cmd/feed2mdir/main.go

   1 /*
   2 feeder  -- newsfeeds aggregator
   3 Copyright (C) 2022-2023 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 General Public License as published by
   7 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 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         "crypto/sha512"
  22         "encoding/base64"
  23         "encoding/hex"
  24         "flag"
  25         "fmt"
  26         "log"
  27         "mime"
  28         "os"
  29         "path"
  30         "path/filepath"
  31         "strings"
  32         "time"
  33
  34         "github.com/mmcdole/gofeed"
  35 )
  36
  37 func main() {
  38         maxEntries := flag.Uint("max-entries", 0, "Max entries to process (0=unlimited)")
  39         flag.Parse()
  40         mdir := flag.Arg(0)
  41         fp := gofeed.NewParser()
  42         feed, err := fp.Parse(os.Stdin)
  43         if err != nil {
  44                 log.Fatalln(err)
  45         }
  46
  47         guids := make(map[string]struct{}, len(feed.Items))
  48         useGUID := true
  49         for _, item := range feed.Items {
  50                 if _, exists := guids[item.GUID]; exists {
  51                         useGUID = false
  52                         break
  53                 } else {
  54                         guids[item.GUID] = struct{}{}
  55                 }
  56         }
  57
  58         feedTitle := feed.Title
  59         if len(feedTitle) == 0 {
  60                 feedTitle, err = filepath.Abs(mdir)
  61                 if err != nil {
  62                         log.Fatalln(err)
  63                 }
  64                 feedTitle = path.Base(feedTitle)
  65         }
  66
  67         h := sha512.New()
  68         news := 0
  69         var when *time.Time
  70         now := time.Now()
  71         latest := &time.Time{}
  72         for n, item := range feed.Items {
  73                 if *maxEntries > 0 && n == int(*maxEntries) {
  74                         break
  75                 }
  76                 when = nil
  77                 if item.PublishedParsed != nil {
  78                         when = item.PublishedParsed
  79                 } else if item.UpdatedParsed != nil {
  80                         when = item.UpdatedParsed
  81                 } else {
  82                         when = &now
  83                 }
  84                 if latest.Before(*when) {
  85                         latest = when
  86                 }
  87                 var what string
  88                 if len(item.Content) > len(item.Description) {
  89                         what = item.Content
  90                 } else {
  91                         what = item.Description
  92                 }
  93                 if media, ok := item.Extensions["media"]; ok {
  94                         if mediagroups, ok := media["group"]; ok {
  95                                 if len(mediagroups) == 1 {
  96                                         if mediadescription, ok := mediagroups[0].Children["description"]; ok {
  97                                                 if len(mediadescription[0].Value) > len(what) {
  98                                                         what = mediadescription[0].Value
  99                                                 }
 100                                         }
 101                                 }
 102                         }
 103                 }
 104                 what = strings.TrimPrefix(what, "<![CDATA[")
 105                 what = strings.TrimSuffix(what, "]]>")
 106                 h.Reset()
 107                 if useGUID {
 108                         h.Write([]byte(item.GUID))
 109                 } else {
 110                         h.Write([]byte(item.Title))
 111                         h.Write([]byte{0})
 112                         h.Write([]byte(what))
 113                 }
 114                 fn := hex.EncodeToString(h.Sum(nil)[:sha512.Size/2])
 115                 exists := false
 116                 for _, d := range []string{"cur", "new"} {
 117                         entries, err := os.ReadDir(path.Join(mdir, d))
 118                         if err != nil {
 119                                 log.Fatalln(err)
 120                         }
 121                         for _, entry := range entries {
 122                                 if strings.HasPrefix(entry.Name(), fn) {
 123                                         exists = true
 124                                         break
 125                                 }
 126                         }
 127                 }
 128                 if exists {
 129                         continue
 130                 }
 131                 fn = path.Join(mdir, "new", fn)
 132                 fd, err := os.OpenFile(fn, os.O_WRONLY|os.O_CREATE|os.O_EXCL, os.FileMode(0666))
 133                 if err != nil {
 134                         log.Fatalln(err)
 135                 }
 136                 fd.WriteString("From: \"" + feedTitle + "\" <feeder@localhost>\n")
 137                 fd.WriteString("Date: " + when.UTC().Format(time.RFC1123Z) + "\n")
 138                 fd.WriteString("Subject: " + mime.BEncoding.Encode("UTF-8", item.Title) + "\n")
 139                 fd.WriteString("MIME-Version: 1.0\n")
 140                 fd.WriteString("Content-Type: text/html; charset=utf-8\n")
 141                 fd.WriteString("Content-Transfer-Encoding: base64\n")
 142                 for _, author := range item.Authors {
 143                         if len(author.Name) > 0 {
 144                                 fd.WriteString("X-Author: " + author.Name + "\n")
 145                         }
 146                 }
 147                 for _, link := range item.Links {
 148                         fd.WriteString("X-URL: " + link + "\n")
 149                 }
 150                 for _, enc := range item.Enclosures {
 151                         fd.WriteString("X-Enclosure: " + enc.URL + "\n")
 152                 }
 153                 if len(item.Categories) > 0 {
 154                         fd.WriteString("X-Categories: " + strings.Join(item.Categories, ", ") + "\n")
 155                 }
 156                 fd.WriteString("\n")
 157                 what = base64.StdEncoding.EncodeToString([]byte(what))
 158                 for i := 0; i < len(what); i += 72 {
 159                         b := i + 72
 160                         if b > len(what) {
 161                                 b = len(what)
 162                         }
 163                         fd.WriteString(what[i:b] + "\n")
 164                 }
 165                 fd.Close()
 166                 if err = os.Chtimes(fn, *when, *when); err != nil {
 167                         log.Fatalln(err)
 168                 }
 169                 news++
 170         }
 171         for _, d := range []string{"cur", "new"} {
 172                 if err = os.Chtimes(path.Join(mdir, d), *latest, *latest); err != nil {
 173                         log.Fatalln(err)
 174                 }
 175         }
 176         fmt.Println(feedTitle)
 177 }