Sergiusz Bazanski | c315aac | 2020-01-02 16:43:39 +0100 | [diff] [blame] | 1 | package main |
| 2 | |
| 3 | import ( |
| 4 | "flag" |
| 5 | "fmt" |
| 6 | "io" |
| 7 | "io/ioutil" |
| 8 | "net/http" |
| 9 | "regexp" |
| 10 | |
| 11 | "code.hackerspace.pl/hscloud/go/mirko" |
| 12 | "github.com/dgraph-io/ristretto" |
| 13 | tgbotapi "github.com/go-telegram-bot-api/telegram-bot-api" |
| 14 | "github.com/golang/glog" |
| 15 | "github.com/ulule/limiter/v3" |
| 16 | "github.com/ulule/limiter/v3/drivers/store/memory" |
| 17 | ) |
| 18 | |
| 19 | func init() { |
| 20 | flag.Set("logtostderr", "true") |
| 21 | } |
| 22 | |
| 23 | var ( |
| 24 | flagPublicListen string |
| 25 | flagTelegramToken string |
Sergiusz Bazanski | effafe9 | 2020-01-05 22:31:39 +0100 | [diff] [blame] | 26 | reTelegram = regexp.MustCompile(`/fileid/([a-zA-Z0-9_-]+).([a-z0-9]+)`) |
Sergiusz Bazanski | c315aac | 2020-01-02 16:43:39 +0100 | [diff] [blame] | 27 | ) |
| 28 | |
| 29 | type server struct { |
| 30 | cache *ristretto.Cache |
| 31 | limiter *limiter.Limiter |
| 32 | tel *tgbotapi.BotAPI |
| 33 | } |
| 34 | |
| 35 | func main() { |
| 36 | flag.StringVar(&flagPublicListen, "public_listen", "127.0.0.1:5000", "Listen address for public HTTP handler") |
| 37 | flag.StringVar(&flagTelegramToken, "telegram_token", "", "Telegram Bot API Token") |
| 38 | flag.Parse() |
| 39 | |
| 40 | if flagTelegramToken == "" { |
| 41 | glog.Exitf("telegram_token must be set") |
| 42 | } |
| 43 | |
| 44 | cache, err := ristretto.NewCache(&ristretto.Config{ |
| 45 | NumCounters: 1e7, // number of keys to track frequency of (10M). |
| 46 | MaxCost: 1 << 30, // maximum cost of cache (1GB). |
| 47 | BufferItems: 64, // number of keys per Get buffer. |
| 48 | }) |
| 49 | if err != nil { |
| 50 | glog.Exit(err) |
| 51 | } |
| 52 | |
| 53 | tel, err := tgbotapi.NewBotAPI(flagTelegramToken) |
| 54 | if err != nil { |
| 55 | glog.Exitf("Error when creating telegram bot: %v", err) |
| 56 | } |
| 57 | |
| 58 | rate, err := limiter.NewRateFromFormatted("10-M") |
| 59 | if err != nil { |
| 60 | glog.Exit(err) |
| 61 | } |
| 62 | |
| 63 | store := memory.NewStore() |
| 64 | instance := limiter.New(store, rate, limiter.WithTrustForwardHeader(true)) |
| 65 | |
| 66 | s := &server{ |
| 67 | cache: cache, |
| 68 | limiter: instance, |
| 69 | tel: tel, |
| 70 | } |
| 71 | |
| 72 | m := mirko.New() |
| 73 | if err := m.Listen(); err != nil { |
| 74 | glog.Exitf("Listen(): %v", err) |
| 75 | } |
| 76 | |
| 77 | if err := m.Serve(); err != nil { |
| 78 | glog.Exitf("Serve(): %v", err) |
| 79 | } |
| 80 | |
| 81 | publicMux := http.NewServeMux() |
| 82 | publicMux.HandleFunc("/", s.publicHandler) |
| 83 | publicSrv := http.Server{ |
| 84 | Addr: flagPublicListen, |
| 85 | Handler: publicMux, |
| 86 | } |
| 87 | go func() { |
| 88 | if err := publicSrv.ListenAndServe(); err != nil { |
| 89 | glog.Exitf("public ListenAndServe: %v", err) |
