refactor(docs): async await version of examples/chat (#482)

* fix: performance bottleneck in stat.js (#463)

Array.shift seems to be very slow, perhaps linear, on some
engines, resulting in  _update consuming a lot of CPU.

* docs(fix): correct docs and example for pnet (#464)

* docs(fix): correct docs and example for pnet

* docs(fix): correct pnet docs

* docs(fix): update README.md language (#468)

* docs: reciprocate (#474)

* docs(example): fix ipfs cat (#475)

`ipfs.files.cat` is incorrect. the correct function is `ipfs.cat`

* fix: async-await example chat

* fix: move handler before start

* fix: examples readme typos (#481)

* fix: simplify libp2p bundle for echo example

* chore: remove unused vars

Author: dirkmc

examples/chat/src/dialer.js

@@ -4,76 +4,44 @@
 const PeerId = require('peer-id')
 const PeerInfo = require('peer-info')
 const Node = require('./libp2p-bundle')
-const pull = require('pull-stream')
-const async = require('async')
-const Pushable = require('pull-pushable')
-const p = Pushable()
-let idListener
+const { stdinToStream, streamToConsole } = require('./stream')
 
-async.parallel([
-  (callback) => {
-    PeerId.createFromJSON(require('./peer-id-dialer'), (err, idDialer) => {
-      if (err) {
-        throw err
-      }
-      callback(null, idDialer)
-    })
-  },
-  (callback) => {
-    PeerId.createFromJSON(require('./peer-id-listener'), (err, idListener) => {
-      if (err) {
-        throw err
-      }
-      callback(null, idListener)
-    })
-  }
-], (err, ids) => {
-  if (err) throw err
-  const peerDialer = new PeerInfo(ids[0])
+async function run() {
+  const [idDialer, idListener] = await Promise.all([
+    PeerId.createFromJSON(require('./peer-id-dialer')),
+    PeerId.createFromJSON(require('./peer-id-listener'))
+  ])
+
+  // Create a new libp2p node on localhost with a randomly chosen port
+  const peerDialer = new PeerInfo(idDialer)
   peerDialer.multiaddrs.add('/ip4/0.0.0.0/tcp/0')
   const nodeDialer = new Node({
     peerInfo: peerDialer
   })
 
-  const peerListener = new PeerInfo(ids[1])
-  idListener = ids[1]
+  // Create a PeerInfo with the listening peer's address
+  const peerListener = new PeerInfo(idListener)
   peerListener.multiaddrs.add('/ip4/127.0.0.1/tcp/10333')
-  nodeDialer.start((err) => {
-    if (err) {
-      throw err
-    }
 
-    console.log('Dialer ready, listening on:')
+  // Start the libp2p host
+  await nodeDialer.start()
 
-    peerListener.multiaddrs.forEach((ma) => {
-      console.log(ma.toString() + '/p2p/' + idListener.toB58String())
-    })
+  // Output this node's address
+  console.log('Dialer ready, listening on:')
+  peerListener.multiaddrs.forEach((ma) => {
+    console.log(ma.toString() + '/p2p/' + idListener.toB58String())
+  })
 
-    nodeDialer.dialProtocol(peerListener, '/chat/1.0.0', (err, conn) => {
-      if (err) {
-        throw err
-      }
-      console.log('nodeA dialed to nodeB on protocol: /chat/1.0.0')
-      console.log('Type a message and see what happens')
-      // Write operation. Data sent as a buffer
-      pull(
-        p,
-        conn
-      )
-      // Sink, data converted from buffer to utf8 string
-      pull(
-        conn,
-        pull.map((data) => {
-          return data.toString('utf8').replace('\n', '')
-        }),
-        pull.drain(console.log)
-      )
+  // Dial to the remote peer (the "listener")
+  const { stream } = await nodeDialer.dialProtocol(peerListener, '/chat/1.0.0')
 
-      process.stdin.setEncoding('utf8')
-      process.openStdin().on('data', (chunk) => {
-        var data = chunk.toString()
-        p.push(data)
-      })
-    })
-  })
-})
+  console.log('Dialer dialed to listener on protocol: /chat/1.0.0')
+  console.log('Type a message and see what happens')
+
+  // Send stdin to the stream
+  stdinToStream(stream)
+  // Read the stream and output to console
+  streamToConsole(stream)
+}
+
+run()

examples/chat/src/libp2p-bundle.js

@@ -1,41 +1,12 @@
 'use strict'
 
 const TCP = require('libp2p-tcp')
-const MulticastDNS = require('libp2p-mdns')
 const WS = require('libp2p-websockets')
-const Bootstrap = require('libp2p-bootstrap')
-const spdy = require('libp2p-spdy')
-const KadDHT = require('libp2p-kad-dht')
 const mplex = require('libp2p-mplex')
 const secio = require('libp2p-secio')
 const defaultsDeep = require('@nodeutils/defaults-deep')
 const libp2p = require('../../..')
 
