/* uploader -- simplest form file uploader Copyright (C) 2018-2020 Sergey Matveev This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 3 of the License. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . */ package main import ( "bufio" "encoding/base64" "encoding/hex" "flag" "fmt" "html/template" "io" "io/ioutil" "log" "mime" "net" "net/http" "os" "os/exec" "strings" "time" "golang.org/x/crypto/blake2b" "golang.org/x/net/netutil" ) const ( WriteBufSize = 1 << 20 FileFieldName = "fileupload" CommentFieldName = "comment" SendmailCmd = "/usr/sbin/sendmail" ) var ( Index = template.Must(template.New("index").Parse(` Upload 
Example command line usage:
  curl -F fileupload=@somedata.tar.gpg [-F comment="optional comment"] http://.../upload/
  b2sum -a blake2b somedata.tar.gpg


`)) NotifyFromAddr *string NotifyToAddr *string ) func notify(filename, timestamp string, size int64, comment string) { if *NotifyToAddr == "" { return } cmd := exec.Command(SendmailCmd, *NotifyToAddr) cmd.Stdin = io.MultiReader( strings.NewReader(fmt.Sprintf( `From: %s To: %s Subject: %s MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: base64 `, *NotifyFromAddr, *NotifyToAddr, mime.BEncoding.Encode("UTF-8", fmt.Sprintf( "%s (%d KiB)", filename, size/1024, )), )), strings.NewReader(base64.StdEncoding.EncodeToString([]byte(fmt.Sprintf( "Timestamp: %s\nSize: %d bytes\nComment: %s\n", timestamp, size, comment, )))), ) cmd.Run() } func upload(w http.ResponseWriter, r *http.Request) { log.Println(r.RemoteAddr, "connected") if r.Method == http.MethodGet { if err := Index.Execute(w, FileFieldName); err != nil { log.Println(r.RemoteAddr, err) } return } mr, err := r.MultipartReader() if err != nil { log.Println(r.RemoteAddr, err) return } p, err := mr.NextPart() if err != nil { log.Println(r.RemoteAddr, err) return } if p.FormName() != FileFieldName { log.Println(r.RemoteAddr, "non file form field") return } h, err := blake2b.New512(nil) if err != nil { panic(err) } fn := time.Now().Format(time.RFC3339Nano) fnOrig := p.FileName() fd, err := os.OpenFile(fn+".part", os.O_WRONLY|os.O_CREATE, 0600) if err != nil { log.Println(r.RemoteAddr, fn, fnOrig, err) return } fdBuf := bufio.NewWriterSize(fd, WriteBufSize) mw := io.MultiWriter(fdBuf, h) n, err := io.Copy(mw, p) if err != nil { log.Println(r.RemoteAddr, fn, fnOrig, err) fd.Close() return } if n == 0 { log.Println(r.RemoteAddr, fn, fnOrig, "empty") os.Remove(fn + ".part") fd.Close() fmt.Fprintf(w, "Empty file") return } if err = fdBuf.Flush(); err != nil { log.Println(r.RemoteAddr, fn, fnOrig, err) fd.Close() return } fd.Close() sum := hex.EncodeToString(h.Sum(nil)) if err = os.Rename(fn+".part", fn); err != nil { log.Println(r.RemoteAddr, fn, fnOrig, n, sum, err) return } fmt.Fprintf(w, "Timestamp: %s\nBytes: %d\nBLAKE2b: %s\n", fn, n, sum) log.Println(r.RemoteAddr, fn, fnOrig, n, sum) p, err = mr.NextPart() if err != nil || p.FormName() != CommentFieldName { go notify(fnOrig, fn, n, "") return } comment, err := ioutil.ReadAll(p) if err != nil || len(comment) == 0 { go notify(fnOrig, fn, n, "") return } ioutil.WriteFile(fn+".txt", comment, os.FileMode(0600)) go notify(fnOrig, fn, n, string(comment)) } func main() { bind := flag.String("bind", "[::]:8086", "Address to bind to") conns := flag.Int("conns", 2, "Maximal number of connections") NotifyFromAddr = flag.String("notify-from", "uploader@example.com", "Address notifications are send to") NotifyToAddr = flag.String("notify-to", "", "Address notifications are send from") flag.Parse() if len(*NotifyFromAddr) == 0 && len(*NotifyToAddr) > 0 { log.Fatalln("notify-from address can not be empty, if notify-to is set") } ln, err := net.Listen("tcp", *bind) if err != nil { log.Fatalln(err) } log.Println("listening", *bind) ln = netutil.LimitListener(ln, *conns) s := &http.Server{ ReadHeaderTimeout: 10 * time.Second, MaxHeaderBytes: 10 * (1 << 10), } http.HandleFunc("/upload/", upload) s.Serve(ln) }