cmd/sgblog/http.go

   1 /*
   2 SGBlog -- Git-backed CGI/UCSPI blogging/phlogging/gemlogging 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 package main
  19
  20 import (
  21         "bytes"
  22         "compress/gzip"
  23         "crypto/sha1"
  24         _ "embed"
  25         "encoding/hex"
  26         "encoding/xml"
  27         "errors"
  28         "fmt"
  29         "hash"
  30         "html"
  31         "io"
  32         "log"
  33         "net/http"
  34         "net/url"
  35         "os"
  36         "strconv"
  37         "strings"
  38         "text/template"
  39         "time"
  40
  41         "github.com/go-git/go-git/v5"
  42         "github.com/go-git/go-git/v5/plumbing"
  43         "github.com/go-git/go-git/v5/plumbing/object"
  44         "go.stargrave.org/sgblog"
  45         "go.stargrave.org/sgblog/cmd/sgblog/atom"
  46         "golang.org/x/crypto/blake2b"
  47 )
  48
  49 const (
  50         AtomPostsFeed    = "feed.atom"
  51         AtomCommentsFeed = "comments.atom"
  52 )
  53
  54 var (
  55         renderableSchemes = map[string]struct{}{
  56                 "finger": {},
  57                 "ftp":    {},
  58                 "gemini": {},
  59                 "gopher": {},
  60                 "http":   {},
  61                 "https":  {},
  62                 "irc":    {},
  63                 "ircs":   {},
  64                 "news":   {},
  65                 "telnet": {},
  66         }
  67
  68         //go:embed http-index.tmpl
  69         TmplHTMLIndexRaw string
  70         TmplHTMLIndex    = template.Must(template.New("http-index").Parse(TmplHTMLIndexRaw))
  71
  72         //go:embed http-entry.tmpl
  73         TmplHTMLEntryRaw string
  74         TmplHTMLEntry    = template.Must(template.New("http-entry").Funcs(
  75                 template.FuncMap{"lineURLize": lineURLizeInTemplate},
  76         ).Parse(TmplHTMLEntryRaw))
  77 )
  78
  79 type TableEntry struct {
  80         Commit      *object.Commit
  81         CommentsRaw []byte
  82         TopicsRaw   []byte
  83         Num         int
  84         Title       string
  85         LinesNum    int
  86         CommentsNum int
  87         DomainURLs  []string
  88         Topics      []string
  89 }
  90
  91 type CommentEntry struct {
  92         HeaderLines []string
  93         BodyLines   []string
  94 }
  95
  96 func makeA(href, text string) string {
  97         return `<a href="` + href + `">` + text + `</a>`
  98 }
  99
 100 func etagString(etag hash.Hash) string {
 101         return `"` + hex.EncodeToString(etag.Sum(nil)) + `"`
 102 }
 103
 104 func urlParse(what string) *url.URL {
 105         if u, err := url.ParseRequestURI(what); err == nil {
 106                 if _, exists := renderableSchemes[u.Scheme]; exists {
 107                         return u
 108                 }
 109         }
 110         return nil
 111 }
 112
 113 func lineURLize(urlPrefix, line string) string {
 114         cols := strings.Split(html.EscapeString(line), " ")
 115         for i, col := range cols {
 116                 if u := urlParse(col); u != nil {
 117                         cols[i] = makeA(col, col)
 118                         continue
 119                 }
 120                 cols[i] = sha1DigestRe.ReplaceAllString(col, makeA(urlPrefix+"/$1", "$1"))
 121         }
 122         return strings.Join(cols, " ")
 123 }
 124
 125 func lineURLizeInTemplate(urlPrefix, line interface{}) string {
 126         return lineURLize(urlPrefix.(string), line.(string))
 127 }
 128
 129 func startHeader(etag hash.Hash, gziped bool) string {
 130         lines := []string{
 131                 "Content-Type: text/html; charset=utf-8",
 132                 "ETag: " + etagString(etag),
 133         }
 134         if gziped {
 135                 lines = append(lines, "Content-Encoding: gzip")
 136         }
 137         lines = append(lines, "")
 138         lines = append(lines, "")
 139         return strings.Join(lines, "\n")
 140 }
 141
 142 func makeErr(err error, status int) {
 143         fmt.Println("Status:", status)
 144         fmt.Print("Content-Type: text/plain; charset=utf-8\n\n")
 145         fmt.Println(err)
 146         log.Fatalln(err)
 147 }
 148
 149 func checkETag(etag hash.Hash) {
 150         ifNoneMatch := os.Getenv("HTTP_IF_NONE_MATCH")
 151         if ifNoneMatch != "" && ifNoneMatch == etagString(etag) {
 152                 fmt.Printf("Status: 304\nETag: %s\n\n", ifNoneMatch)
 153                 os.Exit(0)
 154         }
 155 }
 156
 157 func bytes2uuid(b []byte) string {
 158         raw := new([16]byte)
 159         copy(raw[:], b)
