHttpHeaders spends a good portion of time creating throwaway StringBuilders.
Modification:
Handle cookies lazily by using a ThreadLocal StringBuilder and then converting it to the H1 header at the end.
Result:
Less allocations.
Motivation:
Usages of HttpResponseStatus may result in more object allocation then necessary due to not looking for cached objects and the AsciiString parsing method not being used due to CharSequence method being used instead.
Modifications:
- HttpResponseDecoder should attempt to get the HttpResponseStatus from cache instead of allocating a new object
- HttpResponseStatus#parseLine(CharSequence) should check if the type is AsciiString and redirect to the AsciiString parsing method which may not require an additional toString call
- HttpResponseStatus#parseLine(AsciiString) can be optimized and doesn't require and may not require object allocation
Result:
Less allocations when dealing with HttpResponseStatus.
Motivation:
HttpConversionUtil#toHttp2Headers has special code to filter the TE header name. However this filtering code may result in adding the <TE, TRAILERS> tuple in scenarios that are not appropriate. For example if a value containing trailers is seen it will be added, but the value could not actually be equal to trailers. Also CSV values are not supported.
Modifications:
- Account for CSV header values
- Account for the value containing 'trailers' but not actually being equal to 'trailers'
Result:
More robust parsing of the TE header.
Modifications:
HttpConversionUtil#toLowercaseMap requires an intermediate List to be allocated. This can be avoided with the recently added value iterator methods.
Modifications:
- Use HttpHeaders#valueCharSequenceIterator instead of getAll
Result:
Less intermediate object allocation and copying.
Motivation:
Netty could handle "connection" or "te" headers more gently when
converting from http/1.1 to http/2 headers. Http/2 headers don't
support single-hop headers, so when we convert from http/1.1 to http/2,
we should drop all single-hop headers. This includes headers like
"transfer-encoding" and "connection", but also the headers that
"connection" points to, since "connection" can be used to designate
other headers as single-hop headers. For the "te" header, we can more
permissively convert it by just dropping non-conforming headers (ie
non-"trailers" headers) which is what we do for all other headers when
we convert.
Modifications:
Add a new blacklist to the http/1.1 to http/2 conversion, which is
constructed from the values of the "connection" header, and stop
throwing an exception when a "te" header is passed with a non-"trailers"
value. Instead, drop all values except for "trailers". Add unit tests
for "connection" and "te" headers when converting from http/1.1 to http/2.
Result:
This will improve the h2c upgrade request, and also conversions from
http/1.1 to http/2. This will simplify implementing spec-compliant
http/2 servers that want to share code between their http/1.1 and http/2
implementations.
[Fixes#7355]
Motivation:
Http2ServerDowngrader is specifically built for server channels where
inbound Http2StreamFrames are converted into HttpRequests, and outbound
HttpResponses are converted into Http2StreamFrames. It can be easily
made to be more generic to work with client channels where inbound
Http2StreamFrames are converted into HttpResponses, and outbound
HttpRequests are converted into Http2StreamFrames.
Modification:
- Renamed Http2ServerDowngrader to a more general
Http2StreamFrameToHttpObjectCodec
- Made it take in an "isServer" parameter to determine whether encoding
inbound Http2StreamFrames should create HttpRequests (for server) or
HttpResponses (for client)
- Norman fixed a leak in the unit test. Thanks! :-)
Result:
Now Http2StreamFrameToHttpObjectCodec can be used to translate
Http2StreamFrame to HttpObject for both server and client.
Motivation:
The construction `new AsciiString(string.substring(...))` can be replaced with the `new AsciiString(string, start, length)` to avoid extra allocation.
Modifications:
Apply the described replacement in `HttpConversionUtil#setHttp2Authority`.
Result:
Less allocations.
