feat(pubsub): Add pubsub api (#493)

* feat(pubsub): Add pubsub api

Author: dignifiedquire

README.md

@@ -139,6 +139,30 @@ $ ipfs config --json API.HTTPHeaders.Access-Control-Allow-Methods "[\"PUT\", \"P
 
 > `js-ipfs-api` follows the spec defined by [`interface-ipfs-core`](https://github.com/ipfs/interface-ipfs-core), which concerns the interface to expect from IPFS implementations. This interface is a currently active endeavor. You can use it today to consult the methods available.
 
+#### Caveats
+
+##### Pubsub
+
+**Currently, the [PubSub API only works in Node.js envinroment](https://github.com/ipfs/js-ipfs-api/issues/518)**
+
+We currently don't support pubsub when run in the browser, and we test it with separate set of tests to make sure if it's being used in the browser, pubsub errors.
+
+More info: https://github.com/ipfs/js-ipfs-api/issues/518
+
+This means:
+- You can use pubsub from js-ipfs-api in Node.js
+- You can use pubsub from js-ipfs-api in Electron
+  (when js-ipfs-api is ran in the main process of Electron)
+- You can't use pubsub from js-ipfs-api in the browser
+- You can't use pubsub from js-ipfs-api in Electron's
+  renderer process
+- You can use pubsub from js-ipfs in the browsers
+- You can use pubsub from js-ipfs in Node.js
+- You can use pubsub from js-ipfs in Electron
+  (in both the main process and the renderer process)
+- See https://github.com/ipfs/js-ipfs for details on
+  pubsub in js-ipfs
+
 ##### [bitswap]()
 
 - [`ipfs.bitswap.wantlist()`]()

package.json

@@ -66,7 +66,7 @@
     "eslint-plugin-react": "^6.10.3",
     "gulp": "^3.9.1",
     "hapi": "^16.1.0",
-    "interface-ipfs-core": "~0.26.1",
+    "interface-ipfs-core": "~0.26.2",
     "ipfsd-ctl": "~0.20.0",
     "pre-commit": "^1.2.2",
     "socket.io": "^1.7.3",

src/api/pubsub.js

@@ -0,0 +1,162 @@
+'use strict'
+
+const promisify = require('promisify-es6')
+const EventEmitter = require('events')
+const eos = require('end-of-stream')
+const isNode = require('detect-node')
+const PubsubMessageStream = require('../pubsub-message-stream')
+const stringlistToArray = require('../stringlist-to-array')
+
+const NotSupportedError = () => new Error('pubsub is currently not supported when run in the browser')
+
+/* Public API */
+module.exports = (send) => {
+  /* Internal subscriptions state and functions */
+  const ps = new EventEmitter()
+  const subscriptions = {}
+  ps.id = Math.random()
+  return {
+    subscribe: (topic, options, handler, callback) => {
+      const defaultOptions = {
+        discover: false
+      }
+
+      if (typeof options === 'function') {
+        callback = handler
+        handler = options
+        options = defaultOptions
+      }
+
+      if (!options) {
+        options = defaultOptions
+      }
+
+      // Throw an error if ran in the browsers
+      if (!isNode) {
+        if (!callback) {
+          return Promise.reject(NotSupportedError())
+        }
+        return callback(NotSupportedError())
+      }
+
+      // promisify doesn't work as we always pass a
+      // function as last argument (`handler`)
+      if (!callback) {
+        return new Promise((resolve, reject) => {
+          subscribe(topic, options, handler, (err) => {
+            if (err) {
+              return reject(err)
+            }
+            resolve()
+          })
+        })
+      }
+
+      subscribe(topic, options, handler, callback)
+    },
+    unsubscribe: (topic, handler) => {
+      if (!isNode) {
+        throw NotSupportedError()
+      }
+
+      if (ps.listenerCount(topic) === 0 || !subscriptions[topic]) {
+        throw new Error(`Not subscribed to '${topic}'`)
+      }
+
+      ps.removeListener(topic, handler)
+
+      // Drop the request once we are actualy done
+      if (ps.listenerCount(topic) === 0) {
+        subscriptions[topic].abort()
+        subscriptions[topic] = null
+      }
+    },
+    publish: promisify((topic, data, callback) => {
+      if (!isNode) {
+        return callback(NotSupportedError())
+      }
+
+      if (!Buffer.isBuffer(data)) {
+        return callback(new Error('data must be a Buffer'))
+      }
+
+      const request = {
+        path: 'pubsub/pub',
+        args: [topic, data]
+      }
+
+      send(request, callback)
+    }),
+    ls: promisify((callback) => {
+      if (!isNode) {
+        return callback(NotSupportedError())
+      }
+
+      const request = {
+        path: 'pubsub/ls'
+      }
+
+      send.andTransform(request, stringlistToArray, callback)
+    }),
+    peers: promisify((topic, callback) => {
+      if (!isNode) {
+        return callback(NotSupportedError())
+      }
+
+      const request = {
+        path: 'pubsub/peers',
+        args: [topic]
+      }
+
+      send.andTransform(request, stringlistToArray, callback)
+    }),
+    setMaxListeners (n) {
+      return ps.setMaxListeners(n)
+    }
+  }
+
+  function subscribe (topic, options, handler, callback) {
+    ps.on(topic, handler)
+    if (subscriptions[topic]) {
+      return callback()
+    }
+
+    // Request params
+    const request = {
+      path: 'pubsub/sub',
+      args: [topic],
+      qs: {
+        discover: options.discover
+      }
+    }
+
+    // Start the request and transform the response
+    // stream to Pubsub messages stream
+    subscriptions[topic] = send.andTransform(request, PubsubMessageStream.from, (err, stream) => {
+      if (err) {
+        subscriptions[topic] = null
+        ps.removeListener(topic, handler)
+        return callback(err)
+      }
+
+      stream.on('data', (msg) => {
+        ps.emit(topic, msg)
+      })
+
+      stream.on('error', (err) => {
+        ps.emit('error', err)
+      })
+
+      eos(stream, (err) => {
+        if (err) {
+          ps.emit('error', err)
+        }
+
+        subscriptions[topic] = null
+        ps.removeListener(topic, handler)
+      })
+
+      callback()
+    })
+  }
+}

