Creating a download link to a file within the .torrent

[Nashorn]

I've been trying a simple demo to show a download link, but the getBlobUrl() seems to never run, can't get my debugger; to hit.

Example posted by another user:
https://gist.github.com/DiegoRBaquero/4235c7283e7ff579cdd093305803e799

This is what I am trying:

window.addEventListener("DOMContentLoaded", function(e) {
                var downloadBtn = document.querySelector("button#download-btn");
                downloadBtn.addEventListener("click", startDownload, false);
        	}, false);



            function startDownload(){
                var torrentId   = document.querySelector("textarea#magnet-uri").value;
                var client = new WebTorrent();
                    client.add(torrentId, onTorrentReady);
            }

            function onTorrentReady (torrent) {
              torrent.files[0].getBlobURL(function(err, url) {
                debugger;
                  if (err) return console.log(err)
                  var a = document.createElement('a')
                  a.target = '_blank'
                  a.download = torrent.files[0].name
                  a.href = url
                  a.textContent = 'Download ' + torrent.files[0].name
                  document.body.appendChild(a)
              })
            }

[Nashorn]

I've now replaced the hardcoded index check for the forEach just incase I might be missing the file, still not able to get the getBlobURL() to run.

torrent.files.forEach(function (file) { file.getBlobURL(function(err, url) { debugger; if (err) return console.log(err) var a = document.createElement('a') a.target = '_blank' a.download = file.name a.href = url a.textContent = 'Download ' + file.name document.body.appendChild(a) }) })

[Nashorn]

Here is a live code snippet showing that the download links are never rendered because getBlobURL does not work.

http://embed.plnkr.co/6Jr7qH/

[Nashorn]

OK more info on this issue. I left the download demo running in my tab in Chrome, and roughly 10 mins later the getBlobURL() fires off and was able to render my download link which did work.

I also opened the seeding tab and my download demo tab on FF, about 10 mins later the getBlobURL fired off and worked.....

Chrome also gave this error:

29webtorrent.js:7 Uncaught DOMException: Failed to construct 'RTCPeerConnection': Cannot create so many PeerConnections
at new r (file:///Users/xxx/Documents/SublimeWorkspace/WebTorrent/webtorrent.js:7:10096)
at r._createPeer (file:///Users/xxx/Documents/SublimeWorkspace/WebTorrent/webtorrent.js:3:1086)
at r._onAnnounceResponse (file:///Users/xxx/Documents/SublimeWorkspace/WebTorrent/webtorrent.js:2:30590)
at r._onSocketData (file:///Users/xxx/Documents/SublimeWorkspace/WebTorrent/webtorrent.js:2:29620)
at r.e._onSocketDataBound (file:///Users/xxx/Documents/SublimeWorkspace/WebTorrent/webtorrent.js:2:28859)
at r.emit (file:///Users/xxx/Documents/SublimeWorkspace/WebTorrent/webtorrent.js:4:7236)
at s (file:///Users/xxx/Documents/SublimeWorkspace/WebTorrent/webtorrent.js:6:5613)
at r.i.push (file:///Users/xxx/Documents/SublimeWorkspace/WebTorrent/webtorrent.js:6:9364)
at r._onMessage (file:///Users/xxx/Documents/SublimeWorkspace/WebTorrent/webtorrent.js:7:24456)
at WebSocket.t._ws.onmessage (file:///Users/xxx/Documents/SublimeWorkspace/WebTorrent/webtorrent.js:7:22598)

[alxhotel]

OK more info on this issue. I left the download demo running in my tab in Chrome, and roughly 10 mins later the getBlobURL() fires off and was able to render my download link which did work.

The callback of getBlobURL() is called when the file is fully downloaded. That is why you need to wait a while to get the blob URL.

Chrome also gave this error:
webtorrent.js:7 Uncaught DOMException: Failed to construct 'RTCPeerConnection': Cannot create so many PeerConnections
...

From what I see in your code snippet you are using an old version of Webtorrent (0.27.3). Try using the latest one (0.99.3):

https://cdn.jsdelivr.net/npm/webtorrent@latest/webtorrent.min.js

[Nashorn]

I'll get latest. What's a way to generate a download link will waiting for the full file to be downloaded?

[feross]

@Nashorn You can show a download link on your site however you want to. This is not really a WebTorrent concern.

WebTorrent can't generate the Blob URL until the data is fully downloaded. This is just how Blobs work in the browser. You need all the data available at the time you create the Blob.

So, I would show some UI that let's the user know the file is still downloading before you show the link. Or, you can show a link and let them click it, and then show the download progress until the callback is called.

You can check the progress by checking file.progress (from 0 to 1)