func (p *PushStream) Finish() {
p.writeHeader()
end := new(frames.DATA)
end.StreamID = p.streamID
end.Data = []byte{}
end.Flags = common.FLAG_FIN
p.output <- end
p.Close()
}
// Write is used to send data to the connection. This
// takes care of the windowing. Although data may be
// buffered, rather than actually sent, this is not
// visible to the caller.
func (f *flowControl) Write(data []byte) (int, error) {
l := len(data)
if l == 0 {
return 0, nil
}
if f.buffer == nil || f.stream == nil {
return 0, errors.New("Error: Stream closed.")
}
// Transfer window processing.
f.CheckInitialWindow()
if f.constrained {
f.Flush()
}
f.Lock()
var window uint32
if f.transferWindow < 0 {
window = 0
} else {
window = uint32(f.transferWindow)
}
constrained := false
sending := uint32(len(data))
if sending > window {
sending = window
constrained = true
}
f.sent += sending
f.transferWindow -= int64(sending)
if constrained {
f.buffer = append(f.buffer, data[window:])
data = data[:window]
f.constrained = true
debug.Printf("Stream %d is now constrained.\n", f.streamID)
}
f.Unlock()
if len(data) == 0 {
return l, nil
}
dataFrame := new(frames.DATA)
dataFrame.StreamID = f.streamID
dataFrame.Data = data
f.output <- dataFrame
return l, nil
}
// Flush is used to send buffered data to
// the connection, if the transfer window
// will allow. Flush does not guarantee
// that any or all buffered data will be
// sent with a single flush.
func (f *flowControl) Flush() {
f.CheckInitialWindow()
if !f.constrained || f.transferWindow == 0 {
return
}
out := make([]byte, 0, f.transferWindow)
left := f.transferWindow
for i := 0; i < len(f.buffer); i++ {
if l := int64(len(f.buffer[i])); l <= left {
out = append(out, f.buffer[i]...)
left -= l
f.buffer = f.buffer[1:]
} else {
out = append(out, f.buffer[i][:left]...)
f.buffer[i] = f.buffer[i][left:]
left = 0
}
if left == 0 {
break
}
}
f.transferWindow -= int64(len(out))
if f.transferWindow > 0 {
f.constrained = false
debug.Printf("Stream %d is no longer constrained.\n", f.streamID)
}
dataFrame := new(frames.DATA)
dataFrame.StreamID = f.streamID
dataFrame.Data = out
f.output <- dataFrame
}
// run is the main control path of
// the stream. It is prepared, the
// registered handler is called,
// and then the stream is cleaned
// up and closed.
func (s *ResponseStream) Run() error {
// Catch any panics.
defer func() {
if v := recover(); v != nil {
if s != nil && s.state != nil && !s.state.Closed() {
log.Printf("Encountered stream error: %v (%[1]T)\n", v)
}
}
}()
// Make sure Request is prepared.
if s.requestBody == nil || s.request.Body == nil {
s.requestBody = new(bytes.Buffer)
s.request.Body = &common.ReadCloser{s.requestBody}
}
// Wait until the full request has been received.
<-s.ready
/***************
*** HANDLER ***
***************/
s.handler.ServeHTTP(s, s.request)
// Make sure any queued data has been sent.
if err := s.flow.Wait(); err != nil {
log.Println(err)
}
// Close the stream with a SYN_REPLY if
// none has been sent, or an empty DATA
// frame, if a SYN_REPLY has been sent
// already.
// If the stream is already closed at
// this end, then nothing happens.
if !s.unidirectional {
if s.state.OpenHere() && !s.wroteHeader {
s.header.Set(":status", "200")
s.header.Set(":version", "HTTP/1.1")
// Create the response SYN_REPLY.
synReply := new(frames.SYN_REPLY)
synReply.Flags = common.FLAG_FIN
synReply.StreamID = s.streamID
synReply.Header = make(http.Header)
for name, values := range s.header {
for _, value := range values {
synReply.Header.Add(name, value)
}
s.header.Del(name)
}
s.output <- synReply
} else if s.state.OpenHere() {
// Create the DATA.
data := new(frames.DATA)
data.StreamID = s.streamID
data.Flags = common.FLAG_FIN
data.Data = []byte{}
s.output <- data
}
}
// Clean up state.
s.state.CloseHere()
if s.state.Closed() {
return s.Close()
}
return nil
}
// send is run in a separate goroutine. It's used
// to ensure clear interleaving of frames and to
// provide assurances of priority and structure.
func (c *Conn) send() {
// Catch any panics.
defer func() {
if v := recover(); v != nil {
if !c.Closed() {
log.Printf("Encountered send error: %v (%[1]T)\n", v)
}
}
}()
for i := 1; ; i++ {
if i >= 5 {
i = 0 // Once per 5 frames, pick randomly.
