fastcgi: Optimize FastCGI transport (#4978)

* break up code and use lazy reading and pool bufio.Writer

* close underlying connection when operation failed

* allocate bufWriter and streamWriter only once

* refactor record writing

* rebase from master

* handle err

* Fix type assertion

Also reduce some duplication

* Refactor client and clientCloser for logging

Should reduce allocations

* Minor cosmetic adjustments; apply Apache license

* Appease the linter

Co-authored-by: Matthew Holt <mholt@users.noreply.github.com>
This commit is contained in:
WeidiDeng 2022-09-03 06:57:55 +08:00 committed by GitHub
parent 005c5a6382
commit 83b26975bd
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
8 changed files with 400 additions and 315 deletions

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@ -26,9 +26,6 @@ package fastcgi
import (
"bufio"
"bytes"
"context"
"encoding/binary"
"errors"
"io"
"mime/multipart"
"net"
@ -40,7 +37,6 @@ import (
"path/filepath"
"strconv"
"strings"
"sync"
"time"
"go.uber.org/zap"
@ -122,285 +118,60 @@ const (
maxPad = 255
)
type header struct {
Version uint8
Type uint8
ID uint16
ContentLength uint16
PaddingLength uint8
Reserved uint8
}
// for padding so we don't have to allocate all the time
// not synchronized because we don't care what the contents are
var pad [maxPad]byte
func (h *header) init(recType uint8, reqID uint16, contentLength int) {
h.Version = 1
h.Type = recType
h.ID = reqID
h.ContentLength = uint16(contentLength)
h.PaddingLength = uint8(-contentLength & 7)
}
type record struct {
h header
rbuf []byte
}
func (rec *record) read(r io.Reader) (buf []byte, err error) {
if err = binary.Read(r, binary.BigEndian, &rec.h); err != nil {
return
}
if rec.h.Version != 1 {
err = errors.New("fcgi: invalid header version")
return
}
if rec.h.Type == EndRequest {
err = io.EOF
return
}
n := int(rec.h.ContentLength) + int(rec.h.PaddingLength)
if len(rec.rbuf) < n {
rec.rbuf = make([]byte, n)
}
if _, err = io.ReadFull(r, rec.rbuf[:n]); err != nil {
return
}
buf = rec.rbuf[:int(rec.h.ContentLength)]
return
}
// FCGIClient implements a FastCGI client, which is a standard for
// client implements a FastCGI client, which is a standard for
// interfacing external applications with Web servers.
type FCGIClient struct {
mutex sync.Mutex
rwc io.ReadWriteCloser
h header
buf bytes.Buffer
stderr bytes.Buffer
keepAlive bool
reqID uint16
logger *zap.Logger
}
// DialWithDialerContext connects to the fcgi responder at the specified network address, using custom net.Dialer
// and a context.
// See func net.Dial for a description of the network and address parameters.
func DialWithDialerContext(ctx context.Context, network, address string, dialer net.Dialer) (fcgi *FCGIClient, err error) {
var conn net.Conn
conn, err = dialer.DialContext(ctx, network, address)
if err != nil {
return
}
fcgi = &FCGIClient{
rwc: conn,
keepAlive: false,
reqID: 1,
}
return
}
// DialContext is like Dial but passes ctx to dialer.Dial.
func DialContext(ctx context.Context, network, address string) (fcgi *FCGIClient, err error) {
// TODO: why not set timeout here?
return DialWithDialerContext(ctx, network, address, net.Dialer{})
}
// Dial connects to the fcgi responder at the specified network address, using default net.Dialer.
// See func net.Dial for a description of the network and address parameters.
func Dial(network, address string) (fcgi *FCGIClient, err error) {
return DialContext(context.Background(), network, address)
}
// Close closes fcgi connection
func (c *FCGIClient) Close() {
c.rwc.Close()
}
func (c *FCGIClient) writeRecord(recType uint8, content []byte) (err error) {
c.mutex.Lock()
defer c.mutex.Unlock()
c.buf.Reset()
c.h.init(recType, c.reqID, len(content))
if err := binary.Write(&c.buf, binary.BigEndian, c.h); err != nil {
return err
}
if _, err := c.buf.Write(content); err != nil {
return err
}
if _, err := c.buf.Write(pad[:c.h.PaddingLength]); err != nil {
return err
}
_, err = c.rwc.Write(c.buf.Bytes())
return err
}
func (c *FCGIClient) writeBeginRequest(role uint16, flags uint8) error {
b := [8]byte{byte(role >> 8), byte(role), flags}
return c.writeRecord(BeginRequest, b[:])
}
func (c *FCGIClient) writePairs(recType uint8, pairs map[string]string) error {
w := newWriter(c, recType)
b := make([]byte, 8)
nn := 0
for k, v := range pairs {
m := 8 + len(k) + len(v)
