Improve duplicate torrent handling

app/lib/components/Chat/FileChatEntry.jsx

@@ -28,36 +28,63 @@ class FileChatEntry extends Component
 		});
 	};
 
+	handleTorrent = (torrent) =>
+	{
+		// Torrent already done, this can happen if the
+		// same file was sent multiple times.
+		if (torrent.progress === 1)
+		{
+			this.setState({
+				files: torrent.files,
+				numPeers: torrent.numPeers,
+				progress: 1,
+				active: false
+			});
+
+			return;
+		}
+
+		const onProgress = () =>
+		{
+			this.setState({
+				numPeers : torrent.numPeers,
+				progress : torrent.progress
+			});
+		};
+
+		onProgress();
+
+		setInterval(onProgress, 500);
+
+		torrent.on('done', () => 
+		{
+			onProgress();
+			clearInterval(onProgress);
+
+			this.setState({
+				files : torrent.files,
+				active: false
+			});
+		});
+	};
+
 	download = () =>
 	{
 		this.setState({
 			active : true
 		});
+		
+		const magnet = this.props.message.file.magnet;
 
-		client.add(this.props.message.file.magnet, (torrent) =>
+		const existingTorrent = client.get(magnet);
+
+		if (existingTorrent)
 		{
-			const onProgress = () =>
-			{
-				this.setState({
-					numPeers : torrent.numPeers,
-					progress : torrent.progress
-				});
-			};
+			// Never add duplicate torrents, use the existing one instead.
+			return this.handleTorrent(existingTorrent);
+		}
 
-			setInterval(onProgress, 500);
-			onProgress();
-
-			torrent.on('done', () => 
-			{
-				onProgress();
-				clearInterval(onProgress);
-
-				this.setState({
-					files : torrent.files,
-					active: false
-				});
-			});
-		});
+		client.add(magnet, this.handleTorrent);
 	}
 
 	render()

app/lib/components/Chat/FileSharing.jsx

@@ -1,9 +1,11 @@
 import React, { Component } from 'react';
 import WebTorrent from 'webtorrent';
+import createTorrent from 'create-torrent';
 import dragDrop from 'drag-drop';
 import * as stateActions from '../../redux/stateActions';
 import * as requestActions from '../../redux/requestActions';
 import { store } from '../../store';
+import { promisify } from 'util';
 
 export const client = new WebTorrent();
 
@@ -15,17 +17,35 @@ const notifyPeers = (file) =>
 	store.dispatch(requestActions.sendChatFile(file, displayName, picture));
 };
 
-const shareFiles = (files) =>
+const shareFiles = async (files) =>
 {
-	client.seed(files, (torrent) => 
+	createTorrent(files, (err, torrent) =>
 	{
-		notifyPeers({
-			magnet : torrent.magnetURI
+		if (err)
+		{
+			console.error('Error creating torrent', err);
+			return;
+		}
+
+		const existingTorrent = client.get(torrent);
+
+		if (existingTorrent)
+		{
+			return notifyPeers({
+				magnet: existingTorrent.magnetURI
+			});
+		}
+	
+		client.seed(files, (newTorrent) =>
+		{
+			notifyPeers({
+				magnet : newTorrent.magnetURI
+			});
 		});
 	});
 };
 
-dragDrop('body', shareFiles);
+dragDrop('body', async (files) => await shareFiles(files));
 
 class FileSharing extends Component 
 {
@@ -36,11 +56,11 @@ class FileSharing extends Component
 		this.fileInput = React.createRef();
 	}
 
-	handleFileChange = (event) =>
+	handleFileChange = async (event) =>
 	{
 		if (event.target.files.length > 0)
 		{
-			shareFiles(event.target.files);
+			await shareFiles(event.target.files);
 		}
 	};
 

app/package-lock.json

@@ -3109,9 +3109,9 @@
       }
     },
     "create-torrent": {
-      "version": "3.32.0",
-      "resolved": "https://registry.npmjs.org/create-torrent/-/create-torrent-3.32.0.tgz",
-      "integrity": "sha512-l9chXj5LLyVFfPF6nFCWlm5/Wt+04d+mXUpG5LJAogeyRruWfjnUozfmQspAi6iW91ibp7qKBuFMPJViz5lp1Q==",
+      "version": "3.32.1",
+      "resolved": "https://registry.npmjs.org/create-torrent/-/create-torrent-3.32.1.tgz",
+      "integrity": "sha512-8spZUeFyVc+2mGnWBRTuLOhuHmHrmUomFWf7QvxztCEvTpn5SIrvF8F+HKdkzBPM9B7v/2w+f/65jqLWBXSndg==",
       "requires": {
         "bencode": "^2.0.0",
         "block-stream2": "^1.0.0",

app/package.json

@@ -9,6 +9,7 @@
   "dependencies": {
     "babel-runtime": "^6.26.0",
     "classnames": "^2.2.6",
+    "create-torrent": "^3.32.1",
     "debug": "^3.1.0",
     "domready": "^1.0.8",
     "drag-drop": "^4.2.0",