 160         raw[6] = (raw[6] & 0x0F) | uint8(4<<4) // version 4
 161         return fmt.Sprintf("%x-%x-%x-%x-%x", raw[0:4], raw[4:6], raw[6:8], raw[8:10], raw[10:])
 162 }
 163
 164 type CommitIterNext interface {
 165         Next() (*object.Commit, error)
 166 }
 167
 168 func serveHTTP() {
 169         cfgPath := os.Getenv("SGBLOG_CFG")
 170         if cfgPath == "" {
 171                 log.Fatalln("SGBLOG_CFG is not set")
 172         }
 173         cfg, err := readCfg(cfgPath)
 174         if err != nil {
 175                 log.Fatalln(err)
 176         }
 177
 178         pathInfo := os.Getenv("PATH_INFO")
 179         if len(pathInfo) == 0 {
 180                 pathInfo = "/"
 181         }
 182         queryValues, err := url.ParseQuery(os.Getenv("QUERY_STRING"))
 183         if err != nil {
 184                 makeErr(err, http.StatusBadRequest)
 185         }
 186
 187         etagHash, err := blake2b.New256(nil)
 188         if err != nil {
 189                 panic(err)
 190         }
 191         for _, s := range []string{
 192                 "SGBLOG",
 193                 sgblog.Version,
 194                 cfg.GitPath,
 195                 cfg.Branch,
 196                 cfg.Title,
 197                 cfg.URLPrefix,
 198                 cfg.AtomBaseURL,
 199                 cfg.AtomId,
 200                 cfg.AtomAuthor,
 201         } {
 202                 if _, err = etagHash.Write([]byte(s)); err != nil {
 203                         panic(err)
 204                 }
 205         }
 206         etagHashForWeb := []string{
 207                 cfg.CSS,
 208                 cfg.Webmaster,
 209                 cfg.AboutURL,
 210                 cfg.CommentsNotesRef,
 211                 cfg.CommentsEmail,
 212         }
 213         for _, gitURL := range cfg.GitURLs {
 214                 etagHashForWeb = append(etagHashForWeb, gitURL)
 215         }
 216
 217         headHash, err := initRepo(cfg)
 218         if err != nil {
 219                 makeErr(err, http.StatusInternalServerError)
 220         }
 221
 222         if notes, err := repo.Notes(); err == nil {
 223                 var notesRef *plumbing.Reference
 224                 var commentsRef *plumbing.Reference
 225                 notes.ForEach(func(ref *plumbing.Reference) error {
 226                         switch string(ref.Name()) {
 227                         case "refs/notes/commits":
 228                                 notesRef = ref
 229                         case cfg.CommentsNotesRef:
 230                                 commentsRef = ref
 231                         }
 232                         return nil
 233                 })
 234                 if notesRef != nil {
 235                         if commentsCommit, err := repo.CommitObject(notesRef.Hash()); err == nil {
 236                                 notesTree, _ = commentsCommit.Tree()
 237                         }
 238                 }
 239                 if commentsRef != nil {
 240                         if commentsCommit, err := repo.CommitObject(commentsRef.Hash()); err == nil {
 241                                 commentsTree, _ = commentsCommit.Tree()
 242                         }
 243                 }
 244         }
 245
 246         var outBuf bytes.Buffer
 247         var out io.Writer
 248         out = &outBuf
 249         var gzipWriter *gzip.Writer
 250         acceptEncoding := os.Getenv("HTTP_ACCEPT_ENCODING")
 251         for _, encoding := range strings.Split(acceptEncoding, ", ") {
 252                 if encoding == "gzip" {
 253                         gzipWriter = gzip.NewWriter(&outBuf)
 254                         out = gzipWriter
 255                 }
 256         }
 257
 258         if pathInfo == "/" {
 259                 offset := 0
 260                 if offsetRaw, exists := queryValues["offset"]; exists {
 261                         offset, err = strconv.Atoi(offsetRaw[0])
 262                         if err != nil {
 263                                 makeErr(err, http.StatusBadRequest)
 264                         }
 265                 }
 266                 repoLog, err := repo.Log(&git.LogOptions{From: *headHash})
 267                 if err != nil {
 268                         makeErr(err, http.StatusInternalServerError)
 269                 }
 270                 topicsCache, err := getTopicsCache(cfg, repoLog)
 271                 if err != nil {
 272                         makeErr(err, http.StatusInternalServerError)
 273                 }
 274                 repoLog, err = repo.Log(&git.LogOptions{From: *headHash})
 275                 if err != nil {
 276                         makeErr(err, http.StatusInternalServerError)
