2 SGBlog -- Git-based CGI blogging engine
3 Copyright (C) 2020 Sergey Matveev <stargrave@stargrave.org>
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.
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.
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/>.
18 // Git-based CGI blogging engine
40 "github.com/hjson/hjson-go"
41 "go.cypherpunks.ru/netstring/v2"
42 "golang.org/x/crypto/blake2b"
43 "golang.org/x/tools/blog/atom"
44 "gopkg.in/src-d/go-git.v4"
45 "gopkg.in/src-d/go-git.v4/plumbing"
46 "gopkg.in/src-d/go-git.v4/plumbing/object"
51 WhenFmt = "2006-01-02 15:04:05Z07:00"
52 AtomFeed = "feed.atom"
57 sha1DigestRe = regexp.MustCompilePOSIX("([0-9a-f]{40,40})")
58 defaultLinks = []string{}
60 notesTree *object.Tree
61 commentsTree *object.Tree
63 renderableSchemes = map[string]struct{}{
71 type TableEntry struct {
92 CommentsNotesRef string
96 func makeA(href, text string) string {
97 return `<a href="` + href + `">` + text + `</a>`
100 func etagString(etag hash.Hash) string {
101 return `"` + hex.EncodeToString(etag.Sum(nil)) + `"`
104 func urlParse(what string) *url.URL {
105 if u, err := url.ParseRequestURI(what); err == nil {
106 if _, exists := renderableSchemes[u.Scheme]; exists {
113 func msgSplit(msg string) []string {
114 lines := strings.Split(msg, "\n")
115 lines = lines[:len(lines)-1]
117 lines = []string{lines[0], "", ""}
122 func getNote(tree *object.Tree, what plumbing.Hash) []byte {
126 entry, err := tree.FindEntry(what.String())
130 blob, err := repo.BlobObject(entry.Hash)
134 r, err := blob.Reader()
138 data, err := ioutil.ReadAll(r)
142 return bytes.TrimSuffix(data, []byte{'\n'})
145 func parseComments(data []byte) []string {
146 comments := []string{}
147 nsr := netstring.NewReader(bytes.NewReader(data))
149 if _, err := nsr.Next(); err != nil {
152 if comment, err := ioutil.ReadAll(nsr); err == nil {
153 comments = append(comments, string(comment))
159 func startHeader(etag hash.Hash, gziped bool) string {
161 "Content-Type: text/html; charset=UTF-8",
162 "ETag: " + etagString(etag),
165 lines = append(lines, "Content-Encoding: gzip")
167 lines = append(lines, "")
168 lines = append(lines, "")
169 return strings.Join(lines, "\n")
172 func startHTML(title string, additional []string) string {
173 return fmt.Sprintf(`<html>
175 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
176 <meta name="generator" content="SGBlog %s">
183 strings.Join(append(defaultLinks, additional...), "\n "),
187 func makeErr(err error) {
188 fmt.Print("Content-Type: text/plain; charset=UTF-8\n\n")
193 func checkETag(etag hash.Hash) {
194 ifNoneMatch := os.Getenv("HTTP_IF_NONE_MATCH")
195 if ifNoneMatch != "" && ifNoneMatch == etagString(etag) {
196 fmt.Printf("Status: 304\nETag: %s\n\n", ifNoneMatch)
202 cfgPath := os.Getenv("SGBLOG_CFG")
204 log.Fatalln("SGBLOG_CFG is not set")
206 pathInfo, exists := os.LookupEnv("PATH_INFO")
210 queryValues, err := url.ParseQuery(os.Getenv("QUERY_STRING"))
215 cfgRaw, err := ioutil.ReadFile(cfgPath)
219 var cfgGeneral map[string]interface{}
220 if err = hjson.Unmarshal(cfgRaw, &cfgGeneral); err != nil {
223 cfgRaw, err = json.Marshal(cfgGeneral)
228 if err = json.Unmarshal(cfgRaw, &cfg); err != nil {
232 etagHash, err := blake2b.New256(nil)
236 etagHash.Write([]byte("SGBLOG"))
237 etagHash.Write([]byte(cfg.GitPath))
238 etagHash.Write([]byte(cfg.Branch))
239 etagHash.Write([]byte(cfg.Title))
240 etagHash.Write([]byte(cfg.BaseURL))
241 etagHash.Write([]byte(cfg.URLPrefix))
242 etagHash.Write([]byte(cfg.AtomId))
243 etagHash.Write([]byte(cfg.AtomAuthor))
245 etagHashForWeb := [][]byte{}
247 defaultLinks = append(defaultLinks, `<link rel="stylesheet" type="text/css" href="`+cfg.CSS+`">`)
248 etagHashForWeb = append(etagHashForWeb, []byte(cfg.CSS))
250 if cfg.Webmaster != "" {
