CODEWITHSUNDEEP
javascriptpeerjs
user3331344
user3331344

Reputation: 991

Peerjs how can I tell if a connection to a peer has been successfully established?

Is there a way with peerjs to tell if a connection has been successfully made when using peer.connect(). Reading the docs the only events emitted for a DataConnection are data, open, close and error. And error doesn't emit if there was no connection made.

I am trying to create a peer to peer file transfer by sending chunks of data. My current flow is to first connect to the user and save that connection for future use. Then I would like to send them a message that a transfer has been initialized so they can either accept or deny the transfer.

My big problem is there is no error emitted when a connection cannot be established. You can attach an error handler to the peer itself but it just emit a generic error something like cannot connect to peer {peerid}. This isn't really useful because I would have to unreliably parse this string to get the connection id. So there is really no way of knowing whether peer.connect({peerid}) was actually connected or not.

So if I were to write a function to connect to a peer then there is really now way of knowing if the connection is successful. So something like so:

async function connect(to) {
  return new Promise((resolve, reject) => {
    const conn = peer.connect(to)

    // This doesn't exist
    conn.on('success', () => {
      connections.set(to, conn)
      resolve(conn)
    })

    // This exists but doesn't emit on unsuccessful connection
    conn.on('error', (err) => reject(err))
  })
}

Then if I can store the connection I can just grab the connection and send with it.

function send(to, data){
  const conn = connections.get(to)
  if(!conn) throw new Error('No connection available')

  conn.send(data)
}

So currently I have resorted to using the listAllPeers() function to get a list of connected peers. Then running that in a setInterval until the peer has been found. This seems like a bit more work than needs to be done and also requires and extra call to the peer server for no reason other than to check if a peer is available before connecting which seems stupid. I could also probably set up a mechanism to just try send messages at an interval and wait for a response. This all seems like a poor solution.

So is there a good way to tell if a connection has been established or am I stuck with my current solution?

Upvotes: 1

Views: 650

Answers (1)

Red
Red

Reputation: 9

Just use conn.on("open");

const conn = peer.connect(to)

// This exists
conn.on('open', () => {
  connections.set(to, conn)
  resolve(conn)
})

// This exists but doesn't emit on unsuccessful connection
conn.on('error', (err) => reject(err))

Upvotes: -1

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