Creating middleware in Laravel - Visual Walkthrough

Concept Flow - Creating middleware

Request enters app

↓

Middleware invoked

↓

Middleware checks condition

↓

Allow request

↓

Controller runs

↓

Response returns to client

The request passes through middleware which checks conditions and either allows it to continue or blocks it.

Execution Sample

Laravel

php artisan make:middleware CheckAge

public function handle($request, Closure $next) {
  if ($request->age < 18) {
    return redirect('home');
  }
  return $next($request);
}

This middleware checks if the user's age is less than 18 and redirects if true, otherwise it lets the request continue.

Execution Table

Step	Action	Condition Checked	Result	Next Step
1	Request enters middleware	N/A	Middleware starts	Check age condition
2	Check if age < 18	age = 16	True	Redirect to home
3	Redirect response sent	N/A	Request blocked	End
4	Request ends	N/A	No controller reached	End

💡 Request blocked because age < 18 condition was true, so middleware redirected.

Variable Tracker

Variable	Start	After Step 2	Final
age	unknown	16	16
request_status	incoming	checked	redirected

Key Moments - 2 Insights

Why does the request stop and not reach the controller?

Because at step 2 in the execution_table, the condition age < 18 is true, so middleware returns a redirect response instead of calling $next($request).

What does $next($request) do in middleware?

It passes the request to the next middleware or the controller. Without calling $next, the request stops in middleware.

Visual Quiz - 3 Questions

Look at the execution_table, what happens at step 2 when age is 16?

A The request is allowed to continue to the controller

B The request is redirected to home

C The middleware throws an error

D The request is logged but continues

💡 Hint

Check the 'Result' column in step 2 of execution_table.

At which step does the middleware stop the request from continuing?

A Step 1

B Step 3

C Step 2

D Step 4

💡 Hint

Look for when the redirect response is sent in execution_table.

If age was 20, how would the execution_table change?

A Step 2 condition would be false and request continues

B Step 3 redirect would still happen

C Middleware would throw an error

D Request would be blocked at step 1

💡 Hint

Think about the condition age < 18 in step 2.

Concept Snapshot

Creating middleware in Laravel:
- Use 'php artisan make:middleware Name' to create.
- Middleware handle() checks request conditions.
- Return redirect or response to block.
- Call $next($request) to continue.
- Middleware runs before controller.
- Useful for auth, logging, filters.

Full Transcript

Middleware in Laravel acts like a gatekeeper for requests. When a request comes in, it first passes through middleware. The middleware checks conditions, like if the user's age is less than 18. If the condition is true, the middleware can stop the request and redirect it elsewhere, like to the home page. If the condition is false, the middleware calls $next($request) to let the request continue to the controller. This process helps control access and modify requests before they reach the main app logic.