From abc2051b886d3ea64408574327ff63792796789f Mon Sep 17 00:00:00 2001
From: Brad Marsden <silentbot1@gmail.com>
Date: Fri, 18 May 2018 01:39:07 +0100
Subject: [PATCH 1/2] Implements BEP53 to allow file selection using &so in
 magnetURI.

---
 lib/torrent.js | 22 +++++++++++++++++-----
 package.json   |  1 +
 2 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/lib/torrent.js b/lib/torrent.js
index c0e8aafc..3a59aa1a 100644
--- a/lib/torrent.js
+++ b/lib/torrent.js
@@ -30,6 +30,7 @@ var speedometer = require('speedometer')
 var uniq = require('uniq')
 var utMetadata = require('ut_metadata')
 var utPex = require('ut_pex') // browser exclude
+var parseRange = require('parse-numeric-range')
 
 var File = require('./file')
 var Peer = require('./peer')
@@ -482,11 +483,6 @@ Torrent.prototype._onMetadata = function (metadata) {
     })
   }
 
-  // start off selecting the entire torrent with low priority
-  if (self.pieces.length !== 0) {
-    self.select(0, self.pieces.length - 1, false)
-  }
-
   self._rarityMap = new RarityMap(self)
 
   self.store = new ImmediateChunkStore(
@@ -509,6 +505,22 @@ Torrent.prototype._onMetadata = function (metadata) {
     return new File(self, file)
   })
 
+  // Only select specified files (BEP53)
+  if (self.so) {
+    var specificFiles = parseRange.parse(self.so)
+    // https://github.com/webtorrent/webtorrent/issues/164
+    self.deselect(0, self.pieces.length - 1, false)
+
+    self.files.forEach(function (v, i) {
+      specificFiles.indexOf(i) === -1 ? self.files[i].deselect() : self.files[i].select(true)
+    })
+  } else {
+    // start off selecting the entire torrent with low priority
+    if (self.pieces.length !== 0) {
+      self.select(0, self.pieces.length - 1, false)
+    }
+  }
+
   self._hashes = self.pieces
 
   self.pieces = self.pieces.map(function (hash, i) {
diff --git a/package.json b/package.json
index 71e49537..763ab5f0 100644
--- a/package.json
+++ b/package.json
@@ -42,6 +42,7 @@
     "mime": "^2.2.0",
     "multistream": "^2.0.5",
     "package-json-versionify": "^1.0.2",
+    "parse-numeric-range": "^0.0.2",
     "parse-torrent": "^6.0.0",
     "pump": "^3.0.0",
     "random-iterate": "^1.0.1",

From 113363223b4e77d766a5f917b649c7435974c56a Mon Sep 17 00:00:00 2001
From: Brad Marsden <silentbot1@gmail.com>
Date: Fri, 18 May 2018 15:16:40 +0100
Subject: [PATCH 2/2] Makes things clearer and removes redundant / unused code.

---
 lib/torrent.js | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/lib/torrent.js b/lib/torrent.js
index 3a59aa1a..6d53ee9c 100644
--- a/lib/torrent.js
+++ b/lib/torrent.js
@@ -505,14 +505,12 @@ Torrent.prototype._onMetadata = function (metadata) {
     return new File(self, file)
   })
 
-  // Only select specified files (BEP53)
+  // Select only specified files (BEP53) http://www.bittorrent.org/beps/bep_0053.html
   if (self.so) {
-    var specificFiles = parseRange.parse(self.so)
-    // https://github.com/webtorrent/webtorrent/issues/164
-    self.deselect(0, self.pieces.length - 1, false)
+    var selectOnlyFiles = parseRange.parse(self.so)
 
     self.files.forEach(function (v, i) {
-      specificFiles.indexOf(i) === -1 ? self.files[i].deselect() : self.files[i].select(true)
+      if (selectOnlyFiles.includes(i)) self.files[i].select(true)
     })
   } else {
     // start off selecting the entire torrent with low priority