Welcome back! In the previous lesson, you set up a basic interface for your personal tutor using Flask and HTML. This laid the foundation for creating a user-friendly educational web application. Now, we will take the next step by connecting this interface to our backend API. This connection is crucial for transforming our static interface into a dynamic, interactive tutoring experience. By the end of this lesson, you will understand how to integrate the frontend with the backend, enabling real-time communication between the student and the tutor system.

In this lesson, we will enhance our tutor interface by connecting it to the backend API using the Fetch API. This tool will allow us to capture student input and send it to the server, transforming our tutor into a dynamic application.

The Fetch API is a modern interface that allows you to make network requests from your web page. It provides a more powerful and flexible feature set for handling HTTP requests and responses. With Fetch, you can send and receive data from the server in the background, creating a smoother and more interactive educational experience.

Here's how it works:

1. Making a Request: When you want to get or send data, you use the fetch() function. You tell it where to send the request (the URL) and what kind of request it is.

2. Handling the Response: After the request is sent, the server will reply. The Fetch API lets you handle this reply using .then(). You can think of this as receiving an answer from your tutor.

3. Dealing with Errors: Sometimes things go wrong, like if the server is down. The Fetch API lets you handle these problems using .catch(), so your web page can show a message or try again.

Here's a simple example of how the Fetch API works within a function:

In this example, the fetchData function uses the fetch() method to send a request to the server. You specify the endpoint and HTTP method and use the then and catch methods to handle the server's response and any errors. This process happens in the background, so your web page stays responsive and interactive.

Now that we have a basic understanding of how HTTP requests work in Flask, let's prepare our tutor application by initializing some variables to store the current session and student IDs. These variables will help us manage and track each tutoring session as we implement dynamic functionalities.

In your HTML file, you can use JavaScript to store these variables:

These variables are initialized to null and will be used to store the session and student IDs once a new tutoring session is created.

Previously, the startNewSession function simply cleared the chat history. Now, we will update it to initialize a new tutoring session by making a request to the backend.

In your HTML file, you can use JavaScript to send a request to the Flask backend:

This updated function now makes a POST request to the /api/create_session endpoint on our Flask backend. When the server responds, we process the JSON data and store the returned session_id and student_id in our previously initialized variables. We then clear the message container to start a fresh conversation. If there's an error during this process, we display an alert to notify the user that there was a problem creating the tutoring session.

The sendQuery function will now send the student's question to the server and display the tutor's response in the interface.

In your HTML file, you can use JavaScript to send the query:

This enhanced sendQuery function now handles the complete interaction flow between the student and the tutor. First, it retrieves the student's query from the input field, trims any whitespace, and checks if the query is empty. If there's a valid query, it displays the student's message in the chat interface using the appendMessage function and clears the input field.

Then, it sends the query to the backend by making a POST request to the /api/send_query endpoint. The request includes important headers like 'Content-Type': 'application/json' to tell the server we're sending JSON data. The body parameter uses JSON.stringify() to convert our JavaScript object (containing the session ID and query) into a JSON string that can be transmitted to the server. This conversion is essential because HTTP requests can only send text, not JavaScript objects directly.

When the server responds, the function extracts the tutor's response from the data and displays it in the chat interface. If there's an error during this process, an alert notifies the user that there was a problem sending the query.

To help you better understand how the backend communicates with the frontend, let's look at some sample response bodies you might receive from the /api/send_query endpoint.

When a student's question is successfully processed, the backend returns a JSON object containing the session ID and the tutor's response message:

On the other hand, if something goes wrong — such as a missing or invalid session ID — the backend will return an error response. This response includes a status, an error message, and an error code:

In your frontend, you can check for the presence of an error and show a helpful message to the user, ensuring a smooth and user-friendly experience.

In this lesson, you learned how to connect the tutor interface to a backend API using Flask and HTTP requests. We covered the setup of API endpoints, the integration of the frontend with the backend, and the implementation of tutoring functionality. This connection is a crucial step in creating a dynamic and interactive educational application.

As you move on to the practice exercises, focus on reinforcing these concepts and experimenting with the code. This hands-on practice will deepen your understanding and prepare you for the next unit, where we will continue to enhance the personal tutor's capabilities. Keep up the great work, and let's continue building this exciting educational tool together!