AWS: API (Lambda), Dynamo, and Frontend Applications

AWS Lambda Application Performance and Integration

• DynamoDB Non-relational Database Structure

The DynamoDB database is a non-relational, schema-less database that uses partition and sort keys to optimize queries. In this implementation, fields such as Field02 and Field04 are used as the partition and sort keys, respectively, to create an efficient index for data retrieval. This allows structured querying while maintaining flexibility in the schema.

• Lambda Function Using Node.js

The AWS Lambda function is written in Node.js and is designed to asynchronously handle API calls. It receives parameters from the frontend, parses them from the request body, and performs queries using a GSI (Global Secondary Index) on the DynamoDB table. The function uses structured key conditions and error handling to manage missing or malformed data inputs.

• IAM Permissions for Secure Access

IAM (Identity and Access Management) permissions are configured to restrict and authorize access to the DynamoDB service. This ensures that only the Lambda function with proper permissions can read from or write to the database, enhancing the security posture of the system.

• Exposing Lambda as an API with Function URL

The Lambda function is made accessible as a RESTful API using the 'Function URL' feature in AWS. This enables external systems, such as frontend applications, to make HTTP requests directly to the function, simplifying API integration.

• Frontend PHP Integration with Lambda API

The frontend PHP application sends HTTP POST requests to the Lambda function using cURL. It captures user input (channel, start date, end date), encodes it into JSON, and transmits it via the configured Lambda URL. This enables dynamic querying of the DynamoDB database through a web interface.

• Monitoring with AWS CloudWatch

AWS CloudWatch is used to monitor performance and detect potential security issues across the application stack, including the database, Lambda functions, and frontend access patterns. Logs provide visibility into execution times, errors, and anomalies for ongoing optimization and security auditing.

• Lambda Query Execution Flow Explained

The Lambda function structure includes parsing the incoming event, validating parameters, building the query command with a KeyConditionExpression, and awaiting a response from DynamoDB. Responses are returned in JSON format to the frontend. Errors are captured using try-catch blocks, and appropriate HTTP status codes are returned.

• PHP Form and cURL Call to Lambda

The PHP form captures user inputs and uses cURL to send them to the Lambda API. It includes methods to handle HTTP headers, return codes, and display responses, offering a seamless connection between frontend and backend services for database querying.