golang简单静态服务器在终端上打印

Question

this is my initial golang code :

package main
import (
    "net/http"
    "io"
)

const hello = `hello world`


func helloHandler(w http.ResponseWriter, r *http.Request) {
    io.WriteString(w, hello)
}


func main() {
    http.HandleFunc("/", helloHandler)
    http.ListenAndServe(":1088", nil)
}

it is a simple http server, i need add new function, every get request print in linux terminal ip, METHOD, /request.

example output in terminal need:

95.250.33.36 GET /
95.250.33.36 GET /favicon.ico
95.250.33.36 GET /robots.txt

how i can do this ?

Answer 1

The best thing about Golang is interfaces. Your helloHandler actually implements the HandlerFunc interface. Using the Open/Close Principle we can take helloHandler and extend it for logging the request in the following way:

func wrapHandlerWithLogging(wrappedHandler http.Handler) http.HandlerFunc {
    return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
       log.Printf("--> %s %s", req.Method, req.URL.Path)
       wrappedHandler.ServeHTTP(w, req)
    })
}

func main() {
    ...
    http.HandleFunc("/", wrapHandlerWithLogging(http.HandlerFunc(helloHandler)))
    ...
 }

So basically, we wrap helloHandler which implements HandlerFunc with another HandlerFunc.

In this example, we only log the request method (GET, POST, PUT and etc) and the request path (e.g. '/'). However, you can log other data:

• req.RemoteAddr network address that sent the request
• req.Proto the protocol version
• req.Host specifies the host on which URL is sought