 277                 }
 278
 279                 commitN := 0
 280                 var commits CommitIterNext
 281                 var topic string
 282                 if t, exists := queryValues["topic"]; exists {
 283                         topic = t[0]
 284                         hashes := topicsCache[topic]
 285                         if hashes == nil {
 286                                 makeErr(errors.New("no posts with that topic"), http.StatusBadRequest)
 287                         }
 288                         if len(hashes) > offset {
 289                                 hashes = hashes[offset:]
 290                                 commitN += offset
 291                         }
 292                         commits = &HashesIter{hashes}
 293                 } else {
 294                         for i := 0; i < offset; i++ {
 295                                 if _, err = repoLog.Next(); err != nil {
 296                                         break
 297                                 }
 298                                 commitN++
 299                         }
 300                         commits = repoLog
 301                 }
 302
 303                 entries := make([]TableEntry, 0, PageEntries)
 304                 logEnded := false
 305                 for _, data := range etagHashForWeb {
 306                         etagHash.Write([]byte(data))
 307                 }
 308                 etagHash.Write([]byte("INDEX"))
 309                 etagHash.Write([]byte(topic))
 310                 for i := 0; i < PageEntries; i++ {
 311                         commit, err := commits.Next()
 312                         if err != nil {
 313                                 logEnded = true
 314                                 break
 315                         }
 316                         etagHash.Write(commit.Hash[:])
 317                         commentsRaw := sgblog.GetNote(repo, commentsTree, commit.Hash)
 318                         etagHash.Write(commentsRaw)
 319                         topicsRaw := sgblog.GetNote(repo, topicsTree, commit.Hash)
 320                         etagHash.Write(topicsRaw)
 321                         entries = append(entries, TableEntry{
 322                                 Commit:      commit,
 323                                 CommentsRaw: commentsRaw,
 324                                 TopicsRaw:   topicsRaw,
 325                         })
 326                 }
 327                 checkETag(etagHash)
 328
 329                 for i, entry := range entries {
 330                         commitN++
 331                         entry.Num = commitN
 332                         lines := msgSplit(entry.Commit.Message)
 333                         entry.Title = lines[0]
 334                         entry.LinesNum = len(lines) - 2
 335                         for _, line := range lines[2:] {
 336                                 u := urlParse(line)
 337                                 if u == nil {
 338                                         break
 339                                 }
 340                                 entry.DomainURLs = append(entry.DomainURLs, makeA(line, u.Host))
 341                         }
 342                         entry.CommentsNum = len(sgblog.ParseComments(entry.CommentsRaw))
 343                         entry.Topics = sgblog.ParseTopics(entry.TopicsRaw)
 344                         entries[i] = entry
 345                 }
 346                 offsetPrev := offset - PageEntries
 347                 if offsetPrev < 0 {
 348                         offsetPrev = 0
 349                 }
 350                 os.Stdout.Write([]byte(startHeader(etagHash, gzipWriter != nil)))
 351                 err = TmplHTMLIndex.Execute(out, struct {
 352                         Version          string
 353                         Cfg              *Cfg
 354                         Topic            string
 355                         TopicsEnabled    bool
 356                         Topics           []string
 357                         CommentsEnabled  bool
 358                         AtomPostsFeed    string
 359                         AtomCommentsFeed string
 360                         Offset           int
 361                         OffsetPrev       int
 362                         OffsetNext       int
 363                         LogEnded         bool
 364                         Entries          []TableEntry
 365                 }{
 366                         Version:          sgblog.Version,
 367                         Cfg:              cfg,
 368                         Topic:            topic,
