$_REQUEST behavior in PHP - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to access a value from the $_REQUEST superglobal.

PHP

<?php
$value = $_REQUEST[[1]];
echo $value;
?>

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

A"email"

B"username"

C"password"

D"age"

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting quotes around the key name.

Using $_REQUEST without a key.

$_REQUEST is an associative array that contains data from GET, POST, and COOKIE. You access values by their key as a string.

2fill in blank

medium

Complete the code to check if a key exists in $_REQUEST.

PHP

<?php
if (isset($_REQUEST[[1]])) {
    echo "Key exists.";
} else {
    echo "Key does not exist.";
}
?>

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

Auser_name

B"user_name"

C"user"

Duser

Attempts:

3 left

💡 Hint

Common Mistakes

Using a variable without quotes as the key.

Using empty quotes or wrong key name.

Keys in $_REQUEST must be strings, so you need quotes around the key name when checking with isset().

3fill in blank

hard

Fix the error in the code to correctly retrieve a POST value using $_REQUEST.

PHP

<?php
// Assume form method is POST
$name = $_REQUEST[1]"name"];
echo $name;
?>

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

A("

B->

C"

D[

Attempts:

3 left

💡 Hint

Common Mistakes

Using parentheses instead of square brackets.

Using object operator -> on an array.

To access an element in an array, use square brackets []. Parentheses or arrows are incorrect for arrays.

4fill in blank

hard

Fill both blanks to create a filtered array from $_REQUEST with keys longer than 4 characters.

PHP

<?php
$filtered = array_filter($_REQUEST, function($key) {
    return strlen($key) [1] 4;
}, [2]);
print_r($filtered);
?>

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

A>

B==

CARRAY_FILTER_USE_KEY

DARRAY_FILTER_USE_BOTH

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong comparison operator.

Not specifying the flag to filter by keys.

Use > to check keys longer than 4 characters. Use ARRAY_FILTER_USE_KEY to apply the callback to keys.

5fill in blank

hard

Fill all three blanks to create a new array with uppercase keys and values from $_REQUEST where values are not empty.

PHP

<?php
$result = array_combine(
    array_map([1], array_keys($_REQUEST)),
    array_filter($_REQUEST, function($value) {
        return $value [2] '';
    })
);
print_r($result);
?>

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

Astrtoupper

B!=

C!==

Dempty

Attempts:

3 left

💡 Hint

Common Mistakes

Using empty() inside array_filter callback incorrectly.

Using wrong comparison operators.

Use strtoupper to convert keys to uppercase. Use != to check values not equal to empty string.

Practice

1. What does the PHP superglobal $_REQUEST contain?

easy

A. Data from GET, POST, and COOKIE combined

B. Only data sent via GET method

C. Only data sent via POST method

D. Only data stored in cookies

Solution

1. Step 1: Understand the purpose of $_REQUEST

   $_REQUEST is designed to collect data from multiple sources: GET, POST, and COOKIE.

2. Step 2: Identify what $_REQUEST includes

   It merges these three superglobals into one array for easier access.

3. Final Answer:

   Data from GET, POST, and COOKIE combined -> Option A

4. Quick Check:

   $_REQUEST = GET + POST + COOKIE [OK]

Hint: Remember: $_REQUEST mixes GET, POST, and COOKIE data [OK]

Common Mistakes:

• Thinking $_REQUEST only contains GET or POST data
• Confusing $_REQUEST with $_POST or $_GET
• Assuming $_REQUEST excludes cookies

2. Which of the following is the correct way to access a form field named username using $_REQUEST in PHP?

easy

A. $_REQUEST->username

B. request['username']

C. $_REQUEST.username

D. $_REQUEST['username']

Solution

1. Step 1: Recall PHP array syntax

   PHP superglobals like $_REQUEST are associative arrays accessed with square brackets and quotes for keys.

2. Step 2: Identify correct syntax for accessing 'username'

   The correct syntax is $_REQUEST['username']. Using arrows or dots is invalid for arrays.

