Optimize PAC generation.

pac.go

@@ -1,7 +1,6 @@
 package main
 
 import (
-	"bytes"
 	"fmt"
 	"io"
 	"os"
@@ -9,8 +8,6 @@ import (
 	"text/template"
 )
 
-var pacDirect = []byte("function FindProxyForURL(url, host) {return 'DIRECT'; };")
-
 const pacRawTmpl = `var direct = 'DIRECT';
 var httpProxy = '{{.ProxyAddr}}';
 
@@ -90,6 +87,11 @@ func initProxyServerAddr() {
 	}
 }
 
+// No need for content-length as we are closing connection
+var pacHeader = []byte("HTTP/1.1 200 OK\r\nServer: cow-proxy\r\n" +
+	"Content-Type: application/x-ns-proxy-autoconfig\r\nConnection: close\r\n\r\n")
+var pacDirect = []byte("function FindProxyForURL(url, host) { return 'DIRECT'; };")
+
 func sendPAC(w io.Writer) {
 	// domains in PAC file needs double quote
 	ds1 := strings.Join(alwaysDirectDs.toArray(), "\",\n\"")
@@ -103,9 +105,10 @@ func sendPAC(w io.Writer) {
 		ds = ds1 + "\",\n\"" + ds2
 	}
 	if ds == "" {
-		return pacDirect
-	} else {
-		ds = ",\n\"" + ds + "\""
+		// Empty direct domain list
+		w.Write(pacHeader)
+		w.Write(pacDirect)
+		return
 	}
 
 	data := struct {
@@ -113,19 +116,16 @@ func sendPAC(w io.Writer) {
 		DirectDomains string
 	}{
 		proxyServerAddr,
-		ds,
+		",\n\"" + ds + "\"",
 	}
 
+	if _, err := w.Write(pacHeader); err != nil {
+		debug.Println("Error writing pac header")
+		return
+	}
 	// debug.Println("direct:", data.DirectDomains)
-
-	buf := new(bytes.Buffer)
-	if err := pacTmpl.Execute(buf, data); err != nil {
+	if err := pacTmpl.Execute(w, data); err != nil {
 		errl.Println("Error generating pac file:", err)
-		os.Exit(1)
+		return
 	}
-	header := new(bytes.Buffer)
-	header.WriteString("HTTP/1.1 200 Okay\r\nServer: cow-proxy\r\nContent-Type: text/html\r\nConnection: close\r\n")
-	header.WriteString(fmt.Sprintf("Content-Length: %d\r\n\r\n", buf.Len()))
-	w.Write(header.Bytes())
-	w.Write(buf.Bytes())
 }

proxy.go

@@ -725,7 +725,7 @@ func (h *Handler) setStateResponsReceived(host string) {
 	}
 }
 
-var connEstablished = []byte("HTTP/1.0 200 Connection established\r\nProxy-agent: cow-proxy/0.1\r\n\r\n")
+var connEstablished = []byte("HTTP/1.0 200 Connection established\r\nProxy-agent: cow-proxy\r\n\r\n")
 
 // Do HTTP CONNECT
 func (h *Handler) doConnect(r *Request, c *clientConn) (err error) {