 369                         TopicsEnabled:    topicsTree != nil,
 370                         Topics:           topicsCache.Topics(),
 371                         CommentsEnabled:  commentsTree != nil,
 372                         AtomPostsFeed:    AtomPostsFeed,
 373                         AtomCommentsFeed: AtomCommentsFeed,
 374                         Offset:           offset,
 375                         OffsetPrev:       offsetPrev,
 376                         OffsetNext:       offset + PageEntries,
 377                         LogEnded:         logEnded,
 378                         Entries:          entries,
 379                 })
 380                 if err != nil {
 381                         makeErr(err, http.StatusInternalServerError)
 382                 }
 383         } else if pathInfo == "/twtxt.txt" {
 384                 commit, err := repo.CommitObject(*headHash)
 385                 if err != nil {
 386                         makeErr(err, http.StatusInternalServerError)
 387                 }
 388                 etagHash.Write([]byte("TWTXT POSTS"))
 389                 etagHash.Write(commit.Hash[:])
 390                 checkETag(etagHash)
 391                 repoLog, err := repo.Log(&git.LogOptions{From: *headHash})
 392                 if err != nil {
 393                         makeErr(err, http.StatusInternalServerError)
 394                 }
 395                 for i := 0; i < PageEntries; i++ {
 396                         commit, err = repoLog.Next()
 397                         if err != nil {
 398                                 break
 399                         }
 400                         fmt.Fprintf(
 401                                 out, "%s\t%s\n",
 402                                 commit.Author.When.Format(time.RFC3339),
 403                                 msgSplit(commit.Message)[0],
 404                         )
 405                 }
 406                 os.Stdout.WriteString("Content-Type: text/plain; charset=utf-8\n")
 407                 os.Stdout.WriteString("ETag: " + etagString(etagHash) + "\n")
 408                 if gzipWriter != nil {
 409                         os.Stdout.WriteString("Content-Encoding: gzip\n")
 410                         gzipWriter.Close()
 411                 }
 412                 os.Stdout.WriteString("\n")
 413                 os.Stdout.Write(outBuf.Bytes())
 414                 return
 415         } else if pathInfo == "/"+AtomPostsFeed {
 416                 commit, err := repo.CommitObject(*headHash)
 417                 if err != nil {
 418                         makeErr(err, http.StatusInternalServerError)
 419                 }
 420
 421                 var topic string
 422                 if t, exists := queryValues["topic"]; exists {
 423                         topic = t[0]
 424                 }
 425
 426                 etagHash.Write([]byte("ATOM POSTS"))
 427                 etagHash.Write([]byte(topic))
 428                 etagHash.Write(commit.Hash[:])
 429                 checkETag(etagHash)
 430                 var title string
 431                 if topic == "" {
 432                         title = cfg.Title
 433                 } else {
 434                         title = fmt.Sprintf("%s (topic: %s)", cfg.Title, topic)
 435                 }
 436                 idHasher, err := blake2b.New256(nil)
 437                 if err != nil {
 438                         panic(err)
 439                 }
 440                 idHasher.Write([]byte("ATOM POSTS"))
 441                 idHasher.Write([]byte(cfg.AtomId))
 442                 idHasher.Write([]byte(topic))
 443                 feed := atom.Feed{
 444                         Title:   title,
 445                         ID:      "urn:uuid:" + bytes2uuid(idHasher.Sum(nil)),
 446                         Updated: atom.Time(commit.Author.When),
 447                         Link: []atom.Link{{
 448                                 Rel:  "self",
 449                                 Href: cfg.AtomBaseURL + cfg.URLPrefix + "/" + AtomPostsFeed,
 450                         }},
 451                         Author: &atom.Person{Name: cfg.AtomAuthor},
 452                 }
 453
 454                 repoLog, err := repo.Log(&git.LogOptions{From: *headHash})
 455                 if err != nil {
 456                         makeErr(err, http.StatusInternalServerError)
 457                 }
 458                 var commits CommitIterNext
 459                 if topic == "" {
 460                         commits = repoLog
 461                 } else {
 462                         topicsCache, err := getTopicsCache(cfg, repoLog)
 463                         if err != nil {
