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https://github.com/gopl-zh/gopl-zh.github.com.git
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62 lines
1.3 KiB
Go
62 lines
1.3 KiB
Go
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// Copyright © 2016 Alan A. A. Donovan & Brian W. Kernighan.
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// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
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// See page 194.
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// Http3 is an e-commerce server that registers the /list and /price
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// endpoints by calling (*http.ServeMux).Handle.
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package main
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import (
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"fmt"
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"log"
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"net/http"
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)
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type dollars float32
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func (d dollars) String() string { return fmt.Sprintf("$%.2f", d) }
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//!+main
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func main() {
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db := database{"shoes": 50, "socks": 5}
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mux := http.NewServeMux()
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mux.Handle("/list", http.HandlerFunc(db.list))
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mux.Handle("/price", http.HandlerFunc(db.price))
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log.Fatal(http.ListenAndServe("localhost:8000", mux))
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}
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type database map[string]dollars
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func (db database) list(w http.ResponseWriter, req *http.Request) {
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for item, price := range db {
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fmt.Fprintf(w, "%s: %s\n", item, price)
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}
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}
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func (db database) price(w http.ResponseWriter, req *http.Request) {
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item := req.URL.Query().Get("item")
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price, ok := db[item]
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if !ok {
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w.WriteHeader(http.StatusNotFound) // 404
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fmt.Fprintf(w, "no such item: %q\n", item)
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return
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}
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fmt.Fprintf(w, "%s\n", price)
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}
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//!-main
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/*
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//!+handlerfunc
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package http
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type HandlerFunc func(w ResponseWriter, r *Request)
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func (f HandlerFunc) ServeHTTP(w ResponseWriter, r *Request) {
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f(w, r)
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}
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//!-handlerfunc
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*/
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