Heads up! To view this whole video, sign in with your Courses Plus account or enroll in your free 7-day trial. Sign In Enroll
Preview
Start a free Courses trial
to watch this video
Once we have our application talking Facebook, we need to store the data somewhere. This video shows us how to get our application talking to a database to persist the data we get from Facebook.
This video doesn't have any notes.
Related Discussions
Have questions about this video? Start a discussion with the community and Treehouse staff.
Sign upRelated Discussions
Have questions about this video? Start a discussion with the community and Treehouse staff.
Sign up
[??] [CODE/RACER - Database Access]
0:00
In our last set of videos, we learned how to sign in and authenticate with Facebook.
0:05
In this video, we're going to save that information from Facebook
0:11
to our own local database.
0:15
In order to do this, we're going to use a project called Sequelize.
0:18
Sequelize is an object-relational-mapper for node.js.
0:23
In order to install it, we have to add it to our packages,
0:28
so let's open up our package.json and add it in.
0:33
Save the file and then run npm install to install it.
0:45
Great. Now we have Sequelize installed.
1:02
Let's tell our application how to use it.
1:05
First, we'll open up our app.coffee and import it.
1:08
Now let's take a look at the documentation and see what we do next.
1:23
It looks like we have to configure it.
1:27
Let's go ahead and open up our configuration file that we made earlier.
1:30
Now we'll add our database credentials into this configuration file.
1:36
Since we're going to be working in development,
1:45
I'm going to create a key for development right here.
1:49
This way, when we go to deploy it, we can specify a production environment as well.
1:53
We're going to use the MySQL database locally to work with it,
2:21
and we'll specify that we're logging.
2:26
This helps a lot when trying to debug errors.
2:30
Now let's go back and see how we initialize Sequelize.
2:36
When initializing it, we'll give it the keys that we just specified over in our configuration file.
2:46
In this part down here, the define key says timestamps are true.
3:30
What that will do is add a created_at and updated_at field to each of our models.
3:36
Every time a model is created or saved, those fields will be updated automatically.
3:42
Now that we've got Sequelize installed, let's create a User model
3:47
to save our Facebook data.
3:51
I'm going to do that back on the console and make a models directory.
3:53
Inside of the models directory is where I'll put the user file.
4:00
Now let's open up the User model.
4:09
Let's refer back to the Sequelize documentation to see how we create a model.
4:13
It looks like we use the define keyword.
4:19
We're not going to use any validations right now.
4:23
Since we're storing our model in a separate file,
4:28
it looks like we're going to have to use the import method.
4:31
Before we create our model, we need to create our database
4:34
and also add a table to it.
4:38
I'm going to use Sequel Pro in order to do that.
4:42
However, that's not completely necessary.
4:45
Now we're going to create our users table.
4:53
We're only going to save a few attributes that we get back from Facebook.
5:06
For right now I'll just save the Facebook ID, the first name, last name, and email.
5:10
In a real application, you would probably want to use an unsigned integer for the Facebook ID.
5:32
However, since this is just an example, using a varchar is going to be a lot easier.
5:38
Now that we've got our database set up, let's go ahead and create our model.
5:44
Since our User model is in a separate file, we're going to have to export that information.
5:49
Now let's refer back to the documentation.
6:04
It looks like we have to give it a model and then say the different data types.
6:07
Here we'll enter all of the information we put in the database.
6:24
We're going to want to save certain information that we get back from Facebook.
6:46
We'll do this using a custom method inside of our User model.
6:51
If we look back at the documentation in Sequelize,
6:55
we can see that we can define class methods and instance methods.
6:58
We'll go ahead and define a class method called findOrCreateFromMetadata.
7:03
What this will do is save the metadata from Facebook.
7:09
Or if a user with the Facebook ID already exists,
7:13
it will return that user.
7:17
This way we won't duplicate information inside of the database.
7:20
First, we'll look up to see if the Facebook ID exists.
7:35
If the query is successful, we'll store that information inside of a user object.
7:53
However, this might not actually exist inside of the database.
7:59
The success callback defines whether or not the query was successful.
8:05
So if the user doesn't exist, we'll build and save it.
8:11
At this point we're going to need access to the User model.
8:17
We can't call this.build in order to create our user
8:23
because this now refers to the success callback.
8:28
So what we'll do is define a variable called model up here
8:32
that will have the binding of the User model,
8:37
and then we change the reference over in our build function.
8:45
Now we'll go ahead and assign the metadata to our different database attributes.
8:48
Once we've built the model, we'll save it.
9:17
And if it's successful, we'll assign that again to a user object and run the callback.
9:22
If it fails, we'll go ahead and log the error
9:38
and we'll run the callback with an error and no object.
9:45
Now, that's what happens if we don't have a user in the database.
9:55
If we do, the user should be returned,
9:59
so we'll just run the callback and send in that user object.
10:02
And finally, we need to tell Node what to do
10:09
in case there's an error when querying the database.
10:11
That looks good for now.
10:22
Let's go ahead back to our application.coffee.
10:24
What we have to do is import the User model we just created.
10:29
Now let's scroll down to our authentication portion.
10:47
Instead of just rendering a template saying that we've authenticated,
10:51
what we'll do is call our findOrCreateFromMetadata
10:55
and send in the body of the Facebook response.
10:59
We also have to send in our error and object callbacks.
11:11
So let's see if the user exists.
11:23
In the case that the user does exist, we'll set a user ID session variable
11:34
and redirect to an endpoint called /me.
11:40
We haven't made that endpoint yet, but we will.
11:50
For now, if the user doesn't exist, we'll just redirect them to the homepage.
12:02
Finally, we'll create our /me endpoint.
12:11
First, we'll check to see if there's a user ID key inside of the session.
12:20
If there is a user, we'll go ahead and create a User.findById method.
12:30
You'll notice that we're rendering this me.eco template
12:58
in the event that we find the user.
13:02
Let's go ahead and create that.
13:05
It looks like we have an error on line 13 of our application file.
13:11
Let's go ahead and see what's going on.
13:16
It seems like I've messed up the indentation here when defining our Sequelize variables.
13:19
Let's go ahead and try and run it again.
13:34
So we load up our homepage and click Log In.
13:37
I'm already logged in to Facebook, so it won't ask me to authorize the application.
13:41
It seems our server died. Let's see what happened.
13:48
It says we have no method findOrCreateFromMetadata.
13:51
That's going to be in the User model. Let's open that up and see what's going on.
13:55
It looks like I forgot the classMethods argument.
14:01
Let's try it again.
14:19
It looks like we have another error saying that we have no method findById.
14:25
A quick look in the User model shows that I misspelled it.
14:30
Let's correct it and try again.
14:34
It would seem once more that we're indented just a bit too much.
14:40
These are some of the quirks of CoffeeScript that you have to get used to.
14:45
Here I have another typo.
14:51
And we finally got that to work.
14:57
Let's go ahead and look inside of our database.
15:00
All of our content is there.
15:05
You need to sign up for Treehouse in order to download course files.
Sign upYou need to sign up for Treehouse in order to set up Workspace
Sign up