}
var frame common.Frame
if i == 0 { // Ignore priority.
frame = c.selectFrameToSend(false)
} else { // Normal selection.
frame = c.selectFrameToSend(true)
}
if frame == nil {
c.Close()
return
}
// Process connection-level flow control.
if c.Subversion > 0 {
c.connectionWindowLock.Lock()
if frame, ok := frame.(*frames.DATA); ok {
size := int64(len(frame.Data))
constrained := false
sending := size
if sending > c.connectionWindowSize {
sending = c.connectionWindowSize
constrained = true
}
if sending < 0 {
sending = 0
}
c.connectionWindowSize -= sending
if constrained {
// Chop off what we can send now.
partial := new(frames.DATA)
partial.Flags = frame.Flags
partial.StreamID = frame.StreamID
partial.Data = make([]byte, int(sending))
copy(partial.Data, frame.Data[:sending])
frame.Data = frame.Data[sending:]
// Buffer this frame and try again.
if c.dataBuffer == nil {
c.dataBuffer = []*frames.DATA{frame}
} else {
buffer := make([]*frames.DATA, 1, len(c.dataBuffer)+1)
buffer[0] = frame
buffer = append(buffer, c.dataBuffer...)
c.dataBuffer = buffer
}
frame = partial
}
}
c.connectionWindowLock.Unlock()
}
// Compress any name/value header blocks.
err := frame.Compress(c.compressor)
if err != nil {
log.Printf("Error in compression: %v (type %T).\n", err, frame)
c.Close()
return
}
debug.Printf("Sending %s:\n", frame.Name())
debug.Println(frame)
// Leave the specifics of writing to the
// connection up to the frame.
c.refreshWriteTimeout()
if _, err = frame.WriteTo(c.conn); err != nil {
c.handleReadWriteError(err)
return
}
}
}
// Request is used to make a client request.
func (c *Conn) Request(request *http.Request, receiver common.Receiver, priority common.Priority) (common.Stream, error) {
if c.Closed() {
return nil, common.ErrConnClosed
}
c.goawayLock.Lock()
goaway := c.goawayReceived || c.goawaySent
c.goawayLock.Unlock()
if goaway {
return nil, common.ErrGoaway
}
if c.server != nil {
return nil, errors.New("Error: Only clients can send requests.")
}
// Check stream limit would allow the new stream.
if !c.requestStreamLimit.Add() {
return nil, errors.New("Error: Max concurrent streams limit exceeded.")
}
if !priority.Valid(3) {
return nil, errors.New("Error: Priority must be in the range 0 - 7.")
}
url := request.URL
if url == nil || url.Scheme == "" || url.Host == "" {
return nil, errors.New("Error: Incomplete path provided to resource.")
}
// Prepare the SYN_STREAM.
path := url.Path
if url.RawQuery != "" {
path += "?" + url.RawQuery
}
if url.Fragment != "" {
path += "#" + url.Fragment
}
if !strings.HasPrefix(path, "/") {
path = "/" + path
}
host := url.Host
if len(request.Host) > 0 {
host = request.Host
}
syn := new(frames.SYN_STREAM)
syn.Priority = priority
syn.Header = request.Header
syn.Header.Set(":method", request.Method)
syn.Header.Set(":path", path)
syn.Header.Set(":version", "HTTP/1.1")
syn.Header.Set(":host", host)
syn.Header.Set(":scheme", url.Scheme)
// Prepare the request body, if any.
body := make([]*frames.DATA, 0, 1)
if request.Body != nil {
buf := make([]byte, 32*1024)
n, err := request.Body.Read(buf)
if err != nil && err != io.EOF {
return nil, err
}
total := n
for n > 0 {
data := new(frames.DATA)
data.Data = make([]byte, n)
copy(data.Data, buf[:n])
body = append(body, data)
n, err = request.Body.Read(buf)
if err != nil && err != io.EOF {
return nil, err
}
total += n
}
// Half-close the stream.
if len(body) == 0 {
syn.Flags = common.FLAG_FIN
} else {
syn.Header.Set("Content-Length", fmt.Sprint(total))
body[len(body)-1].Flags = common.FLAG_FIN
}
request.Body.Close()
} else {
syn.Flags = common.FLAG_FIN
}
// Send.
c.streamCreation.Lock()
defer c.streamCreation.Unlock()
c.lastRequestStreamIDLock.Lock()
if c.lastRequestStreamID == 0 {
c.lastRequestStreamID = 1
} else {
c.lastRequestStreamID += 2
}
syn.StreamID = c.lastRequestStreamID
c.lastRequestStreamIDLock.Unlock()
if syn.StreamID > common.MAX_STREAM_ID {
return nil, errors.New("Error: All client streams exhausted.")
}
c.output[0] <- syn
for _, frame := range body {
frame.StreamID = syn.StreamID
c.output[0] <- frame
}
// Create the request stream.
out := NewRequestStream(c, syn.StreamID, c.output[0])
out.Request = request
out.Receiver = receiver
out.AddFlowControl(c.flowControl)
c.streamsLock.Lock()
c.streams[syn.StreamID] = out // Store in the connection map.
c.streamsLock.Unlock()
return out, nil
}
