From 39c0b08d9db707bd9bd5fc86fd462c64142f2927 Mon Sep 17 00:00:00 2001
From: Matheus Cansian <mscansian@gmail.com>
Date: Sat, 5 Oct 2019 17:17:23 -0300
Subject: [PATCH] Remove aws-sdk dependency from AWS Lambda node

---
 .../nodes-base/nodes/Aws/AwsLambda.node.ts    | 45 ++++++++++++------
 .../nodes-base/nodes/Aws/GenericFunctions.ts  | 47 ++++++++++++++++++-
 packages/nodes-base/package.json              |  2 +
 3 files changed, 78 insertions(+), 16 deletions(-)

diff --git a/packages/nodes-base/nodes/Aws/AwsLambda.node.ts b/packages/nodes-base/nodes/Aws/AwsLambda.node.ts
index 87685c75b..70e254342 100644
--- a/packages/nodes-base/nodes/Aws/AwsLambda.node.ts
+++ b/packages/nodes-base/nodes/Aws/AwsLambda.node.ts
@@ -8,7 +8,7 @@ import {
 	IDataObject
 } from 'n8n-workflow';
 
-import { awsConfigCredentials } from './GenericFunctions';
+import { awsApiRequest } from './GenericFunctions';
 
 import { Lambda } from 'aws-sdk';
 
@@ -89,13 +89,9 @@ export class AwsLambda implements INodeType {
 	methods = {
 		loadOptions: {
 			async getFunctions(this: ILoadOptionsFunctions): Promise<INodePropertyOptions[]> {
-				await awsConfigCredentials.call(this);
-
 				const returnData: INodePropertyOptions[] = [];
-
-				let lambda = new Lambda();
 				try {
-					var data = await lambda.listFunctions({}).promise();
+					var data = await awsApiRequest.call(this, 'lambda', 'GET', '/2015-03-31/functions/');
 				} catch (err) {
 					throw new Error(`AWS Error: ${err}`);
 				}
@@ -116,9 +112,6 @@ export class AwsLambda implements INodeType {
 		const items = this.getInputData();
 		const returnData: IDataObject[] = [];
 
-		await awsConfigCredentials.call(this);
-		const lambda = new Lambda();
-
 		for (let i = 0; i < items.length; i++) {
 			const params = {
 				FunctionName: this.getNodeParameter('function', i) as string,
@@ -128,16 +121,38 @@ export class AwsLambda implements INodeType {
 			};
 
 			try {
-				var responseData = await lambda.invoke(params).promise();
+
+				var responseData = await awsApiRequest.call(
+					this,
+					'lambda',
+					'POST',
+					`/2015-03-31/functions/${params.FunctionName}/invocations?Qualifier=${params.Qualifier}`,
+					params.Payload,
+					{
+						'X-Amz-Invocation-Type': params.InvocationType,
+						'Content-Type': 'application/x-amz-json-1.0',
+					},
+				);
 			} catch (err) {
 				throw new Error(`AWS Error: ${err}`);
 			}
 
-			returnData.push({
-				StatusCode: responseData.StatusCode,
-				Result: responseData.Payload,
-				Error: responseData.FunctionError,
-			} as IDataObject);
+			if (responseData.errorMessage === undefined) {
+				returnData.push({
+					FunctionName: params.FunctionName,
+					FunctionQualifier: params.Qualifier,
+					Result: responseData,
+				} as IDataObject);
+			} else {
+				returnData.push({
+					FunctionName: params.FunctionName,
+					FunctionQualifier: params.Qualifier,
+					ErrorMessage: responseData.errorMessage,
+					ErrorType: responseData.errorType,
+					ErrorStackTrace: responseData.stackTrace,
+				} as IDataObject);
+			}
+
 		}
 
 		return [this.helpers.returnJsonArray(returnData)];
diff --git a/packages/nodes-base/nodes/Aws/GenericFunctions.ts b/packages/nodes-base/nodes/Aws/GenericFunctions.ts
index 2bfd2c027..30b3f2f94 100644
--- a/packages/nodes-base/nodes/Aws/GenericFunctions.ts
+++ b/packages/nodes-base/nodes/Aws/GenericFunctions.ts
@@ -6,7 +6,7 @@ import {
 
 import { config } from 'aws-sdk';
 import { OptionsWithUri } from 'request';
-
+import { sign } from 'aws4';
 
 export async function awsConfigCredentials(this: IHookFunctions | IExecuteFunctions | ILoadOptionsFunctions): Promise<void> {
 	const credentials = this.getCredentials('aws');
@@ -21,3 +21,48 @@ export async function awsConfigCredentials(this: IHookFunctions | IExecuteFuncti
 		secretAccessKey: `${credentials.secretAccessKey}`,
 	});
 }
+
+export async function awsApiRequest(this: IHookFunctions | IExecuteFunctions | ILoadOptionsFunctions, service: string, method: string, path: string, body?: string, headers?: object): Promise<any> { // tslint:disable-line:no-any
+	const credentials = this.getCredentials('aws');
+
+	if (credentials === undefined) {
+		throw new Error('No credentials got returned!');
+	}
+
+	const endpoint = `${service}.${credentials.region}.amazonaws.com`
+
+	// Sign AWS API request with the user credentials
+	const signOpts = {headers: headers || {}, host: endpoint, method: method, path: path, body: body}
+	sign(signOpts, {accessKeyId: `${credentials.accessKeyId}`, secretAccessKey: `${credentials.secretAccessKey}`})
+
+	const options: OptionsWithUri = {
+		headers: signOpts.headers,
+		method: method,
+		uri: `https://${endpoint}${signOpts.path}`,
+		body: signOpts.body,
+	};
+
+	let response: string
+	try {
+		response = await this.helpers.request!(options);
+	} catch (error) {
+		console.error(error);
+
+		const errorMessage = error.response.body.message || error.response.body.Message;
+		if (error.statusCode === 403) {
+			if (errorMessage == 'The security token included in the request is invalid.') {
+				throw new Error('The AWS credentials are not valid!');
+			} else if (errorMessage.startsWith('The request signature we calculated does not match the signature you provided')) {
+				throw new Error('The AWS credentials are not valid!');
+			}
+		}
+
+		throw errorMessage;
+	}
+
+	try {
+		return JSON.parse(response);
+	} catch (e) {
+		return response
+	}
+}
diff --git a/packages/nodes-base/package.json b/packages/nodes-base/package.json
index 54a83b531..4ee7ae8d6 100644
--- a/packages/nodes-base/package.json
+++ b/packages/nodes-base/package.json
@@ -106,6 +106,7 @@
         ]
     },
     "devDependencies": {
+        "@types/aws4": "^1.5.1",
         "@types/basic-auth": "^1.1.2",
         "@types/cron": "^1.6.1",
         "@types/express": "^4.16.1",
@@ -126,6 +127,7 @@
         "typescript": "~3.5.2"
     },
     "dependencies": {
+        "aws4": "^1.8.0",
         "aws-sdk": "^2.543.0",
         "basic-auth": "^2.0.1",
         "cron": "^1.6.0",