multiple web workers

src/openpgp.js

@@ -56,11 +56,12 @@ let asyncProxy; // instance of the asyncproxy
 /**
  * Set the path for the web worker script and create an instance of the async proxy
  * @param {String} path            relative path to the worker scripts, default: 'openpgp.worker.js'
- * @param {Object} worker   alternative to path parameter: web worker initialized with 'openpgp.worker.js'
+ * @param {Number} n               number of workers to initialize
+ * @param {Array<Object>} workers  alternative to path parameter: web workers initialized with 'openpgp.worker.js'
  */
-export function initWorker({ path='openpgp.worker.js', worker } = {}) {
+export function initWorker({ path='openpgp.worker.js', n = 1, workers = [] } = {}) {
-  if (worker || (typeof window !== 'undefined' && window.Worker)) {
+  if (workers.length || (typeof window !== 'undefined' && window.Worker)) {
-    asyncProxy = new AsyncProxy({ path, worker, config });
+    asyncProxy = new AsyncProxy({ path, n, workers, config });
     return true;
   }
 }

src/worker/async_proxy.js

@@ -19,24 +19,69 @@ import util from '../util.js';
 import crypto from '../crypto';
 import packet from '../packet';
 
+/**
+ * Message handling
+ */
+function handleMessage(id) {
+  return function(event) {
+    const msg = event.data;
+    switch (msg.event) {
+      case 'method-return':
+        if (msg.err) {
+          // fail
+          const err = new Error(msg.err);
+          // add worker stack
+          err.workerStack = msg.stack;
+          this.tasks[msg.id].reject(err);
+        } else {
+          // success
+          this.tasks[msg.id].resolve(msg.data);
+        }
+        delete this.tasks[msg.id];
+        this.workers[id].requests--;
+        break;
+      case 'request-seed':
+        this.seedRandom(id, msg.amount);
+        break;
+      default:
+        throw new Error('Unknown Worker Event.');
+    }
+  };
+}
+
 /**
  * Initializes a new proxy and loads the web worker
  * @constructor
  * @param {String} path            The path to the worker or 'openpgp.worker.js' by default
+ * @param {Number} n               number of workers to initialize
  * @param {Object} config          config The worker configuration
- * @param {Object} worker   alternative to path parameter: web worker initialized with 'openpgp.worker.js'
+ * @param {Array<Object>} worker   alternative to path parameter: web worker initialized with 'openpgp.worker.js'
  * @return {Promise}
  */
-export default function AsyncProxy({ path='openpgp.worker.js', worker, config } = {}) {
+export default function AsyncProxy({ path='openpgp.worker.js', n = 1, workers = [], config } = {}) {
-  this.worker = worker || new Worker(path);
+
-  this.worker.onmessage = this.onMessage.bind(this);
+  if (workers.length) {
-  this.worker.onerror = e => {
+    this.workers = workers;
+  }
+  else {
+    this.workers = [];
+    while (this.workers.length < n) {
+      this.workers.push(new Worker(path));
+    }
+  }
+
+  let workerId = 0;
+  this.workers.forEach(worker => {
+    worker.requests = 0;
+    worker.onmessage = handleMessage(workerId++).bind(this);
+    worker.onerror = e => {
       throw new Error('Unhandled error in openpgp worker: ' + e.message + ' (' + e.filename + ':' + e.lineno + ')');
     };
 
     if (config) {
-    this.worker.postMessage({ event:'configure', config });
+      worker.postMessage({ event:'configure', config });
     }
+  });
 
   // Cannot rely on task order being maintained, use object keyed by request ID to track tasks
   this.tasks = {};
@@ -51,47 +96,22 @@ AsyncProxy.prototype.getID = function() {
   return this.currentID++;
 };
 
-/**
- * Message handling
- */
-AsyncProxy.prototype.onMessage = function(event) {
-  const msg = event.data;
-  switch (msg.event) {
-    case 'method-return':
-      if (msg.err) {
-        // fail
-        const err = new Error(msg.err);
-        // add worker stack
-        err.workerStack = msg.stack;
-        this.tasks[msg.id].reject(err);
-      } else {
-        // success
-        this.tasks[msg.id].resolve(msg.data);
-      }
-      delete this.tasks[msg.id];
-      break;
-    case 'request-seed':
-      this.seedRandom(msg.amount);
-      break;
-    default:
-      throw new Error('Unknown Worker Event.');
-  }
-};
-
 /**
  * Send message to worker with random data
  * @param  {Integer} size Number of bytes to send
  */
-AsyncProxy.prototype.seedRandom = async function(size) {
+AsyncProxy.prototype.seedRandom = async function(id, size) {
   const buf = await crypto.random.getRandomBytes(size);
-  this.worker.postMessage({ event:'seed-random', buf }, util.getTransferables(buf));
+  this.workers[id].postMessage({ event:'seed-random', buf }, util.getTransferables(buf));
 };
 
 /**
- * Terminates the worker
+ * Terminates the workers
  */
 AsyncProxy.prototype.terminate = function() {
-  this.worker.terminate();
+  this.workers.forEach(worker => {
+    worker.terminate();
+  });
 };
 
 /**
@@ -101,11 +121,21 @@ AsyncProxy.prototype.terminate = function() {
  * @return {Promise}          see the corresponding public api functions for their return types
  */
 AsyncProxy.prototype.delegate = function(method, options) {
+
   const id = this.getID();
+  const requests = this.workers.map(worker => worker.requests);
+  const minRequests = Math.min(requests);
+  let workerId = 0;
+  for(; workerId < this.workers.length; workerId++) {
+    if (this.workers[workerId].requests === minRequests) {
+      break;
+    }
+  }
 
   return new Promise((resolve, reject) => {
     // clone packets (for web worker structured cloning algorithm)
-    this.worker.postMessage({ id:id, event:method, options:packet.clone.clonePackets(options) }, util.getTransferables(options));
+    this.workers[workerId].postMessage({ id:id, event:method, options:packet.clone.clonePackets(options) }, util.getTransferables(options));
+    this.workers[workerId].requests++;
 
     // remember to handle parsing cloned packets from worker
     this.tasks[id] = { resolve: data => resolve(packet.clone.parseClonedPackets(data, method)), reject };

test/general/openpgp.js

@@ -363,7 +363,7 @@ describe('OpenPGP.js public api tests', function() {
         postMessage: function() {}
       };
       openpgp.initWorker({
-        worker: workerStub
+        workers: [workerStub]
       });
       expect(openpgp.getWorker()).to.exist;
       openpgp.destroyWorker();
@@ -522,7 +522,7 @@ describe('OpenPGP.js public api tests', function() {
         postMessage: function() {}
       };
       openpgp.initWorker({
-        worker: workerStub
+        workers: [workerStub]
       });
       const proxyGenStub = stub(openpgp.getWorker(), 'delegate');
       getWebCryptoAllStub.returns();

test/worker/async_proxy.js

@@ -50,7 +50,7 @@ function tests() {
   describe('Random number pipeline', function() {
     it('Random number buffer automatically reseeded', function() {
       const worker = new Worker('../dist/openpgp.worker.js');
-      const wProxy = new openpgp.AsyncProxy({ path:'../dist/openpgp.worker.js', worker });
+      const wProxy = new openpgp.AsyncProxy({ path:'../dist/openpgp.worker.js', workers: [worker] });
 
       return wProxy.delegate('encrypt', { publicKeys:[pubKey], data:plaintext });
     });