01 - Sign In Method

In this module, we'll start making the sign-in method (signin) to create a new session.

The Code

Let's create our signin route. Add the following to the bottom of usercontroller.js file in controllers. Like the createuser route, each step will keep building on top of the previous until we have the finished product at the end:

        //7
router.post('/signin', function(req, res) {
            //1     //2       //3                                   //4
    User.findOne( { where: { username: req.body.user.username } } ).then(

        //5
        function(user) {
            if (user) {
                res.json(user);
            } else {
                res.status(500).send({ error: "you failed, yo" }); //6
            }
        }
    );
});

Analysis

Try reading the code above to see if you can get an intuitive sense of what is happening. Then, take a look at the following points for guidance or clarification:

1. The findOne() method is a Sequelize method that does exactly what it says: it tries to find something within the database that we tell it to look for. This is called Data Retrieval. Check out the Sequelize docs here.

2. where is an object within Sequelize that tells the database to look for something matching its properties.

3. We're looking in the username column in the user table for one thing that matches the value passed from the client.

4. The promise is handled within the .then() function.

5. Here we have a function that is called when the promise is resolved, and if successful, sends the user object back in the response.

6. Function called if the promise is rejected. We print the error to the console.

7. We're sending data this time, so we use router.post instead of router.get.

Test

Start your server and open Postman. Send a request to the signin route with the username of one of the users in your database. NOTE: THIS USER SHOULD EXIST IN YOUR DB. You should see the user object print to the console:

screenshot

Send another request, this time with a user not in the database. You should be hitting the error function and seeing something like this:

Fail

.