http2

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Published: Jul 22, 2016 License: BSD-3-Clause, MIT Imports: 23 Imported by: 0

README

This is a work-in-progress HTTP/2 implementation for Go.

It will eventually live in the Go standard library and won't require
any changes to your code to use.  It will just be automatic.

Status:

* The server support is pretty good. A few things are missing
  but are being worked on.
* The client work has just started but shares a lot of code
  is coming along much quicker.

Docs are at https://godoc.org/golang.org/x/net/http2

Demo test server at https://http2.golang.org/

Help & bug reports welcome!

Contributing: https://golang.org/doc/contribute.html
Bugs:         https://golang.org/issue/new?title=x/net/http2:+

Documentation

Overview

Package http2 implements the HTTP/2 protocol.

This package is low-level and intended to be used directly by very few people. Most users will use it indirectly through the automatic use by the net/http package (from Go 1.6 and later). For use in earlier Go versions see ConfigureServer. (Transport support requires Go 1.6 or later)

See https://http2.github.io/ for more information on HTTP/2.

See https://http2.golang.org/ for a test server running this code.

Index

Constants

View Source
const (
	// ClientPreface is the string that must be sent by new
	// connections from clients.
	ClientPreface = "PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n"

	// NextProtoTLS is the NPN/ALPN protocol negotiated during
	// HTTP/2's TLS setup.
	NextProtoTLS = "h2"
)

Variables

View Source
var DebugGoroutines = os.Getenv("DEBUG_HTTP2_GOROUTINES") == "1"
View Source
var ErrFrameTooLarge = errors.New("http2: frame too large")

ErrFrameTooLarge is returned from Framer.ReadFrame when the peer sends a frame that is larger than declared with SetMaxReadFrameSize.

View Source
var ErrNoCachedConn = errors.New("http2: no cached connection was available")
View Source
var (
	VerboseLogs bool
)

Functions

func ConfigureServer

func ConfigureServer(s *http.Server, conf *Server) error

ConfigureServer adds HTTP/2 support to a net/http Server.

The configuration conf may be nil.

ConfigureServer must be called before s begins serving.

func ConfigureTransport

func ConfigureTransport(t1 *http.Transport) error

ConfigureTransport configures a net/http HTTP/1 Transport to use HTTP/2. It requires Go 1.6 or later and returns an error if the net/http package is too old or if t1 has already been HTTP/2-enabled.

Types

type ClientConn

type ClientConn struct {
	// contains filtered or unexported fields
}

ClientConn is the state of a single HTTP/2 client connection to an HTTP/2 server.

func (*ClientConn) CanTakeNewRequest

func (cc *ClientConn) CanTakeNewRequest() bool

func (*ClientConn) RoundTrip

func (cc *ClientConn) RoundTrip(req *http.Request) (*http.Response, error)

type ClientConnPool

type ClientConnPool interface {
	GetClientConn(req *http.Request, addr string) (*ClientConn, error)
	MarkDead(*ClientConn)
}

ClientConnPool manages a pool of HTTP/2 client connections.

type ConnectionError

type ConnectionError ErrCode

ConnectionError is an error that results in the termination of the entire connection.

func (ConnectionError) Error

func (e ConnectionError) Error() string

type ContinuationFrame

type ContinuationFrame struct {
	FrameHeader
	// contains filtered or unexported fields
}

A ContinuationFrame is used to continue a sequence of header block fragments. See http://http2.github.io/http2-spec/#rfc.section.6.10

func (*ContinuationFrame) HeaderBlockFragment

func (f *ContinuationFrame) HeaderBlockFragment() []byte

func (*ContinuationFrame) HeadersEnded

func (f *ContinuationFrame) HeadersEnded() bool

type DataFrame

type DataFrame struct {
	FrameHeader
	// contains filtered or unexported fields
}

A DataFrame conveys arbitrary, variable-length sequences of octets associated with a stream. See http://http2.github.io/http2-spec/#rfc.section.6.1

func (*DataFrame) Data

func (f *DataFrame) Data() []byte

Data returns the frame's data octets, not including any padding size byte or padding suffix bytes. The caller must not retain the returned memory past the next call to ReadFrame.

