Adding keep alive for https connections

gistfile1.js

function addKeepAliveTimeout(agent) {
  function fail(msg) {
    console.warn(msg + ', node version: ' + process.version);
    return agent;
  }
  // Check it's what we expect
  var old_listeners = agent.listeners('free');
  if (!old_listeners || old_listeners.length !== 1) {
    return fail('Unexpected lacking "free" listener');
  }
  var expected_listener =
      'function (socket, host, port) {\n'
    + '    var name = host + \':\' + port;\n'
    + '    if (self.requests[name] && self.requests[name].length) {\n'
    + '      self.requests[name].shift().onSocket(socket);\n'
    + '      if (self.requests[name].length === 0) {\n'
    + '        // don\'t leak\n'
    + '        delete self.requests[name];\n'
    + '      }\n'
    + '    } else {\n'
    + '      // If there are no pending requests just destroy the\n'
    + '      // socket and it will get removed from the pool. This\n'
    + '      // gets us out of timeout issues and allows us to\n'
    + '      // default to Connection:keep-alive.\n'
    + '      socket.destroy();\n'
    + '    }\n'
    + '  }';
  var expected_addRequest =
      'function (req, host, port) {\n'
    + '  var name = host + \':\' + port;\n'
    + '  if (!this.sockets[name]) {\n'
    + '    this.sockets[name] = [];\n'
    + '  }\n'
    + '  if (this.sockets[name].length < this.maxSockets) {\n'
    + '    // If we are under maxSockets create a new one.\n'
    + '    req.onSocket(this.createSocket(name, host, port));\n'
    + '  } else {\n'
    + '    // We are over limit so we\'ll add it to the queue.\n'
    + '    if (!this.requests[name]) {\n'
    + '      this.requests[name] = [];\n'
    + '    }\n'
    + '    this.requests[name].push(req);\n'
    + '  }\n'
    + '}';

  if (old_listeners[0].toString() !== expected_listener) {
    console.log(require('util').inspect(old_listeners[0].toString()));
    return fail('Listener not defined as expected');
  }
  if (agent.addRequest.toString() !== expected_addRequest) {
    console.log(require('util').inspect(agent.addRequest.toString()));
    return fail('addRequest not defined as expected');
  }

  console.log('Using wrapped listener agent');

  assert.ok(!agent.free_sockets); // We're adding this field

  // Remove old listener
  agent.removeAllListeners('free');

  agent.free_sockets = {};
  agent.on('free', function(socket, host, port) {
    var name = host + ':' + port;
    if (agent.requests[name] && agent.requests[name].length) {
      agent.requests[name].shift().onSocket(socket);
      if (agent.requests[name].length === 0) {
        // don't leak
        delete agent.requests[name];
      }
    } else {
      // save the socket for at least a little while
      var obj = {
        socket: socket
      };
      obj.timeout_id = setTimeout(function() {
        var idx = agent.free_sockets[name].indexOf(obj);
        Assert.ok(idx !== -1);
        agent.free_sockets[name].splice(idx, 1);
        if (!agent.free_sockets[name].length) {
          delete agent.free_sockets[name];
        }
        socket.destroy();
      }, 10000);
      if (!agent.free_sockets[name]) {
        agent.free_sockets[name] = [];
      }
      agent.free_sockets[name].push(obj);
    }
  });

  agent.addRequest = function(req, host, port) {
    var name = host + ':' + port;
    if (this.free_sockets[name] && this.free_sockets[name].length) {
      // Has a free socket, use it
      var obj = this.free_sockets[name].shift();
      clearTimeout(obj.timeout_id);
      req.onSocket(obj.socket);
    } else {
      if (!this.sockets[name]) {
        this.sockets[name] = [];
      }
      if (this.sockets[name].length < this.maxSockets) {
        // If we are under maxSockets create a new one.
        req.onSocket(this.createSocket(name, host, port));
      } else {
        // We are over limit so we'll add it to the queue.
        if (!this.requests[name]) {
          this.requests[name] = [];
        }
        this.requests[name].push(req);
      }
    }
  };
  return agent;
}