azure-function-express/lib/ExpressAdapter.js

Allows Express usage with Azure Function

"use strict";

exports.__esModule = true;
exports.default = void 0;

var _events = _interopRequireDefault(require("events"));

var _OutgoingMessage = _interopRequireDefault(require("./OutgoingMessage"));

var _IncomingMessage = _interopRequireDefault(require("./IncomingMessage"));

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

/**
 * @param {Object} context Azure Function native context object
 * @throws {Error}
 * @private
 */
function assertContext(context) {
  if (!context) {
    throw new Error("context is null or undefined");
  }

  if (!context.bindings) {
    throw new Error("context.bindings is null or undefined");
  }

  if (!context.bindings.req) {
    throw new Error("context.bindings.req is null or undefined");
  }

  if (!context.bindings.req.originalUrl) {
    throw new Error("context.bindings.req.originalUrl is null or undefined");
  }
}
/**
 * Express adapter allowing to handle Azure Function requests by wrapping in request events.
 *
 * @class
 * @fires request
 */


class ExpressAdapter extends _events.default {
  /**
   * @param {Object=} requestListener Request listener (typically an express/connect instance)
   */
  constructor(requestListener) {
    super();

    if (requestListener !== undefined) {
      this.addRequestListener(requestListener);
    }
  }
  /**
   * Adds a request listener (typically an express/connect instance).
   *
   * @param {Object} requestListener Request listener (typically an express/connect instance)
   */


  addRequestListener(requestListener) {
    this.addListener("request", requestListener);
  }
  /**
   * Handles Azure Function requests.
   *
   * @param {Object} context Azure context object for a single request
   */


  handleAzureFunctionRequest(context) {
    assertContext(context); // 1. Context basic initialization

    context.res = context.res || {}; // 2. Wrapping

    const req = new _IncomingMessage.default(context);
    const res = new _OutgoingMessage.default(context); // 3. Synchronously calls each of the listeners registered for the event

    this.emit("request", req, res);
  }
  /**
   * Create function ready to be exposed to Azure Function for request handling.
   *
   * @returns {function(context: Object)} Azure Function handle
   */


  createAzureFunctionHandler() {
    return this.handleAzureFunctionRequest.bind(this);
  }

}

exports.default = ExpressAdapter;
module.exports = exports["default"];