251 defaultLinks = append(defaultLinks, `<link rev="made" href="mailto:`+cfg.Webmaster+`">`)
252 etagHashForWeb = append(etagHashForWeb, []byte(cfg.Webmaster))
254 if cfg.AboutURL != "" {
255 etagHashForWeb = append(etagHashForWeb, []byte(cfg.AboutURL))
257 for _, gitURL := range cfg.GitURLs {
258 defaultLinks = append(defaultLinks, `<link rel="vcs-git" href="`+gitURL+`" title="Git repository">`)
259 etagHashForWeb = append(etagHashForWeb, []byte(gitURL))
261 if cfg.CommentsNotesRef != "" {
262 etagHashForWeb = append(etagHashForWeb, []byte(cfg.CommentsNotesRef))
264 if cfg.CommentsEmail != "" {
265 etagHashForWeb = append(etagHashForWeb, []byte(cfg.CommentsEmail))
268 defaultLinks = append(defaultLinks, `<link rel="top" href="`+cfg.URLPrefix+`/" title="top">`)
269 atomURL := cfg.BaseURL + cfg.URLPrefix + "/" + AtomFeed
270 defaultLinks = append(defaultLinks, `<link rel="alternate" title="Atom feed" href="`+atomURL+`" type="application/atom+xml">`)
272 repo, err = git.PlainOpen(cfg.GitPath)
276 head, err := repo.Reference(plumbing.ReferenceName(cfg.Branch), false)
281 if notes, err := repo.Notes(); err == nil {
282 var notesRef *plumbing.Reference
283 var commentsRef *plumbing.Reference
284 notes.ForEach(func(ref *plumbing.Reference) error {
285 switch string(ref.Name()) {
286 case "refs/notes/commits":
288 case cfg.CommentsNotesRef:
294 if commentsCommit, err := repo.CommitObject(notesRef.Hash()); err == nil {
295 notesTree, _ = commentsCommit.Tree()
298 if commentsRef != nil {
299 if commentsCommit, err := repo.CommitObject(commentsRef.Hash()); err == nil {
300 commentsTree, _ = commentsCommit.Tree()
305 var outBuf bytes.Buffer
308 var gzipWriter *gzip.Writer
309 acceptEncoding := os.Getenv("HTTP_ACCEPT_ENCODING")
310 for _, encoding := range strings.Split(acceptEncoding, ", ") {
311 if encoding == "gzip" {
312 gzipWriter = gzip.NewWriter(&outBuf)
319 if offsetRaw, exists := queryValues["offset"]; exists {
320 offset, err = strconv.Atoi(offsetRaw[0])
325 log, err := repo.Log(&git.LogOptions{From: head.Hash()})
330 for i := 0; i < offset; i++ {
331 if _, err = log.Next(); err != nil {
337 entries := make([]TableEntry, 0, PageEntries)
339 for _, data := range etagHashForWeb {
342 etagHash.Write([]byte("INDEX"))
343 for i := 0; i < PageEntries; i++ {
344 commit, err := log.Next()
349 etagHash.Write(commit.Hash[:])
350 commentsRaw := getNote(commentsTree, commit.Hash)
351 etagHash.Write(commentsRaw)
352 entries = append(entries, TableEntry{commit, commentsRaw})
356 var table bytes.Buffer
358 "<table border=1>\n<tr>" +
362 "<th size=\"5%\">L</th>" +
363 "<th size=\"5%\">C</th>" +
364 "<th>Linked to</th></tr>\n")
365 for _, entry := range entries {
367 lines := msgSplit(entry.commit.Message)
368 domains := []string{}
369 for _, line := range lines[2:] {
370 if u := urlParse(line); u == nil {
373 domains = append(domains, makeA(line, u.Host))
376 var commentsValue string
377 if l := len(parseComments(entry.commentsRaw)); l > 0 {
378 commentsValue = strconv.Itoa(l)
380 commentsValue = " "
382 table.WriteString(fmt.Sprintf(
383 "<tr><td>%d</td><td><tt>%s</tt></td>"+
385 "<td>%d</td><td>%s</td>"+
386 "<td>%s</td></tr>\n",
387 commentN, entry.commit.Author.When.Format(WhenFmt),
388 makeA(cfg.URLPrefix+"/"+entry.commit.Hash.String(), lines[0]),
391 strings.Join(domains, " "),
394 table.WriteString("</table>")
398 var refs bytes.Buffer
400 if offsetPrev := offset - PageEntries; offsetPrev > 0 {
401 href = cfg.URLPrefix + "/?offset=" + strconv.Itoa(offsetPrev)
403 href = cfg.URLPrefix + "/"
405 links = append(links, `<link rel="prev" href="`+href+`" title="newer">`)
406 refs.WriteString(makeA(href, " [prev]"))
409 href = cfg.URLPrefix + "/?offset=" + strconv.Itoa(offset+PageEntries)
410 links = append(links, `<link rel="next" href="`+href+`" title="older">`)
411 refs.WriteString(makeA(href, " [next]"))
