Function Agent

lib/_http_agent.js:153–269

(options)

}

function Agent(options) {
  if (!(this instanceof Agent))
    return new Agent(options);

  EventEmitter.call(this);

  this.options = { __proto__: null, ...options };

  this.defaultPort = this.options.defaultPort || 80;
  this.protocol = this.options.protocol || 'http:';

  if (this.options.noDelay === undefined)
    this.options.noDelay = true;

  // Don't confuse net and make it think that we're connecting to a pipe
  this.options.path = null;
  this.requests = { __proto__: null };
  this.sockets = { __proto__: null };
  this.freeSockets = { __proto__: null };
  this.keepAliveMsecs = this.options.keepAliveMsecs || 1000;
  this.keepAlive = this.options.keepAlive || false;
  this.maxSockets = this.options.maxSockets || Agent.defaultMaxSockets;
  this.maxFreeSockets = this.options.maxFreeSockets || 256;
  this.scheduling = this.options.scheduling || 'lifo';
  this.maxTotalSockets = this.options.maxTotalSockets;
  this.totalSocketCount = 0;

  this.agentKeepAliveTimeoutBuffer =
    typeof this.options.agentKeepAliveTimeoutBuffer === 'number' &&
    this.options.agentKeepAliveTimeoutBuffer >= 0 &&
    NumberIsFinite(this.options.agentKeepAliveTimeoutBuffer) ?
      this.options.agentKeepAliveTimeoutBuffer :
      1000;

  const proxyEnv = this.options.proxyEnv;
  if (typeof proxyEnv === 'object' && proxyEnv !== null) {
    this[kProxyConfig] = parseProxyConfigFromEnv(proxyEnv, this.protocol, this.keepAlive);
    debug(`new ${this.protocol} agent with proxy config`, this[kProxyConfig]);
  }

  validateOneOf(this.scheduling, 'scheduling', ['fifo', 'lifo']);

  if (this.maxTotalSockets !== undefined) {
    validateNumber(this.maxTotalSockets, 'maxTotalSockets', 1);
  } else {
    this.maxTotalSockets = Infinity;
  }

  this.on('free', (socket, options) => {
    const name = this.getName(options);
    debug('agent.on(free)', name);

    // TODO(ronag): socket.destroy(err) might have been called
    // before coming here and have an 'error' scheduled. In the
    // case of socket.destroy() below this 'error' has no handler
    // and could cause unhandled exception.

    if (!socket.writable) {