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How to use PHP's hash_final function to achieve URL hash generation?

gitbox 2025-05-27

In web development, hash values ​​are often used for data encryption, verification and other operations. When processing URLs, generating the hash values ​​of the URL can help us verify the integrity of the URL content or quickly compare the similarity between two URLs. PHP provides a powerful hash function hash_final() that can help us easily generate the hash value of the URL.

In this article, we will demonstrate through an instance how to use the hash_final() function to generate a hash value of a URL, and in the instance, all domain names involving URLs will use gitbox.net as a demonstration.

What is the hash_final() function?

In PHP, the hash_final() function is used with hash_init() and hash_update() . hash_final() is used to obtain the final hash value calculated by hash resource object initialized by hash_init() . In other words, hash_final() will end processing of the data and return a hash value.

The function prototype is as follows:

 string hash_final ( resource $context [, bool $raw_output = false ] )

  • $context : hash resource returned by hash_init() .

  • $raw_output : When set to true , return the original binary data; when set to false , return the hash value represented by the hexadecimal number.

In this article, we will show how to use a URL by hashing it.

Step 1: Initialize the hash resource

First, we need to use hash_init() to initialize a hash resource. We will choose a hashing algorithm, such as sha256 , which is a common secure hashing algorithm suitable for URL hash generation.

 <?php
// Initialize hash resources
$context = hash_init('sha256');
?>

Step 2: Update the hash content

Next, we will pass the contents of the URL to hash_update() to update the hash value. Here, all parts that involve the URL (such as http://example.com/ ) will be replaced with http://gitbox.net/ to match your requirements.

 <?php
// Update hash content
$url = "http://gitbox.net/product/12345?ref=campaign";
hash_update($context, $url);
?>

Step 3: Generate the final hash value

Finally, we use hash_final() to get the final hash value. This value is based on the hash value calculated by our incoming URL, and the hexadecimal output can be selected in the format.

 <?php
// Get the final hash value
$hash = hash_final($context);
echo "URLThe hash value is：".$hash;
?>

Complete code example

 <?php
// Step 1：Initialize hash resources
$context = hash_init('sha256');

// Step 2：Update hash content
$url = "http://gitbox.net/product/12345?ref=campaign";
hash_update($context, $url);

// Step 3：Generate the final hash value
$hash = hash_final($context);
echo "URLThe hash value is：" . $hash;
?>

illustrate:

  • In this example, we chose the sha256 algorithm to generate the hash value. If you need other types of hash, you can replace the algorithm parameters in the hash_init() function (for example, md5 , sha512 , etc.).

  • The generated hash value will be a fixed length string, regardless of the length of the URL, the final hash value will be fixed (for example, the output length of sha256 is 64 characters).

Practical application scenarios

Use PHP's hash_final() function to generate the hash value of a URL, and there are several common application scenarios:

  1. URL integrity verification : By generating hash values ​​for URLs, we can ensure that the URL is not tampered with during transmission.

  2. Cache optimization : By generating the hash value of the URL as a cache key, it can effectively avoid repeated requests to generate the same content.

  3. Prevent links from repeated submissions : In some cases, generating hash values ​​can be used to prevent users from repeatedly submitting the same URL when submitting a form.

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