if m > maxWrite {
// param data size exceed 65535 bytes"
vl := maxWrite - 8 - len(k)
v = v[:vl]
}
n := encodeSize(b, uint32(len(k)))
n += encodeSize(b[n:], uint32(len(v)))
m = n + len(k) + len(v)
if (nn + m) > maxWrite {
w.Flush()
nn = 0
}
nn += m
if _, err := w.Write(b[:n]); err != nil {
return err
}
if _, err := w.WriteString(k); err != nil {
return err
}
if _, err := w.WriteString(v); err != nil {
return err
}
}
w.Close()
return nil
}
func encodeSize(b []byte, size uint32) int {
if size > 127 {
size |= 1 << 31
binary.BigEndian.PutUint32(b, size)
return 4
}
b[0] = byte(size)
return 1
}
// bufWriter encapsulates bufio.Writer but also closes the underlying stream when
// Closed.
type bufWriter struct {
closer io.Closer
*bufio.Writer
}
func (w *bufWriter) Close() error {
if err := w.Writer.Flush(); err != nil {
w.closer.Close()
return err
}
return w.closer.Close()
}
func newWriter(c *FCGIClient, recType uint8) *bufWriter {
s := &streamWriter{c: c, recType: recType}
w := bufio.NewWriterSize(s, maxWrite)
return &bufWriter{s, w}
}
// streamWriter abstracts out the separation of a stream into discrete records.
// It only writes maxWrite bytes at a time.
type streamWriter struct {
c *FCGIClient
recType uint8
}
func (w *streamWriter) Write(p []byte) (int, error) {
nn := 0
for len(p) > 0 {
n := len(p)
if n > maxWrite {
n = maxWrite
}
if err := w.c.writeRecord(w.recType, p[:n]); err != nil {
return nn, err
}
nn += n
p = p[n:]
}
return nn, nil
}
func (w *streamWriter) Close() error {
// send empty record to close the stream
return w.c.writeRecord(w.recType, nil)
}
type streamReader struct {
c *FCGIClient
buf []byte
}
func (w *streamReader) Read(p []byte) (n int, err error) {
if len(p) > 0 {
if len(w.buf) == 0 {
// filter outputs for error log
for {
rec := &record{}
var buf []byte
buf, err = rec.read(w.c.rwc)
if err != nil {
return
}
// standard error output
if rec.h.Type == Stderr {
w.c.stderr.Write(buf)
continue
}
w.buf = buf
break
}
}
n = len(p)
if n > len(w.buf) {
n = len(w.buf)
}
copy(p, w.buf[:n])
w.buf = w.buf[n:]
}
return
type client struct {
rwc net.Conn
// keepAlive bool // TODO: implement
reqID uint16
stderr bool
logger *zap.Logger
}
// Do made the request and returns a io.Reader that translates the data read
// from fcgi responder out of fcgi packet before returning it.
func (c *FCGIClient) Do(p map[string]string, req io.Reader) (r io.Reader, err error) {
err = c.writeBeginRequest(uint16(Responder), 0)
func (c *client) Do(p map[string]string, req io.Reader) (r io.Reader, err error) {
writer := &streamWriter{c: c}
writer.buf = bufPool.Get().(*bytes.Buffer)
writer.buf.Reset()
defer bufPool.Put(writer.buf)
err = writer.writeBeginRequest(uint16(Responder), 0)
if err != nil {
return
}
err = c.writePairs(Params, p)
writer.recType = Params
err = writer.writePairs(p)
if err != nil {
return
}
body := newWriter(c, Stdin)
writer.recType = Stdin
if req != nil {
_, _ = io.Copy(body, req)
_, err = io.Copy(writer, req)
if err != nil {
return nil, err
}
}
err = writer.FlushStream()
if err != nil {
return nil, err
}
body.Close()
r = &streamReader{c: c}
return
}
// clientCloser is a io.ReadCloser. It wraps a io.Reader with a Closer
// that closes FCGIClient connection.
// that closes the client connection.
type clientCloser struct {
*FCGIClient
rwc net.Conn
r *streamReader
io.Reader
status int
@ -408,9 +179,9 @@ type clientCloser struct {
}
func (f clientCloser) Close() error {
stderr := f.FCGIClient.stderr.Bytes()
stderr := f.r.stderr.Bytes()
if len(stderr) == 0 {
return f.FCGIClient.rwc.Close()
return f.rwc.Close()
}
if f.status >= 400 {
@ -418,12 +189,13 @@ func (f clientCloser) Close() error {
} else {
f.logger.Warn("stderr", zap.ByteString("body", stderr))
}
return f.FCGIClient.rwc.Close()
return f.rwc.Close()
}
// Request returns a HTTP Response with Header and Body
// from fcgi responder
func (c *FCGIClient) Request(p map[string]string, req io.Reader) (resp *http.Response, err error) {
func (c *client) Request(p map[string]string, req io.Reader) (resp *http.Response, err error) {
r, err := c.Do(p, req)
if err != nil {
return
@ -458,26 +230,27 @@ func (c *FCGIClient) Request(p map[string]string, req io.Reader) (resp *http.Res
resp.TransferEncoding = resp.Header["Transfer-Encoding"]
resp.ContentLength, _ = strconv.ParseInt(resp.Header.Get("Content-Length"), 10, 64)
