http tracker: support multiple info_hash scrapes

Author: feross

server.js

@@ -114,23 +114,22 @@ Server.prototype._onHttpRequest = function (req, res) {
   var s = req.url.split('?')
   var params = querystring.parse(s[1])
 
-  // TODO: support multiple info_hash parameters as a concatenation of individual requests
-  var infoHash = params.info_hash && bytewiseDecodeURIComponent(params.info_hash).toString('hex')
+  if (s[0] === '/announce') {
+    var infoHash = typeof params.info_hash === 'string' &&
+      bytewiseDecodeURIComponent(params.info_hash).toString('hex')
+    var port = Number(params.port)
+    var peerId = typeof params.peer_id === 'string' &&
+      bytewiseDecodeURIComponent(params.peer_id).toString('utf8')
 
-  if (!infoHash) return error('missing info_hash')
-  if (infoHash.length !== 40) return error('invalid info_hash')
+    if (!infoHash) return error('invalid info_hash')
+    if (infoHash.length !== 40) return error('invalid info_hash')
+    if (!port) return error('invalid port')
+    if (!peerId) return error('invalid peer_id')
 
-  if (s[0] === '/announce' || s[0] === '/') {
     var ip = self._trustProxy
       ? req.headers['x-forwarded-for'] || req.connection.remoteAddress
       : req.connection.remoteAddress.replace(REMOVE_IPV6_RE, '') // force ipv4
-    var port = Number(params.port)
     var addr = ip + ':' + port
-    var peerId = params.peer_id && bytewiseDecodeURIComponent(params.peer_id).toString('utf8')
-
-    if (!port) return error('missing port')
-    if (!peerId) return error('missing peer_id')
-
     var swarm = self._getSwarm(infoHash)
     var peer = swarm.peers[addr]
 
@@ -219,18 +218,34 @@ Server.prototype._onHttpRequest = function (req, res) {
     res.end(bencode.encode(response))
 
   } else if (s[0] === '/scrape') { // unofficial scrape message
-    var swarm = self._getSwarm(infoHash)
-    var response = { files : { } }
+    if (typeof params.info_hash === 'string') {
+      params.info_hash = [ params.info_hash ]
+    }
+    if (!Array.isArray(params.info_hash)) return error('invalid info_hash')
 
-    response.files[params.info_hash] = {
-      complete: swarm.complete,
-      incomplete: swarm.incomplete,
-      downloaded: swarm.complete, // TODO: this only provides a lower-bound
+    var response = {
+      files: {},
       flags: {
         min_request_interval: self._intervalMs
       }
     }
 
+    params.info_hash.some(function (infoHash) {
+      var infoHashHex = bytewiseDecodeURIComponent(infoHash).toString('hex')
+      if (infoHashHex.length !== 40) {
+        error('invalid info_hash')
+        return true // early return
+      }
+
+      var swarm = self._getSwarm(infoHashHex)
+
+      response.files[infoHash] = {
+        complete: swarm.complete,
+        incomplete: swarm.incomplete,
+        downloaded: swarm.complete // TODO: this only provides a lower-bound
+      }
+    })
+
     res.end(bencode.encode(response))
   }