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Storing session data in RAM is fine for development, but would quickly crash a production server. In this lesson learn how to use a MongoDB-based data store for your session variables, which provides a scalable solution for a production server.
Mongo Shell Cheatsheet
You first need to log into the Mongo shell — mongo in the terminal for Macs and Linux, or start mongo.exe for Windows.
-
show dbs— display the databases -
use bookworm— specify the database you're going to work with -
show collections— shows the document collections for the selected database -
db.users.find()— display all the documents in theuserscollection -
db.users.find().pretty()— nicer format for output documents within the shell
Resources
- connect-mongo A MongoDB session store for Connect and Express
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When a user logs in we store
their user ID in a session, and
0:00
retrieve it when we want
to see who's logged in.
0:04
Our authentication system
relies on sessions.
0:07
However, our basic system stores
the session data in the server's memory.
0:10
Server RAM is a limited resource and
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it can quickly fill up if a lot
of folks sign up and login.
0:17
Too many logins and the server will
slow down and eventually crash.
0:20
For a production server you should
use a more scalable solution.
0:26
There are many sessions
storage options for
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express including ones that use fast
databases like Redis and Mongo.
0:31
Since we're already using
Mongo in this course,
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let's use Mongo db to store session data.
0:38
Fortunately for us, someone's
already written a middleware module
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called Connect Mongo which makes it very
simple to add a Mongo session store.
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Let me show you how it works.
0:50
First, I need to install
the connect Mongo module.
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I'll open up the terminal.
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And, make sure I'm in
the project's root directory.
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And then,
I'll run NPM install connect dash
1:00
Mongo dash dash save to download
the module and include it in our project.
1:05
Then, in my text editor,
I'll open app dot JS.
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To use the module I'll have to require it.
1:16
I'll add this line after the line
that loads our session module.
1:20
You'll notice that I'm not
only loading this module, but
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I'm also calling it passing our
express session as an argument.
1:29
This lets the connect Mongo
middleware access the sessions.
1:33
Now, let's find the middleware
where we configure the session.
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I'm going to add a new key called store.
1:44
And, in it I'll store a new
instance of Mongo store.
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The session constructor function
takes a configuration object, and
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all we need to do is set
Mongoose connection to DB.
1:56
If you look at the code
to connect to Mongo DB.
2:01
You'll see a line where we set a variable,
DB,
2:05
to the Mongoose connection, after we've
connected to the local Mongo DB instance.
2:08
Now, I just noticed that our DB
connection is defined down here
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after we use it in our session.
2:17
That'll cause an error since DB isn't yet
defined.
2:19
So, I'll go up here and
cut our session code.
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And then,
2:28
just paste it in here after
the Mongo DB connection.
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Believe it or not,
that's all there is to it.
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Passing the same Mmongoose connection
is all it takes to start using Mongo DB
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as a session store.
2:42
Now, our application stores session
data in Mongo instead of in RAM.
2:44
To prove it let's use the application and
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see that a new collection
is added to our database.
2:51
But, first let's look at the collections
we currently have in our database.
2:54
I'll switch to the terminal and
open a new tab.
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I'll open the Mongo shell by typing Mongo.
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Now, if you're on Windows you'll
need to run the Mongo executable.
3:05
And, if you get an error you
might not have Mongo running, so
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make sure you've got it started.
3:12
In this shell you can see all your
Mongo databases by typing show dbs.
3:14
There's the bookworm database.
3:20
But what's in it?
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To see the collections in
the database we need to select it.
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Use bookworm.
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Then we show the collections
by typing show collections.
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There is the system dot indexes, that's
some internal collection used by Mongo.
3:35
And, there is our users
collection that holds user data.
3:39
I'll switch to another tab, and start
up our application by typing Nodemon.
3:42
Now, if I login to the site,
a new collection is created, and
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my session is stored in it.
3:54
Let's go back to the terminal and
the Mongo shell.
3:56
I'll type show collections again,
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and you'll see there's a new
collection called sessions.
4:00
Let's see what's inside it,
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db dot sessions dot find.
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Voila, there's the session and
there's my user id.
4:13
Let's see what happens if I log out.
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I'll log out, return to the terminal and
see what's inside the sessions collection.
4:18
Nothing it's empty.
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Remember our log out route
deletes the user session.
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So, my session's now gone.
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All right, this authentication
system is capable of handling
4:32
thousands of users without
bringing down the server.
4:37
In the next video, I'll wrap up the course
and talk to you about a few next steps
4:40
you could explore for
enhancing authentication on your sites.
4:44
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