Login and logout in Laravel - Step-by-Step Execution

Concept Flow - Login and logout

User submits login form

↓

Validate credentials

↓

Create session

↓

User logged in

↓

User requests logout

↓

Destroy session

↓

User logged out

This flow shows how Laravel handles user login by validating credentials, creating a session, and logout by destroying the session.

Execution Sample

Laravel

<?php
// Login Controller method
public function login(Request $request) {
  $credentials = $request->validate(['email' => 'required|email', 'password' => 'required']);
  if (Auth::attempt($credentials)) {
    $request->session()->regenerate();
    return redirect()->intended('dashboard');
  }
  return back()->withErrors(['email' => 'Invalid credentials']);
}

This code checks user credentials and logs them in if valid, otherwise shows an error.

Execution Table

Step	Action	Input/Condition	Result	Next Step
1	User submits login form	email and password entered	Credentials received	Validate credentials
2	Validate credentials	Check email and password	Credentials valid?	If valid: Create session, else: Show error
3	Credentials valid?	Auth::attempt returns true	Session created, user logged in	Redirect to dashboard
4	Redirect	User logged in	Dashboard page shown	Wait for logout request
5	User requests logout	Click logout button	Logout request received	Destroy session
6	Destroy session	Session destroyed	User logged out	Redirect to login page
7	Redirect	User logged out	Login page shown	End

💡 User logs out, session destroyed, flow ends at login page.

Variable Tracker

Variable	Start	After Step 2	After Step 3	After Step 6	Final
credentials	null	{email, password}	{email, password}	null	null
Auth::attempt	false	true or false	true	false	false
session	empty	empty	created	destroyed	empty
user_logged_in	false	false	true	false	false

Key Moments - 3 Insights

Why does the session regenerate after login?

Regenerating the session after login prevents session fixation attacks by creating a new session ID, as shown in step 3 of the execution_table.

What happens if credentials are invalid?

If credentials are invalid, Auth::attempt returns false (step 2), and the user is sent back with an error message instead of logging in.

How does logout clear the user state?

Logout destroys the session (step 6), removing all user data and marking the user as logged out.

Visual Quiz - 3 Questions

Look at the execution_table, what is the state of 'user_logged_in' after step 3?

A true

B false

C null

D undefined

💡 Hint

Check variable_tracker row for 'user_logged_in' after Step 3.

At which step does the session get destroyed?

A Step 3

B Step 5

C Step 6

D Step 7

💡 Hint

Look at the 'Action' column in execution_table for session destruction.

If the credentials are invalid, what happens next according to the execution_table?

A Session is created

B Show error and stay on login page

C User is redirected to dashboard

D Session is destroyed

💡 Hint

Refer to Step 2 and the 'Result' column for invalid credentials.

Concept Snapshot

Laravel Login and Logout:
- Use Auth::attempt() to check credentials.
- On success, regenerate session and redirect.
- On failure, return error message.
- Logout destroys session and redirects to login.
- Protects user data and session security.

Full Transcript

This visual execution shows how Laravel handles login and logout. When a user submits the login form, Laravel validates the credentials. If valid, it creates a session and logs the user in, redirecting to the dashboard. If invalid, it shows an error message. When the user logs out, Laravel destroys the session and redirects back to the login page. Key steps include session regeneration after login to improve security and session destruction on logout to clear user data.