Support for API Gateway

closes #226
closes #221
closes #69

Author: gpotter2

README.md

@@ -160,22 +160,23 @@ lambda-local -l index.js -h handler -e examples/s3-put.js
 lambda-local -l index.js -h handler -e examples/s3-put.js -E '{"key":"value","key2":"value2"}'
 ```
 
-#### Running lambda functions as a HTTP Server
-A simple way you can run lambda functions locally, without the need to create any special template files (like Serverless plugin and SAM requires), just adding the parameter `--watch`. It will raise a http server listening to the specified port (default is 8008), then you can pass the event payload to the handler via request body.
+#### Running lambda functions as a HTTP Server (Amazon API Gateway payload format version 2.0.)
+
+A simple way you can run lambda functions locally, without the need to create any special template files (like Serverless plugin and SAM requires), just adding the parameter `--watch`. It will raise a http server listening to the specified port (default is 8008). You can then call the lambda as mentionned here:
+https://docs.aws.amazon.com/lambda/latest/dg/urls-invocation.html
 
 ```bash
-lambda-local -l examples/handler_helloworld.js -h handler --watch 8008
+lambda-local -l examples/handler_gateway2.js -h handler --watch 8008
 
 curl --request POST \
   --url http://localhost:8008/ \
   --header 'content-type: application/json' \
   --data '{
-	"event": {
-		"key1": "value1",
-		"key2": "value2",
-		"key3": "value3"
-	}
+        "key1": "value1",
+        "key2": "value2",
+        "key3": "value3"
 }'
+{"message":"This is a response"}
 ```
 
 ## About: Definitions
@@ -187,7 +188,7 @@ Event data are just JSON objects exported:
 ```js
 // Sample event data
 module.exports = {
-	foo: "bar"
+    foo: "bar"
 };
 ```
 

examples/handler_gateway2.js

@@ -0,0 +1,7 @@
+/*
+ * Example Lambda function.
+ */
+
+exports.handler = async function(event, context) {
+    return { message: "Hello ! Here's a full copy of the event:", event };
+};

package.json

@@ -1,6 +1,6 @@
 {
   "name": "lambda-local",
-  "version": "2.0.3",
+  "version": "2.0.0",
   "description": "Commandline tool to run Lambda functions on your local machine.",
   "main": "build/lambdalocal.js",
   "types": "build/lambdalocal.d.ts",
@@ -43,7 +43,7 @@
   "devDependencies": {
     "@types/node": "^18.7.16",
     "chai": "^4.3.6",
-    "mocha": "^10.0.0",
+    "mocha": "^10.2.0",
     "sinon": "^14.0.0",
     "typescript": "^4.8.3"
   },

src/lambdalocal.ts

@@ -11,6 +11,7 @@ import fs = require('fs');
 import path = require('path');
 import os = require('os');
 import { createServer, IncomingMessage, ServerResponse } from 'http';
+
 import utils = require('./lib/utils.js');
 import Context = require('./lib/context.js');
 require("./lib/streaming.js");
@@ -64,12 +65,11 @@ export function watch(opts) {
             return res.end(JSON.stringify({ error }));
         }
         try {
-            if(req.headers['content-type'] !== 'application/json') throw 'Invalid header Content-Type (Expected application/json)';
             _getRequestPayload(req, async (error, result) => {
                 try {
                     if(error) throw error;
-                    const data = await execute({ ...opts, event: () => result });
-                    const ans = JSON.stringify({ data });
+                    const data = await execute({ ...opts, event: result });
+                    const ans = _formatResponsePayload(res, data);
                     logger.log('info', log_msg + ` -> OK (${ans.length * 2} bytes)`);
                     return res.end(ans);
                 } catch(error) {
@@ -86,26 +86,75 @@ export function watch(opts) {
 }
 
 function _getRequestPayload(req, callback) {
+    /*
+     * Handle HTTP server functions.
+     */
     let body = '';
     req.on('data', chunk => {
         body += chunk.toString();
     });
     req.on('end', () => {
         let payload;
         try {
-            payload = JSON.parse(body);
+            payload = JSON.parse(body || '{}');
         } catch(err) {
             callback(err);
             return;
         }
-        if(!payload.event) {
-            callback('Invalid body (Expected "event" property)');
-            return;
-        }
-        callback(null, payload.event);
+        // Format: https://docs.aws.amazon.com/apigateway/latest/developerguide/http-api-develop-integrations-lambda.html#http-api-develop-integrations-lambda.proxy-format
+        const url = new URL(req.url, `http://${req.headers.host}`);
+        const event = {
+            version: "2.0",
+            routeKey: "$default",
+            rawPath: url.pathname,
+            rawQueryString: url.search,
+            cookies: utils.parseCookies(req),
+            headers: req.headers,
+            queryStringParameters: Object.fromEntries(url.searchParams),
+            requestContext: {
+                accountId: "123456789012",
+                apiId: "api-id",
+                authentication: {},
+                authorizer: {},
+                http: {
+                    method: req.method,
+                    path: url.pathname,
+                    protocol: "HTTP/" + req.httpVersion,
+                    sourceIp: req.socket.localAddress,
+                    userAgent: req.headers['user-agent'],
+                },
+                requestId: "id",
+                routeKey: "$default",
+                stage: "$default",
+                time: new Date().toISOString(),
+                timeEpoch: new Date().getTime(),
+            },
+            body: payload,
+            isBase64Encoded: req.headers['content-type'] !== 'application/json',
+        };
+        callback(null, event);
     });
 }
 
+function _formatResponsePayload(res, data) {
+    /*
+     * Handle HTTP server function output.
+     */
+    // https://docs.aws.amazon.com/apigateway/latest/developerguide/http-api-develop-integrations-lambda.html#http-api-develop-integrations-lambda.response
+    if (!data.statusCode) {
+        data = {
+            isBase64Encoded: false,
+            statusCode: 200,
+            body: data,
+            headers: {
+                "content-type": "application/json",
+            }
+        }
+    }
+    res.writeHead(data.statusCode, data.headers);
+    return JSON.stringify(data.body);
+}
+
 function updateEnv(env) {
     /*
      * Update environment vars if not already in place

src/lib/utils.ts

@@ -96,6 +96,23 @@ export function processJSON(json) {
     }
 };
 
+export function parseCookies (request) {
+    const list = {};
+    const cookieHeader = request.headers?.cookie;
+    if (!cookieHeader) return list;
+
+    cookieHeader.split(`;`).forEach(function(cookie) {
+        let [ name, ...rest] = cookie.split(`=`);
+        name = name?.trim();
+        if (!name) return;
+        const value = rest.join(`=`).trim();
+        if (!value) return;
+        list[name] = decodeURIComponent(value);
+    });
+
+    return list;
+}
+
 export class TimeoutError extends Error {
     constructor(m: string) {
         super(m);