Token management in Laravel - Step-by-Step Execution

Concept Flow - Token management

User sends login request

↓

Validate credentials

↓

Create token

↓

Send token to user

↓

User sends token with requests

↓

Validate token

↓

Allow access

This flow shows how Laravel handles token creation after login and validates tokens on user requests.

Execution Sample

Laravel

<?php
// Login controller method
public function login(Request $request) {
  $user = User::where('email', $request->email)->first();
  if (!$user || !Hash::check($request->password, $user->password)) {
    return response()->json(['error' => 'Invalid credentials'], 401);
  }
  $token = $user->createToken('auth_token')->plainTextToken;
  return response()->json(['access_token' => $token]);
}

This code checks user credentials and creates a token if valid, returning it to the user.

Execution Table

Step	Action	Input/Condition	Result	Next Step
1	Receive login request	Email and password	Request data ready	Validate credentials
2	Check user exists	User with email found?	User found	Verify password
3	Verify password	Password matches?	Password correct	Create token
4	Create token	User authenticated	Token generated	Return token
5	Return token	Token created	Token sent in response	User stores token
6	User sends token with request	Token included in header	Token received	Validate token
7	Validate token	Token valid?	Token valid	Allow access
8	Allow access	Token accepted	Request processed	End
9	If any check fails	Invalid credentials or token	Error response sent	End

💡 Execution stops when user is either granted access or receives an error due to invalid credentials or token.

Variable Tracker

Variable	Start	After Step 2	After Step 3	After Step 4	After Step 5	After Step 6	After Step 7	Final
$user	null	User object or null	User object	User object	User object	User object	User object	User object or null
$token	null	null	null	Token string	Token string	Token string	Token string	Token string or null
Request status	Pending	Pending	Pending	Pending	Token sent	Token received	Validated	Access granted or denied

Key Moments - 3 Insights

Why does the code check both user existence and password correctness separately?

Because if the user is not found, password check is skipped. This prevents errors and improves security, as shown in steps 2 and 3 of the execution_table.

What happens if the token sent by the user is invalid or expired?

The token validation step (step 7) fails, and the user receives an error response (step 9), stopping access.

Why is the token sent back as plainTextToken instead of the token object?

Because plainTextToken is the actual string the user needs to store and send with requests. The token object contains metadata but is not sent to the client.

Visual Quiz - 3 Questions

Look at the execution_table, what is the result after step 4?

A User object is null

B Error response sent

C Token generated

D Password check skipped

💡 Hint

Check the 'Result' column for step 4 in the execution_table.

At which step does the system decide to allow access to the user?

A Step 3

B Step 8

C Step 5

D Step 9

💡 Hint

Look for the step labeled 'Allow access' in the execution_table.

If the password is incorrect, which step will the execution jump to next?

A Step 9

B Step 4

C Step 6

D Step 7

💡 Hint

Refer to the 'Next Step' column after 'Verify password' in the execution_table.

Concept Snapshot

Token management in Laravel:
- User logs in with email and password
- If valid, create a token with createToken()
- Return token string to user
- User sends token with requests
- Laravel validates token
- Access granted if token valid, else error

Full Transcript

Token management in Laravel starts when a user sends a login request with email and password. The system checks if the user exists and verifies the password. If both are correct, Laravel creates a token string using createToken() and sends it back to the user. The user stores this token and includes it in the header of future requests. Each request's token is validated by Laravel. If the token is valid, the user is allowed access. If any check fails, an error response is sent. This process ensures secure authentication and authorization using tokens.