Motivation:
The `AsciiString#toString` method calculate string value and cache it into field. If an `AsciiString` created from the `String` value, we can avoid rebuilding strings if we cache them immediately when creating `AsciiString`. It would be useful for constants strings, which already stored in the JVMs string table, or in cases where an unavoidable `#toString `method call is assumed.
Modifications:
- Add new static method `AsciiString#cache(String)` which save string value into cache field.
- Apply a "benign" data race in the `#hashCode` and `#toString` methods.
Result:
Less memory usage in some `AsciiString` use cases.
Motivation:
In a `HttpConversionUtil#toHttp2Headers` a status code conversion can be replaced with using `HttpResponseStatus#codeAsText` method.
Modifications:
Apply `HttpResponseStatus#codeAsText` method.
Result:
Less allocations.
Motivation:
codec-http2 couples the dependency tree state with the remainder of the stream state (Http2Stream). This makes implementing constraints where stream state and dependency tree state diverge in the RFC challenging. For example the RFC recommends retaining dependency tree state after a stream transitions to closed [1]. Dependency tree state can be exchanged on streams in IDLE. In practice clients may use stream IDs for the purpose of establishing QoS classes and therefore retaining this dependency tree state can be important to client perceived performance. It is difficult to limit the total amount of state we retain when stream state and dependency tree state is combined.
Modifications:
- Remove dependency tree, priority, and weight related items from public facing Http2Connection and Http2Stream APIs. This information is optional to track and depends on the flow controller implementation.
- Move all dependency tree, priority, and weight related code from DefaultHttp2Connection to WeightedFairQueueByteDistributor. This is currently the only place which cares about priority. We can pull out the dependency tree related code in the future if it is generally useful to expose for other implementations.
- DefaultHttp2Connection should explicitly limit the number of reserved streams now that IDLE streams are no longer created.
Result:
More compliant with the HTTP/2 RFC.
Fixes https://github.com/netty/netty/issues/6206.
[1] https://tools.ietf.org/html/rfc7540#section-5.3.4
Motivation:
http/2 and http/1.1 have similar protocols, and it's useful to be able
to implement a single server against a single interface. There's an
injection from http/1.1 messages to http/2 ones, so it makes sense to
make folks program against http/1.1 and upgrade them under the hood.
Modifications:
added a MessageToMessageCodec<Http2StreamFrame, HttpObject> which turns
every kind of Http2StreamFrame domain object into an HttpObject domain
object, and then back again on the way out. This one is specialized for
servers, but it should be straightforward to make a symmetric one for
clients, or else extend this one.
Result:
fixes#5199, and it's now simple to make your Http2MultiplexCodec speak
Http1.1
Motivation:
Some codecs should be considered unstable as these are relative new. For this purpose we should introduce an annotation which these codecs should us to be marked as unstable in terms of API.
Modifications:
- Add UnstableApi annotation and use it on codecs that are not stable
- Move http2.hpack to http2.internal.hpack as it is internal.
Result:
Better document unstable APIs.
Modifications:
When constructing the FullHttpMessage pass in the ByteBuf to use via the ByteBufAllocator assigned via the context.
Result:
The ByteBuf assigned to the FullHttpMessage can now be configured as a pooled/unpooled, direct/heap based ByteBuf via the ByteBufAllocator used.
Motivation:
In HttpConversionUtil's toHttpRequest and toHttpResponse methods can
allocate FullHttpMessage objects, and if an exeception is thrown during
the header conversion then this object will not be released. If a
FullHttpMessage is not fired up the pipeline, and the stream is closed
then we remove from the map, but do not release the object. This leads
to a ByteBuf leak. Some of the logic related to stream lifetime management
and FullHttpMessage also predates the RFC being finalized and is not correct.
Modifications:
- Fix leaks in HttpConversionUtil
- Ensure the objects are released when they are removed from the map.
- Correct logic and unit tests where they are found to be incorrect.