3. Final Answer:

   $_REQUEST['username'] -> Option D

4. Quick Check:

   Array access uses brackets and quotes [OK]

Hint: Use square brackets with quotes for $_REQUEST keys [OK]

Common Mistakes:

• Using object notation (->) instead of array syntax
• Using dot notation like in JavaScript
• Forgetting quotes around the key

3. Given the following PHP code, what will be the output if the URL is script.php?color=red and the form sends color=blue via POST?

<?php
print_r($_REQUEST['color']);
?>

medium

A. red

B. Array

C. blue

D. Undefined index error

Solution

1. Step 1: Understand the order of variables in $_REQUEST

   By default, PHP's $_REQUEST uses the order: GET, POST, COOKIE. POST data overrides GET if keys are the same.

2. Step 2: Determine which value $_REQUEST['color'] holds

   Since POST sends color=blue, it overrides the GET color=red. So, $_REQUEST['color'] is 'blue'.

3. Final Answer:

   blue -> Option C

4. Quick Check:

   POST overrides GET in $_REQUEST [OK]

Hint: POST data overrides GET in $_REQUEST by default [OK]

Common Mistakes:

• Assuming GET value appears first
• Confusing $_REQUEST with $_GET or $_POST
• Expecting an array output

4. Consider this PHP snippet:

<?php
print_r($_REQUEST['user']);
?>

If the form sends no 'user' field and the URL has no 'user' parameter, what error will occur and how to fix it?

medium

A. No error; prints empty string

B. Notice: Undefined index; fix by checking with isset()

C. Warning: Invalid argument; fix by casting to string

D. Fatal error: Undefined variable; fix by declaring variable

Solution

1. Step 1: Identify the error from accessing missing key

   Accessing $_REQUEST['user'] when 'user' is not set causes a Notice: Undefined index.

2. Step 2: Fix by checking if key exists

   Use isset($_REQUEST['user']) before accessing to avoid the notice.

3. Final Answer:

   Notice: Undefined index; fix by checking with isset() -> Option B

4. Quick Check:

   Check keys with isset() to avoid notices [OK]

Hint: Always check isset() before accessing $_REQUEST keys [OK]

Common Mistakes:

• Ignoring undefined index notices
• Confusing undefined index with undefined variable
• Assuming no error occurs when key missing

5. You want to safely get a user's preferred language from either GET, POST, or COOKIE using $_REQUEST, but prefer POST over GET and GET over COOKIE. Which code snippet correctly respects this priority?

hard

A. if(isset($_POST['lang'])) { $lang = $_POST['lang']; } elseif(isset($_GET['lang'])) { $lang = $_GET['lang']; } elseif(isset($_COOKIE['lang'])) { $lang = $_COOKIE['lang']; } else { $lang = 'en'; }

B. $lang = $_REQUEST['lang'] ?? 'en';

C. $lang = $_COOKIE['lang'] ?? $_GET['lang'] ?? $_POST['lang'] ?? 'en';

D. $lang = $_GET['lang'] ?? $_POST['lang'] ?? $_COOKIE['lang'] ?? 'en';

Solution

1. Step 1: Understand priority order requirement

   The priority is POST > GET > COOKIE, so check in that order.

2. Step 2: Analyze each option's order

   if(isset($_POST['lang'])) { $lang = $_POST['lang']; } elseif(isset($_GET['lang'])) { $lang = $_GET['lang']; } elseif(isset($_COOKIE['lang'])) { $lang = $_COOKIE['lang']; } else { $lang = 'en'; } checks POST first, then GET, then COOKIE, assigning default 'en' if none set. $lang = $_REQUEST['lang'] ?? 'en'; uses $_REQUEST which merges but order depends on php.ini and is less explicit. Options C and D check in wrong orders.

3. Final Answer:

   Option A code snippet -> Option A

4. Quick Check:

   Explicit checks respect priority best [OK]

Hint: Check POST, then GET, then COOKIE explicitly for priority [OK]

Common Mistakes:

• Relying on $_REQUEST without knowing order
• Checking keys in wrong priority order
• Not providing a default value