 464                                 makeErr(err, http.StatusInternalServerError)
 465                         }
 466                         hashes := topicsCache[topic]
 467                         if hashes == nil {
 468                                 makeErr(errors.New("no posts with that topic"), http.StatusBadRequest)
 469                         }
 470                         commits = &HashesIter{hashes}
 471                 }
 472
 473                 for i := 0; i < PageEntries; i++ {
 474                         commit, err = commits.Next()
 475                         if err != nil {
 476                                 break
 477                         }
 478                         lines := msgSplit(commit.Message)
 479                         var categories []atom.Category
 480                         for _, topic := range sgblog.ParseTopics(sgblog.GetNote(
 481                                 repo, topicsTree, commit.Hash,
 482                         )) {
 483                                 categories = append(categories, atom.Category{Term: topic})
 484                         }
 485                         htmlized := make([]string, 0, len(lines))
 486                         htmlized = append(htmlized, "<pre>")
 487                         for _, l := range lines[2:] {
 488                                 htmlized = append(htmlized, lineURLize(cfg.AtomBaseURL+cfg.URLPrefix, l))
 489                         }
 490                         htmlized = append(htmlized, "</pre>")
 491                         feed.Entry = append(feed.Entry, &atom.Entry{
 492                                 Title: lines[0],
 493                                 ID:    "urn:uuid:" + bytes2uuid(commit.Hash[:]),
 494                                 Link: []atom.Link{{
 495                                         Rel:  "alternate",
 496                                         Href: cfg.AtomBaseURL + cfg.URLPrefix + "/" + commit.Hash.String(),
 497                                 }},
 498                                 Published: atom.Time(commit.Author.When),
 499                                 Updated:   atom.Time(commit.Author.When),
 500                                 Summary:   &atom.Text{Type: "text", Body: lines[0]},
 501                                 Content: &atom.Text{
 502                                         Type: "html",
 503                                         Body: strings.Join(htmlized, "\n"),
 504                                 },
 505                                 Category: categories,
 506                         })
 507                 }
 508                 data, err := xml.MarshalIndent(&feed, "", "  ")
 509                 if err != nil {
 510                         makeErr(err, http.StatusInternalServerError)
 511                 }
 512                 out.Write(data)
 513                 goto AtomFinish
 514         } else if pathInfo == "/"+AtomCommentsFeed {
 515                 commit, err := repo.CommitObject(commentsRef.Hash())
 516                 if err != nil {
 517                         makeErr(err, http.StatusInternalServerError)
 518                 }
 519                 etagHash.Write([]byte("ATOM COMMENTS"))
 520                 etagHash.Write(commit.Hash[:])
 521                 checkETag(etagHash)
 522                 idHasher, err := blake2b.New256(nil)
 523                 if err != nil {
 524                         panic(err)
 525                 }
 526                 idHasher.Write([]byte("ATOM COMMENTS"))
 527                 idHasher.Write([]byte(cfg.AtomId))
 528                 feed := atom.Feed{
 529                         Title:   cfg.Title + " comments",
 530                         ID:      "urn:uuid:" + bytes2uuid(idHasher.Sum(nil)),
 531                         Updated: atom.Time(commit.Author.When),
 532                         Link: []atom.Link{{
 533                                 Rel:  "self",
 534                                 Href: cfg.AtomBaseURL + cfg.URLPrefix + "/" + AtomCommentsFeed,
 535                         }},
 536                         Author: &atom.Person{Name: cfg.AtomAuthor},
 537                 }
 538                 repoLog, err := repo.Log(&git.LogOptions{From: commentsRef.Hash()})
 539                 if err != nil {
 540                         makeErr(err, http.StatusInternalServerError)
 541                 }
 542                 for i := 0; i < PageEntries; i++ {
 543                         commit, err = repoLog.Next()
 544                         if err != nil {
 545                                 break
 546                         }
 547                         fileStats, err := commit.Stats()
