英文:
Setting up a http handler in go
问题
我正在遵循Go Tour，并且其中一个练习要求我构建一对HTTP处理程序。
以下是代码：
package main
import (
"fmt"
"net/http"
)
type String string
type Struct struct {
Greeting string
Punct string
Who string
}
func (s String) ServeHTTP(w http.ResponseWriter, r *http.Request){
fmt.Fprint(w, s)
}
func (s *Struct) ServeHTTP(w http.ResponseWriter, r *http.Request){
fmt.Fprint(w, "This is a struct. Yey!")
}
func main() {
// 在这里添加你的http.Handle调用
http.ListenAndServe("localhost:4000", nil)
http.Handle("/string", String("I'm a frayed knot"))
http.Handle("/struct", &Struct{"Hello",":","Gophers!"})
}
代码可以编译和运行，但是当我访问localhost:4000/string或localhost:4000/struct时，我只得到了默认的HTTP处理程序返回的404错误。
我是否漏掉了什么步骤？
英文:
I was following the go tour and one of the exercises asked me to build a couple http handlers.
Here is the code:
package main
import (
"fmt"
"net/http"
)
type String string
type Struct struct {
Greeting string
Punct string
Who string
}
func (s String) ServeHTTP(w http.ResponseWriter, r *http.Request){
fmt.Fprint(w, s)
}
func (s *Struct) ServeHTTP(w http.ResponseWriter, r *http.Request){
fmt.Fprint(w, "This is a struct. Yey!")
}
func main() {
// your http.Handle calls here
http.ListenAndServe("localhost:4000", nil)
http.Handle("/string", String("I'm a frayed knot"))
http.Handle("/struct", &Struct{"Hello",":","Gophers!"})
}
The code compiles & runs just fine however I am not sure why when I navigate to localhost:4000/string or localhost:4000/struct all I get is a 404 error from the default http handler.
Am I missing a step here or?
答案1
得分: 3
你的代码停在ListenAndServe这里，它是一个阻塞的操作。（顺便说一下，如果ListenAndServe不阻塞，main函数会返回并且进程会退出）
在此之前注册处理程序。
英文:
Your code stops at ListenAndServe, which is blocking. (BTW, if ListenAndServe didn't block, main would return and the process would exit)
Register the handlers before that.
答案2
得分: 1
将main函数中的代码进行修改，修改后的代码如下：
func main() {
http.Handle("/string", String("I'm a frayed knot"))
http.Handle("/struct", &Struct{"Hello", ":", "Gophers!"})
// your http.Handle calls here
log.Fatal(http.ListenAndServe("localhost:4000", nil))
}
http.ListenAndServe会阻塞程序直到终止。
通常会添加一个记录退出值的日志：
log.Fatal(http.ListenAndServe(...))
英文:
Change main from
func main() {
// your http.Handle calls here
http.ListenAndServe("localhost:4000", nil)
http.Handle("/string", String("I'm a frayed knot"))
http.Handle("/struct", &Struct{"Hello",":","Gophers!"})
}
to
func main() {
http.Handle("/string", String("I'm a frayed knot"))
http.Handle("/struct", &Struct{"Hello",":","Gophers!"})
// your http.Handle calls here
http.ListenAndServe("localhost:4000", nil)
}
http.ListenAndServe blocks until you terminate the program.
is common to add a log of the exit value:
log.Fatal(http.ListenAndServe(...))
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