Adding sessions with KituraSession

You can save user session data in your Kitura app by using the Kitura-Session middleware. In this tutorial, we will be storing an email address in our session and destroying our session data to emulate logging in and out of a website.

How to setup Kitura-Session

Before being abe to create sessions, you must have the Kitura-Session dependency added in your Package.swift file:

.Package(url: "https://github.com/IBM-Swift/Kitura-Session.git", majorVersion: 0, minor: 26),

Hint: If you have already built your app you will need to generate a new xcodeproj in order to use import KituraSession

To integrate sessions in your Kitura app, you will need the following imports:

import Foundation
import KituraSession
import SwiftyJSON

Next, you want your Kitura router to use the session middleware and have the ability to store the current session in a variable:

// Where we will store the current session data
var sess: SessionState?

// Initialising our KituraSession
let session = Session(secret: "kitura_session")

router.all(middleware: session)

We will be adding two routes: / and /login

Creating session data

Starting with the /login router, which is where we will be getting the POST data from the login:

router.post("/login") {
	request, response, next in
	
	//Get current session 
	sess = request.session

In order to get the data from the request we must add another middleware:

router.all(middleware: session)

router.all(middleware: BodyParser())

Kitura can get both urlEncoded and JSON data usign the BodyParser() middleware:

    var maybeEmail: String?
    
    switch request.body {
    case .urlEncoded(let params)?:
        maybeEmail = params["email"]
    case .json(let params)?:
        maybeEmail = params["email"].string
    default: break
    }

Next we will:

• add the email value to our session
  • In order to add the value we must convert to JSON format
• respond back to the client:

	if let email = maybeEmail, let sess = sess {
        sess["email"] = JSON(email)
        try response.send("done").end()
    }
}

Now we can add our route for "/" :

router.get("/") {
	request, response, next in
	
	//Again get the current session
	sess = request.session
	
	//Check if we have a session and it has a value for email
	if let sess = sess, let email = sess["email"].string {
		try response.send(fileName: pathToFile).end()
    } else {
       try response.send(fileName: pathToAnotherFile).end()
    }
}

The above snippet checks whether or not we have already "logged in" and takes us straight to index.html if we have and if not we ask the user to "log in" to gain access.

Once we have set that up we can create some basic HTML and jQuery to use what we have made. For this example we will be creating two HTML files, login.html and index.html.

Our login.html will look something like this:

<script src="//ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
    <script>
        $(document).ready(function(){
            var email,pass;
            $("#submit").click(function(){
                email=$("#email").val();
                pass=$("#password").val();
                /*
                * Add your authentication here
                */
                 $.post("http://localhost:8090/login",{email:email}, function(data){
	                  if(data==='done')
	                       {
	                            window.location.href="/";
	                       }
                 });
            });
        });
     </script>
        

        <h1>Please login</h1>
        <input type="text" size="40" placeholder="Type your email" id="email"><br />
        <input type="password" size="40" placeholder="Type your password" id="password"><br />
        <input type="button" value="Submit" id="submit">

Our index.html can look like anything for now.

So far we have:

• Created a session
• Used the session data to determine what to respond with
• And created the corresponding html and jQuery that will use all the code

All of this allows a "user" to "login" to the website and have the ability to refresh or open the website again and still be logged in.

Next:

• We will destroy session data

• Customize our session e.g How long a session will last etc.

Destroying session data

We are going to add another route for /logout now, so we can destroy all our session data.

Destroying session data is very simple:

router.post("/logout") {
    request, response, next in
    
    //Destroy all data in our session
    sess?.destroy() {
        (error: NSError?) in
        if let error = error {
            if Log.isLogging(.error) {
                Log.error("\(error)")
            }
        }
    }
    try response.send("done").end()
}

And that's it for removing the data from our session.

To be able to destroy our data in this example we are going to have to modify our index.html to actually use this, it will end up looking something like this:

<script src="//ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script>
	$(document).ready(function(){
		$("#submit").click(function(){
			$.post("http://localhost:8090/logout" ,function(data){
				if(data==='done')
				{
				    window.location.href="/";
				}
			});
		});
	});
</script>

And the html:

<h1>Your profile</h1>
<input type="button" value="Logout" id="submit">

Clicking on the button will destroy the session data and take us back to the login page.

#Customizing your session

To customize your session you will have to add some extra values when you create your session:

public init(secret: String, cookie: [CookieParameter]?=nil, store: Store?=nil)

Where:

• secret: is a String to be used for session encoding.
• cookie: is a list of options for session cookies
  • name: defaults to "kitura-session-id"
  • path: defaults to "/"
  • secure: defaults to false
  • maxAge: defaults to no expiration
• store: is an instance of a plugin for session backing store that implements Store protocol. If not set, InMemoryStore is used (all data will be lost on server restart).

Notes

To stop all data being lost on server restart, you can use Kitura-Session-Redis along with a redis server