good good study, day day up!

vendor/gopl.io/ch12/search/main.go

@@ -0,0 +1,60 @@
+// Copyright © 2016 Alan A. A. Donovan & Brian W. Kernighan.
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+
+// See page 348.
+
+// Search is a demo of the params.Unpack function.
+package main
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+)
+
+//!+
+
+import "gopl.io/ch12/params"
+
+// search implements the /search URL endpoint.
+func search(resp http.ResponseWriter, req *http.Request) {
+	var data struct {
+		Labels     []string `http:"l"`
+		MaxResults int      `http:"max"`
+		Exact      bool     `http:"x"`
+	}
+	data.MaxResults = 10 // set default
+	if err := params.Unpack(req, &data); err != nil {
+		http.Error(resp, err.Error(), http.StatusBadRequest) // 400
+		return
+	}
+
+	// ...rest of handler...
+	fmt.Fprintf(resp, "Search: %+v\n", data)
+}
+
+//!-
+
+func main() {
+	http.HandleFunc("/search", search)
+	log.Fatal(http.ListenAndServe(":12345", nil))
+}
+
+/*
+//!+output
+$ go build gopl.io/ch12/search
+$ ./search &
+$ ./fetch 'http://localhost:12345/search'
+Search: {Labels:[] MaxResults:10 Exact:false}
+$ ./fetch 'http://localhost:12345/search?l=golang&l=programming'
+Search: {Labels:[golang programming] MaxResults:10 Exact:false}
+$ ./fetch 'http://localhost:12345/search?l=golang&l=programming&max=100'
+Search: {Labels:[golang programming] MaxResults:100 Exact:false}
+$ ./fetch 'http://localhost:12345/search?x=true&l=golang&l=programming'
+Search: {Labels:[golang programming] MaxResults:10 Exact:true}
+$ ./fetch 'http://localhost:12345/search?q=hello&x=123'
+x: strconv.ParseBool: parsing "123": invalid syntax
+$ ./fetch 'http://localhost:12345/search?q=hello&max=lots'
+max: strconv.ParseInt: parsing "lots": invalid syntax
+//!-output
+*/