if chunked(resp.TransferEncoding) {
resp.Body = clientCloser{
FCGIClient: c,
Reader: httputil.NewChunkedReader(rb),
status: resp.StatusCode,
logger: c.logger,
}
} else {
resp.Body = clientCloser{
FCGIClient: c,
Reader: rb,
status: resp.StatusCode,
logger: c.logger,
}
// wrap the response body in our closer
closer := clientCloser{
rwc: c.rwc,
r: r.(*streamReader),
Reader: rb,
status: resp.StatusCode,
logger: noopLogger,
}
if chunked(resp.TransferEncoding) {
closer.Reader = httputil.NewChunkedReader(rb)
}
if c.stderr {
closer.logger = c.logger
}
resp.Body = closer
return
}
// Get issues a GET request to the fcgi responder.
func (c *FCGIClient) Get(p map[string]string, body io.Reader, l int64) (resp *http.Response, err error) {
func (c *client) Get(p map[string]string, body io.Reader, l int64) (resp *http.Response, err error) {
p["REQUEST_METHOD"] = "GET"
p["CONTENT_LENGTH"] = strconv.FormatInt(l, 10)
@ -486,7 +259,7 @@ func (c *FCGIClient) Get(p map[string]string, body io.Reader, l int64) (resp *ht
}
// Head issues a HEAD request to the fcgi responder.
func (c *FCGIClient) Head(p map[string]string) (resp *http.Response, err error) {
func (c *client) Head(p map[string]string) (resp *http.Response, err error) {
p["REQUEST_METHOD"] = "HEAD"
p["CONTENT_LENGTH"] = "0"
@ -495,7 +268,7 @@ func (c *FCGIClient) Head(p map[string]string) (resp *http.Response, err error)
}
// Options issues an OPTIONS request to the fcgi responder.
func (c *FCGIClient) Options(p map[string]string) (resp *http.Response, err error) {
func (c *client) Options(p map[string]string) (resp *http.Response, err error) {
p["REQUEST_METHOD"] = "OPTIONS"
p["CONTENT_LENGTH"] = "0"
@ -505,7 +278,7 @@ func (c *FCGIClient) Options(p map[string]string) (resp *http.Response, err erro
// Post issues a POST request to the fcgi responder. with request body
// in the format that bodyType specified
func (c *FCGIClient) Post(p map[string]string, method string, bodyType string, body io.Reader, l int64) (resp *http.Response, err error) {
func (c *client) Post(p map[string]string, method string, bodyType string, body io.Reader, l int64) (resp *http.Response, err error) {
if p == nil {
p = make(map[string]string)
}
@ -528,7 +301,7 @@ func (c *FCGIClient) Post(p map[string]string, method string, bodyType string, b
// PostForm issues a POST to the fcgi responder, with form
// as a string key to a list values (url.Values)
func (c *FCGIClient) PostForm(p map[string]string, data url.Values) (resp *http.Response, err error) {
func (c *client) PostForm(p map[string]string, data url.Values) (resp *http.Response, err error) {
body := bytes.NewReader([]byte(data.Encode()))
return c.Post(p, "POST", "application/x-www-form-urlencoded", body, int64(body.Len()))
}
@ -536,7 +309,7 @@ func (c *FCGIClient) PostForm(p map[string]string, data url.Values) (resp *http.
// PostFile issues a POST to the fcgi responder in multipart(RFC 2046) standard,
// with form as a string key to a list values (url.Values),
// and/or with file as a string key to a list file path.
func (c *FCGIClient) PostFile(p map[string]string, data url.Values, file map[string]string) (resp *http.Response, err error) {
func (c *client) PostFile(p map[string]string, data url.Values, file map[string]string) (resp *http.Response, err error) {
buf := &bytes.Buffer{}
writer := multipart.NewWriter(buf)
bodyType := writer.FormDataContentType()
@ -577,18 +350,18 @@ func (c *FCGIClient) PostFile(p map[string]string, data url.Values, file map[str
// SetReadTimeout sets the read timeout for future calls that read from the
// fcgi responder. A zero value for t means no timeout will be set.
func (c *FCGIClient) SetReadTimeout(t time.Duration) error {
if conn, ok := c.rwc.(net.Conn); ok && t != 0 {
return conn.SetReadDeadline(time.Now().Add(t))
func (c *client) SetReadTimeout(t time.Duration) error {
if t != 0 {
return c.rwc.SetReadDeadline(time.Now().Add(t))
}
return nil
}
// SetWriteTimeout sets the write timeout for future calls that send data to
// the fcgi responder. A zero value for t means no timeout will be set.
func (c *FCGIClient) SetWriteTimeout(t time.Duration) error {
if conn, ok := c.rwc.(net.Conn); ok && t != 0 {
return conn.SetWriteDeadline(time.Now().Add(t))
func (c *client) SetWriteTimeout(t time.Duration) error {
if t != 0 {
return c.rwc.SetWriteDeadline(time.Now().Add(t))
}
return nil
}

