Welcome to the next step in our journey of building a personal tutor service with DeepSeek models. In the previous lesson, we explored the TutorService class, which acts as a bridge between managing tutoring session data and generating AI responses. Now, we will focus on the TutorController, a crucial component that manages tutoring sessions and handles student queries by interacting with both the model and service layers. The controller is responsible for orchestrating the flow of data between the student interface and the backend services, ensuring that student interactions are processed efficiently and effectively.

The TutorController class is the heart of our controller layer. It is responsible for managing tutoring sessions and processing student queries. Let's begin by examining the structure of the TutorController class.

In this snippet, we:

• Use require 'securerandom' from Ruby's standard library for generating unique identifiers.
• Use require_relative to import the TutorService class for managing tutoring data and processing student queries.
• Initialize the TutorController with an instance of TutorService.
• Create an instance variable @test_session as a hash to simulate session management for testing purposes.

The @test_session hash is used to mimic the behavior of student sessions typically managed by a web application. In a real-world scenario, student sessions help track individual students as they interact with an application, maintaining their state and data across multiple requests. By using @test_session, we can focus on testing the core functionality of the TutorController without needing a full session management system. Once we are confident that the controller works correctly, we will later integrate a more robust session management solution when developing our RESTful API.

Before creating a tutoring session, we need to ensure that a student session exists. The ensure_student_session method checks if a student ID is present in @test_session. If not, it generates a new student ID.

This method ensures that a student session is available by checking the @test_session hash for a :student_id key. If it doesn't exist, a new student ID is generated using SecureRandom.uuid and stored in the session. The method then returns the student ID, either the newly created one or the existing one.

One of the primary responsibilities of the TutorController is to create new tutoring sessions. The create_session method handles session creation requests.

In this method, we:

1. Retrieve the student_id: We first check the @test_session hash for a :student_id.

2. Handle Session Expiry: If the session has expired (i.e., no student_id is found), we return an error response using our helper method error_response with a 401 status code. (We will implement these helper methods for formatting responses in a later section.)

3. Create a Tutoring Session: If the session is valid, we call the create_session method of the TutorService with the student ID to create a new tutoring session. We then return a success response containing a unique session ID and a success message using our helper method success_response. (These helper methods will be explained and implemented shortly.)

The send_query method is responsible for processing student queries and returning the tutor's response or an error message.

In this method:

1. We first check if the student session is valid by retrieving the student_id from @test_session. If no student_id is found, we return an error response with a 401 status code. (The error_response helper method will be described in the next section.)

2. We then validate that both session_id and student_query are provided. If either is missing, we return an error response with a 400 status code.

3. If all validations pass, we attempt to process the query using the process_query method of the TutorService. This method takes the student_id, session_id, and as parameters.

The TutorController includes two helper methods for formatting responses: success_response and error_response. These methods ensure consistent response formats throughout the controller.

These methods create standardized response formats:

• success_response returns a hash with a :status field set to "success" and a :data field containing the provided data.
• error_response returns an array containing a hash (with a :status field set to "error" and an :error field with message and code details) and the status code.

To see the TutorController in action, let's integrate it into the main application. This example demonstrates how to create a tutoring session and handle a student query, showcasing the controller's functionality.

In this example, we first initialize the TutorController. We ensure a student session is available for testing. We then create a new tutoring session and handle the response. If successful, we simulate a student query about the differences between mitosis and meiosis and use the send_query method to process it. The response is checked for errors, and either the error message or the tutor's response is printed. This example demonstrates the flow from ensuring a student session to creating a tutoring session and handling a student query, highlighting the controller's role in managing interactions.

In this lesson, we explored the TutorController class and its role in managing tutoring sessions and handling student queries. We learned how to implement the controller, create tutoring sessions, and process student questions using the TutorService. The controller is a vital component of our personal tutor application, ensuring that student interactions are managed efficiently and effectively.

As you move on to the practice exercises, take the opportunity to experiment with the TutorController's functionality. This hands-on practice will reinforce the concepts covered in this lesson and prepare you for the next steps in our course. Keep up the great work, and I look forward to seeing your progress!