code.octet-stream.net Git - broadcaster/blob - protocol/protocol.go

   1 package protocol
   2
   3 import (
   4         "encoding/json"
   5         "errors"
   6         "fmt"
   7 )
   8
   9 const (
  10         StartTimeFormat = "2006-01-02T15:04"
  11         LocalTimeFormat = "Mon _2 Jan 2006 15:04:05"
  12
  13         // Radio to server
  14
  15         AuthenticateType = "authenticate"
  16         StatusType       = "status"
  17
  18         // Server to radio
  19
  20         FilesType     = "files"
  21         PlaylistsType = "playlists"
  22
  23         // Status values
  24
  25         StatusIdle         = "idle"
  26         StatusDelay        = "delay"
  27         StatusChannelInUse = "channel_in_use"
  28         StatusPlaying      = "playing"
  29 )
  30
  31 // Base message type to determine what type of payload is expected.
  32 type Message struct {
  33         T string
  34 }
  35
  36 // Initial message from Radio to authenticate itself with a token string.
  37 type AuthenticateMessage struct {
  38         T     string
  39         Token string
  40 }
  41
  42 // Server updates the radio with the list of files that currently exist.
  43 // This will be provided on connect and when there are any changes.
  44 // The radio is expected to obtain all these files and cache them locally.
  45 type FilesMessage struct {
  46         T     string
  47         Files []FileSpec
  48 }
  49
  50 type PlaylistsMessage struct {
  51         T         string
  52         Playlists []PlaylistSpec
  53 }
  54
  55 type StatusMessage struct {
  56         T string
  57
  58         // Status w.r.t. playing a playlist
  59         Status string
  60
  61         // File being played or about to be played - empty string in idle status
  62         Filename string
  63
  64         // Name of playlist being played - empty string in idle status
  65         Playlist string
  66
  67         // Seconds until playback begins - never mind latency
  68         DelaySecondsRemaining int
  69
  70         // Number of seconds file has been actually playing
  71         PlaybackSecondsElapsed int
  72
  73         // Number of seconds waiting for channel to clear
  74         WaitingForChannelSeconds int
  75
  76         PTT         bool
  77         COS         bool
  78         FilesInSync bool
  79
  80         // Timestamp of the current time on this radio, using LocalTimeFormat
  81         LocalTime string
  82
  83         // Time zone in use, e.g. "Australia/Hobart"
  84         TimeZone string
  85 }
  86
  87 // Description of an individual file available in the broadcasting system.
  88 type FileSpec struct {
  89         // Filename, e.g. "broadcast.wav"
  90         Name string
  91         // SHA-256 hash of the file's contents
  92         Hash string
  93 }
  94
  95 type PlaylistSpec struct {
  96         Id        int
  97         Name      string
  98         StartTime string
  99         Entries   []EntrySpec
 100 }
 101
 102 type EntrySpec struct {
 103         Filename     string
 104         DelaySeconds int
 105         IsRelative   bool
 106 }
 107
 108 func ParseMessage(data []byte) (string, interface{}, error) {
 109         var t Message
 110         err := json.Unmarshal(data, &t)
 111         if err != nil {
 112                 return "", nil, err
 113         }
 114
 115         if t.T == AuthenticateType {
 116                 var auth AuthenticateMessage
 117                 err = json.Unmarshal(data, &auth)
 118                 if err != nil {
 119                         return "", nil, err
 120                 }
 121                 return t.T, auth, nil
 122         }
 123
 124         if t.T == FilesType {
 125                 var files FilesMessage
 126                 err = json.Unmarshal(data, &files)
 127                 if err != nil {
 128                         return "", nil, err
 129                 }
 130                 return t.T, files, nil
 131         }
 132
 133         if t.T == PlaylistsType {
 134                 var playlists PlaylistsMessage
 135                 err = json.Unmarshal(data, &playlists)
 136                 if err != nil {
 137                         return "", nil, err
 138                 }
 139                 return t.T, playlists, nil
 140         }
 141
 142         if t.T == StatusType {
 143                 var status StatusMessage
 144                 err = json.Unmarshal(data, &status)
 145                 if err != nil {
 146                         return "", nil, err
 147                 }
 148                 return t.T, status, nil
 149         }
 150
 151         return "", nil, errors.New(fmt.Sprintf("unknown message type %v", t.T))
 152 }