Result:
Fixes https://github.com/netty/netty/issues/4780
Fixes https://github.com/netty/netty/issues/3619
Motivation:
HttpConversionUtil.toHttp2Headers currently has a throws Exception as part of the signature. This comes from the signature of ByteProcessor.process, but is not necessary because the ByteProcessor used does not throw.
Modifications:
- Remove throws Exception from the signature of HttpConversionUtil.toHttp2Headers.
Result:
HttpConversionUtil.toHttp2Headers interface does not propagate a throws Exception when it is used.
Motivation:
DefaultHeaders creates an array of size 16 for all headers. This may waste a good deal of memory if applications only have a small number of headers. This memory may be critical when the number of connections grows large.
Modifications:
- Make the size of the array for DefaultHeaders configurable
Result:
Applications can control the size of the DefaultHeaders array and save memory.
Motivation:
The HTTP/2 RFC (https://tools.ietf.org/html/rfc7540#section-8.1.2) indicates that header names consist of ASCII characters. We currently use ByteString to represent HTTP/2 header names. The HTTP/2 RFC (https://tools.ietf.org/html/rfc7540#section-10.3) also eludes to header values inheriting the same validity characteristics as HTTP/1.x. Using AsciiString for the value type of HTTP/2 headers would allow for re-use of predefined HTTP/1.x values, and make comparisons more intuitive. The Headers<T> interface could also be expanded to allow for easier use of header types which do not have the same Key and Value type.
Motivation:
- Change Headers<T> to Headers<K, V>
- Change Http2Headers<ByteString> to Http2Headers<CharSequence, CharSequence>
- Remove ByteString. Having AsciiString extend ByteString complicates equality comparisons when the hash code algorithm is no longer shared.
Result:
Http2Header types are more representative of the HTTP/2 RFC, and relationship between HTTP/2 header name/values more directly relates to HTTP/1.x header names/values.
Motivation:
We had an unused paramter on a method, we should just remove it to keep code clean.
Modifications:
- Remove parameter
- Fix typo in javadoc
Result:
Cleanup done.
Motiviation:
The http2 spec https://tools.ietf.org/html/rfc7540#section-8.1.2.3 states that the :authority header should be copied into the HOST header when converting from HTTP/2 to HTTP/1.x. We currently have an extension header to preserve the authority.
Modifications:
- Remove AUTHORITY extension header
- HTTP/2 :authority should map to HOST header when converting to HTTP/1.x.
Result:
More spec compliant.
Motivation:
HttpConversionUtil.toHttp2Headers does not convert urlencoded uri to http2 path properly.
Modifications:
Use getRawPath(), getRawQuery(), getRawFragment() in java.net.URI when converts to http2 path
Result:
HttpConversionUtil.toHttp2Headers does not urldecode uri unproperly.
Motivation:
Currently there is a HttpConversionUtil.addHttp2ToHttpHeaders which requires a FullHttpMessage, but this may not always be available. There is no interface that can be used with just Http2Headers and HttpHeaders.
Modifications:
- add an overload for HttpConversionUtil.addHttp2ToHttpHeaders which does not take FullHttpMessage
Result:
An overload for HttpConversionUtil.addHttp2ToHttpHeaders exists which does not require FullHttpMessage.
Motivation:
The HTTP/2 header name validation was removed, and does not currently exist.
Modifications:
- Header name validation for HTTP/2 should be restored and set to the default mode of operation.
Result:
HTTP/2 header names are validated according to https://tools.ietf.org/html/rfc7540
Motivation:
There currently exists http.HttpUtil, http2.HttpUtil, and http.HttpHeaderUtil. Having 2 HttpUtil methods can be confusing and the utilty methods in the http package could be consolidated.
Modifications:
- Rename http2.HttpUtil to http2.HttpConversionUtil
- Move http.HttpHeaderUtil methods into http.HttpUtil
Result:
Consolidated utilities whose names don't overlap.
Fixes https://github.com/netty/netty/issues/4120
