publish ch1/...

ch1/server3/main.go

@@ -0,0 +1,52 @@
+// Copyright © 2016 Alan A. A. Donovan & Brian W. Kernighan.
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+
+// See page 21.
+//!+
+
+// Server3 is a minimal "echo" and counter server.
+package main
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+	"sync"
+)
+
+var mu sync.Mutex
+var count int
+
+func main() {
+	http.HandleFunc("/", handler)
+	http.HandleFunc("/count", counter)
+	log.Fatal(http.ListenAndServe("localhost:8000", nil))
+}
+
+//!+handler
+// handler echoes the HTTP request.
+func handler(w http.ResponseWriter, r *http.Request) {
+	fmt.Fprintf(w, "%s %s %s\n", r.Method, r.URL, r.Proto)
+	for k, v := range r.Header {
+		fmt.Fprintf(w, "Header[%q] = %q\n", k, v)
+	}
+	fmt.Fprintf(w, "Host = %q\n", r.Host)
+	fmt.Fprintf(w, "RemoteAddr = %q\n", r.RemoteAddr)
+	if err := r.ParseForm(); err != nil {
+		log.Print(err)
+	}
+	for k, v := range r.Form {
+		fmt.Fprintf(w, "Form[%q] = %q\n", k, v)
+	}
+}
+
+//!-handler
+
+// counter echoes the number of calls so far.
+func counter(w http.ResponseWriter, r *http.Request) {
+	mu.Lock()
+	fmt.Fprintf(w, "Count %d", count)
+	mu.Unlock()
+}
+
+//!-