 548                         if err != nil {
 549                                 makeErr(err, http.StatusInternalServerError)
 550                         }
 551                         t, err := commit.Tree()
 552                         if err != nil {
 553                                 makeErr(err, http.StatusInternalServerError)
 554                         }
 555                         commentedHash := plumbing.NewHash(strings.ReplaceAll(
 556                                 fileStats[0].Name, "/", "",
 557                         ))
 558                         commit, err = repo.CommitObject(commentedHash)
 559                         if err != nil {
 560                                 continue
 561                         }
 562                         comments := sgblog.ParseComments(sgblog.GetNote(repo, t, commentedHash))
 563                         if len(comments) == 0 {
 564                                 continue
 565                         }
 566                         commentN := strconv.Itoa(len(comments) - 1)
 567                         lines := strings.Split(comments[len(comments)-1], "\n")
 568                         from := strings.TrimPrefix(lines[0], "From: ")
 569                         date := strings.TrimPrefix(lines[1], "Date: ")
 570                         htmlized := make([]string, 0, len(lines))
 571                         htmlized = append(htmlized, "<pre>")
 572                         for _, l := range lines[2:] {
 573                                 htmlized = append(htmlized, lineURLize(cfg.AtomBaseURL+cfg.URLPrefix, l))
 574                         }
 575                         htmlized = append(htmlized, "</pre>")
 576                         idHasher.Reset()
 577                         idHasher.Write([]byte("COMMENT"))
 578                         idHasher.Write(commit.Hash[:])
 579                         idHasher.Write([]byte(commentN))
 580                         feed.Entry = append(feed.Entry, &atom.Entry{
 581                                 Title: fmt.Sprintf(
 582                                         "Comment %s for \"%s\" by %s",
 583                                         commentN, msgSplit(commit.Message)[0], from,
 584                                 ),
 585                                 Author: &atom.Person{Name: from},
 586                                 ID:     "urn:uuid:" + bytes2uuid(idHasher.Sum(nil)),
 587                                 Link: []atom.Link{{
 588                                         Rel: "alternate",
 589                                         Href: strings.Join([]string{
 590                                                 cfg.AtomBaseURL, cfg.URLPrefix, "/",
 591                                                 commit.Hash.String(), "#comment", commentN,
 592                                         }, ""),
 593                                 }},
 594                                 Published: atom.TimeStr(strings.Replace(date, " ", "T", -1)),
 595                                 Updated:   atom.TimeStr(strings.Replace(date, " ", "T", -1)),
 596                                 Content: &atom.Text{
 597                                         Type: "html",
 598                                         Body: strings.Join(htmlized, "\n"),
 599                                 },
 600                         })
 601                 }
 602                 data, err := xml.MarshalIndent(&feed, "", "  ")
 603                 if err != nil {
 604                         makeErr(err, http.StatusInternalServerError)
 605                 }
 606                 out.Write(data)
 607                 goto AtomFinish
 608         } else if sha1DigestRe.MatchString(pathInfo[1:]) {
 609                 commit, err := repo.CommitObject(plumbing.NewHash(pathInfo[1 : 1+sha1.Size*2]))
 610                 if err != nil {
 611                         makeErr(err, http.StatusBadRequest)
 612                 }
 613                 for _, data := range etagHashForWeb {
 614                         etagHash.Write([]byte(data))
 615                 }
 616                 etagHash.Write([]byte("ENTRY"))
 617                 etagHash.Write(commit.Hash[:])
 618                 atomCommentsURL := strings.Join([]string{
 619                         cfg.AtomBaseURL, cfg.URLPrefix, "/",
 620                         commit.Hash.String(), "/", AtomCommentsFeed,
 621                 }, "")
 622                 commentsRaw := sgblog.GetNote(repo, commentsTree, commit.Hash)
 623                 etagHash.Write(commentsRaw)
 624                 topicsRaw := sgblog.GetNote(repo, topicsTree, commit.Hash)
 625                 etagHash.Write(topicsRaw)