func (*DataFrame) StreamEnded

func (f *DataFrame) StreamEnded() bool

type ErrCode

type ErrCode uint32

An ErrCode is an unsigned 32-bit error code as defined in the HTTP/2 spec.

const (
	ErrCodeNo                 ErrCode = 0x0
	ErrCodeProtocol           ErrCode = 0x1
	ErrCodeInternal           ErrCode = 0x2
	ErrCodeFlowControl        ErrCode = 0x3
	ErrCodeSettingsTimeout    ErrCode = 0x4
	ErrCodeStreamClosed       ErrCode = 0x5
	ErrCodeFrameSize          ErrCode = 0x6
	ErrCodeRefusedStream      ErrCode = 0x7
	ErrCodeCancel             ErrCode = 0x8
	ErrCodeCompression        ErrCode = 0x9
	ErrCodeConnect            ErrCode = 0xa
	ErrCodeEnhanceYourCalm    ErrCode = 0xb
	ErrCodeInadequateSecurity ErrCode = 0xc
	ErrCodeHTTP11Required     ErrCode = 0xd
)

func (ErrCode) String

func (e ErrCode) String() string

type Flags

type Flags uint8

Flags is a bitmask of HTTP/2 flags. The meaning of flags varies depending on the frame type.

const (
	// Data Frame
	FlagDataEndStream Flags = 0x1
	FlagDataPadded    Flags = 0x8

	// Headers Frame
	FlagHeadersEndStream  Flags = 0x1
	FlagHeadersEndHeaders Flags = 0x4
	FlagHeadersPadded     Flags = 0x8
	FlagHeadersPriority   Flags = 0x20

	// Settings Frame
	FlagSettingsAck Flags = 0x1

	// Ping Frame
	FlagPingAck Flags = 0x1

	// Continuation Frame
	FlagContinuationEndHeaders Flags = 0x4

	FlagPushPromiseEndHeaders Flags = 0x4
	FlagPushPromisePadded     Flags = 0x8
)

Frame-specific FrameHeader flag bits.

func (Flags) Has

func (f Flags) Has(v Flags) bool

Has reports whether f contains all (0 or more) flags in v.

type Frame

type Frame interface {
	Header() FrameHeader
	// contains filtered or unexported methods
}

A Frame is the base interface implemented by all frame types. Callers will generally type-assert the specific frame type: *HeadersFrame, *SettingsFrame, *WindowUpdateFrame, etc.

Frames are only valid until the next call to Framer.ReadFrame.

type FrameHeader

type FrameHeader struct {

	// Type is the 1 byte frame type. There are ten standard frame
	// types, but extension frame types may be written by WriteRawFrame
	// and will be returned by ReadFrame (as UnknownFrame).
	Type FrameType

	// Flags are the 1 byte of 8 potential bit flags per frame.
	// They are specific to the frame type.
	Flags Flags

	// Length is the length of the frame, not including the 9 byte header.
	// The maximum size is one byte less than 16MB (uint24), but only
	// frames up to 16KB are allowed without peer agreement.
	Length uint32

	// StreamID is which stream this frame is for. Certain frames
	// are not stream-specific, in which case this field is 0.
	StreamID uint32
	// contains filtered or unexported fields
}

A FrameHeader is the 9 byte header of all HTTP/2 frames.

See http://http2.github.io/http2-spec/#FrameHeader

func ReadFrameHeader

func ReadFrameHeader(r io.Reader) (FrameHeader, error)

ReadFrameHeader reads 9 bytes from r and returns a FrameHeader. Most users should use Framer.ReadFrame instead.

func (FrameHeader) Header

func (h FrameHeader) Header() FrameHeader

Header returns h. It exists so FrameHeaders can be embedded in other specific frame types and implement the Frame interface.