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@ -118,12 +118,14 @@ func (s FastCGIServer) ServeHTTP(resp http.ResponseWriter, req *http.Request) {
}
func sendFcgi(reqType int, fcgiParams map[string]string, data []byte, posts map[string]string, files map[string]string) (content []byte) {
fcgi, err := Dial("tcp", ipPort)
conn, err := net.Dial("tcp", ipPort)
if err != nil {
log.Println("err:", err)
return
}
fcgi := client{rwc: conn, reqID: 1}
length := 0
var resp *http.Response
@ -168,7 +170,7 @@ func sendFcgi(reqType int, fcgiParams map[string]string, data []byte, posts map[
content, _ = io.ReadAll(resp.Body)
log.Println("c: send data length ≈", length, string(content))
fcgi.Close()
conn.Close()
time.Sleep(1 * time.Second)
if bytes.Contains(content, []byte("FAILED")) {

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@ -15,7 +15,6 @@
package fastcgi
import (
"context"
"crypto/tls"
"fmt"
"net"
@ -129,13 +128,7 @@ func (t Transport) RoundTrip(r *http.Request) (*http.Response, error) {
return nil, fmt.Errorf("building environment: %v", err)
}
// TODO: doesn't dialer have a Timeout field?
ctx := r.Context()
if t.DialTimeout > 0 {
var cancel context.CancelFunc
ctx, cancel = context.WithTimeout(ctx, time.Duration(t.DialTimeout))
defer cancel()
}
// extract dial information from request (should have been embedded by the reverse proxy)
network, address := "tcp", r.URL.Host
@ -150,32 +143,41 @@ func (t Transport) RoundTrip(r *http.Request) (*http.Response, error) {
ShouldLogCredentials: logCreds,
}
loggableEnv := loggableEnv{vars: env, logCredentials: logCreds}
t.logger.Debug("roundtrip",
logger := t.logger.With(
zap.Object("request", loggableReq),
zap.String("dial", address),
zap.Object("env", loggableEnv),
)
logger.Debug("roundtrip",
zap.String("dial", address),
zap.Object("env", loggableEnv),
zap.Object("request", loggableReq))
fcgiBackend, err := DialContext(ctx, network, address)
// connect to the backend
dialer := net.Dialer{Timeout: time.Duration(t.DialTimeout)}
conn, err := dialer.DialContext(ctx, network, address)
if err != nil {
// TODO: wrap in a special error type if the dial failed, so retries can happen if enabled
return nil, fmt.Errorf("dialing backend: %v", err)
}
if t.CaptureStderr {
fcgiBackend.logger = t.logger.With(
zap.Object("request", loggableReq),
zap.Object("env", loggableEnv),
)
} else {
fcgiBackend.logger = noopLogger
defer func() {
// conn will be closed with the response body unless there's an error
if err != nil {
conn.Close()
}
}()
// create the client that will facilitate the protocol
client := client{
rwc: conn,
reqID: 1,
logger: logger,
}
// fcgiBackend gets closed when response body is closed (see clientCloser)
// read/write timeouts
if err := fcgiBackend.SetReadTimeout(time.Duration(t.ReadTimeout)); err != nil {
if err = client.SetReadTimeout(time.Duration(t.ReadTimeout)); err != nil {
return nil, fmt.Errorf("setting read timeout: %v", err)
}
if err := fcgiBackend.SetWriteTimeout(time.Duration(t.WriteTimeout)); err != nil {
if err = client.SetWriteTimeout(time.Duration(t.WriteTimeout)); err != nil {
return nil, fmt.Errorf("setting write timeout: %v", err)
}
@ -187,16 +189,19 @@ func (t Transport) RoundTrip(r *http.Request) (*http.Response, error) {
var resp *http.Response
switch r.Method {
case http.MethodHead:
resp, err = fcgiBackend.Head(env)
resp, err = client.Head(env)
case http.MethodGet:
resp, err = fcgiBackend.Get(env, r.Body, contentLength)
resp, err = client.Get(env, r.Body, contentLength)
case http.MethodOptions:
resp, err = fcgiBackend.Options(env)
resp, err = client.Options(env)
default:
resp, err = fcgiBackend.Post(env, r.Method, r.Header.Get("Content-Type"), r.Body, contentLength)
resp, err = client.Post(env, r.Method, r.Header.Get("Content-Type"), r.Body, contentLength)
}
if err != nil {
return nil, err
}
return resp, err
return resp, nil
}
// buildEnv returns a set of CGI environment variables for the request.

