How to Encode and Decode URLs in PHP ?

In PHP, encoding and decoding URLs is a common task when working with web applications, especially when handling user input or constructing URLs dynamically. URL encoding is necessary to ensure that special characters in URLs are properly represented, while URL decoding is used to retrieve the original data from encoded URLs.

Syntax

// Encode a URL
$encodedURL = urlencode("https://geeksforgeeks.org/?q=hello geeks");

// Decode a URL
$decodedURL = urldecode($encodedURL);

echo $encodedURL; // Output: https%3A%2F%geeksforgeeks.org%2F%3Fq%3Dhello+geeks
echo $decodedURL; // Output: https://geeksforgeeks.org/?q=hello geeks

Important Points:

• URL encoding is necessary to represent special characters, such as spaces, ampersands, or question marks, in a URL format that is safe for transmission over the internet.
• URL decoding is used to retrieve the original data from URL-encoded strings.
• It’s essential to use encoding and decoding functions consistently to ensure data integrity and prevent security vulnerabilities.

Difference between urlencode() and urldecode()

urlencode()	urldecode()
Encodes a string for use in a URL	Decodes a URL-encoded string
Replaces special characters with their hexadecimal representation	Converts hexadecimal representations back to their original characters

Usage

• Data Transmission: URL encoding ensures that data transmitted via URLs is properly formatted and can be safely interpreted by web servers and browsers.
• Data Integrity: URL decoding retrieves the original data from URL-encoded strings, preserving data integrity and preventing loss of information.
• Security: Properly encoding and decoding URLs helps prevent security vulnerabilities such as injection attacks or unexpected behavior due to malformed URLs.