src/uploader/main.go

   1 /*
   2 uploader -- simplest form file uploader
   3 Copyright (C) 2018 Sergey Matveev <stargrave@stargrave.org>
   4 */
   5
   6 package main
   7
   8 import (
   9         "bufio"
  10         "encoding/hex"
  11         "flag"
  12         "fmt"
  13         "io"
  14         "net"
  15         "net/http"
  16         "os"
  17         "time"
  18
  19         "golang.org/x/crypto/blake2s"
  20         "golang.org/x/net/netutil"
  21 )
  22
  23 const (
  24         WriteBufSize = 1 << 20
  25 )
  26
  27 func upload(w http.ResponseWriter, r *http.Request) {
  28         if r.Method == http.MethodGet {
  29                 w.Write([]byte(`<html>
  30 <head><title>Upload</title></head><body>
  31 <form enctype="multipart/form-data" action="/upload/" method="post">
  32 <input type="file" name="fileupload" /><input type="submit" />
  33 </form></body></html>`))
  34                 return
  35         }
  36         mr, err := r.MultipartReader()
  37         if err != nil {
  38                 fmt.Println(err)
  39                 return
  40         }
  41         p, err := mr.NextPart()
  42         if err != nil {
  43                 fmt.Println(err)
  44                 return
  45         }
  46         if p.FormName() != "fileupload" {
  47                 fmt.Println("non file form field")
  48                 return
  49         }
  50         now := time.Now()
  51         fd, err := os.OpenFile(now.Format(time.RFC3339Nano), os.O_WRONLY|os.O_CREATE, 0600)
  52         if err != nil {
  53                 fmt.Println(err)
  54                 return
  55         }
  56         defer fd.Close()
  57         h, err := blake2s.New256(nil)
  58         if err != nil {
  59                 panic(err)
  60         }
  61         fdBuf := bufio.NewWriterSize(fd, WriteBufSize)
  62         mw := io.MultiWriter(fdBuf, h)
  63         n, err := io.Copy(mw, p)
  64         if err != nil {
  65                 fmt.Println(err)
  66                 return
  67         }
  68         if err = fdBuf.Flush(); err != nil {
  69                 fmt.Println(err)
  70                 return
  71         }
  72         fmt.Fprintf(w, "bytes: %d\nBLAKE2s: %s\n", n, hex.EncodeToString(h.Sum(nil)))
  73 }
  74
  75 func main() {
  76         bind := flag.String("bind", "[::]:8086", "Address to bind to")
  77         conns := flag.Int("conns", 2, "Maximal number of connections")
  78         flag.Parse()
  79         ln, err := net.Listen("tcp", *bind)
  80         if err != nil {
  81                 panic(err)
  82         }
  83         fmt.Println("listening on", *bind)
  84         ln = netutil.LimitListener(ln, *conns)
  85         s := &http.Server{
  86                 ReadHeaderTimeout: 10 * time.Second,
  87                 MaxHeaderBytes:    10 * (1 << 10),
  88         }
  89         http.HandleFunc("/upload/", upload)
  90         s.Serve(ln)
  91 }