continuation-local-storage - npm Package Compare versions

Comparing version 2.2.1 to 2.3.0

context.js

 'use strict';
 
 var assert = require('assert');
+var wrap   = require('shimmer').wrap;
 
@@ -83,2 +84,62 @@ // load polyfill if native support is unavailable
 
+Namespace.prototype.bindEmitter = function (source) {
+  assert.ok(source.on && source.addListener && source.emit, "can only bind real EEs");
+
+  var namespace = this;
+  var contextName = '__' + this.name;
+
+  function capturer(on) {
+    return function (event, listener) {
+      listener[contextName] = namespace.active;
+
+      var returned = on.call(this, event, listener);
+
+      // FIXME: ReadableStreams overwrite on / addListener; find out why
+      wrap(this, 'on',          capturer);
+      wrap(this, 'addListener', capturer);
+
+      return returned;
+    };
+  }
+
+  function prepare(handlers) {
+    var replacements = [];
+    for (var i = 0; i < handlers.length; i++) {
+      var handler = handlers[i];
+      if (handler[contextName]) {
+        replacements.push(namespace.bind(handler, handler[contextName]));
+      }
+      else {
+        replacements.push(handler);
+      }
+    }
+
+    return replacements;
+  }
+
+  function puncher(emit) {
+    return function (event) {
+      if (!this._events[event]) return emit.apply(this, arguments);
+
+      // setup
+      var events = this._events[event];
+      if (typeof events === 'function' && events[contextName]) {
+        this._events[event] = namespace.bind(events, events[contextName]);
+      }
+      else if (events.length) {
+        this._events[event] = prepare(events);
+      }
+
+      // application
+      var returned = emit.apply(this, arguments);
+      this._events[event] = events;
+      return returned;
+    };
+  }
+
+  wrap(source, 'addListener', capturer);
+  wrap(source, 'on',          capturer);
+  wrap(source, 'emit',        puncher);
+};
+
 function get(name) {
@@ -85,0 +146,0 @@ return namespaces[name];

package.json

 {
   "name": "continuation-local-storage",
-  "version": "2.2.1",
+  "version": "2.3.0",
   "description": "userland implementation of https://github.com/joyent/node/issues/5243",
@@ -35,3 +35,6 @@ "main": "context.js",
     "async-listener": ">=0.1.2"
+  },
+  "dependencies": {
+    "shimmer": "~0.7"
   }
 }

README.md

@@ -189,2 +189,22 @@ # Continuation-Local Storage
 
+### namespace.bindEmitter(emitter)
+
+Bind an EventEmitter to a namespace. Operates similarly to `domain.add`, with a
+less generic name and the additional caveat that unlike domains, namespaces
+never implicitly bind EventEmitters to themselves when they're created within
+the context of an active namespace.
+
+The most likely time you'd want to use this is when you're using Express or
+Connect and want to make sure your middleware execution plays nice with CLS, or
+are doing other things with HTTP listeners:
+
+```javascript
+http.createServer(function (req, res) {
+  writer.add(req);
+  writer.add(rew);
+
+  // do other stuff, some of which is asynchronous
+});
+```
+
 ### namespace.createContext()
@@ -191,0 +211,0 @@

test/bind-emitter.tap.js

 'use strict';
+
+var test         = require('tap').test
+  , EventEmitter = require('events').EventEmitter
+  , cls          = require('../context.js')
+  ;
+
+function fresh(name, context) {
+  context.tearDown(function () {
+    cls.destroyNamespace(name);
+  });
+  return cls.createNamespace(name);
+}
+
+test("event emitters bound to CLS context", function (t) {
+  t.plan(3);
+
+  t.test("handler registered in context", function (t) {
+    t.plan(1);
+
+    var n  = fresh('in', this)
+      , ee = new EventEmitter()
+      ;
+
+    n.run(function () {
+      n.set('value', 'hello');
+      n.bindEmitter(ee);
+      ee.on('event', function () {
+        t.equal(n.get('value'), 'hello', "value still set in EE.");
+      });
+    });
+
+    ee.emit('event');
+  });
+
+  t.test("handler registered out of context", function (t) {
+    t.plan(1);
+
+    var n  = fresh('out', this)
+      , ee = new EventEmitter()
+      ;
+
+    ee.on('event', function () {
+      t.equal(n.get('value'), 'hello', "value still set in EE.");
+    });
+
+    n.run(function () {
+      n.set('value', 'hello');
+      n.bindEmitter(ee);
+
+      ee.emit('event');
+    });
+  });
+
+  t.test("handler added but used entirely out of context", function (t) {
+    t.plan(1);
+
+    var n  = fresh('none', this)
+      , ee = new EventEmitter()
+      ;
+
+    ee.on('event', function () {
+      t.notOk(n.get('value'), "value shouldn't be visible");
+    });
+
+    n.run(function () {
+      n.set('value', 'hello');
+      n.bindEmitter(ee);
+    });
+
+    ee.emit('event');
+  });
+});

No alert changes

Improved metrics

Total package byte prevSize

72154

increased by5.63%

Lines of code

1694

increased by6.54%

Number of lines in readme file

240

increased by9.09%

Worsened metrics

Dependency count

2

increased by100%

Dependency changes

• + Addedshimmer@~0.7

• + Addedshimmer@0.7.3(transitive)