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 "go.stargrave.org/sgblog"
43 "golang.org/x/crypto/blake2b"
44 "golang.org/x/tools/blog/atom"
45 "gopkg.in/src-d/go-git.v4"
46 "gopkg.in/src-d/go-git.v4/plumbing"
47 "gopkg.in/src-d/go-git.v4/plumbing/object"
52 AtomFeed = "feed.atom"
56 sha1DigestRe = regexp.MustCompilePOSIX("([0-9a-f]{40,40})")
57 defaultLinks = []string{}
59 notesTree *object.Tree
60 commentsTree *object.Tree
62 renderableSchemes = map[string]struct{}{
70 type TableEntry struct {
91 CommentsNotesRef string
95 func makeA(href, text string) string {
96 return `<a href="` + href + `">` + text + `</a>`
99 func etagString(etag hash.Hash) string {
100 return `"` + hex.EncodeToString(etag.Sum(nil)) + `"`
103 func urlParse(what string) *url.URL {
104 if u, err := url.ParseRequestURI(what); err == nil {
105 if _, exists := renderableSchemes[u.Scheme]; exists {
112 func msgSplit(msg string) []string {
113 lines := strings.Split(msg, "\n")
114 lines = lines[:len(lines)-1]
116 lines = []string{lines[0], "", ""}
121 func lineURLize(urlPrefix, line string) string {
122 cols := strings.Split(html.EscapeString(line), " ")
123 for i, col := range cols {
124 if u := urlParse(col); u != nil {
125 cols[i] = makeA(col, col)
128 cols[i] = sha1DigestRe.ReplaceAllString(col, makeA(
129 urlPrefix+"/$1", "$1",
132 return strings.Join(cols, " ")
135 func getNote(tree *object.Tree, what plumbing.Hash) []byte {
139 var entry *object.TreeEntry
141 paths := make([]string, 3)
142 paths[0] = what.String()
143 paths[1] = paths[0][:2] + "/" + paths[0][2:]
144 paths[2] = paths[1][:4+1] + "/" + paths[1][4+1:]
145 for _, p := range paths {
146 entry, err = tree.FindEntry(p)
154 blob, err := repo.BlobObject(entry.Hash)
158 r, err := blob.Reader()
162 data, err := ioutil.ReadAll(r)
166 return bytes.TrimSuffix(data, []byte{'\n'})
169 func parseComments(data []byte) []string {
170 comments := []string{}
171 nsr := netstring.NewReader(bytes.NewReader(data))
173 if _, err := nsr.Next(); err != nil {
176 if comment, err := ioutil.ReadAll(nsr); err == nil {
177 comments = append(comments, string(comment))
183 func startHeader(etag hash.Hash, gziped bool) string {
185 "Content-Type: text/html; charset=UTF-8",
186 "ETag: " + etagString(etag),
189 lines = append(lines, "Content-Encoding: gzip")
191 lines = append(lines, "")
192 lines = append(lines, "")
193 return strings.Join(lines, "\n")
196 func startHTML(title string, additional []string) string {
197 return fmt.Sprintf(`<html>
199 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
200 <meta name="generator" content="SGBlog %s">
206 sgblog.Version, title,
207 strings.Join(append(defaultLinks, additional...), "\n "),
211 func makeErr(err error) {
212 fmt.Print("Content-Type: text/plain; charset=UTF-8\n\n")
217 func checkETag(etag hash.Hash) {
218 ifNoneMatch := os.Getenv("HTTP_IF_NONE_MATCH")
219 if ifNoneMatch != "" && ifNoneMatch == etagString(etag) {