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@ -0,0 +1,32 @@
// Copyright 2015 Matthew Holt and The Caddy Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package fastcgi
type header struct {
Version uint8
Type uint8
ID uint16
ContentLength uint16
PaddingLength uint8
Reserved uint8
}
func (h *header) init(recType uint8, reqID uint16, contentLength int) {
h.Version = 1
h.Type = recType
h.ID = reqID
h.ContentLength = uint16(contentLength)
h.PaddingLength = uint8(-contentLength & 7)
}

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@ -0,0 +1,26 @@
// Copyright 2015 Matthew Holt and The Caddy Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package fastcgi
import (
"bytes"
"sync"
)
var bufPool = sync.Pool{
New: func() any {
return new(bytes.Buffer)
},
}

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@ -0,0 +1,44 @@
// Copyright 2015 Matthew Holt and The Caddy Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package fastcgi
import (
"bytes"
"io"
)
type streamReader struct {
c *client
rec record
stderr bytes.Buffer
}
func (w *streamReader) Read(p []byte) (n int, err error) {
for !w.rec.hasMore() {
err = w.rec.fill(w.c.rwc)
if err != nil {
return 0, err
}
// standard error output
if w.rec.h.Type == Stderr {
if _, err = io.Copy(&w.stderr, &w.rec); err != nil {
return 0, err
}
}
}
return w.rec.Read(p)
}

