Local server for testing lambda-api

lambda-api-local.ts

/**
 * refs. https://github.com/jeremydaly/lambda-api/issues/53#issuecomment-450578262
 */

import { api } from "./src/app";
import {
  APIGatewayProxyEventV2,
  APIGatewayEventRequestContextV2,
  APIGatewayProxyEventHeaders,
  Context,
} from "aws-lambda";
import * as urlLib from "url";
import * as http from "http";

const serverWrapper: http.Server = http.createServer(
  async (
    request: http.IncomingMessage,
    response: http.ServerResponse
  ): Promise<void> => {
    if (!request.method) {
      return;
    }
    const url = new urlLib.URL(
      request.url || "",
      `http://${request.headers.host}/`
    );
    let body = "";
    request.on("data", (chunk) => {
      body += chunk;
    });

    // The event object we're faking is a lightweight based on:
    // https://docs.aws.amazon.com/lambda/latest/dg/eventsources.html#eventsources-api-gateway-request
    const path = url.pathname;
    const event: APIGatewayProxyEventV2 = {
      version: "2.0",
      routeKey: "ANY /nodejs-apig-function-1G3XMPLZXVXYI",
      rawPath: path,
      cookies: [
        "s_fid=7AABXMPL1AFD9BBF-0643XMPL09956DE2",
        "regStatus=pre-register",
      ],
      rawQueryString: "",
      queryStringParameters: Array.from(url.searchParams.keys()).reduce(
        (output: Record<string, string>, key): Record<string, string> => {
          output[key] = url.searchParams.get(key) || "";
          return output;
        },
        {}
      ),
      headers: request.headers as APIGatewayProxyEventHeaders,
      requestContext: {
        http: {
          method: request.method.toUpperCase(),
          path: path,
          protocol: "HTTP/1.1",
          sourceIp: "127.0.0.1",
          userAgent: request.headers?.[`user-agent`] || "",
        },
        stage: "default",
      } as APIGatewayEventRequestContextV2,
      pathParameters: {},
      stageVariables: {},
      isBase64Encoded: false,
      body: body,
    };
    console.log(event);
    try {
      const res = await api.run(event, {} as Context);
      let { body, headers, statusCode } = res;

      if (res.isBase64Encoded) {
        body = Buffer.from(body, "base64");
      }

      if (!headers["content-length"] && body) {
        headers["content-length"] = body.length;
      }

      response.writeHead(statusCode, headers);
      response.end(body);
    } catch (err) {
      console.error("Something went horribly, horribly wrong");
      console.error(err);
      response.writeHead(500, { "content-length": 0 });
      response.end("");
    }
  }
);

serverWrapper.listen(process.env.PORT || 3000, () => {
  const address = serverWrapper.address();
  if (address && typeof address === "object") {
    console.log(`Listening on http://localhost:${address.port}/`);
  }
});