了解Golang中的MUX路由器

Question

here is my code trying to display a base64 image it worked before using mux.

I've used http handlefunc before using mux, here i want to use mux and get the value of key.

package main

import (
"fmt"
"net/http"
"strconv"
base64 "encoding/base64"
"log"
"io"
    "io/ioutil"
    "os"
    "github.com/gorilla/mux"
)


var (
    Trace   *log.Logger
    Info    *log.Logger
    Warning *log.Logger
    Error   *log.Logger
)

func Init(
traceHandle io.Writer,
infoHandle io.Writer,
warningHandle io.Writer,
errorHandle io.Writer) {

    Trace = log.New(traceHandle,
        "TRACE: ",
        log.Ldate|log.Ltime|log.Lshortfile)

    Info = log.New(infoHandle,
        "INFO: ",
        log.Ldate|log.Ltime|log.Lshortfile)

    Warning = log.New(warningHandle,
        "WARNING: ",
        log.Ldate|log.Ltime|log.Lshortfile)

    Error = log.New(errorHandle,
        "ERROR: ",
        log.Ldate|log.Ltime|log.Lshortfile)
}

func get_info(r *http.Request){
fmt.Println(r.RemoteAddr)
fmt.Println(r.Header.Get("x-forwarded-for"))
fmt.Println(r.UserAgent())
fmt.Println(r.Referer())
}


func pix(w http.ResponseWriter, r *http.Request) {
    Info.Println("Hi there, I love %s!", r.URL.Path[1:])
    vars := mux.Vars(r)
    key := vars["key"]
    Info.Println("key", key)
    var cookie  *http.Cookie
    cookie , err := r.Cookie("csrftoken")
    if (err != nil ){
        fmt.Printf("error")
        fmt.Println(err)
    }
    get_info(r)
    fmt.Printf(cookie.Value)
    w.Header().Set("Content-Type", "image/jpeg")
    p, err := base64.StdEncoding.DecodeString("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")
    if err != nil {
        http.Error(w, "internal error", 500)
        return
    }
    w.Header().Set("Content-Length", strconv.Itoa(len(p))) //len(dec)
    w.Write(p)
}


func main() {
    Init(ioutil.Discard, os.Stdout, os.Stdout, os.Stderr)
    Info.Println("1")
    r := mux.NewRouter()
    Info.Println("2")
    r.HandleFunc("/pix/{key}/pixel.gif", pix)
    err := http.ListenAndServe(":9080", nil)
    Info.Println("3")
    if err != nil {
        fmt.Println(err)
    }
}

It seems that when i call http://localhost:9080/pix/2/pixel.gif it doesn't call pix.

the url for calling it seems correct

any idea why ?

regards and thanks

Answer 1

It appears that you are not assigning r to anything, you should add the following at the end of your main:

http.Handle("/", r)