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
  46         guids := make(map[string]struct{}, len(feed.Items))
  47         useGUID := true
  48         for _, item := range feed.Items {
  49                 if _, exists := guids[item.GUID]; exists {
  50                         useGUID = false
  51                         break
  52                 } else {
  53                         guids[item.GUID] = struct{}{}
  54                 }
  55         }
  56
  57         h := sha512.New()
  58         news := 0
  59         var when *time.Time
  60         now := time.Now()
  61         for n, item := range feed.Items {
  62                 if n == int(*maxEntries) {
  63                         break
  64                 }
  65                 when = nil
  66                 if item.PublishedParsed != nil {
  67                         when = item.PublishedParsed
  68                 } else if item.UpdatedParsed != nil {
  69                         when = item.UpdatedParsed
  70                 } else {
  71                         when = &now
  72                 }
  73                 var what string
  74                 if len(item.Content) == 0 {
  75                         what = item.Description
  76                 } else {
  77                         what = item.Content
  78                 }
  79                 what = strings.TrimPrefix(what, "<![CDATA[")
  80                 what = strings.TrimSuffix(what, "]]>")
  81                 h.Reset()
  82                 if useGUID {
  83                         h.Write([]byte(item.GUID))
  84                 } else {
  85                         h.Write([]byte(item.Title))
  86                         h.Write([]byte{0})
  87                         h.Write([]byte(what))
  88                 }
  89                 fn := hex.EncodeToString(h.Sum(nil)[:sha512.Size/2])
  90                 exists := false
  91                 for _, d := range []string{"cur", "new"} {
  92                         entries, err := os.ReadDir(path.Join(mdir, d))
  93                         if err != nil {
  94                                 log.Fatalln(err)
  95                         }
  96                         for _, entry := range entries {
  97                                 if strings.HasPrefix(entry.Name(), fn) {
  98                                         exists = true
  99                                         break
 100                                 }
 101                         }
 102                 }
 103                 if exists {
 104                         continue
 105                 }
 106                 fn = path.Join(mdir, "new", fn)
 107                 fd, err := os.OpenFile(fn, os.O_WRONLY|os.O_CREATE|os.O_EXCL, os.FileMode(0666))
 108                 if err != nil {
 109                         log.Fatalln(err)
 110                 }
 111                 fd.WriteString("From: \"" + feed.Title + "\" <feeder@go.stargrave.org>\n")
 112                 fd.WriteString("Date: " + when.UTC().Format(time.RFC1123Z) + "\n")
 113                 fd.WriteString("Subject: " + mime.BEncoding.Encode("UTF-8", item.Title) + "\n")
 114                 fd.WriteString("MIME-Version: 1.0\n")
 115                 fd.WriteString("Content-Type: text/html; charset=utf-8\n")
 116                 fd.WriteString("Content-Transfer-Encoding: base64\n")
 117                 for _, link := range item.Links {
 118                         fd.WriteString("X-URL: " + link + "\n")
 119                 }
 120                 for _, author := range item.Authors {
 121                         fd.WriteString("X-Author: " + author.Name + "\n")
 122                 }
 123                 for _, cat := range item.Categories {
 124                         fd.WriteString("X-Category: " + cat + "\n")
 125                 }
 126                 fd.WriteString("\n")
 127                 what = base64.StdEncoding.EncodeToString([]byte(what))
 128                 for i := 0; i < len(what); i += 72 {
 129                         b := i + 72
 130                         if b > len(what) {
 131                                 b = len(what)
 132                         }
 133                         fd.WriteString(what[i:b] + "\n")
 134                 }
 135                 fd.Close()
 136                 if err = os.Chtimes(fn, *when, *when); err != nil {
 137                         log.Fatalln(err)
 138                 }
 139                 news++
 140         }
 141         when = nil
 142         if feed.PublishedParsed != nil {
 143                 when = feed.PublishedParsed
 144         } else if feed.UpdatedParsed != nil {
 145                 when = feed.UpdatedParsed
 146         }
 147         if when != nil {
 148                 for _, d := range []string{"cur", "new"} {
 149                         if err = os.Chtimes(path.Join(mdir, d), *when, *when); err != nil {
 150                                 log.Fatalln(err)
 151                         }
 152                 }
 153         }
 154         fmt.Println(feed.Title)
 155 }