cmd/sgblog-comment-add/main.go

   1 /*
   2 SGBlog -- Git-backed CGI/inetd blogging/phlogging 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-backed CGI/inetd blogging/phlogging engine
  19 package main
  20
  21 import (
  22         "bytes"
  23         "crypto/sha1"
  24         "encoding/hex"
  25         "flag"
  26         "fmt"
  27         "io/ioutil"
  28         "log"
  29         "mime"
  30         "net/mail"
  31         "os"
  32         "os/exec"
  33         "regexp"
  34         "strconv"
  35         "strings"
  36         "syscall"
  37         "time"
  38
  39         "go.stargrave.org/sgblog"
  40 )
  41
  42 var hashFinder = regexp.MustCompile("([0-9a-f]{40})")
  43
  44 // Remove various whitespaces and excess lines, because git-notes-add
  45 // will remove and we have to know exact bytes count
  46 func cleanupBody(body string) []string {
  47         lines := strings.Split(string(body), "\n")
  48         for i, line := range lines {
  49                 line = strings.ReplaceAll(line, "       ", "    ")
  50                 line = strings.TrimRight(line, " \r")
  51                 lines[i] = line
  52         }
  53         for lines[0] == "" {
  54                 lines = lines[1:]
  55         }
  56         for lines[len(lines)-1] == "" {
  57                 lines = lines[:len(lines)-1]
  58         }
  59         withoutDups := make([]string, 0, len(lines))
  60         emptyMet := false
  61         for _, line := range lines {
  62                 if line == "" {
  63                         if emptyMet {
  64                                 continue
  65                         }
  66                         emptyMet = true
  67                 } else {
  68                         emptyMet = false
  69                 }
  70                 withoutDups = append(withoutDups, line)
  71         }
  72         return withoutDups
  73 }
  74
  75 func main() {
  76         gitCmd := flag.String("git-cmd", "/usr/local/bin/git", "Path to git executable")
  77         gitDir := flag.String("git-dir", "", "Path to .git repository")
  78         notesRef := flag.String("ref", "comments", "notes reference name")
  79         umask := flag.String("umask", "027", "umask value")
  80         dryRun := flag.Bool("dryrun", false, "Show comment, do not add")
  81         committerEmail := flag.String(
  82                 "committer-email",
  83                 "comment@blog.example.com",
  84                 "Git committer's email",
  85         )
  86         flag.Parse()
  87         uid := syscall.Geteuid()
  88         if err := syscall.Setuid(uid); err != nil {
  89                 log.Fatal(err)
  90         }
  91         umaskInt, err := strconv.ParseUint(*umask, 8, 16)
  92         if err != nil {
  93                 panic(err)
  94         }
  95         syscall.Umask(int(umaskInt))
  96
  97         msg, err := mail.ReadMessage(os.Stdin)
  98         if err != nil {
  99                 log.Fatal(err)
 100         }
 101         subj, r, err := parseEmail(msg)
 102         if err != nil {
 103                 log.Fatal(err)
 104         }
 105         body, err := ioutil.ReadAll(r)
 106         if err != nil {
 107                 log.Fatal(err)
 108         }
 109         from := msg.Header.Get("From")
 110         if from == "" {
 111                 log.Fatal("From is missing")
 112         }
 113         if len(body) == 0 {
 114                 log.Fatal("no body")
 115         }
 116         from, err = new(mime.WordDecoder).DecodeHeader(from)
 117         if err != nil {
 118                 log.Fatal(err)
 119         }
 120
 121         subj = hashFinder.FindString(subj)
 122         if subj == "" {
 123                 log.Fatal("no commit hash found in subject")
 124         }
 125         if h, err := hex.DecodeString(subj); err != nil || len(h) != sha1.Size {
 126                 os.Exit(0)
 127         }
 128         fromCols := strings.Fields(from)
 129         if len(fromCols) == 1 {
 130                 if idx := strings.Index(from, "@"); idx != -1 {
 131                         from = strings.Trim(from[:idx], "<>")
 132                 }
 133         } else {
 134                 from = strings.Join(fromCols[:len(fromCols)-1], " ")
 135         }
 136
 137         cmd := exec.Command(
 138                 *gitCmd, "--git-dir", *gitDir,
 139                 "notes", "--ref", *notesRef, "show", subj,
 140         )
 141         note, _ := cmd.Output()
 142         note = bytes.TrimRight(note, "\r\n")
 143
 144         buf := bytes.NewBuffer(note)
 145         buf.WriteString(fmt.Sprintf(
 146                 "\n\nFrom: %s\nDate: %s\nBody:\n",
 147                 from,
 148                 time.Now().UTC().Format(sgblog.WhenFmt),
 149         ))
 150         for _, s := range cleanupBody(string(body)) {
 151                 buf.WriteString("+ ")
 152                 buf.WriteString(s)
 153                 buf.WriteString("\n")
 154         }
 155
 156         if *dryRun {
 157                 fmt.Print(buf.String())
 158                 os.Exit(0)
 159         }
 160
 161         cmd = exec.Command(
 162                 *gitCmd, "--git-dir", *gitDir,
 163                 "notes", "--ref", *notesRef, "add",
 164                 "-F", "-", "-f", subj,
 165         )
 166         cmd.Env = append(
 167                 cmd.Env,
 168                 "GIT_AUTHOR_NAME=SGBlog "+sgblog.Version,
 169                 "GIT_AUTHOR_EMAIL="+*committerEmail,
 170                 "GIT_COMMITTER_NAME=SGBlog "+sgblog.Version,
 171                 "GIT_COMMITTER_EMAIL="+*committerEmail,
 172         )
 173         cmd.Stdin = buf
 174         if err = cmd.Run(); err != nil {
 175                 log.Fatal(err)
 176         }
 177 }