220 fmt.Printf("Status: 304\nETag: %s\n\n", ifNoneMatch)
226 cfgPath := os.Getenv("SGBLOG_CFG")
228 log.Fatalln("SGBLOG_CFG is not set")
230 pathInfo, exists := os.LookupEnv("PATH_INFO")
234 queryValues, err := url.ParseQuery(os.Getenv("QUERY_STRING"))
239 cfgRaw, err := ioutil.ReadFile(cfgPath)
243 var cfgGeneral map[string]interface{}
244 if err = hjson.Unmarshal(cfgRaw, &cfgGeneral); err != nil {
247 cfgRaw, err = json.Marshal(cfgGeneral)
252 if err = json.Unmarshal(cfgRaw, &cfg); err != nil {
256 etagHash, err := blake2b.New256(nil)
260 etagHash.Write([]byte("SGBLOG"))
261 etagHash.Write([]byte(sgblog.Version))
262 etagHash.Write([]byte(cfg.GitPath))
263 etagHash.Write([]byte(cfg.Branch))
264 etagHash.Write([]byte(cfg.Title))
265 etagHash.Write([]byte(cfg.BaseURL))
266 etagHash.Write([]byte(cfg.URLPrefix))
267 etagHash.Write([]byte(cfg.AtomId))
268 etagHash.Write([]byte(cfg.AtomAuthor))
270 etagHashForWeb := [][]byte{}
272 defaultLinks = append(defaultLinks, `<link rel="stylesheet" type="text/css" href="`+cfg.CSS+`">`)
273 etagHashForWeb = append(etagHashForWeb, []byte(cfg.CSS))
275 if cfg.Webmaster != "" {
276 defaultLinks = append(defaultLinks, `<link rev="made" href="mailto:`+cfg.Webmaster+`">`)
277 etagHashForWeb = append(etagHashForWeb, []byte(cfg.Webmaster))
279 if cfg.AboutURL != "" {
280 etagHashForWeb = append(etagHashForWeb, []byte(cfg.AboutURL))
282 for _, gitURL := range cfg.GitURLs {
283 defaultLinks = append(defaultLinks, `<link rel="vcs-git" href="`+gitURL+`" title="Git repository">`)
284 etagHashForWeb = append(etagHashForWeb, []byte(gitURL))
286 if cfg.CommentsNotesRef != "" {
287 etagHashForWeb = append(etagHashForWeb, []byte(cfg.CommentsNotesRef))
289 if cfg.CommentsEmail != "" {
290 etagHashForWeb = append(etagHashForWeb, []byte(cfg.CommentsEmail))
293 defaultLinks = append(defaultLinks, `<link rel="top" href="`+cfg.URLPrefix+`/" title="top">`)
294 atomURL := cfg.BaseURL + cfg.URLPrefix + "/" + AtomFeed
295 defaultLinks = append(defaultLinks, `<link rel="alternate" title="Atom feed" href="`+atomURL+`" type="application/atom+xml">`)
297 repo, err = git.PlainOpen(cfg.GitPath)
301 head, err := repo.Reference(plumbing.ReferenceName(cfg.Branch), false)
306 if notes, err := repo.Notes(); err == nil {
307 var notesRef *plumbing.Reference
308 var commentsRef *plumbing.Reference
309 notes.ForEach(func(ref *plumbing.Reference) error {
310 switch string(ref.Name()) {
311 case "refs/notes/commits":
313 case cfg.CommentsNotesRef:
319 if commentsCommit, err := repo.CommitObject(notesRef.Hash()); err == nil {
320 notesTree, _ = commentsCommit.Tree()
323 if commentsRef != nil {
324 if commentsCommit, err := repo.CommitObject(commentsRef.Hash()); err == nil {
325 commentsTree, _ = commentsCommit.Tree()
330 var outBuf bytes.Buffer
333 var gzipWriter *gzip.Writer
334 acceptEncoding := os.Getenv("HTTP_ACCEPT_ENCODING")
