package main

import (
    "fmt"
    "io"
    "io/ioutil"
    "net/http"
)

func main() {
    http.HandleFunc("/", index)
    http.Handle("/favicon.ico", http.NotFoundHandler())
    http.ListenAndServe(":8080", nil)
}

func index(res http.ResponseWriter, req *http.Request) {
    var s string
    fmt.Println(req.Method)
    if req.Method == http.MethodPost {
        f, h, err := req.FormFile("q")
        if err != nil {
            http.Error(res, err.Error(), http.StatusInternalServerError)
            return
        }
        defer f.Close()
        fmt.Println("\nfile: ", f, "\nheader: ", h, "\nerr", err)
        bs, err := ioutil.ReadAll(f)
        if err != nil {
            http.Error(res, err.Error(), http.StatusInternalServerError)
            return
        }
        s = string(bs)
    }
    res.Header().Set("Content-Type", "text/html; charset=utf-8")
    io.WriteString(res, `
        <form method="POST" enctype="multipart/form-data">
            <input type="file" name="q" />
            <input type="submit" />
        </form>
    `+s)
}