Fix the case of Transfer-Encoding: chunked (#368)

* Fix the case of Transfer-Encoding: chunked

* Make the test code more robust

* Fix typo

Author: panjf2000

lessons/229/myapp/cmd/gnet/server.go

@@ -1,11 +1,14 @@
 package main
 
 import (
+	"bufio"
 	"bytes"
 	"context"
 	"encoding/json"
 	"errors"
+	"io"
 	"log/slog"
+	"net/http"
 	"strconv"
 	"sync"
 	"time"
@@ -43,7 +46,10 @@ type httpCodec struct {
 	m             *mon.Metrics
 }
 
-var CRLF = []byte("0\r\n")
+var (
+	CRLF      = []byte("\r\n\r\n")
+	lastChunk = []byte("0\r\n\r\n")
+)
 
 func (hc *httpCodec) parse(data []byte) (int, []byte, error) {
 	bodyOffset, err := hc.parser.Parse(data)
@@ -53,11 +59,31 @@ func (hc *httpCodec) parse(data []byte) (int, []byte, error) {
 
 	contentLength := hc.getContentLength()
 	if contentLength > -1 {
-		return bodyOffset + contentLength, data[bodyOffset : bodyOffset+contentLength], nil
+		bodyEnd := bodyOffset + contentLength
+		var body []byte
+		if len(data) >= bodyEnd {
+			body = data[bodyOffset:bodyEnd]
+		}
+		return bodyEnd, body, nil
+	}
+
+	// Transfer-Encoding: chunked
+	if idx := bytes.Index(data[bodyOffset:], lastChunk); idx != -1 {
+		bodyEnd := idx + 5
+		var body []byte
+		if len(data) >= bodyEnd {
+			req, err := http.ReadRequest(bufio.NewReader(bytes.NewReader(data[:bodyEnd])))
+			if err != nil {
+				return bodyEnd, nil, err
+			}
+			body, _ = io.ReadAll(req.Body)
+		}
+		return bodyEnd, body, nil
 	}
 
+	// Request without a body.
 	if idx := bytes.Index(data, CRLF); idx != -1 {
-		return idx + 3, nil, nil
+		return idx + 4, nil, nil
 	}
 
 	return 0, nil, errors.New("invalid http request")
@@ -200,15 +226,18 @@ func (hs *httpServer) OnOpen(c gnet.Conn) ([]byte, gnet.Action) {
 
 func (hs *httpServer) OnTraffic(c gnet.Conn) gnet.Action {
 	hc := c.Context().(*httpCodec)
-	buf, _ := c.Next(-1)
+	buf, _ := c.Peek(-1)
+	n := len(buf)
 
 pipeline:
 	nextOffset, body, err := hc.parse(buf)
+	hc.resetParser()
 	if err != nil {
 		goto response
 	}
-
-	hc.resetParser()
+	if len(buf) < nextOffset { // incomplete request
+		goto response
+	}
 	writeResponse(c, body)
 	buf = buf[nextOffset:]
 	if len(buf) > 0 {
@@ -219,6 +248,7 @@ response:
 		c.Write(hc.resp.Bytes())
 	}
 	hc.reset()
+	c.Discard(n - len(buf))
 	return gnet.None
 }