hikarie.go #2最後のお題

gistfile1.go

package main

import (
    "encoding/json"
    "fmt"
    "io/ioutil"
    "net/http"
    "strconv"
)

type User struct {
    Name string `json:"name"`
    Age int `json:"age"`
}

func (u User) ToJSON() string {
    b, err := json.Marshal(u)
    if err != nil {
        fmt.Errorf("%s", err)
    }
    return string(b)
}

func main() {
    http.HandleFunc("/api", func(w http.ResponseWriter, r *http.Request) {
        queryParam := r.URL.Query()
        var user User
        user.Name = queryParam.Get("name")
        user.Age, _ = strconv.Atoi(queryParam.Get("age"))
        json := user.ToJSON()
        fmt.Fprint(w, json)
        ioutil.WriteFile("./apidata.txt", []byte(json), 0644)
    })
    http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
        t, err := ioutil.ReadFile("./apidata.txt")
        if err != nil {
            fmt.Errorf("%s\n", err)
        }
        fmt.Fprint(w, string(t))
    })
    http.ListenAndServe(":4000", nil)
}