335 for _, encoding := range strings.Split(acceptEncoding, ", ") {
336 if encoding == "gzip" {
337 gzipWriter = gzip.NewWriter(&outBuf)
344 if offsetRaw, exists := queryValues["offset"]; exists {
345 offset, err = strconv.Atoi(offsetRaw[0])
350 log, err := repo.Log(&git.LogOptions{From: head.Hash()})
355 for i := 0; i < offset; i++ {
356 if _, err = log.Next(); err != nil {
362 entries := make([]TableEntry, 0, PageEntries)
364 for _, data := range etagHashForWeb {
367 etagHash.Write([]byte("INDEX"))
368 for i := 0; i < PageEntries; i++ {
369 commit, err := log.Next()
374 etagHash.Write(commit.Hash[:])
375 commentsRaw := getNote(commentsTree, commit.Hash)
376 etagHash.Write(commentsRaw)
377 entries = append(entries, TableEntry{commit, commentsRaw})
381 var table bytes.Buffer
383 "<table border=1>\n<tr>" +
387 "<th size=\"5%\">L</th>" +
388 "<th size=\"5%\">C</th>" +
389 "<th>Linked to</th></tr>\n")
390 for _, entry := range entries {
392 lines := msgSplit(entry.commit.Message)
393 domains := []string{}
394 for _, line := range lines[2:] {
395 if u := urlParse(line); u == nil {
398 domains = append(domains, makeA(line, u.Host))
401 var commentsValue string
402 if l := len(parseComments(entry.commentsRaw)); l > 0 {
403 commentsValue = strconv.Itoa(l)
405 commentsValue = " "
407 table.WriteString(fmt.Sprintf(
408 "<tr><td>%d</td><td><tt>%s</tt></td>"+
410 "<td>%d</td><td>%s</td>"+
411 "<td>%s</td></tr>\n",
412 commentN, entry.commit.Author.When.Format(sgblog.WhenFmt),
413 makeA(cfg.URLPrefix+"/"+entry.commit.Hash.String(), lines[0]),
416 strings.Join(domains, " "),
419 table.WriteString("</table>")
423 var refs bytes.Buffer
425 if offsetPrev := offset - PageEntries; offsetPrev > 0 {
426 href = cfg.URLPrefix + "/?offset=" + strconv.Itoa(offsetPrev)
428 href = cfg.URLPrefix + "/"
430 links = append(links, `<link rel="prev" href="`+href+`" title="newer">`)
431 refs.WriteString(makeA(href, " [prev]"))
434 href = cfg.URLPrefix + "/?offset=" + strconv.Itoa(offset+PageEntries)
435 links = append(links, `<link rel="next" href="`+href+`" title="older">`)
436 refs.WriteString(makeA(href, " [next]"))
439 os.Stdout.Write([]byte(startHeader(etagHash, gzipWriter != nil)))
440 out.Write([]byte(startHTML(
441 fmt.Sprintf("%s (%d-%d)", cfg.Title, offset, offset+PageEntries),
444 if cfg.AboutURL != "" {
445 out.Write([]byte(fmt.Sprintf("[%s]", makeA(cfg.AboutURL, "about"))))
447 out.Write(refs.Bytes())
448 out.Write(table.Bytes())
449 out.Write(refs.Bytes())
450 out.Write([]byte("\n"))
451 } else if pathInfo == "/"+AtomFeed {
452 commit, err := repo.CommitObject(head.Hash())
456 etagHash.Write([]byte("ATOM"))
457 etagHash.Write(commit.Hash[:])
462 Updated: atom.Time(commit.Author.When),
467 Author: &atom.Person{Name: cfg.AtomAuthor},
469 log, err := repo.Log(&git.LogOptions{From: head.Hash()})
473 for i := 0; i < PageEntries; i++ {
474 commit, err = log.Next()
479 feedIdRaw := new([16]byte)
480 copy(feedIdRaw[:], commit.Hash[:])
