episodecache.go

   1 package anidb
   2
   3 import (
   4         "github.com/EliasFleckenstein03/go-fscache"
   5         "strconv"
   6         "strings"
   7         "time"
   8 )
   9
  10 var _ cacheable = &Episode{}
  11
  12 func (e *Episode) setCachedTS(ts time.Time) {
  13         e.Cached = ts
  14 }
  15
  16 func (e *Episode) IsStale() bool {
  17         if e == nil {
  18                 return true
  19         }
  20         return time.Now().Sub(e.Cached) > EpisodeCacheDuration
  21 }
  22
  23 // Unique Episode IDentifier.
  24 type EID int
  25
  26 // Retrieves the Episode corresponding to this EID from the cache.
  27 func (eid EID) Episode() *Episode {
  28         var e Episode
  29         if CacheGet(&e, "eid", eid) == nil {
  30                 return &e
  31         }
  32         return nil
  33 }
  34
  35 func cacheEpisode(ep *Episode) {
  36         CacheSet(ep.AID, "aid", "by-eid", ep.EID)
  37         CacheSet(ep, "eid", ep.EID)
  38 }
  39
  40 // Retrieves an Episode by its EID.
  41 //
  42 // If we know which AID owns this EID, then it's equivalent
  43 // to an Anime query. Otherwise, uses both the HTTP and UDP
  44 // APIs to retrieve it.
  45 func (adb *AniDB) EpisodeByID(eid EID) <-chan *Episode {
  46         key := []fscache.CacheKey{"eid", eid}
  47         ch := make(chan *Episode, 1)
  48
  49         if eid < 1 {
  50                 ch <- nil
  51                 close(ch)
  52                 return ch
  53         }
  54
  55         ic := make(chan notification, 1)
  56         go func() { ch <- (<-ic).(*Episode); close(ch) }()
  57         if intentMap.Intent(ic, key...) {
  58                 return ch
  59         }
  60
  61         if !Cache.IsValid(InvalidKeyCacheDuration, key...) {
  62                 intentMap.NotifyClose((*Episode)(nil), key...)
  63                 return ch
  64         }
  65
  66         e := eid.Episode()
  67         if !e.IsStale() {
  68                 intentMap.NotifyClose(e, key...)
  69                 return ch
  70         }
  71
  72         go func() {
  73                 // The UDP API data is worse than the HTTP API anime data and
  74                 // might even get truncated on some pathological cases;
  75                 // try and get from the corresponding Anime, which uses the HTTP
  76                 // API episode list.
  77
  78                 aid := AID(0)
  79                 _, err := Cache.Get(&aid, "aid", "by-eid", eid)
  80                 ok := err == nil
  81
  82                 udpDone := false
  83
  84                 for i := 0; i < 2; i++ {
  85                         if !ok && udpDone {
  86                                 // couldn't get anime and we already ran the EPISODE query
  87                                 break
  88                         }
  89
  90                         if !ok {
  91                                 // We don't know what the AID is yet.
  92                                 reply := <-adb.udp.SendRecv("EPISODE", paramMap{"eid": eid})
  93
  94                                 if reply.Error() == nil {
  95                                         parts := strings.Split(reply.Lines()[1], "|")
  96
  97                                         if id, err := strconv.ParseInt(parts[1], 10, 32); err == nil {
  98                                                 ok = true
  99                                                 aid = AID(id)
 100                                         } else {
 101                                                 break
 102                                         }
 103                                 } else if reply.Code() == 340 {
 104                                         Cache.SetInvalid(key...)
 105                                         break
 106                                 } else {
 107                                         break
 108                                 }
 109                                 udpDone = true
 110                         }
 111                         a := <-adb.AnimeByID(AID(aid)) // updates the episode cache as well
 112                         ep := a.EpisodeByEID(eid)
 113
 114                         if ep != nil {
 115                                 e = ep
 116                                 break
 117                         } else {
 118                                 // the EID<->AID map broke
 119                                 ok = false
 120                                 Cache.Delete("aid", "by-eid", eid)
 121                         }
 122                 }
 123                 intentMap.NotifyClose(e, key...)
 124         }()
 125         return ch
 126 }