-function mapMuxers (list) {
-  return list.map((pref) => {
-    if (typeof pref !== 'string') {
-      return pref
-    }
-    switch (pref.trim().toLowerCase()) {
-      case 'spdy': return spdy
-      case 'mplex': return mplex
-      default:
-        throw new Error(pref + ' muxer not available')
-    }
-  })
-}
-
-function getMuxers (muxers) {
-  const muxerPrefs = process.env.LIBP2P_MUXER
-  if (muxerPrefs && !muxers) {
-    return mapMuxers(muxerPrefs.split(','))
-  } else if (muxers) {
-    return mapMuxers(muxers)
-  } else {
-    return [mplex, spdy]
-  }
-}
-
 class Node extends libp2p {
   constructor (_options) {
     const defaults = {
@@ -44,29 +15,8 @@ class Node extends libp2p {
           TCP,
           WS
         ],
-        streamMuxer: getMuxers(_options.muxer),
-        connEncryption: [ secio ],
-        peerDiscovery: [
-          MulticastDNS,
-          Bootstrap
-        ],
-        dht: KadDHT
-      },
-      config: {
-        peerDiscovery: {
-          mdns: {
-            interval: 10000,
-            enabled: false
-          },
-          bootstrap: {
-            interval: 10000,
-            enabled: false,
-            list: _options.bootstrapList
-          }
-        },
-        dht: {
-          kBucketSize: 20
-        }
+        streamMuxer: [ mplex ],
+        connEncryption: [ secio ]
       }
     }
 

examples/chat/src/listener.js

@@ -4,53 +4,38 @@
 const PeerId = require('peer-id')
 const PeerInfo = require('peer-info')
 const Node = require('./libp2p-bundle.js')
-const pull = require('pull-stream')
-const Pushable = require('pull-pushable')
-const p = Pushable()
+const { stdinToStream, streamToConsole } = require('./stream')
 
-PeerId.createFromJSON(require('./peer-id-listener'), (err, idListener) => {
-  if (err) {
-    throw err
-  }
+async function run() {
+  // Create a new libp2p node with the given multi-address
+  const idListener = await PeerId.createFromJSON(require('./peer-id-listener'))
   const peerListener = new PeerInfo(idListener)
   peerListener.multiaddrs.add('/ip4/0.0.0.0/tcp/10333')
   const nodeListener = new Node({
     peerInfo: peerListener
   })
 
-  nodeListener.start((err) => {
-    if (err) {
-      throw err
-    }
-
-    nodeListener.on('peer:connect', (peerInfo) => {
-      console.log(peerInfo.id.toB58String())
-    })
-
-    nodeListener.handle('/chat/1.0.0', (protocol, conn) => {
-      pull(
-        p,
-        conn
-      )
+  // Log a message when a remote peer connects to us
+  nodeListener.on('peer:connect', (peerInfo) => {
+    console.log(peerInfo.id.toB58String())
+  })
 
-      pull(
-        conn,
-        pull.map((data) => {
-          return data.toString('utf8').replace('\n', '')
-        }),
-        pull.drain(console.log)
-      )
+  // Handle messages for the protocol
+  await nodeListener.handle('/chat/1.0.0', async ({ stream }) => {
+    // Send stdin to the stream
+    stdinToStream(stream)
+    // Read the stream and output to console
+    streamToConsole(stream)
+  })
 
-      process.stdin.setEncoding('utf8')
-      process.openStdin().on('data', (chunk) => {
-        var data = chunk.toString()
-        p.push(data)
-      })
-    })
+  // Start listening
+  await nodeListener.start()
 
-    console.log('Listener ready, listening on:')
-    peerListener.multiaddrs.forEach((ma) => {
-      console.log(ma.toString() + '/p2p/' + idListener.toB58String())
-    })
+  // Output listen addresses to the console
+  console.log('Listener ready, listening on:')
+  peerListener.multiaddrs.forEach((ma) => {
+    console.log(ma.toString() + '/p2p/' + idListener.toB58String())
   })
-})
+}
+
+run()

examples/chat/src/stream.js

@@ -0,0 +1,40 @@
+'use strict'
+/* eslint-disable no-console */
+
+const pipe = require('it-pipe')
+const lp = require('it-length-prefixed')
+
+function stdinToStream(stream) {
+  // Read utf-8 from stdin
+  process.stdin.setEncoding('utf8')
+  pipe(
+    // Read from stdin (the source)
+    process.stdin,
+    // Encode with length prefix (so receiving side knows how much data is coming)
+    lp.encode(),
+    // Write to the stream (the sink)
+    stream.sink
+  )
+}
+
+function streamToConsole(stream) {
+  pipe(
+    // Read from the stream (the source)
+    stream.source,
+    // Decode length-prefixed data
+    lp.decode(),
+    // Sink function
+    async function (source) {
+      // For each chunk of data
+      for await (const msg of source) {
+        // Output the data as a utf8 string
+        console.log('> ' + msg.toString('utf8').replace('\n', ''))
+      }
+    }
+  )
+}
+
+module.exports = {
+  stdinToStream,
+  streamToConsole
+}