 626                 if strings.HasSuffix(pathInfo, AtomCommentsFeed) {
 627                         etagHash.Write([]byte("ATOM COMMENTS"))
 628                         checkETag(etagHash)
 629                         type Comment struct {
 630                                 n    string
 631                                 from string
 632                                 date string
 633                                 body []string
 634                         }
 635                         commentsRaw := sgblog.ParseComments(commentsRaw)
 636                         var toSkip int
 637                         if len(commentsRaw) > PageEntries {
 638                                 toSkip = len(commentsRaw) - PageEntries
 639                         }
 640                         comments := make([]Comment, 0, len(commentsRaw)-toSkip)
 641                         for i := len(commentsRaw) - 1; i >= toSkip; i-- {
 642                                 lines := strings.Split(commentsRaw[i], "\n")
 643                                 from := strings.TrimPrefix(lines[0], "From: ")
 644                                 date := strings.TrimPrefix(lines[1], "Date: ")
 645                                 comments = append(comments, Comment{
 646                                         n:    strconv.Itoa(i),
 647                                         from: from,
 648                                         date: strings.Replace(date, " ", "T", 1),
 649                                         body: lines[3:],
 650                                 })
 651                         }
 652                         idHasher, err := blake2b.New256(nil)
 653                         if err != nil {
 654                                 panic(err)
 655                         }
 656                         idHasher.Write([]byte("ATOM COMMENTS"))
 657                         idHasher.Write(commit.Hash[:])
 658                         feed := atom.Feed{
 659                                 Title:  fmt.Sprintf("\"%s\" comments", msgSplit(commit.Message)[0]),
 660                                 ID:     "urn:uuid:" + bytes2uuid(idHasher.Sum(nil)),
 661                                 Link:   []atom.Link{{Rel: "self", Href: atomCommentsURL}},
 662                                 Author: &atom.Person{Name: cfg.AtomAuthor},
 663                         }
 664                         if len(comments) > 0 {
 665                                 feed.Updated = atom.TimeStr(comments[0].date)
 666                         } else {
 667                                 feed.Updated = atom.Time(commit.Author.When)
 668                         }
 669                         for _, comment := range comments {
 670                                 idHasher.Reset()
 671                                 idHasher.Write([]byte("COMMENT"))
 672                                 idHasher.Write(commit.Hash[:])
 673                                 idHasher.Write([]byte(comment.n))
 674                                 htmlized := make([]string, 0, len(comment.body))
 675                                 htmlized = append(htmlized, "<pre>")
 676                                 for _, l := range comment.body {
 677                                         htmlized = append(
 678                                                 htmlized,
 679                                                 lineURLize(cfg.AtomBaseURL+cfg.URLPrefix, l),
 680                                         )
 681                                 }
 682                                 htmlized = append(htmlized, "</pre>")
 683                                 feed.Entry = append(feed.Entry, &atom.Entry{
 684                                         Title:  fmt.Sprintf("Comment %s by %s", comment.n, comment.from),
 685                                         Author: &atom.Person{Name: comment.from},
 686                                         ID:     "urn:uuid:" + bytes2uuid(idHasher.Sum(nil)),
 687                                         Link: []atom.Link{{
 688                                                 Rel: "alternate",
 689                                                 Href: strings.Join([]string{
 690                                                         cfg.AtomBaseURL,
 691                                                         cfg.URLPrefix, "/",
 692                                                         commit.Hash.String(),
 693                                                         "#comment", comment.n,
 694                                                 }, ""),
 695                                         }},
 696                                         Published: atom.TimeStr(