481 feedIdRaw[6] = (feedIdRaw[6] & 0x0F) | uint8(4<<4) // version 4
482 feedId := fmt.Sprintf(
491 lines := msgSplit(commit.Message)
492 feed.Entry = append(feed.Entry, &atom.Entry{
494 ID: "urn:uuid:" + feedId,
497 Href: cfg.BaseURL + cfg.URLPrefix + "/" + commit.Hash.String(),
499 Published: atom.Time(commit.Author.When),
500 Updated: atom.Time(commit.Author.When),
507 Body: strings.Join(lines[2:], "\n"),
511 data, err := xml.MarshalIndent(&feed, "", " ")
516 os.Stdout.WriteString("Content-Type: text/xml; charset=UTF-8\n")
517 os.Stdout.WriteString("ETag: " + etagString(etagHash) + "\n")
518 if gzipWriter != nil {
519 os.Stdout.WriteString("Content-Encoding: gzip\n")
522 os.Stdout.WriteString("\n")
523 os.Stdout.Write(outBuf.Bytes())
525 } else if sha1DigestRe.MatchString(pathInfo[1:]) {
526 commit, err := repo.CommitObject(plumbing.NewHash(pathInfo[1:]))
530 for _, data := range etagHashForWeb {
533 etagHash.Write([]byte("ENTRY"))
534 etagHash.Write(commit.Hash[:])
535 notesRaw := getNote(notesTree, commit.Hash)
536 etagHash.Write(notesRaw)
537 commentsRaw := getNote(commentsTree, commit.Hash)
538 etagHash.Write(commentsRaw)
540 lines := msgSplit(commit.Message)
542 when := commit.Author.When.Format(sgblog.WhenFmt)
543 os.Stdout.Write([]byte(startHeader(etagHash, gzipWriter != nil)))
546 if len(commit.ParentHashes) > 0 {
547 parent = commit.ParentHashes[0].String()
548 links = append(links, `<link rel="prev" href="`+cfg.URLPrefix+"/"+parent+`" title="older">`)
550 out.Write([]byte(startHTML(fmt.Sprintf("%s (%s)", title, when), links)))
551 if cfg.AboutURL != "" {
552 out.Write([]byte(fmt.Sprintf("[%s] ", makeA(cfg.AboutURL, "about"))))
555 out.Write([]byte(fmt.Sprintf(
557 makeA(cfg.URLPrefix+"/"+parent, "older"),
560 out.Write([]byte(fmt.Sprintf(
561 "[<tt>%s</tt>] [<tt>%s</tt>]<hr/>\n<h2>%s</h2>\n<pre>\n",
562 when, commit.Hash.String(), title,
564 for _, line := range lines[2:] {
565 out.Write([]byte(lineURLize(cfg.URLPrefix, line) + "\n"))
567 out.Write([]byte("</pre>\n<hr/>\n"))
568 if len(notesRaw) > 0 {
569 out.Write([]byte("Note:<pre>\n" + string(notesRaw) + "\n</pre>\n<hr/>\n"))
571 if cfg.CommentsEmail != "" {
572 out.Write([]byte("[" + makeA(
573 "mailto:"+cfg.CommentsEmail+"?subject="+commit.Hash.String(),
577 out.Write([]byte("<dl>\n"))
578 for i, comment := range parseComments(commentsRaw) {
579 out.Write([]byte(fmt.Sprintf(
580 "<dt><a name=\"comment%d\"><a href=\"#comment%d\">comment %d</a>:"+
581 "</dt>\n<dd><pre>\n",
584 lines = strings.Split(comment, "\n")
585 for _, line := range lines[:3] {
586 out.Write([]byte(line + "\n"))
588 for _, line := range lines[3:] {
589 out.Write([]byte(lineURLize(cfg.URLPrefix, line) + "\n"))
591 out.Write([]byte("</pre></dd>\n"))
593 out.Write([]byte("</dl>\n"))
595 makeErr(errors.New("unknown URL action"))
597 out.Write([]byte("</body></html>\n"))
598 if gzipWriter != nil {
601 os.Stdout.Write(outBuf.Bytes())