The Email API provides functionalities to connect with users' mailboxes, authenticate via OAuth2, check for new emails since a given timestamp, and calculate the hypothetical cost of processing emails using a model.

• Architecture
• Decisions Made
• Challenges
• Getting Started
• Contributing
• License

1. Authentication: Uses OAuth2 to authenticate users with their email providers (Google and Microsoft).
2. Email Retrieval: Fetches emails since a given timestamp.

1. The user initiates an OAuth2 flow by providing their email.
2. Once authenticated, the user can query for new emails since a timestamp.

1. OAuth2 for Authentication: Chose OAuth2 due to its widespread adoption and security. It also provides a seamless experience for users.
2. Express.js Framework: Used Express.js for its simplicity, performance, and extensive middleware support.
3. Modular Structure: Adopted a modular directory structure to separate concerns, making the codebase scalable and maintainable.

• Node.js (v13.2.0 or above)
• A Google Developer account with OAuth2 credentials set up.
• A Microsoft Azure account with OAuth2 credentials set up.

1. Clone the repository:

```bash git clone https://github.com/umer-shaikhh/email-api.git cd email-api ```

2. Install the dependencies:

```bash npm install ```

3. Create a .env file in the root directory and add your OAuth2 credentials:

```env GOOGLE_CLIENT_ID=YOUR_GOOGLE_CLIENT_ID GOOGLE_CLIENT_SECRET=YOUR_GOOGLE_CLIENT_SECRET MICROSOFT_CLIENT_ID=YOUR_MICROSOFT_CLIENT_ID MICROSOFT_CLIENT_SECRET=YOUR_MICROSOFT_CLIENT_SECRET SESSION_SECRET=some_random_secret ```

4. Start the server:

```bash npm start ```

The server will start on http://localhost:3000.

To authenticate with an email provider, use the /auth/connect endpoint:

``` GET /auth/connect?email=[email protected] ```

The server will redirect to the appropriate OAuth flow based on the email domain.

To check if a user has received new emails since a given timestamp:

``` GET /email/search?since=timestamp ```

To calculate the cost of processing emails from the last 24 hours:

``` GET /email/cost ```

To run the test suite:

```bash npm test ```