func (FrameHeader) String

func (h FrameHeader) String() string

type FrameType

type FrameType uint8

A FrameType is a registered frame type as defined in http://http2.github.io/http2-spec/#rfc.section.11.2

const (
	FrameData         FrameType = 0x0
	FrameHeaders      FrameType = 0x1
	FramePriority     FrameType = 0x2
	FrameRSTStream    FrameType = 0x3
	FrameSettings     FrameType = 0x4
	FramePushPromise  FrameType = 0x5
	FramePing         FrameType = 0x6
	FrameGoAway       FrameType = 0x7
	FrameWindowUpdate FrameType = 0x8
	FrameContinuation FrameType = 0x9
)

func (FrameType) String

func (t FrameType) String() string

type Framer

type Framer struct {

	// AllowIllegalWrites permits the Framer's Write methods to
	// write frames that do not conform to the HTTP/2 spec. This
	// permits using the Framer to test other HTTP/2
	// implementations' conformance to the spec.
	// If false, the Write methods will prefer to return an error
	// rather than comply.
	AllowIllegalWrites bool

	// AllowIllegalReads permits the Framer's ReadFrame method
	// to return non-compliant frames or frame orders.
	// This is for testing and permits using the Framer to test
	// other HTTP/2 implementations' conformance to the spec.
	AllowIllegalReads bool
	// contains filtered or unexported fields
}

A Framer reads and writes Frames.

func NewFramer

func NewFramer(w io.Writer, r io.Reader) *Framer

NewFramer returns a Framer that writes frames to w and reads them from r.

func (*Framer) ReadFrame

func (fr *Framer) ReadFrame() (Frame, error)

ReadFrame reads a single frame. The returned Frame is only valid until the next call to ReadFrame.

If the frame is larger than previously set with SetMaxReadFrameSize, the returned error is ErrFrameTooLarge. Other errors may be of type ConnectionError, StreamError, or anything else from from the underlying reader.

func (*Framer) SetMaxReadFrameSize

func (fr *Framer) SetMaxReadFrameSize(v uint32)

SetMaxReadFrameSize sets the maximum size of a frame that will be read by a subsequent call to ReadFrame. It is the caller's responsibility to advertise this limit with a SETTINGS frame.

func (*Framer) WriteContinuation

func (f *Framer) WriteContinuation(streamID uint32, endHeaders bool, headerBlockFragment []byte) error

WriteContinuation writes a CONTINUATION frame.

It will perform exactly one Write to the underlying Writer. It is the caller's responsibility to not call other Write methods concurrently.

func (*Framer) WriteData

func (f *Framer) WriteData(streamID uint32, endStream bool, data []byte) error

WriteData writes a DATA frame.

It will perform exactly one Write to the underlying Writer. It is the caller's responsibility to not call other Write methods concurrently.

func (*Framer) WriteGoAway

func (f *Framer) WriteGoAway(maxStreamID uint32, code ErrCode, debugData []byte) error

func (*Framer) WriteHeaders

func (f *Framer) WriteHeaders(p HeadersFrameParam) error

WriteHeaders writes a single HEADERS frame.

This is a low-level header writing method. Encoding headers and splitting them into any necessary CONTINUATION frames is handled elsewhere.

It will perform exactly one Write to the underlying Writer. It is the caller's responsibility to not call other Write methods concurrently.

func (*Framer) WritePing

func (f *Framer) WritePing(ack bool, data [8]byte) error

func (*Framer) WritePriority

func (f *Framer) WritePriority(streamID uint32, p PriorityParam) error

WritePriority writes a PRIORITY frame.

It will perform exactly one Write to the underlying Writer. It is the caller's responsibility to not call other Write methods concurrently.

func (*Framer) WritePushPromise

func (f *Framer) WritePushPromise(p PushPromiseParam) error

WritePushPromise writes a single PushPromise Frame.

As with Header Frames, This is the low level call for writing individual frames. Continuation frames are handled elsewhere.

It will perform exactly one Write to the underlying Writer. It is the caller's responsibility to not call other Write methods concurrently.

func (*Framer) WriteRSTStream

func (f *Framer) WriteRSTStream(streamID uint32, code ErrCode) error

WriteRSTStream writes a RST_STREAM frame.

