suntong · June 7, 2019 23:27 · Jun 7, 2019
diff --git a/foo.go b/foo.go
@@ -0,0 +1,140 @@
+////////////////////////////////////////////////////////////////////////////
+// Program: dbab-svr
+// Purpose: Pixel Server in Go
+// Authors: Tong Sun (c) 2019, All rights reserved
+////////////////////////////////////////////////////////////////////////////
+
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"net"
+	"net/http"
+	"os"
+	"regexp"
+	"strings"
+	"time"
+)
+
+////////////////////////////////////////////////////////////////////////////
+// Constant and data type/structure definitions
+
+const (
+	confFile  = "dbab.addr"
+	proxyFile = "dbab.proxy"
+
+	pixel = "\x47\x49\x46\x38\x39\x61\x01\x00\x01\x00\x80\x00\x00\xFF\xFF\xFF\x00\x00\x00\x21\xF9\x04\x01\x00\x00\x00\x00\x2C\x00\x00\x00\x00\x01\x00\x01\x00\x00\x02\x02\x44\x01\x00\x3B"
+)
+
+type proxyHandler struct {
+	setting string
+}
+
+////////////////////////////////////////////////////////////////////////////
+// Global variables definitions
+
+var (
+	progname = "dbab-svr"
+)
+
+////////////////////////////////////////////////////////////////////////////
+// Function definitions
+
+func pixelServ(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("ETag", "dbab")
+	w.Header().Set("Connection", "close")
+	w.Header().Set("Content-Type", "image/gif")
+	w.Header().Set("Cache-Control", "public, max-age=31536000")
+	w.Write([]byte(pixel))
+}
+
+func (h *proxyHandler) handle(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Connection", "close")
+	w.Header().Set("Content-Type", "application/octet-stream")
+	w.Write([]byte(h.setting))
+}
+
+//==========================================================================
+// support functions
+
+// readFile returns the single-line file content (less trailing \n) of the file by the given fname
+func readFile(fname string) string {
+	b, err := ioutil.ReadFile(fname)
+	abortOn("Reading input file: "+fname, err)
+	return strings.TrimSuffix(string(b), "\n")
+}
+
+// abortOn will quit on anticipated errors gracefully without stack trace
+func abortOn(errCase string, e error) {
+	if e != nil {
+		fmt.Fprintf(os.Stderr, "[%s] %s error: %v\n", progname, errCase, e)
+		os.Exit(1)
+	}
+}
+
+//==========================================================================
+// Main
+
+func main() {
+	httpPort := readFile(confFile)
+	_httpPort := os.Getenv("DBAB_SERVER_ADDR")
+	if _httpPort != "" {
+		httpPort = _httpPort
+
+	}
+	autoProxy := &proxyHandler{fmt.Sprintf(
+		"function FindProxyForURL(url, host) { return \"PROXY %s:3128; DIRECT\"; }",
+		readFile(proxyFile))}
+	_ = autoProxy
+
+	l, err := net.Listen("tcp", httpPort)
+	if err != nil {
+		log.Fatal(err)
+	}
+	re := regexp.MustCompile(`\s*(\w+)\s*([^\s]+)\s*HTTP\/(\d.\d)`)
+	for {
+		c, err := l.Accept()
+		if err != nil {
+			log.Fatal(err)
+		}
+		if err := c.SetReadDeadline(time.Now().Add(2 * time.Second)); err != nil {
+			log.Fatal(err)
+		}
+		s := bufio.NewScanner(c)
+		var req struct {
+			Method  string
+			URL     string
+			Version string
+		}
+		for s.Scan() {
+			line := s.Text()
+			matches := re.FindStringSubmatch(line)
+			if matches != nil {
+				req.Method = strings.ToUpper(matches[1])
+				req.URL = matches[2]
+				req.Version = matches[3]
+				continue
+			}
+			if line == "" {
+				break
+			}
+		}
+		if err := s.Err(); err != nil {
+			continue
+		}
+		if req.Method == "GET" && (req.URL == "/proxy.pac" || req.URL == "/wpad.dat") {
+			// Ignore the proxy-stuff, it doesn't matter for the benchmark
+		} else {
+			fmt.Fprintf(c, "HTTP/1.0 200 OK\r\n")
+			fmt.Fprintf(c, "Connection: close\r\n")
+			fmt.Fprintf(c, "Content-type: image/gif\r\n")
+			fmt.Fprintf(c, "Content-length: 43\r\n\r\n")
+			c.Write([]byte(pixel))
+		}
+		c.Close()
+	}
+	l.Close()
+}