cmd/sgblog-comment-add/main.go

   1 /*
   2 SGBlog -- Git-backed CGI/inetd blogging/phlogging engine
   3 Copyright (C) 2020-2021 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.cypherpunks.ru/recfile"
  40         "go.stargrave.org/sgblog"
  41 )
  42
  43 var hashFinder = regexp.MustCompile("([0-9a-f]{40})")
  44
  45 // Remove various whitespaces and excess lines, because git-notes-add
  46 // will remove and we have to know exact bytes count
  47 func cleanupBody(body string) []string {
  48         lines := strings.Split(string(body), "\n")
  49         for i, line := range lines {
  50                 line = strings.ReplaceAll(line, "       ", "    ")
  51                 line = strings.TrimRight(line, " \r")
  52                 lines[i] = line
  53         }
  54         for lines[0] == "" {
  55                 lines = lines[1:]
  56         }
  57         for lines[len(lines)-1] == "" {
  58                 lines = lines[:len(lines)-1]
  59         }
  60         withoutDups := make([]string, 0, len(lines))
  61         emptyMet := false
  62         for _, line := range lines {
  63                 if line == "" {
  64                         if emptyMet {
  65                                 continue
  66                         }
  67                         emptyMet = true
  68                 } else {
  69                         emptyMet = false
  70                 }
  71                 withoutDups = append(withoutDups, line)
  72         }
  73         return withoutDups
  74 }
  75
  76 func main() {
  77         gitCmd := flag.String("git-cmd", "/usr/local/bin/git", "Path to git executable")
  78         gitDir := flag.String("git-dir", "", "Path to .git repository")
  79         notesRef := flag.String("ref", "comments", "notes reference name")
  80         umask := flag.String("umask", "027", "umask value")
  81         dryRun := flag.Bool("dryrun", false, "Show comment, do not add")
  82         committerEmail := flag.String(
  83                 "committer-email",
  84                 "comment@blog.example.com",
  85                 "Git committer's email",
  86         )
  87         flag.Parse()
  88         uid := syscall.Geteuid()
  89         if err := syscall.Setuid(uid); err != nil {
  90                 log.Fatal(err)
  91         }
  92         umaskInt, err := strconv.ParseUint(*umask, 8, 16)
  93         if err != nil {
  94                 panic(err)
  95         }
  96         syscall.Umask(int(umaskInt))
  97
  98         msg, err := mail.ReadMessage(os.Stdin)
  99         if err != nil {
 100                 log.Fatal(err)
 101         }
 102         subj, r, err := parseEmail(msg)
 103         if err != nil {
 104                 log.Fatal(err)
 105         }
 106         body, err := ioutil.ReadAll(r)
 107         if err != nil {
 108                 log.Fatal(err)
 109         }
 110         from := msg.Header.Get("From")
 111         if from == "" {
 112                 log.Fatal("From is missing")
 113         }
 114         if len(body) == 0 {
 115                 log.Fatal("no body")
 116         }
 117         from, err = new(mime.WordDecoder).DecodeHeader(from)
 118         if err != nil {
 119                 log.Fatal(err)
 120         }
 121
 122         subj = hashFinder.FindString(subj)
 123         if subj == "" {
 124                 log.Fatal("no commit hash found in subject")
 125         }
 126         if h, err := hex.DecodeString(subj); err != nil || len(h) != sha1.Size {
 127                 os.Exit(0)
 128         }
 129         fromCols := strings.Fields(from)
 130         if len(fromCols) == 1 {
 131                 if idx := strings.Index(from, "@"); idx != -1 {
 132                         from = strings.Trim(from[:idx], "<>")
 133                 }
 134         } else {
 135                 from = strings.Join(fromCols[:len(fromCols)-1], " ")
 136         }
 137
 138         cmd := exec.Command(
 139                 *gitCmd, "--git-dir", *gitDir,
 140                 "notes", "--ref", *notesRef, "show", subj,
 141         )
 142         note, _ := cmd.Output()
 143         note = bytes.TrimRight(note, "\r\n")
 144
 145         buf := bytes.NewBuffer(note)
 146         recfileW := recfile.NewWriter(buf)
 147         if _, err = recfileW.RecordStart(); err != nil {
 148                 log.Fatal(err)
 149         }
 150         // We trimmed newline, so have to start record twice
 151         if _, err = recfileW.RecordStart(); err != nil {
 152                 log.Fatal(err)
 153         }
 154         if _, err = recfileW.WriteFields(
 155                 recfile.Field{Name: "From", Value: from},
 156                 recfile.Field{Name: "Date", Value: time.Now().UTC().Format(sgblog.WhenFmt)},
 157         ); err != nil {
 158                 log.Fatal(err)
 159         }
 160         if _, err = recfileW.WriteFieldMultiline(
 161                 "Body", append([]string{""}, cleanupBody(string(body))...),
 162         ); err != nil {
 163                 log.Fatal(err)
 164         }
 165
 166         if *dryRun {
 167                 fmt.Print(buf.String())
 168                 os.Exit(0)
 169         }
 170
 171         cmd = exec.Command(
 172                 *gitCmd, "--git-dir", *gitDir,
 173                 "notes", "--ref", *notesRef, "add",
 174                 "-F", "-", "-f", subj,
 175         )
 176         cmd.Env = append(
 177                 cmd.Env,
 178                 "GIT_AUTHOR_NAME=SGBlog "+sgblog.Version,
 179                 "GIT_AUTHOR_EMAIL="+*committerEmail,
 180                 "GIT_COMMITTER_NAME=SGBlog "+sgblog.Version,
 181                 "GIT_COMMITTER_EMAIL="+*committerEmail,
 182         )
 183         cmd.Stdin = buf
 184         if err = cmd.Run(); err != nil {
 185                 log.Fatal(err)
 186         }
 187 }