Hoot Back-End Create Comment

Learning objective: By the end of this lesson, students will be able build a route that adds an embedded comment document to a specific hoot.

Overview

In this section, we will make a route to add a new comment to a specific hoot. This route will be a POST request to /hoots/:hootId/comments, and will return a JSON response with the new comment document. 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: POST
Path: /hoots/:hootId/comments
Response: JSON
Success Status Code: 201 Created
Success Response Body: A new comment 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

Our route will listen for POST requests on /hoots/:hootId/comments:

POST /hoots/:hootId/comments

We’ll need to include the hootId as a parameter here, so that the new comment can be added to the appropriate parent document.

Add the following to controllers/hoots.js:

// controllers/hoots.js

router.post("/:hootId/comments", verifyToken, async (req, res) => {
  // add route
});

❗ A user needs to be logged in to create a comment, so be sure to include the verifyToken middleware.

Code the controller function

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

As we did when creating hoots, we’ll first append req.user._id to req.body.author. This updates the form data that will be used to create the resource, and ensures that the logged in user is marked as the author of a comment.
Next we’ll call upon the Hoot model’s findById() method. The retrieved hoot is the parent document we wish to add a comment to.
Because comments are embedded inside hoot’s, the commentSchema has not been compiled into a model. As a result, we cannot call upon the create() method to produce a new comment. Instead, we’ll use the Array.prototype.push() method, provide it with req.body, and add the new comment data to the comments array inside the hoot document.
To save the comment to our database, we call upon the save() method of the hoot document instance.
After saving the hoot document, we locate the newComment using its position at the end of the hoot.comments array, append the author property with a user object, and issue the newComment as a JSON response.

Add the following to controllers/hoots.js:

// controllers/hoots.js

router.post("/:hootId/comments", verifyToken, async (req, res) => {
  try {
    req.body.author = req.user._id;
    const hoot = await Hoot.findById(req.params.hootId);
    hoot.comments.push(req.body);
    await hoot.save();

    // Find the newly created comment:
    const newComment = hoot.comments[hoot.comments.length - 1];

    newComment._doc.author = req.user;

    // Respond with the newComment:
    res.status(201).json(newComment);
  } catch (err) {
    res.status(500).json({ err: err.message });
  }
});

Test the route in Postman

Now that we have finished the route let’s test it with Postman. We’ll do this by sending a POST request to /hoots/:hootId/comments.

Create a new request called Create Comment and set the request type to POST.

❗ This request requires authentication, so ensure the Authorization tab is configured correctly.

Your Postman URL should look something like this:

http://localhost:3000/hoots/61b646f65f455c912b4f2f8d/comments

Add the following to the body in Postman. Within the Body tab, select raw, and change the Text dropdown to JSON.

{
  "text": "my super cool comment"
}

After completing the steps above, your request in Postman should look something like this:

Create comment request

A successful response will look like the following:

Create comment response

Update `show` controller

Now that we added a route to create comments, we need to make a small change to our show controller function. In addition to populating the author of each hoot, we also want to populate the author of each comment in the comments array:

// controllers/hoots.js

router.get('/:hootId', verifyToken, async (req, res) => {
  try {
    // populate author of hoot and comments
    const hoot = await Hoot.findById(req.params.hootId).populate([
      'author',
      'comments.author',
    ]);
    res.status(200).json(hoot);
  } catch (err) {
    res.status(500).json({ err: err.message });
  }
});