| 90 | } |
| 91 | }() |
| 92 | |
| 93 | <-m.Done() |
| 94 | } |
| 95 | |
| 96 | func setMime(w http.ResponseWriter, ext string) { |
| 97 | switch ext { |
| 98 | case "jpg": |
| 99 | w.Header().Set("Content-Type", "image/jpeg") |
| 100 | case "mp4": |
| 101 | w.Header().Set("Content-Type", "video/mp4") |
| 102 | } |
| 103 | } |
| 104 | |
| 105 | func (s *server) publicHandler(w http.ResponseWriter, r *http.Request) { |
| 106 | ctx := r.Context() |
| 107 | |
| 108 | if !reTelegram.MatchString(r.URL.Path) { |
| 109 | http.NotFound(w, r) |
| 110 | return |
| 111 | } |
| 112 | parts := reTelegram.FindStringSubmatch(r.URL.Path) |
| 113 | fileid := parts[1] |
| 114 | fileext := parts[2] |
| 115 | glog.Infof("FileID: %s", fileid) |
| 116 | |
| 117 | c, ok := s.cache.Get(fileid) |
| 118 | if ok { |
| 119 | glog.Infof("Get %q - cache hit", fileid) |
| 120 | // cache hit |
| 121 | setMime(w, fileext) |
| 122 | w.Write(c.([]byte)) |
| 123 | return |
| 124 | } |
| 125 | |
| 126 | glog.Infof("Get %q - cache miss", fileid) |
| 127 | |
| 128 | limit, err := s.limiter.Get(ctx, s.limiter.GetIPKey(r)) |
| 129 | if err != nil { |
| 130 | w.WriteHeader(500) |
| 131 | fmt.Fprintf(w, ":(") |
| 132 | glog.Errorf("limiter.Get(%q): %v", s.limiter.GetIPKey(r), err) |
| 133 | return |
| 134 | } |
| 135 | |
| 136 | if limit.Reached { |
| 137 | w.WriteHeader(420) |
| 138 | fmt.Fprintf(w, "enhance your calm") |
| 139 | glog.Warningf("Limit reached by %q", s.limiter.GetIPKey(r)) |
| 140 | return |
| 141 | } |
| 142 | |
| 143 | f, err := s.tel.GetFile(tgbotapi.FileConfig{fileid}) |
| 144 | if err != nil { |
| 145 | w.WriteHeader(502) |
| 146 | fmt.Fprintf(w, "telegram mumbles.") |
| 147 | glog.Errorf("tel.GetFile(%q): %v", fileid, err) |
| 148 | return |
| 149 | } |
| 150 | |
| 151 | target := f.Link(flagTelegramToken) |
| 152 | |
| 153 | req, err := http.NewRequest("GET", target, nil) |
| 154 | if err != nil { |
| 155 | w.WriteHeader(500) |
| 156 | fmt.Fprintf(w, ":(") |
| 157 | glog.Errorf("NewRequest(GET, %q, nil): %v", target, err) |
| 158 | return |
| 159 | } |
| 160 | |
| 161 | req = req.WithContext(ctx) |
| 162 | res, err := http.DefaultClient.Do(req) |
| 163 | if err != nil { |
| 164 | w.WriteHeader(500) |
| 165 | fmt.Fprintf(w, ":(") |
| 166 | glog.Errorf("GET(%q): %v", target, err) |
| 167 | return |
| 168 | } |
| 169 | defer res.Body.Close() |
| 170 | |
| 171 | if res.StatusCode != 200 { |
| 172 | // do not cache errors |
| 173 | w.WriteHeader(res.StatusCode) |
| 174 | io.Copy(w, res.Body) |
| 175 | return |
| 176 | } |
| 177 | |
| 178 | b, err := ioutil.ReadAll(res.Body) |
| 179 | if err != nil { |
| 180 | w.WriteHeader(500) |
| 181 | fmt.Fprintf(w, ":(") |
| 182 | glog.Errorf("Read(%q): %v", target, err) |
| 183 | return |
| 184 | } |
| 185 | |
| 186 | s.cache.Set(fileid, b, int64(len(b))) |
| 187 | |
| 188 | setMime(w, fileext) |
| 189 | w.Write(b) |
| 190 | } |