cmd/sgblog-comment-add/main.go

   1 /*
   2 SGBlog -- Git-based CGI blogging engine
   3 Copyright (C) 2020 Sergey Matveev <stargrave@stargrave.org>
   4
   5 This program is free software: you can redistribute it and/or modify
   6 it under the terms of the GNU Affero General Public License as
   7 published by the Free Software Foundation, version 3 of the License.
   8
   9 This program is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 GNU General Public License for more details.
  13
  14 You should have received a copy of the GNU Affero General Public License
  15 along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16 */
  17
  18 // Git-based CGI blogging engine email to comments adder
  19 package main
  20
  21 import (
  22         "bytes"
  23         "crypto/sha1"
  24         "encoding/hex"
  25         "flag"
  26         "fmt"
  27         "io/ioutil"
  28         "log"
  29         "net/mail"
  30         "os"
  31         "os/exec"
  32         "strconv"
  33         "strings"
  34         "syscall"
  35         "time"
  36
  37         "go.cypherpunks.ru/netstring/v2"
  38         "go.stargrave.org/sgblog"
  39 )
  40
  41 func main() {
  42         gitCmd := flag.String("git-cmd", "/usr/local/bin/git", "Path to git executable")
  43         gitDir := flag.String("git-dir", "", "Path to .git repository")
  44         notesRef := flag.String("ref", "comments", "notes reference name")
  45         umask := flag.String("umask", "027", "umask value")
  46         dryRun := flag.Bool("dryrun", false, "Show comment, do not add")
  47         committerEmail := flag.String(
  48                 "committer-email",
  49                 "comment@blog.example.com",
  50                 "Git committer's email",
  51         )
  52         flag.Parse()
  53         uid := syscall.Geteuid()
  54         if err := syscall.Setuid(uid); err != nil {
  55                 log.Fatal(err)
  56         }
  57         umaskInt, err := strconv.ParseUint(*umask, 8, 16)
  58         if err != nil {
  59                 panic(err)
  60         }
  61         syscall.Umask(int(umaskInt))
  62
  63         msg, err := mail.ReadMessage(os.Stdin)
  64         if err != nil {
  65                 log.Fatal(err)
  66         }
  67         subj, r, err := parseEmail(msg)
  68         if err != nil {
  69                 log.Fatal(err)
  70         }
  71         body, err := ioutil.ReadAll(r)
  72         if err != nil {
  73                 log.Fatal(err)
  74         }
  75         from := msg.Header.Get("From")
  76         if from == "" {
  77                 log.Fatal("From is missing")
  78         }
  79         if len(body) == 0 {
  80                 log.Fatal("no body")
  81         }
  82
  83         subj = strings.TrimPrefix(subj, "Re: ")
  84         if h, err := hex.DecodeString(subj); err != nil || len(h) != sha1.Size {
  85                 os.Exit(0)
  86         }
  87         fromCols := strings.Fields(from)
  88         if len(fromCols) == 1 {
  89                 if idx := strings.Index(from, "@"); idx != -1 {
  90                         from = strings.Trim(from[:idx], "<>")
  91                 }
  92         } else {
  93                 from = strings.Join(fromCols[:len(fromCols)-1], " ")
  94         }
  95
  96         cmd := exec.Command(
  97                 *gitCmd, "--git-dir", *gitDir,
  98                 "notes", "--ref", *notesRef, "show", subj,
  99         )
 100         note, _ := cmd.Output()
 101         note = bytes.TrimSuffix(note, []byte{'\n'})
 102
 103         // Remove trailing whitespaces, because git-notes-add will remove
 104         // them anyway, and we have to know exact bytes count
 105         lines := strings.Split(string(body), "\n")
 106         for i, line := range lines {
 107                 lines[i] = strings.TrimRight(line, " ")
 108         }
 109         for lines[len(lines)-1] == "" {
 110                 lines = lines[:len(lines)-1]
 111         }
 112
 113         buf := bytes.NewBuffer(note)
 114         w := netstring.NewWriter(buf)
 115         w.WriteChunk([]byte(fmt.Sprintf(
 116                 "From: %s\nDate: %s\n\n%s",
 117                 from,
 118                 time.Now().UTC().Format(sgblog.WhenFmt),
 119                 strings.Join(lines, "\n"),
 120         )))
 121
 122         if *dryRun {
 123                 fmt.Print(buf.String())
 124                 os.Exit(0)
 125         }
 126
 127         cmd = exec.Command(
 128                 *gitCmd, "--git-dir", *gitDir,
 129                 "notes", "--ref", *notesRef, "add",
 130                 "-F", "-", "-f", subj,
 131         )
 132         cmd.Env = append(
 133                 cmd.Env,
 134                 "GIT_AUTHOR_NAME=SGBlog "+sgblog.Version,
 135                 "GIT_AUTHOR_EMAIL="+*committerEmail,
 136                 "GIT_COMMITTER_NAME=SGBlog "+sgblog.Version,
 137                 "GIT_COMMITTER_EMAIL="+*committerEmail,
 138         )
 139         cmd.Stdin = buf
 140         if err = cmd.Run(); err != nil {
 141                 log.Fatal(err)
 142         }
 143 }