Gmail Email Fetcher API

A Flask-based REST API that fetches and processes emails from Gmail using the Gmail API. This application is designed to retrieve emails matching specific queries and return them in a structured JSON format.

Features

• Gmail API integration with OAuth 2.0 authentication
• Configurable email query parameters
• Returns email data including subject, body, sender, date, and message ID
• Support for both development and production environments
• Automatic token refresh handling

Prerequisites

• Python 3.x
• Google Cloud Platform account
• Gmail API enabled
• OAuth 2.0 credentials configured

Environment Variables

Development

No environment variables required. The application will use local credential files.

Production

The following environment variables must be set:

• DEVELOPMENT: Set to 'false'
• CREDENTIALS_JSON_BASE64: Base64 encoded Google OAuth credentials
• TOKEN_JSON_BASE64: Base64 encoded OAuth token

Installation

1. Clone the repository:

git clone <repository-url>
cd <repository-name>

2. Install dependencies:
```bash
pip install -r requirements.txt

3. Setup Google OAUTH creds:

   a. Go to https://console.cloud.google.com/apis/credentials b. Create new credentials c. Select OAuth 2.0 client IDs d. Select Desktop app e. Download the credentials file and put it in the root of the project as credentials.json

Usage

Starting the Server

1. Start the server:

python3 fetch_emails_app.py

The server will start on port 5002 by default.

API Endpoints

GET /fetch-emails

Fetches emails based on the specified query. If no query is provided, the default query is is:unread.

Query Parameters:

• query

Example Request:

curl "http://localhost:5002/fetch-emails?query=from:[email protected]"
curl "http://localhost:5002/fetch-emails" # default query is "is:unread"

Response Format:

[
  {
    "subject": "Email Subject",
    "body": "Email Body",
    "message_id": "<message-id>",
    "sender": "[email protected]",
    "date": "Email Date"
  }
]

Development vs Production

• Development mode uses local credential files
• Production mode loads credentials from environment variables
• Set DEVELOPMENT=false in production environment

Error Handling

• Invalid credentials will return a 500 error
• Missing environment variables in production will be logged
• Token refresh errors are handled automatically

Security Notes

• Keep your credentials.json and token.json secure
• Never commit these files to version control
• In production, always use environment variables for sensitive data