How to URL Decode a String in PHP

Introduction

URL decoding in PHP is an essential process for extracting and interpreting data accurately from URLs, especially when handling special characters, spaces, and non-alphanumeric characters. It plays a vital role in ensuring data integrity within web applications. In this guide, we will take you through the process of URL decoding a string in PHP, offering both code examples and detailed explanations.

URL Decoding in PHP: Code and Explanation

PHP provides a built-in function called urldecode() for URL decoding strings. Here's how you can use it:

<?php
// Encoded URL string
$encodedString = "Hello+World%21+How+are+you%3F";

// URL decode the string
$decodedString = urldecode($encodedString);

// Display the decoded string
echo "Decoded String: " . $decodedString . "<br>";
?>

Explanation

1. Encoded URL String: Start with the encoded URL string that you want to decode. This string may contain encoded spaces, special characters, or non-alphanumeric characters.

2. URL Decoding: Utilize the urldecode() function to decode the encoded URL string. The function converts %20 back to spaces and decodes other percent-encoded characters to their original form.

3. Display the Decoded String: Finally, you can display the decoded string by echoing it. The resulting string is now in its original form.

Example Output

For the encoded URL string "Hello+World%21+How+are+you%3F," the decoded string would appear as follows:

# Output

Decoded String: Hello World! How are you?

The + symbols have been replaced with spaces, %21 has been restored to an exclamation mark !, and %3F is back to being a question mark ?.

URL decoding is crucial for accurately retrieving and processing data from URLs, making it a fundamental aspect of web development, particularly when handling user input and dynamic URLs.