 697                                                 strings.Replace(comment.date, " ", "T", -1),
 698                                         ),
 699                                         Updated: atom.TimeStr(
 700                                                 strings.Replace(comment.date, " ", "T", -1),
 701                                         ),
 702                                         Content: &atom.Text{
 703                                                 Type: "html",
 704                                                 Body: strings.Join(htmlized, "\n"),
 705                                         },
 706                                 })
 707                         }
 708                         data, err := xml.MarshalIndent(&feed, "", "  ")
 709                         if err != nil {
 710                                 makeErr(err, http.StatusInternalServerError)
 711                         }
 712                         out.Write(data)
 713                         goto AtomFinish
 714                 }
 715                 notesRaw := sgblog.GetNote(repo, notesTree, commit.Hash)
 716                 etagHash.Write(notesRaw)
 717                 checkETag(etagHash)
 718
 719                 lines := msgSplit(commit.Message)
 720                 title := lines[0]
 721                 when := commit.Author.When.Format(sgblog.WhenFmt)
 722                 var parent string
 723                 if len(commit.ParentHashes) > 0 {
 724                         parent = commit.ParentHashes[0].String()
 725                 }
 726                 commentsParsed := sgblog.ParseComments(commentsRaw)
 727                 comments := make([]CommentEntry, 0, len(commentsParsed))
 728                 for _, comment := range commentsParsed {
 729                         lines := strings.Split(comment, "\n")
 730                         comments = append(comments, CommentEntry{lines[:3], lines[3:]})
 731                 }
 732                 var notesLines []string
 733                 if len(notesRaw) > 0 {
 734                         notesLines = strings.Split(string(notesRaw), "\n")
 735                 }
 736
 737                 os.Stdout.Write([]byte(startHeader(etagHash, gzipWriter != nil)))
 738                 err = TmplHTMLEntry.Execute(out, struct {
 739                         Version         string
 740                         Cfg             *Cfg
 741                         Title           string
 742                         TitleEscaped    string
 743                         When            string
 744                         AtomCommentsURL string
 745                         Parent          string
 746                         Commit          *object.Commit
 747                         Lines           []string
 748                         NoteLines       []string
 749                         Comments        []CommentEntry
 750                         Topics          []string
 751                 }{
 752                         Version:         sgblog.Version,
 753                         Cfg:             cfg,
 754                         Title:           title,
 755                         TitleEscaped:    url.PathEscape(fmt.Sprintf("Re: %s (%s)", title, commit.Hash)),
 756                         When:            when,
 757                         AtomCommentsURL: atomCommentsURL,
 758                         Parent:          parent,
 759                         Commit:          commit,
 760                         Lines:           lines[2:],
 761                         NoteLines:       notesLines,
 762                         Comments:        comments,
 763                         Topics:          sgblog.ParseTopics(topicsRaw),
 764                 })
 765                 if err != nil {
 766                         makeErr(err, http.StatusInternalServerError)
 767                 }
 768         } else {
 769                 makeErr(errors.New("unknown URL action"), http.StatusNotFound)
 770         }
 771         out.Write([]byte("</body></html>\n"))
 772         if gzipWriter != nil {
 773                 gzipWriter.Close()
 774         }
 775         os.Stdout.Write(outBuf.Bytes())
 776         return
 777
 778 AtomFinish:
 779         os.Stdout.WriteString("Content-Type: application/atom+xml; charset=utf-8\n")
 780         os.Stdout.WriteString("ETag: " + etagString(etagHash) + "\n")
 781         if gzipWriter != nil {
 782                 os.Stdout.WriteString("Content-Encoding: gzip\n")
 783                 gzipWriter.Close()
 784         }
 785         os.Stdout.WriteString("\n")
 786         os.Stdout.Write(outBuf.Bytes())
 787 }