To extract data from Trustpilot, you'll need to access their API. Start by creating a Trustpilot business account and navigate to the API settings. Obtain your API key and secret by registering your application in the Trustpilot Developer Portal. These credentials are necessary for authenticating API requests.

Use the API key and secret to authenticate your requests to the Trustpilot API. You can use programming languages like Python, Node.js, or Java to send HTTP GET requests to the Trustpilot API endpoints. Decide on the specific data you want to extract (e.g., reviews, ratings, etc.) and construct your API calls accordingly.

After retrieving the data, parse the JSON or XML response from the Trustpilot API. Use a library in your chosen language, such as `json` in Python, to handle the data format. Process the data as needed, such as extracting specific fields, filtering, or formatting the data to match your RabbitMQ message structure.

Set up RabbitMQ on your server or local machine. You can download the appropriate version from the RabbitMQ website and follow the installation instructions for your operating system. Once RabbitMQ is installed, configure it by setting up users, permissions, and creating exchanges and queues that will handle the incoming data from Trustpilot.

Write a script using a RabbitMQ client library (like Pika for Python or amqplib for Node.js) to create a publisher that sends messages to RabbitMQ. The script should take the processed data from Trustpilot, convert it into a message format (e.g., JSON), and publish it to the RabbitMQ exchange. Ensure the script handles connection errors and retries if necessary.

Before full deployment, conduct tests to ensure data flows correctly from Trustpilot to RabbitMQ. Use sample data to verify that the publisher script sends messages successfully and that the RabbitMQ queue receives them. Check for any data loss, formatting issues, or errors in transmission.

Once testing is successful, automate the data extraction and publishing process. Use a scheduler like cron (on Unix/Linux) to run your data retrieval and publishing scripts at regular intervals. Ensure error handling and logging are in place to track any issues that occur during automated runs, allowing for quick troubleshooting and maintenance.

This guide should help you set up a custom data transfer process from Trustpilot to RabbitMQ, tailored specifically to your requirements without relying on third-party connectors or integrations.