Fallback to magnet info-hash when Transmission omits hashString

Transmission addUrl sometimes returns a response without a hashString

(e.g. duplicate or malformed response). Extract the info hash from the

magnet link as a fallback, and log the response if neither works.

Signed-off-by: William Mantly <wmantly@gmail.com>

models/sql/torrent.js

@@ -74,11 +74,26 @@ module.exports = (sequelize, DataTypes, Model) => {
 
         let res = await trClient.addUrl(data.magnetLink, options);
 
+        // Transmission usually returns hashString, but if it doesn't (duplicate, malformed
+        // response, etc.), fall back to parsing the info hash from the magnet link.
+        let hashString = res && (res.hashString || res.id);
+        if(!hashString){
+          let match = data.magnetLink.match(/urn:btih:([A-Fa-f0-9]{40})/i);
+          if(match) hashString = match[1].toLowerCase();
+        }
+
+        if(!hashString){
+          console.error('Transmission addUrl response missing hashString:', res);
+          let error = new Error('TorrentCreateError');
+          error.message = 'Transmission did not return a hash for this torrent';
+          throw error;
+        }
+
         return await super.create({
           magnetLink: data.magnetLink,
-          hashString: res.hashString,
+          hashString,
           isPrivate: data.isPrivate,
-          name: res.name,
+          name: res && res.name,
           added_by: data.added_by,
           category: this.categoryFromTPB(data.category),
           status: 0,