It will perform exactly one Write to the underlying Writer. It is the caller's responsibility to not call other Write methods concurrently.

func (*Framer) WriteRawFrame

func (f *Framer) WriteRawFrame(t FrameType, flags Flags, streamID uint32, payload []byte) error

WriteRawFrame writes a raw frame. This can be used to write extension frames unknown to this package.

func (*Framer) WriteSettings

func (f *Framer) WriteSettings(settings ...Setting) error

WriteSettings writes a SETTINGS frame with zero or more settings specified and the ACK bit not set.

It will perform exactly one Write to the underlying Writer. It is the caller's responsibility to not call other Write methods concurrently.

func (*Framer) WriteSettingsAck

func (f *Framer) WriteSettingsAck() error

WriteSettings writes an empty SETTINGS frame with the ACK bit set.

It will perform exactly one Write to the underlying Writer. It is the caller's responsibility to not call other Write methods concurrently.

func (*Framer) WriteWindowUpdate

func (f *Framer) WriteWindowUpdate(streamID, incr uint32) error

WriteWindowUpdate writes a WINDOW_UPDATE frame. The increment value must be between 1 and 2,147,483,647, inclusive. If the Stream ID is zero, the window update applies to the connection as a whole.

type GoAwayFrame

type GoAwayFrame struct {
	FrameHeader
	LastStreamID uint32
	ErrCode      ErrCode
	// contains filtered or unexported fields
}

A GoAwayFrame informs the remote peer to stop creating streams on this connection. See http://http2.github.io/http2-spec/#rfc.section.6.8

func (*GoAwayFrame) DebugData

func (f *GoAwayFrame) DebugData() []byte

DebugData returns any debug data in the GOAWAY frame. Its contents are not defined. The caller must not retain the returned memory past the next call to ReadFrame.

type HeadersFrame

type HeadersFrame struct {
	FrameHeader

	// Priority is set if FlagHeadersPriority is set in the FrameHeader.
	Priority PriorityParam
	// contains filtered or unexported fields
}

A HeadersFrame is used to open a stream and additionally carries a header block fragment.

func (*HeadersFrame) HasPriority

func (f *HeadersFrame) HasPriority() bool

func (*HeadersFrame) HeaderBlockFragment

func (f *HeadersFrame) HeaderBlockFragment() []byte

func (*HeadersFrame) HeadersEnded

func (f *HeadersFrame) HeadersEnded() bool

func (*HeadersFrame) StreamEnded

func (f *HeadersFrame) StreamEnded() bool

type HeadersFrameParam

type HeadersFrameParam struct {
	// StreamID is the required Stream ID to initiate.
	StreamID uint32
	// BlockFragment is part (or all) of a Header Block.
	BlockFragment []byte

	// EndStream indicates that the header block is the last that
	// the endpoint will send for the identified stream. Setting
	// this flag causes the stream to enter one of "half closed"
	// states.
	EndStream bool

	// EndHeaders indicates that this frame contains an entire
	// header block and is not followed by any
	// CONTINUATION frames.
	EndHeaders bool

	// PadLength is the optional number of bytes of zeros to add
	// to this frame.
	PadLength uint8

	// Priority, if non-zero, includes stream priority information
	// in the HEADER frame.
	Priority PriorityParam
}

HeadersFrameParam are the parameters for writing a HEADERS frame.

type PingFrame

type PingFrame struct {
	FrameHeader
	Data [8]byte
}

A PingFrame is a mechanism for measuring a minimal round trip time from the sender, as well as determining whether an idle connection is still functional. See http://http2.github.io/http2-spec/#rfc.section.6.7

func (*PingFrame) IsAck

func (f *PingFrame) IsAck() bool

type PriorityFrame

type PriorityFrame struct {
	FrameHeader
	PriorityParam
}

A PriorityFrame specifies the sender-advised priority of a stream. See http://http2.github.io/http2-spec/#rfc.section.6.3

type PriorityParam

type PriorityParam struct {
	// StreamDep is a 31-bit stream identifier for the
	// stream that this stream depends on. Zero means no
	// dependency.
	StreamDep uint32

	// Exclusive is whether the dependency is exclusive.
	Exclusive bool

	// Weight is the stream's zero-indexed weight. It should be
	// set together with StreamDep, or neither should be set.  Per
	// the spec, "Add one to the value to obtain a weight between
	// 1 and 256."
	Weight uint8
}

