From 4cf829bd25c3f01a45e1823bb8d07d0fb660d98a Mon Sep 17 00:00:00 2001
From: Sergey Matveev <stargrave@stargrave.org>
Date: Thu, 30 May 2019 20:59:09 +0300
Subject: [PATCH] Ability to send notification about uploaded files

---
 README               |  2 ++
 src/uploader/main.go | 49 +++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/README b/README
index 5d674a9..9f5cf19 100644
--- a/README
+++ b/README
@@ -11,3 +11,5 @@ You can upload files with curl:
 You can verify integrity locally:
 
     b2sum -a blake2b somedata.tar.gpg
+
+You can enable mail notification with -notify-to and -notify-from options.
diff --git a/src/uploader/main.go b/src/uploader/main.go
index a1465cd..788c2ca 100644
--- a/src/uploader/main.go
+++ b/src/uploader/main.go
@@ -7,15 +7,20 @@ 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"
@@ -26,6 +31,8 @@ const (
 	WriteBufSize     = 1 << 20
 	FileFieldName    = "fileupload"
 	CommentFieldName = "comment"
+
+	SendmailCmd = "/usr/sbin/sendmail"
 )
 
 var (
@@ -37,8 +44,41 @@ var (
 <textarea name="comment" cols="80" rows="25" name="comment"></textarea><br/>
 <input type="submit" />
 </form></body></html>`))
+	NotifyFromAddr *string
+	NotifyToAddr   *string
 )
 
+func notify(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)", timestamp, 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 {
@@ -101,10 +141,12 @@ func upload(w http.ResponseWriter, r *http.Request) {
 	log.Println(r.RemoteAddr, fn, p.FileName(), n, sum)
 	p, err = mr.NextPart()
 	if err != nil || p.FormName() != CommentFieldName {
+		go notify(fn, n, "")
 		return
 	}
 	comment, err := ioutil.ReadAll(p)
 	if err != nil || len(comment) == 0 {
+		go notify(fn, n, "")
 		return
 	}
 	ioutil.WriteFile(fn+".txt", comment, os.FileMode(0600))
@@ -114,10 +156,15 @@ func upload(w http.ResponseWriter, r *http.Request) {
 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 {
-		panic(err)
+		log.Fatalln(err)
 	}
 	log.Println("listening", *bind)
 	ln = netutil.LimitListener(ln, *conns)
-- 
2.44.0