AWS Serverless REST API

Example of a serverless REST API built with Amazon Web Services. This API provides create, read, update, and delete (CRUD) functionality.

• Lambda
• API Gateway
• DynamoDB

Prerequisites

• AWS account for provisioning cloud services.
• Postman for testing the API.

Create DynamoDB table

First create a new DynamoDB table. This will be the data source for the API.

• Login to the AWS console using an IAM user.
• Search for DynamoDB.
• Click Create table.
• Enter a table name such as contact-list.
• Enter a partition key such as contactId with a data type of String (leave sort key blank for this example.)
• Leave Table settings as Default settings.
• Click Create table.

Create Lambda function and attach IAM role and policies

• Search for Lambda in AWS Console.
• Click Create function
• Enter a function name such as serverlessRestApi.
• Select Node.js as a runtime.
• Under Permissions select Change default execution role and then Create a new role from AWS policy templates with a name such as serverlessApiRole.
• Click Create function.
• Click Permissions and then click on the role name that was just created.
• Click Attach policies and search for CloudWatchLogsFullAccess, select the policy, then click Attach policy.
• Click Attach policies and search for DynamoDBFullAccess, select the policy, then click Attach policy.

Create API Gateway resource and HTTP methods

• Search for API Gateway in AWS Console.
• Click Create API.
• Go to REST API and click Build.
• Select REST and New API.
• Enter a name such as contactListRestAPI and leave endpoint type as Regional

Creating a /health endpoint:

• Click Actions and then Create resource.
• Enter resource name health and select Enable API Gateway CORS.
• Select the Health resource and then click Actions and Create method.
• Select GET method with Integration type as Lambda
• Select Use Lambda Proxy integration.
• Select the deployment region where the Lambda function will be deployed as us-east-1.
• Search for the Lambda function by name such as serverlessRestApi.

Creating a /contacts endpoint:

• Click Actions and then Create resource.
• Enter resource name contacts and select Enable API Gateway CORS.
• Select the Contacts resource and then click Actions and Create method.
• Select GET method with Integration type as Lambda
• Select Use Lambda Proxy integration.
• Select the deployment region where the Lambda function will be deployed as us-east-1.
• Search for the Lambda function by name such as serverlessRestApi.

Creating a /contact endpoint:

• PUT
• GET
• PATCH
• DELETE

Test API Endpoints in Postman

GET /health

Test the health of the API by sending a GET request to the /health endpoint which should return a 200 OK response.

Request Body:

"None"

Response:

"200 OK"

GET /contacts

Sending a GET request to the /contacts endpoint will return a list of all contacts in the database. Request Body:

"None"

Response:

{
	"contacts": [
		{
			"occupation": "Designer",
			"contactId": "10003",
			"lastName": "Smith",
			"email": "louis.smith@gmail.com",
			"phone": "505-426-8570",
			"firstName": "Louis"
		},
		{
			"occupation": "Designer",
			"contactId": "10002",
			"lastName": "Henson",
			"email": "stacy.henson@hotmail.com",
			"phone": "443-455-0735",
			"firstName": "Stacy"
		},
		{
			"occupation": "Software Engineer",
			"contactId": "10001",
			"lastName": "Neely",
			"email": "stephen.neely@yahoo.com",
			"phone": "803-740-4478",
			"firstName": "Stephen"
		}
	]
}

POST /contact

Add contacts to the database by sending a POST request to the /contact endpoint.

Request Body:

{
	"occupation": "Dentist",
	"contactId": "10004",
	"lastName": "Smith",
	"email": "louis.smith@gmail.com",
	"phone": "505-426-8570",
	"firstName": "Louis"
}

Response:

{
    "Operation": "SAVE",
    "Message": "SUCCESS",
    "Item": {
        "occupation": "Dentist",
        "contactId": "10004",
        "lastName": "Smith",
        "email": "louis.smith@gmail.com",
        "phone": "505-426-8570",
        "firstName": "Louis"
    }
}

GET /contact?contactId=10003

Retrieve a single contact using the /contact endpoint with contactId as q query parameter.

Request Body:

"None"

Response:

{
	"occupation": "Designer",
	"contactId": "10003",
	"lastName": "Smith",
	"email": "louis.smith@gmail.com",
	"phone": "505-426-8570",
	"firstName": "Louis"
}

PATCH /contact

Request Body:

{
    "contactId": "10002",
    "updateKey": "phone",
    "updateValue": "612-999-9903"
}

Response:

{
    "Operation": "UPDATE",
    "Message": "SUCCESS",
    "UpdatedAttributes": {
        "Attributes": {
            "phone": "612-999-0000"
        }
    }
}

DELETE /contact

Request Body:

{
    "contactId": "10004"
}

Response:

{
    "Operation": "DELETE",
    "Message": "SUCCESS",
    "Item": {
        "Attributes": {
            "occupation": "Dentist",
            "contactId": "10004",
            "lastName": "Smith",
            "email": "louis.smith@gmail.com",
            "phone": "505-426-8570",
            "firstName": "Louis"
        }
    }
}