PriorityParam are the stream prioritzation parameters.

func (PriorityParam) IsZero

func (p PriorityParam) IsZero() bool

type PushPromiseFrame

type PushPromiseFrame struct {
	FrameHeader
	PromiseID uint32
	// contains filtered or unexported fields
}

A PushPromiseFrame is used to initiate a server stream. See http://http2.github.io/http2-spec/#rfc.section.6.6

func (*PushPromiseFrame) HeaderBlockFragment

func (f *PushPromiseFrame) HeaderBlockFragment() []byte

func (*PushPromiseFrame) HeadersEnded

func (f *PushPromiseFrame) HeadersEnded() bool

type PushPromiseParam

type PushPromiseParam struct {
	// StreamID is the required Stream ID to initiate.
	StreamID uint32

	// PromiseID is the required Stream ID which this
	// Push Promises
	PromiseID uint32

	// BlockFragment is part (or all) of a Header Block.
	BlockFragment []byte

	// EndHeaders indicates that this frame contains an entire
	// header block and is not followed by any
	// CONTINUATION frames.
	EndHeaders bool

	// PadLength is the optional number of bytes of zeros to add
	// to this frame.
	PadLength uint8
}

PushPromiseParam are the parameters for writing a PUSH_PROMISE frame.

type RSTStreamFrame

type RSTStreamFrame struct {
	FrameHeader
	ErrCode ErrCode
}

A RSTStreamFrame allows for abnormal termination of a stream. See http://http2.github.io/http2-spec/#rfc.section.6.4

type RoundTripOpt

type RoundTripOpt struct {
	// OnlyCachedConn controls whether RoundTripOpt may
	// create a new TCP connection. If set true and
	// no cached connection is available, RoundTripOpt
	// will return ErrNoCachedConn.
	OnlyCachedConn bool
}

RoundTripOpt are options for the Transport.RoundTripOpt method.

type Server

type Server struct {
	// MaxHandlers limits the number of http.Handler ServeHTTP goroutines
	// which may run at a time over all connections.
	// Negative or zero no limit.
	// TODO: implement
	MaxHandlers int

	// MaxConcurrentStreams optionally specifies the number of
	// concurrent streams that each client may have open at a
	// time. This is unrelated to the number of http.Handler goroutines
	// which may be active globally, which is MaxHandlers.
	// If zero, MaxConcurrentStreams defaults to at least 100, per
	// the HTTP/2 spec's recommendations.
	MaxConcurrentStreams uint32

	// MaxReadFrameSize optionally specifies the largest frame
	// this server is willing to read. A valid value is between
	// 16k and 16M, inclusive. If zero or otherwise invalid, a
	// default value is used.
	MaxReadFrameSize uint32

	// PermitProhibitedCipherSuites, if true, permits the use of
	// cipher suites prohibited by the HTTP/2 spec.
	PermitProhibitedCipherSuites bool
}

Server is an HTTP/2 server.

type Setting

type Setting struct {
	// ID is which setting is being set.
	// See http://http2.github.io/http2-spec/#SettingValues
	ID SettingID

	// Val is the value.
	Val uint32
}

Setting is a setting parameter: which setting it is, and its value.

func (Setting) String

func (s Setting) String() string

func (Setting) Valid

func (s Setting) Valid() error

Valid reports whether the setting is valid.

type SettingID

type SettingID uint16

A SettingID is an HTTP/2 setting as defined in http://http2.github.io/http2-spec/#iana-settings

const (
	SettingHeaderTableSize      SettingID = 0x1
	SettingEnablePush           SettingID = 0x2
	SettingMaxConcurrentStreams SettingID = 0x3
	SettingInitialWindowSize    SettingID = 0x4
	SettingMaxFrameSize         SettingID = 0x5
	SettingMaxHeaderListSize    SettingID = 0x6
)

func (SettingID) String

func (s SettingID) String() string

type SettingsFrame

type SettingsFrame struct {
	FrameHeader
	// contains filtered or unexported fields
}

A SettingsFrame conveys configuration parameters that affect how endpoints communicate, such as preferences and constraints on peer behavior.