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@ -0,0 +1,58 @@
// Copyright 2015 Matthew Holt and The Caddy Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package fastcgi
import (
"encoding/binary"
"errors"
"io"
)
type record struct {
h header
lr io.LimitedReader
padding int64
}
func (rec *record) fill(r io.Reader) (err error) {
rec.lr.N = rec.padding
rec.lr.R = r
if _, err = io.Copy(io.Discard, rec); err != nil {
return
}
if err = binary.Read(r, binary.BigEndian, &rec.h); err != nil {
return
}
if rec.h.Version != 1 {
err = errors.New("fcgi: invalid header version")
return
}
if rec.h.Type == EndRequest {
err = io.EOF
return
}
rec.lr.N = int64(rec.h.ContentLength)
rec.padding = int64(rec.h.PaddingLength)
return
}
func (rec *record) Read(p []byte) (n int, err error) {
return rec.lr.Read(p)
}
func (rec *record) hasMore() bool {
return rec.lr.N > 0
}

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@ -0,0 +1,145 @@
// Copyright 2015 Matthew Holt and The Caddy Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package fastcgi
import (
"bytes"
"encoding/binary"
)
// streamWriter abstracts out the separation of a stream into discrete records.
// It only writes maxWrite bytes at a time.
type streamWriter struct {
c *client
h header
buf *bytes.Buffer
recType uint8
}
func (w *streamWriter) writeRecord(recType uint8, content []byte) (err error) {
w.h.init(recType, w.c.reqID, len(content))
w.buf.Write(pad[:8])
w.writeHeader()
w.buf.Write(content)
w.buf.Write(pad[:w.h.PaddingLength])
_, err = w.buf.WriteTo(w.c.rwc)
return err
}
func (w *streamWriter) writeBeginRequest(role uint16, flags uint8) error {
b := [8]byte{byte(role >> 8), byte(role), flags}
return w.writeRecord(BeginRequest, b[:])
}
func (w *streamWriter) Write(p []byte) (int, error) {
// init header
if w.buf.Len() < 8 {
w.buf.Write(pad[:8])
}
nn := 0
for len(p) > 0 {
n := len(p)
nl := maxWrite + 8 - w.buf.Len()
if n > nl {
n = nl
w.buf.Write(p[:n])
if err := w.Flush(); err != nil {
return nn, err
}
// reset headers
w.buf.Write(pad[:8])
} else {
w.buf.Write(p[:n])
}
nn += n
p = p[n:]
}
return nn, nil
}
func (w *streamWriter) endStream() error {
// send empty record to close the stream
return w.writeRecord(w.recType, nil)
}
func (w *streamWriter) writePairs(pairs map[string]string) error {
b := make([]byte, 8)
nn := 0
// init headers
w.buf.Write(b)
for k, v := range pairs {
m := 8 + len(k) + len(v)
if m > maxWrite {
// param data size exceed 65535 bytes"
vl := maxWrite - 8 - len(k)
v = v[:vl]
}
n := encodeSize(b, uint32(len(k)))
n += encodeSize(b[n:], uint32(len(v)))
m = n + len(k) + len(v)
if (nn + m) > maxWrite {
if err := w.Flush(); err != nil {
return err
}
// reset headers
w.buf.Write(b)
nn = 0
}
nn += m
w.buf.Write(b[:n])
w.buf.WriteString(k)
w.buf.WriteString(v)
}
return w.FlushStream()
}
func encodeSize(b []byte, size uint32) int {
if size > 127 {
size |= 1 << 31
binary.BigEndian.PutUint32(b, size)
return 4
}
b[0] = byte(size)
return 1
}
// writeHeader populate header wire data in buf, it abuses buffer.Bytes() modification
func (w *streamWriter) writeHeader() {
h := w.buf.Bytes()[:8]
h[0] = w.h.Version
h[1] = w.h.Type
binary.BigEndian.PutUint16(h[2:4], w.h.ID)
binary.BigEndian.PutUint16(h[4:6], w.h.ContentLength)
h[6] = w.h.PaddingLength
h[7] = w.h.Reserved
}
// Flush write buffer data to the underlying connection, it assumes header data is the first 8 bytes of buf
func (w *streamWriter) Flush() error {
w.h.init(w.recType, w.c.reqID, w.buf.Len()-8)
w.writeHeader()
w.buf.Write(pad[:w.h.PaddingLength])
_, err := w.buf.WriteTo(w.c.rwc)
return err
}
// FlushStream flush data then end current stream
func (w *streamWriter) FlushStream() error {
if err := w.Flush(); err != nil {
return err
}
return w.endStream()
}