414 os.Stdout.Write([]byte(startHeader(etagHash, gzipWriter != nil)))
415 out.Write([]byte(startHTML(
416 fmt.Sprintf("%s (%d-%d)", cfg.Title, offset, offset+PageEntries),
419 if cfg.AboutURL != "" {
420 out.Write([]byte(fmt.Sprintf("[%s]", makeA(cfg.AboutURL, "about"))))
422 out.Write(refs.Bytes())
423 out.Write(table.Bytes())
424 out.Write(refs.Bytes())
425 out.Write([]byte("\n"))
426 } else if pathInfo == "/"+AtomFeed {
427 commit, err := repo.CommitObject(head.Hash())
431 etagHash.Write([]byte("ATOM"))
432 etagHash.Write(commit.Hash[:])
437 Updated: atom.Time(commit.Author.When),
442 Author: &atom.Person{Name: cfg.AtomAuthor},
444 log, err := repo.Log(&git.LogOptions{From: head.Hash()})
448 for i := 0; i < PageEntries; i++ {
449 commit, err = log.Next()
454 feedIdRaw := new([16]byte)
455 copy(feedIdRaw[:], commit.Hash[:])
456 feedIdRaw[6] = (feedIdRaw[6] & 0x0F) | uint8(4<<4) // version 4
457 feedId := fmt.Sprintf(
466 lines := msgSplit(commit.Message)
467 feed.Entry = append(feed.Entry, &atom.Entry{
469 ID: "urn:uuid:" + feedId,
472 Href: cfg.BaseURL + cfg.URLPrefix + "/" + commit.Hash.String(),
474 Published: atom.Time(commit.Author.When),
475 Updated: atom.Time(commit.Author.When),
482 Body: strings.Join(lines[2:], "\n"),
486 data, err := xml.MarshalIndent(&feed, "", " ")
491 os.Stdout.WriteString("Content-Type: text/xml; charset=UTF-8\n")
492 os.Stdout.WriteString("ETag: " + etagString(etagHash) + "\n")
493 if gzipWriter != nil {
494 os.Stdout.WriteString("Content-Encoding: gzip\n")
497 os.Stdout.WriteString("\n")
498 os.Stdout.Write(outBuf.Bytes())
500 } else if sha1DigestRe.MatchString(pathInfo[1:]) {
501 commit, err := repo.CommitObject(plumbing.NewHash(pathInfo[1:]))
505 for _, data := range etagHashForWeb {
508 etagHash.Write([]byte("ENTRY"))
509 etagHash.Write(commit.Hash[:])
510 notesRaw := getNote(notesTree, commit.Hash)
511 etagHash.Write(notesRaw)
512 commentsRaw := getNote(commentsTree, commit.Hash)
513 etagHash.Write(commentsRaw)
515 lines := msgSplit(commit.Message)
517 when := commit.Author.When.Format(WhenFmt)
518 os.Stdout.Write([]byte(startHeader(etagHash, gzipWriter != nil)))
521 if len(commit.ParentHashes) > 0 {
522 parent = commit.ParentHashes[0].String()
523 links = append(links, `<link rel="prev" href="`+cfg.URLPrefix+"/"+parent+`" title="older">`)
525 out.Write([]byte(startHTML(fmt.Sprintf("%s (%s)", title, when), links)))
526 if cfg.AboutURL != "" {
527 out.Write([]byte(fmt.Sprintf("[%s] ", makeA(cfg.AboutURL, "about"))))
530 out.Write([]byte(fmt.Sprintf(
532 makeA(cfg.URLPrefix+"/"+parent, "older"),
535 out.Write([]byte(fmt.Sprintf(
536 "[<tt>%s</tt>] [<tt>%s</tt>]<hr/>\n<h2>%s</h2>\n<pre>\n",
537 when, commit.Hash.String(), title,
539 for _, line := range lines[2:] {
540 line = html.EscapeString(line)
541 cols := strings.Split(line, " ")
542 for i, col := range cols {
543 if u := urlParse(col); u != nil {
544 cols[i] = makeA(col, col)
547 cols[i] = sha1DigestRe.ReplaceAllString(col, makeA(
548 cfg.URLPrefix+"/$1", "$1",
551 line = strings.Join(cols, " ")
552 out.Write([]byte(line + "\n"))
554 out.Write([]byte("</pre>\n<hr/>\n"))
555 if len(notesRaw) > 0 {
556 out.Write([]byte("Note:<pre>\n" + string(notesRaw) + "\n</pre>\n<hr/>\n"))
558 if cfg.CommentsEmail != "" {
559 out.Write([]byte("[" + makeA(
560 "mailto:"+cfg.CommentsEmail+"?subject="+commit.Hash.String(),
564 out.Write([]byte("<dl>\n"))
565 for i, comment := range parseComments(commentsRaw) {
566 out.Write([]byte(fmt.Sprintf(
567 "<dt><a name=\"comment%d\"><a href=\"#comment%d\">comment %d</a>:"+
568 "</dt>\n<dd><pre>\n%s\n</pre></dd>\n",
569 i, i, i, html.EscapeString(comment),
572 out.Write([]byte("</dl>\n"))
574 makeErr(errors.New("unknown URL action"))
576 out.Write([]byte("</body></html>\n"))
577 if gzipWriter != nil {
580 os.Stdout.Write(outBuf.Bytes())