See http://http2.github.io/http2-spec/#SETTINGS

func (*SettingsFrame) ForeachSetting

func (f *SettingsFrame) ForeachSetting(fn func(Setting) error) error

ForeachSetting runs fn for each setting. It stops and returns the first error.

func (*SettingsFrame) IsAck

func (f *SettingsFrame) IsAck() bool

func (*SettingsFrame) Value

func (f *SettingsFrame) Value(s SettingID) (v uint32, ok bool)

type StreamError

type StreamError struct {
	StreamID uint32
	Code     ErrCode
}

StreamError is an error that only affects one stream within an HTTP/2 connection.

func (StreamError) Error

func (e StreamError) Error() string

type Transport

type Transport struct {
	// DialTLS specifies an optional dial function for creating
	// TLS connections for requests.
	//
	// If DialTLS is nil, tls.Dial is used.
	//
	// If the returned net.Conn has a ConnectionState method like tls.Conn,
	// it will be used to set http.Response.TLS.
	DialTLS func(network, addr string, cfg *tls.Config) (net.Conn, error)

	// TLSClientConfig specifies the TLS configuration to use with
	// tls.Client. If nil, the default configuration is used.
	TLSClientConfig *tls.Config

	// ConnPool optionally specifies an alternate connection pool to use.
	// If nil, the default is used.
	ConnPool ClientConnPool

	// DisableCompression, if true, prevents the Transport from
	// requesting compression with an "Accept-Encoding: gzip"
	// request header when the Request contains no existing
	// Accept-Encoding value. If the Transport requests gzip on
	// its own and gets a gzipped response, it's transparently
	// decoded in the Response.Body. However, if the user
	// explicitly requested gzip it is not automatically
	// uncompressed.
	DisableCompression bool

	// MaxHeaderListSize is the http2 SETTINGS_MAX_HEADER_LIST_SIZE to
	// send in the initial settings frame. It is how many bytes
	// of response headers are allow. Unlike the http2 spec, zero here
	// means to use a default limit (currently 10MB). If you actually
	// want to advertise an ulimited value to the peer, Transport
	// interprets the highest possible value here (0xffffffff or 1<<32-1)
	// to mean no limit.
	MaxHeaderListSize uint32
	// contains filtered or unexported fields
}

Transport is an HTTP/2 Transport.

A Transport internally caches connections to servers. It is safe for concurrent use by multiple goroutines.

func (*Transport) CloseIdleConnections

func (t *Transport) CloseIdleConnections()

CloseIdleConnections closes any connections which were previously connected from previous requests but are now sitting idle. It does not interrupt any connections currently in use.

func (*Transport) NewClientConn

func (t *Transport) NewClientConn(c net.Conn) (*ClientConn, error)

func (*Transport) RoundTrip

func (t *Transport) RoundTrip(req *http.Request) (*http.Response, error)

func (*Transport) RoundTripOpt

func (t *Transport) RoundTripOpt(req *http.Request, opt RoundTripOpt) (*http.Response, error)

RoundTripOpt is like RoundTrip, but takes options.

type UnknownFrame

type UnknownFrame struct {
	FrameHeader
	// contains filtered or unexported fields
}

An UnknownFrame is the frame type returned when the frame type is unknown or no specific frame type parser exists.

func (*UnknownFrame) Payload

func (f *UnknownFrame) Payload() []byte

Payload returns the frame's payload (after the header). It is not valid to call this method after a subsequent call to Framer.ReadFrame, nor is it valid to retain the returned slice. The memory is owned by the Framer and is invalidated when the next frame is read.

type WindowUpdateFrame

type WindowUpdateFrame struct {
	FrameHeader
	Increment uint32 // never read with high bit set
}

A WindowUpdateFrame is used to implement flow control. See http://http2.github.io/http2-spec/#rfc.section.6.9

Directories

Path Synopsis
The h2i command is an interactive HTTP/2 console.
The h2i command is an interactive HTTP/2 console.
Package hpack implements HPACK, a compression format for efficiently representing HTTP header fields in the context of HTTP/2.
Package hpack implements HPACK, a compression format for efficiently representing HTTP header fields in the context of HTTP/2.

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