src/load-commands.js

@@ -25,6 +25,7 @@ function requireCommands () {
     refs: require('./api/refs'),
     repo: require('./api/repo'),
     swarm: require('./api/swarm'),
+    pubsub: require('./api/pubsub'),
     update: require('./api/update'),
     version: require('./api/version')
   }

src/pubsub-message-stream.js

@@ -0,0 +1,33 @@
+'use strict'
+
+const TransformStream = require('readable-stream').Transform
+const PubsubMessage = require('./pubsub-message-utils')
+
+class PubsubMessageStream extends TransformStream {
+  constructor (options) {
+    const opts = Object.assign(options || {}, { objectMode: true })
+    super(opts)
+  }
+
+  static from (inputStream, callback) {
+    let outputStream = inputStream.pipe(new PubsubMessageStream())
+    inputStream.on('end', () => outputStream.emit('end'))
+    callback(null, outputStream)
+  }
+
+  _transform (obj, enc, callback) {
+    let msg
+    try {
+      msg = PubsubMessage.deserialize(obj, 'base64')
+    } catch (err) {
+      // Not a valid pubsub message
+      // go-ipfs returns '{}' as the very first object atm, we skip that
+      return callback()
+    }
+
+    this.push(msg)
+    callback()
+  }
+}
+
+module.exports = PubsubMessageStream

src/pubsub-message-utils.js

@@ -0,0 +1,39 @@
+'use strict'
+
+const bs58 = require('bs58')
+
+module.exports = {
+  deserialize (data, enc) {
+    enc = enc ? enc.toLowerCase() : 'json'
+
+    if (enc === 'json') {
+      return deserializeFromJson(data)
+    } else if (enc === 'base64') {
+      return deserializeFromBase64(data)
+    }
+
+    throw new Error(`Unsupported encoding: '${enc}'`)
+  }
+}
+
+function deserializeFromJson (data) {
+  const json = JSON.parse(data)
+  return deserializeFromBase64(json)
+}
+
+function deserializeFromBase64 (obj) {
+  if (!isPubsubMessage(obj)) {
+    throw new Error(`Not a pubsub message`)
+  }
+
+  return {
+    from: bs58.encode(new Buffer(obj.from, 'base64')).toString(),
+    seqno: new Buffer(obj.seqno, 'base64'),
+    data: new Buffer(obj.data, 'base64'),
+    topicCIDs: obj.topicIDs || obj.topicCIDs
+  }
+}
+
+function isPubsubMessage (obj) {
+  return obj && obj.from && obj.seqno && obj.data && (obj.topicIDs || obj.topicCIDs)
+}

test/interface/pubsub.spec.js

@@ -0,0 +1,23 @@
+/* eslint-env mocha */
+
+'use strict'
+
+const test = require('interface-ipfs-core')
+const FactoryClient = require('../ipfs-factory/client')
+const isNode = require('detect-node')
+
+if (isNode) {
+  let fc
+
+  const common = {
+    setup: function (callback) {
+      fc = new FactoryClient()
+      callback(null, fc)
+    },
+    teardown: function (callback) {
+      fc.dismantle(callback)
+    }
+  }
+
+  test.pubsub(common)
+}

test/ipfs-factory/daemon-spawner.js

@@ -84,7 +84,7 @@ function spawnEphemeralNode (callback) {
           node.setConfig(configKey, configVal, cb)
         }, cb)
       },
-      (cb) => node.startDaemon(cb)
+      (cb) => node.startDaemon(['--enable-pubsub-experiment'], cb)
     ], (err) => callback(err, node))
   })
 }