Request validation basics in Laravel - Step-by-Step Execution

Concept Flow - Request validation basics

User sends HTTP request

↓

Laravel receives request

↓

Controller method called

↓

Validate request data

↓

Process data

↓

Send response

This flow shows how Laravel handles a request by validating input data before processing or returning errors.

Execution Sample

Laravel

public function store(Request $request) {
  $validated = $request->validate([
    'name' => 'required|string|max:255',
    'email' => 'required|email',
  ]);
  // Process validated data
}

This code validates 'name' and 'email' fields from a request before processing.

Execution Table

Step	Action	Validation Rules	Input Data	Result	Next Step
1	Receive request	-	{name: 'Alice', email: '[e-mail]'}	Data received	Validate data
2	Validate 'name'	required|string|max:255	'Alice'	Pass	Validate 'email'
3	Validate 'email'	required|email	'[e-mail]'	Pass	Return validated data
4	Return validated data	-	-	{name: 'Alice', email: '[e-mail]'}	Process data
5	Process data	-	-	Data processed successfully	Send success response
6	Send response	-	-	Success response sent	END
7	If validation fails	-	{name: '', email: 'bademail'}	Fail	Return errors

💡 Validation passes or fails; if fails, errors returned; if passes, data processed and response sent.

Variable Tracker

Variable	Start	After Step 2	After Step 3	Final
$request->name	'Alice'	'Alice'	'Alice'	'Alice'
$request->email	'[e-mail]'	'[e-mail]'	'[e-mail]'	'[e-mail]'
$validated	null	null	{name: 'Alice', email: '[e-mail]'}	{name: 'Alice', email: '[e-mail]'}

Key Moments - 2 Insights

Why does validation stop and return errors if a field is missing or invalid?

Because Laravel's validate() method checks each rule and immediately returns errors if any rule fails, as shown in execution_table row 7.

What happens to the $validated variable if validation fails?

It is never assigned because validate() throws an error and returns early, so $validated only has data if validation passes (rows 4 and 5).

Visual Quiz - 3 Questions

Look at the execution table, what is the result of validating the 'email' field at step 3?

A Pass

B Fail

C Skipped

D Error thrown

💡 Hint

Check the 'Result' column at step 3 in the execution_table.

At which step does Laravel return the validated data to the controller?

A Step 2

B Step 4

C Step 6

D Step 7

💡 Hint

Look for the step labeled 'Return validated data' in the execution_table.

If the 'name' field is empty, which step in the execution_table shows what happens next?

A Step 3

B Step 5

C Step 7

D Step 6

💡 Hint

Check the row where validation fails due to bad input.

Concept Snapshot

Laravel Request Validation Basics:
- Use $request->validate([...]) in controller.
- Define rules like 'required', 'string', 'email'.
- If validation fails, errors returned automatically.
- If passes, validated data returned for processing.
- Keeps input safe and app stable.

Full Transcript

In Laravel, when a user sends a request, the controller method receives it. The method calls $request->validate() with rules for each input field. Laravel checks each field against these rules. If all pass, the validated data is returned and the app processes it. If any rule fails, Laravel stops and returns error messages automatically. This protects the app from bad or missing data. The process flow is: receive request, validate data, if valid process it, else return errors. Variables like $request->name hold input values, and $validated holds the cleaned data after validation. Understanding this flow helps beginners see how Laravel keeps apps safe and user-friendly.