PHP process model per request - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start a PHP script that outputs a simple message.

PHP

<?php
 echo [1];
?>

Drag options to blanks, or click blank then click option'

Aecho "Hello, world!"

B'Hello, world!'

CHello, world!

D"Hello, world!"

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting quotes around the string.

Trying to echo without quotes.

The echo statement requires a string in quotes to output text. So, "Hello, world!" is correct.

2fill in blank

medium

Complete the code to define a variable holding the current request method.

PHP

<?php
 $method = [1]['REQUEST_METHOD'];
?>

Drag options to blanks, or click blank then click option'

A$_POST

B$_SERVER

C$_GET

D$_REQUEST

Attempts:

3 left

💡 Hint

Common Mistakes

Using $_GET or $_POST which hold user input, not server info.

Using $_REQUEST which combines GET, POST, and COOKIE.

The $_SERVER superglobal contains server and execution environment information, including the request method.

3fill in blank

hard

Fix the error in the code that tries to start a session per request.

PHP

<?php
 [1]();
 // session code here
?>

Drag options to blanks, or click blank then click option'

Asession_start

Bstart_session

Cbegin_session

DsessionBegin

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect function names like start_session().

Forgetting the underscore in the function name.

The correct PHP function to start a session is session_start(). Other options are invalid function names.

4fill in blank

hard

Fill both blanks to create an associative array with request method and URI.

PHP

<?php
 $request = [
   'method' => [1],
   'uri' => [2]
 ];
?>

Drag options to blanks, or click blank then click option'

A$_SERVER['REQUEST_METHOD']

B$_SERVER['REQUEST_URI']

C$_GET['REQUEST_METHOD']

D$_GET['REQUEST_URI']

Attempts:

3 left

💡 Hint

Common Mistakes

Using $_GET instead of $_SERVER for these values.

Mixing REQUEST_METHOD and REQUEST_URI incorrectly.

$_SERVER holds both REQUEST_METHOD and REQUEST_URI. $_GET does not contain these server variables.

5fill in blank

hard

Fill all three blanks to create a response array with status, headers, and body.

PHP

<?php
 $response = [
   'status' => [1],
   'headers' => [2],
   'body' => [3]
 ];
?>

Drag options to blanks, or click blank then click option'

A200

B['Content-Type' => 'text/html']

C"<h1>Hello</h1>"

D404

Attempts:

3 left

💡 Hint

Common Mistakes

Using status as a string instead of a number.

Not using an array for headers.

Forgetting quotes around the body string.

The status code 200 means OK, headers is an associative array with content type, and body is a string with HTML content.

Practice

1. What happens to PHP variables after a web request finishes?

easy

A. They become global variables accessible by all users

B. They keep their values for the next request automatically

C. They are stored permanently in the server memory

D. They are reset and lost unless saved externally

Solution

1. Step 1: Understand PHP request lifecycle

   PHP starts fresh for each request, so variables exist only during that request.

2. Step 2: Identify variable persistence

   Variables reset after request ends unless saved in sessions or databases.

3. Final Answer:

   They are reset and lost unless saved externally -> Option D

4. Quick Check:

   PHP variables reset each request = D [OK]

Hint: Remember: PHP starts fresh every request, no variable memory [OK]

Common Mistakes:

• Thinking variables persist automatically between requests
• Confusing PHP with long-running server processes
• Assuming global variables keep values across users

2. Which PHP code snippet correctly shows the start of a new request process?

easy

A.

B.

C.

D.

Solution

1. Step 1: Analyze variable initialization

   In a new request, variables start fresh; $count = 0 sets it properly.

2. Step 2: Check other options for persistence

   Options A, B, D try to increment without initialization or rely on static/session which need extra setup.

3. Final Answer:

   <?php $count = 0; echo $count; ?> -> Option C

4. Quick Check:

   New request means fresh variables = C [OK]

Hint: Fresh request means variables start from scratch [OK]

Common Mistakes:

• Assuming static variables keep value across requests
• Using session without starting it
• Incrementing uninitialized variables

3. What will be the output of this PHP code when run twice in separate requests?

<?php
session_start();
if (!isset($_SESSION['visits'])) {
  $_SESSION['visits'] = 1;
} else {
  $_SESSION['visits']++;
}
echo $_SESSION['visits'];
?>

medium

A. 1 then 2

B. 1 then 1

C. 2 then 3

D. Error on second request

Solution

1. Step 1: Understand session persistence

   Session data keeps values across requests, so visits count increases.

2. Step 2: Trace two requests

   First request sets visits=1; second request increments to 2.

3. Final Answer:

   1 then 2 -> Option A

4. Quick Check:

   Session stores visits count = 1 then 2 [OK]

Hint: Sessions keep data between requests, variables do not [OK]

Common Mistakes:

• Thinking variables persist without sessions
• Forgetting to call session_start()
• Expecting static variables to persist across requests

4. Identify the error in this PHP code snippet that tries to keep a counter across requests:

<?php
$count = 0;
$count++;
echo $count;
?>

medium

A. Variables reset each request, so counter never increases

B. Syntax error due to missing semicolon

C. Session not started, so counter is undefined

D. Static variable needed to keep count

Solution

1. Step 1: Check variable behavior per request

   $count is set to 0 every time, so increment always starts fresh.

2. Step 2: Identify persistence issue

   Without sessions or external storage, counter resets each request.

3. Final Answer:

   Variables reset each request, so counter never increases -> Option A

4. Quick Check:

   Variables reset each request = A [OK]

Hint: Variables reset each request; use sessions to persist [OK]

Common Mistakes:

• Assuming static variables persist across requests
• Confusing syntax errors with logic errors
• Forgetting to start sessions for persistence

5. You want to count unique visitors to your PHP website. Which approach correctly uses PHP's process model per request to achieve this?

hard

A. Use a static variable in PHP script to count visitors

B. Store visitor count in a database and increment on each request

C. Increment a PHP variable without sessions or storage

D. Rely on PHP variables to keep count across requests

Solution

1. Step 1: Understand PHP process model limits

   PHP variables reset each request, so they can't keep visitor count.

2. Step 2: Identify persistent storage method

   Database stores data permanently and can be updated each request.

3. Final Answer:

   Store visitor count in a database and increment on each request -> Option B

4. Quick Check:

   Persistent storage needed for visitor count = A [OK]

Hint: Use database or sessions to save data beyond request [OK]

Common Mistakes:

• Using static or normal variables expecting persistence
• Ignoring need for external storage
• Confusing sessions with static variables