アクセスカウンタをgo routineとchanで作ってみた.

count.go

package main

import (
    "net/http"
    "html/template"
)



type Page struct {
    Title string
    Count int
}

func bind(add chan int, result chan int) http.HandlerFunc {
    //w http.ResponseWriter, r *http.ResponseWriter) {
    return func (w http.ResponseWriter, r *http.Request)  {
        t, _ := template.ParseFiles("count.html")
        add <- 1
        p := &Page{Title: "count", Count: <- result}
        t.Execute(w, p)
    }
}

func main() {
    add := make(chan int)
    result := make(chan int)
    go func () {
        acc := 0
        for {
            select {
            case x := <-add:
               acc += x
               result <- acc
            }
        }
    }()
	http.HandleFunc("/", bind(add, result))
	http.ListenAndServe(":8080", nil)
}

count.html

<h1>{{.Title |html}}</h1>

<div> count = {{.Count}} </div>