clean up metadata fetching code (BEP 9) (#27)

1 files changed, 87 insertions, 71 deletions

diff --git a/lib/torrent.js b/lib/torrent.js
index 5a9c988..a5536ac 100644
--- a/lib/torrent.js
+++ b/lib/torrent.js
@@ -9,6 +9,10 @@ var Swarm = require('bittorrent-swarm')
 var METADATA_BLOCK_SIZE = 16 * 1024
 var WIRE_TIMEOUT = 10000
 
+var EXTENDED_MESSAGES = {
+  ut_metadata: 1
+}
+
 inherits(Torrent, EventEmitter)
 
 function Torrent (uri, opts) {
@@ -66,12 +70,14 @@ Torrent.prototype._onWire = function (wire) {
   wire.setKeepAlive(true)
 
   // If peer supports DHT, send PORT message to report DHT node listening port
-  if (wire.peerExtensions.dht)
+  if (wire.peerExtensions.dht) {
+    console.log(wire.remoteAddress, 'supports DHT')
     wire.port(self.dhtPort)
+  }
 
   // When peer sends PORT, add them to the routing table
   wire.on('port', function (port) {
-    console.log('received PORT: ', port)
+    console.log(wire.remoteAddress, 'port', port)
     // TODO: DHT doesn't have a routing table yet
     // dht.add(wire.remoteAddress, port)
   })
@@ -82,12 +88,10 @@ Torrent.prototype._onWire = function (wire) {
   // Support extended messages:
   // - ut_metadata (metadata fetching, trackerless torrents)
   if (wire.peerExtensions.extended) {
-    console.log(wire.remoteAddress + ' supports extended messages', wire.peerExtensions)
+    console.log(wire.remoteAddress, 'supports extended messages', wire.peerExtensions)
 
     var extendedMessage = {
-      m: {
-        ut_metadata: 1
-      }
+      m: EXTENDED_MESSAGES
     }
 
     // Only send metadata_size if we have complete metadata
@@ -98,76 +102,88 @@ Torrent.prototype._onWire = function (wire) {
   }
 
   wire.on('extended', function (ext, buf) {
-    var dict
-    console.log('Received extended message ' + ext + ' from ' + wire.remoteAddress)
-
-    if (ext === 0) { // handshake
+    console.log(wire.remoteAddress, 'extended', ext)
 
-      try {
-        console.log('decoding ' + buf.toString())
-        dict = bncode.decode(buf.toString())
-        console.log('got extended handshake: ' + JSON.stringify(dict))
-      } catch (e) {
-        console.error('Error decoding extended message: ' + e.message)
-      }
+    if (ext === 0) // 0 = handshake
+      self._onExtendedHandshake(wire, buf)
+    else if (ext === EXTENDED_MESSAGES.ut_metadata)
+      self._onUtMetadata(wire, buf)
+  })
+}
 
-      if (dict.m.ut_metadata && dict.metadata_size) {
-        var metadataSize = dict.metadata_size
-        var numPieces = Math.ceil(metadataSize / METADATA_BLOCK_SIZE)
-        console.log('metadata size: ' + metadataSize)
-        console.log(numPieces + ' pieces')
-
-        wire.metadata = new Buffer(metadataSize)
-
-        // request all pieces
-        for (var piece = 0; piece < numPieces; piece++) {
-          wire.extended(dict.m.ut_metadata, {
-            msg_type: 0,
-            piece: piece
-          })
-        }
-      }
+Torrent.prototype._onExtendedHandshake = function (wire, buf) {
+  var self = this
+  var dict
+  try {
+    dict = bncode.decode(buf.toString())
+    console.log(wire.remoteAddress, 'extended handshake' + JSON.stringify(dict))
+  } catch (e) {
+    console.error(wire.remoteAddress, 'extended handshake error', e.message)
+    return
+  }
+  if (!dict) return
+
+  // If torrent is missing metadata and peer supports ut_metadata extension,
+  // then request all metadata pieces
+  if (!self.metadata && dict.metadata_size && dict.m && dict.m.ut_metadata) {
+    var numPieces = Math.ceil(dict.metadata_size / METADATA_BLOCK_SIZE)
+    wire.metadata = new Buffer(dict.metadata_size)
+
+    console.log('metadata size: ' + dict.metadata_size)
+    console.log(numPieces + ' pieces')
+
+    // request all pieces
+    for (var piece = 0; piece < numPieces; piece++) {
+      wire.extended(dict.m.ut_metadata, {
+        msg_type: 0,
+        piece: piece
+      })
+    }
+  }
+}
 
-    } else if (ext === 1) { // ut_metadata
-
-      // 0 - request
-      // 1 - data
-      // 2 - reject
-
-      var str
-      var dataIndex
-      var data
-      try {
-        str = buf.toString()
-        console.log('decoding ' + str)
-        dataIndex = str.indexOf('ee') + 2
-        var msg = str.substring(0, dataIndex)
-        console.log('using ' + msg)
-        dict = bncode.decode(msg)
-        data = buf.slice(dataIndex)
-        console.log('got metadata: ' + JSON.stringify(dict))
-        console.log('got metadata data: ' + data.length + ' bytes')
-      } catch (e) {
-        console.error('Error decoding extended message: ' + e.message)
-      }
+// 0 - request
+// 1 - data
+// 2 - reject
+Torrent.prototype._onUtMetadata = function (wire, buf) {
+  var self = this
 
-      // {'msg_type': 1, 'piece': 0, 'total_size': 3425}
-      if (dict.msg_type === 1) { // data
-        console.log('total_size: ' + dict.total_size)
-        data.copy(wire.metadata, dict.piece * METADATA_BLOCK_SIZE)
-
-        console.log('METADATA')
-        console.log(wire.metadata.toString())
-        self.metadata = {
-          'announce-list': [],
-          info: bncode.decode(wire.metadata),
-          // info_hash:
-        }
-        console.log(self.metadata)
-        self.emit('metadata', this.metadata)
+  var dict
+  var data
+  try {
+    var str = buf.toString()
+    var dataIndex = str.indexOf('ee') + 2
+    dict = bncode.decode(str.substring(0, dataIndex))
+    data = buf.slice(dataIndex)
+    console.log(wire.remoteAddress, 'ut_metadata', JSON.stringify(dict), 'metadata byte length', data.length)
+  } catch (e) {
+    console.error('Error decoding extended message: ' + e.message)
+  }
+  if (!dict) return
+
+  switch (dict.msg_type) {
+    // ut_metadata request (from peer)
+    // example: {'msg_type': 0, 'piece': 0}
+    case 0:
+      // TODO
+      break
+    // ut_metadata data (in response to our request)
+    // example: {'msg_type': 1, 'piece': 0, 'total_size': 3425}
+    case 1:
+      data.copy(wire.metadata, dict.piece * METADATA_BLOCK_SIZE)
+
+      self.metadata = {
+        'announce-list': [],
+        info: bncode.decode(wire.metadata)
       }
-    }
-  })
+      self.emit('metadata', this.metadata)
+      break
+    // ut_metadata reject (peer doesn't have piece we requested)
+    // {'msg_type': 2, 'piece': 0}
+    case 2:
+      // TODO
+      break
+  }
 }
 
 //