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         "log"
  15         "net"
  16         "net/http"
  17         "os"
  18         "time"
  19
  20         "golang.org/x/crypto/blake2s"
  21         "golang.org/x/net/netutil"
  22 )
  23
  24 const (
  25         WriteBufSize = 1 << 20
  26 )
  27
  28 func upload(w http.ResponseWriter, r *http.Request) {
  29         log.Println(r.RemoteAddr, "connected")
  30         if r.Method == http.MethodGet {
  31                 w.Write([]byte(`<html>
  32 <head><title>Upload</title></head><body>
  33 <form enctype="multipart/form-data" action="/upload/" method="post">
  34 <input type="file" name="fileupload" /><input type="submit" />
  35 </form></body></html>`))
  36                 return
  37         }
  38         mr, err := r.MultipartReader()
  39         if err != nil {
  40                 log.Println(r.RemoteAddr, err)
  41                 return
  42         }
  43         p, err := mr.NextPart()
  44         if err != nil {
  45                 log.Println(r.RemoteAddr, err)
  46                 return
  47         }
  48         if p.FormName() != "fileupload" {
  49                 log.Println(r.RemoteAddr, "non file form field")
  50                 return
  51         }
  52         fn := time.Now().Format(time.RFC3339Nano)
  53         fd, err := os.OpenFile(fn, os.O_WRONLY|os.O_CREATE, 0600)
  54         if err != nil {
  55                 log.Println(r.RemoteAddr, fn, p.FileName(), err)
  56                 return
  57         }
  58         defer fd.Close()
  59         h, err := blake2s.New256(nil)
  60         if err != nil {
  61                 panic(err)
  62         }
  63         fdBuf := bufio.NewWriterSize(fd, WriteBufSize)
  64         mw := io.MultiWriter(fdBuf, h)
  65         n, err := io.Copy(mw, p)
  66         if err != nil {
  67                 log.Println(r.RemoteAddr, fn, p.FileName(), err)
  68                 return
  69         }
  70         if err = fdBuf.Flush(); err != nil {
  71                 log.Println(r.RemoteAddr, fn, p.FileName(), err)
  72                 return
  73         }
  74         sum := hex.EncodeToString(h.Sum(nil))
  75         fmt.Fprintf(w, "bytes: %d\nBLAKE2s: %s\n", n, sum)
  76         log.Println(r.RemoteAddr, fn, p.FileName(), n, sum)
  77 }
  78
  79 func main() {
  80         bind := flag.String("bind", "[::]:8086", "Address to bind to")
  81         conns := flag.Int("conns", 2, "Maximal number of connections")
  82         flag.Parse()
  83         ln, err := net.Listen("tcp", *bind)
  84         if err != nil {
  85                 panic(err)
  86         }
  87         log.Println("listening", *bind)
  88         ln = netutil.LimitListener(ln, *conns)
  89         s := &http.Server{
  90                 ReadHeaderTimeout: 10 * time.Second,
  91                 MaxHeaderBytes:    10 * (1 << 10),
  92         }
  93         http.HandleFunc("/upload/", upload)
  94         s.Serve(ln)
  95 }