websockets.js

// Import and load env files
AutoLoad = require("@njs2/base/base/autoload.class");
AutoLoad.loadConfig();
AutoLoad.loadModules();

// Import Executor class
const { sockets, Executor } = require("@njs2/base");
const {
  CONNECTION_HANDLER_METHOD,
  DISCONNECTION_HANDLER_METHOD,
} = require("./src/global/constants");

const executeRequests = async (connectionId, wsEvent, request_id) => {
  const executor = new Executor();
  const resp = await executor.executeRequest(wsEvent);
  if (request_id)
    await sockets.emit(connectionId, { request_id: request_id, body: resp });
};

module.exports.handler = async (event) => {
  const body =
    typeof event.body == "string" ? JSON.parse(event.body) : event.body;
  const requestId = body ? body.request_id : null;

  try {
    let wsEvent = {};

    switch (event.requestContext.eventType) {
      case "CONNECT":
        wsEvent.httpMethod = "GET";
        wsEvent.requestId = null;
        wsEvent.headers = event.queryStringParameters.access_token
          ? {
              access_token: event.queryStringParameters.access_token,
            }
          : {};
        wsEvent.pathParameters = {
          proxy: CONNECTION_HANDLER_METHOD,
        };
        delete event.queryStringParameters.access_token;
        wsEvent.queryStringParameters = {
          socket_id: event.requestContext.connectionId,
          ...event.queryStringParameters,
        };
        CONNECTION_HANDLER_METHOD &&
          (await executeRequests(event.requestContext.connectionId, wsEvent));
        break;

      case "DISCONNECT":
        wsEvent.httpMethod = "GET";
        wsEvent.requestId = null;
        wsEvent.headers = {};
        wsEvent.pathParameters = {
          proxy: DISCONNECTION_HANDLER_METHOD,
        };
        wsEvent.queryStringParameters = {
          socket_id: event.requestContext.connectionId,
        };
        DISCONNECTION_HANDLER_METHOD &&
          (await executeRequests(event.requestContext.connectionId, wsEvent));
        break;

      case "MESSAGE":
        wsEvent.httpMethod = body.method;
        wsEvent.requestId = body.request_id;
        wsEvent.headers =
          body.headers && typeof body.headers == "object" ? body.headers : {};
        wsEvent.pathParameters = {
          proxy: body.action,
        };
        if (body.method == "GET") {
          wsEvent.queryStringParameters = body.body;
        } else if (body.method == "POST") {
          wsEvent.body = body.body;
        }
        await executeRequests(
          event.requestContext.connectionId,
          wsEvent,
          requestId
        );
        break;
    }

    return { statusCode: 200, body: "SUCCESS" };
  } catch (e) {
    console.log(e);
    await sockets.emit(event.requestContext.connectionId, {
      request_id: requestId,
      error: "Invalid Request",
    });
    return { statusCode: 500, body: "Internal server error" };
  }
};