login-system

What it is

A template login system implemented as an AWS Lambda function. It handles user registration, login, and token verification. User credentials are stored in a DynamoDB table with passwords hashed via bcrypt. Authentication state is managed using JSON Web Tokens (JWT).

Features

• User registration with username uniqueness checks
• Secure password hashing using bcryptjs
• JWT-based authentication token generation
• Token verification endpoint for protected routes
• DynamoDB integration for persistent user storage
• CORS-enabled API responses

Architecture

flowchart TD
    Client[Client App] -->|HTTP POST/GET| APIGW[API Gateway]
    APIGW -->|Event| Lambda[AWS Lambda Handler]
    Lambda -->|Read/Write| DynamoDB[(DynamoDB Table)]
    Lambda -->|Sign/Verify| JWT[JSON Web Token]
    Lambda -->|Hash/Compare| Bcrypt[bcryptjs]
    subgraph AWS Cloud
        Lambda
        DynamoDB
    end

How it's built

The core logic resides in a single Lambda handler (`index.js`) that routes HTTP requests to service modules for registration, login, and verification. It uses the `aws-sdk` for DynamoDB interactions, `bcryptjs` for password hashing, and `jsonwebtoken` for token generation and validation. Responses are formatted as API Gateway-compatible JSON objects.

How it runs

sequenceDiagram
    participant C as Client
    participant L as Lambda Handler
    participant S as Service Layer
    participant D as DynamoDB
    participant A as Auth Utils

    C->>L: POST /register or /login
    L->>S: Call register() or login()
    alt Registration
        S->>D: Get User (check existence)
        D-->>S: User Data
        S->>S: Hash Password (bcrypt)
        S->>D: Save User
    else Login
        S->>D: Get User
        D-->>S: User Data
        S->>S: Compare Password (bcrypt)
        S->>A: Generate JWT
        A-->>S: Token
    end
    S-->>L: Response Object
    L-->>C: JSON Response

How to apply & reuse

Deploy this code as an AWS Lambda function behind an API Gateway. Ensure the `audio_client_server_users` DynamoDB table exists in `us-east-2`. Set the `JWT_SECRET` environment variable. Use the exposed endpoints for user management in web or mobile applications.

At a glance