good good study, day day up!

vendor/gopl.io/ch7/http3a/main.go

@@ -0,0 +1,54 @@
+// Copyright © 2016 Alan A. A. Donovan & Brian W. Kernighan.
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+
+// See page 195.
+
+// Http3a is an e-commerce server that registers the /list and /price
+// endpoints by calling (*http.ServeMux).HandleFunc.
+package main
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+)
+
+func main() {
+	db := database{"shoes": 50, "socks": 5}
+	mux := http.NewServeMux()
+	//!+main
+	mux.HandleFunc("/list", db.list)
+	mux.HandleFunc("/price", db.price)
+	//!-main
+	log.Fatal(http.ListenAndServe("localhost:8000", mux))
+}
+
+type database map[string]int
+
+func (db database) list(w http.ResponseWriter, req *http.Request) {
+	for item, price := range db {
+		fmt.Fprintf(w, "%s: $%d\n", item, price)
+	}
+}
+
+func (db database) price(w http.ResponseWriter, req *http.Request) {
+	item := req.URL.Query().Get("item")
+	if price, ok := db[item]; ok {
+		fmt.Fprintf(w, "$%d\n", price)
+	} else {
+		w.WriteHeader(http.StatusNotFound) // 404
+		fmt.Fprintf(w, "no such item: %q\n", item)
+	}
+}
+
+/*
+//!+handlerfunc
+package http
+
+type HandlerFunc func(w ResponseWriter, r *Request)
+
+func (f HandlerFunc) ServeHTTP(w ResponseWriter, r *Request) {
+	f(w, r)
+}
+//!-handlerfunc
+*/