cmd/feed2mdir/main.go

   1 /*
   2 go.stargrave.org/feeder  -- newsfeeds aggregator
   3 Copyright (C) 2022 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         "strings"
  31         "time"
  32
  33         "github.com/mmcdole/gofeed"
  34 )
  35
  36 func main() {
  37         maxEntries := flag.Uint("max-entries", 100, "Max entries to process")
  38         flag.Parse()
  39         mdir := flag.Arg(0)
  40         fp := gofeed.NewParser()
  41         feed, err := fp.Parse(os.Stdin)
  42         if err != nil {
  43                 log.Fatalln(err)
  44         }
  45         news := 0
  46         var when *time.Time
  47         now := time.Now()
  48         max := int(*maxEntries) - 1
  49         for n, item := range feed.Items {
  50                 if n == max {
  51                         break
  52                 }
  53                 when = nil
  54                 if item.PublishedParsed != nil {
  55                         when = item.PublishedParsed
  56                 } else if item.UpdatedParsed != nil {
  57                         when = item.UpdatedParsed
  58                 } else {
  59                         when = &now
  60                 }
  61                 var what string
  62                 if len(item.Content) == 0 {
  63                         what = item.Description
  64                 } else {
  65                         what = item.Content
  66                 }
  67                 what = strings.TrimPrefix(what, "<![CDATA[")
  68                 what = strings.TrimSuffix(what, "]]>")
  69                 h := sha512.New()
  70                 h.Write([]byte(item.Title))
  71                 h.Write([]byte{0})
  72                 h.Write([]byte(what))
  73                 fn := hex.EncodeToString(h.Sum(nil)[:sha512.Size/2])
  74                 exists := false
  75                 for _, d := range []string{"cur", "new"} {
  76                         entries, err := os.ReadDir(path.Join(mdir, d))
  77                         if err != nil {
  78                                 log.Fatalln(err)
  79                         }
  80                         for _, entry := range entries {
  81                                 if strings.HasPrefix(entry.Name(), fn) {
  82                                         exists = true
  83                                         break
  84                                 }
  85                         }
  86                 }
  87                 if exists {
  88                         continue
  89                 }
  90                 fn = path.Join(mdir, "new", fn)
  91                 fd, err := os.OpenFile(fn, os.O_WRONLY|os.O_CREATE|os.O_EXCL, os.FileMode(0666))
  92                 if err != nil {
  93                         log.Fatalln(err)
  94                 }
  95                 fd.WriteString("From: \"" + feed.Title + "\" <feeder@go.stargrave.org>\n")
  96                 fd.WriteString("Date: " + when.UTC().Format(time.RFC1123Z) + "\n")
  97                 fd.WriteString("Subject: " + mime.BEncoding.Encode("UTF-8", item.Title) + "\n")
  98                 fd.WriteString("MIME-Version: 1.0\n")
  99                 fd.WriteString("Content-Type: text/html; charset=utf-8\n")
 100                 fd.WriteString("Content-Transfer-Encoding: base64\n")
 101                 for _, link := range item.Links {
 102                         fd.WriteString("X-URL: " + link + "\n")
 103                 }
 104                 for _, author := range item.Authors {
 105                         fd.WriteString("X-Author: " + author.Name + "\n")
 106                 }
 107                 for _, cat := range item.Categories {
 108                         fd.WriteString("X-Category: " + cat + "\n")
 109                 }
 110                 fd.WriteString("\n")
 111                 what = base64.StdEncoding.EncodeToString([]byte(what))
 112                 for i := 0; i < len(what); i += 72 {
 113                         b := i + 72
 114                         if b > len(what) {
 115                                 b = len(what)
 116                         }
 117                         fd.WriteString(what[i:b] + "\n")
 118                 }
 119                 fd.Close()
 120                 if err = os.Chtimes(fn, *when, *when); err != nil {
 121                         log.Fatalln(err)
 122                 }
 123                 news++
 124         }
 125         when = nil
 126         if feed.PublishedParsed != nil {
 127                 when = feed.PublishedParsed
 128         } else if feed.UpdatedParsed != nil {
 129                 when = feed.UpdatedParsed
 130         }
 131         if when != nil {
 132                 for _, d := range []string{"cur", "new"} {
 133                         if err = os.Chtimes(path.Join(mdir, d), *when, *when); err != nil {
 134                                 log.Fatalln(err)
 135                         }
 136                 }
 137         }
 138         fmt.Println(feed.Title)
 139 }