Hoot Back-End Update Comment

Learning objective: By the end of this lesson, students will be able build a route that updates a comment.

Overview

In this section, we will make a route to create a new comment. This route will be a PUT request to /hoots/<hoot_id>/comments/<comment_id>, and will return a JSON response with the new comment. The purpose of this route is to handle data that is sent along with a form submission.

We will be following these specs when building the route:

• CRUD Action: CREATE
• Method: PUT
• Path: /hoots/<hoot_id>/comments/<comment_id>
• Response: JSON
• Success Status Code: 201 Created
• Success Response Body: A new hoot object
• Error Status Code: 500 Internal Server Error
• Error Response Body: A JSON object with an error key and a message describing the error

Define the route

Next we’ll define a route that listens for PUT requests on /hoots/<hoot_id>/comments/<comment_id>:

PUT /hoots/<hoot_id>/comments/<comment_id>

We’ll make use of our @token_required decorator, as only a logged in user should be able to update a comment.

Add the following to comments_blueprint.py:

@comments_blueprint.route('/hoots/<hoot_id>/comments/<comment_id>', methods=['PUT'])
@token_required

🏆 Any route that requires auth should include the @token_required decorator. These are our protected routes.

Code the controller function

Let’s breakdown what we’ll accomplish inside our controller function.

Our function will use the connection cursor to execute the following SQL query:

UPDATE comments SET text = %s WHERE id = %s RETURNING *

This query updates the text of an existing comment in the comments table. It sets the text column to a new value for the comment with the specified id. The RETURNING * clause ensures that all columns of the updated comment are returned, allowing you to retrieve and verify the updated data immediately.

As we saw when updating a hoot, we’ll need to determine whether the user making the request is, in fact, the comment’s original creator.

This will require two separate queries:

• One to get the comment from the database and check who the author is,

• And the second to actually update the comment.

Add the following to comments_blueprint.py:

@comments_blueprint.route('/hoots/<hoot_id>/comments/<comment_id>', methods=['PUT'])
@token_required
def update_comment(hoot_id, comment_id):
    try:
        updated_comment_data = request.json
        connection = get_db_connection()
        cursor = connection.cursor(cursor_factory=psycopg2.extras.RealDictCursor)
        cursor.execute("SELECT * FROM comments WHERE id = %s", (comment_id,))
        comment_to_update = cursor.fetchone()
        if comment_to_update is None:
            return jsonify({"error": "Comment not found"}), 404
        if comment_to_update["author"] != g.user["id"]:
            return jsonify({"error": "Unauthorized"}), 401
        cursor.execute("UPDATE comments SET text = %s WHERE id = %s RETURNING *",
                       (updated_comment_data["text"], comment_id))
        updated_comment = cursor.fetchone()
        connection.commit()
        connection.close()
        return jsonify({"comment": updated_comment}), 201
    except Exception as error:
        return jsonify({"error": str(error)}), 500

Test the route in Postman

Now that we have the route, let’s test it with Postman.

We’ll do this by sending a PUT request to the following URL:

http://127.0.0.1:5000/hoots/4/comments/1

💡 Be sure to update this with hoot and comment id values that exists in your database!

The body of your request should look like the following:

{
  "text": "Updated comment text"
}

If the request is successful, you should see a response like the one below:

{
  "comment": {
    "author": 4,
    "hoot": 4,
    "id": 1,
    "text": "Updated comment text"
  }
}