Transitioning from PHP 7.0 to PHP 8.1: A Comprehensive Guide

PHP, also known as Hypertext Preprocessor, stands out as a highly sought-after server-side scripting language. Its popularity in web development is attributed to its open-source nature, user-friendly learning curve, and seamless integration of PHP code into HTML. Notably, it can be seamlessly combined with JavaScript and CSS. PHP plays a crucial role in platforms such as WordPress, powering a significant portion of its software and rendering it indispensable for WordPress users. Additionally, other prominent content management systems like Joomla, Drupal, and Magento rely on PHP.?

PHP is compatible with major operating systems, including Windows, macOS, and Linux. It seamlessly syncs with diverse databases like MySQL, MongoDB, and Postgres, and enjoys support from a majority of web servers such as Apache and IIS. Renowned entities like Facebook, Shopify, and Wikipedia have harnessed PHP to craft robust and interactive websites.?

The PHP development team remains proactive, consistently releasing updated versions aligned with contemporary trends and technological advancements. The most recent iteration, PHP 8.1, offers enhanced ease of use and various advantages. If you haven't yet transitioned to PHP 8.1, now is the opportune moment to consider upgrading. This version brings notable improvements in performance, syntax, and security.?

This post not only sheds light on the features of the latest PHP version but also guides you through the PHP migration process from PHP 7.0 to 8.1. Let's get started!??

Why should you upgrade to PHP 8.1??

PHP migration from 7.0 to 8.1 version is a strategic move, and here's why:?

Expanded Functionality: PHP 8.1 introduces a plethora of additions, including new interfaces, classes, and functions. These augmentations contribute to enhanced performance, faster code execution, and increased security against vulnerabilities. The new language functionalities also facilitate the creation of more expressive and maintainable code.?

End of Support for Older Versions: Previous PHP versions, up to 7.4, are now considered outdated and are no longer actively supported. In contrast, PHP 8.1 will receive active support until November 25, 2024, with the promise of additional security updates. Websites or web applications still operating on older PHP versions are missing out on advanced functionalities and lagging in terms of performance.?

Security Considerations: Continuing to use outdated PHP versions exposes your website or web app to security risks such as DoS attacks, XSS vulnerabilities, code execution exploits, directory traversal, and memory corruption. PHP 8.1 ensures a more secure environment, with ongoing support addressing potential security issues.?

In the process of executing PHP code on the server, the results are displayed on the client's web browser. PHP seamlessly integrates with technologies like JavaScript, HTML, and CSS to create dynamic and engaging web experiences .?

Glimpses of Key Updates in PHP 8.1?

Enums??

PHP 8.1 introduces significant updates, including support for Enums (Enumerations). Enums are user-defined data types that encompass a predefined set of values, allowing for value assignment to each case. Users can optionally declare "int" or "string" as backed values, extend classes, and implement interfaces with Enums.?

Fibers??

Another noteworthy addition is Fibers, which are primitives enabling the creation of code blocks that can be paused and resumed similar to generators. Fibers facilitate the implementation of lightweight cooperative concurrency, eliminating the boilerplate code associated with Generator-based coroutines or Promise::then().?

Match Expression??

The Match expression feature provides a concise and flexible way to match values. Users can define various cases along with their corresponding values, and the appropriate case is selected based on the expression's value, utilizing the "match" keyword.?

Performance-related Enhancements??

PHP 8.1 also brings several performance enhancements, including JIT improvements and fixes, optimizations in memory usage and SPL file-system operators, and enhancements in serializing or unserializing processes. This version enables the avoidance of hash lookup, lowercasing, and the relinking of classes for every request.?

Nullsafe Operator??

The introduction of the Nullsafe Operator allows for seamless chaining of method calls without concerns about null references. This operator ensures that a method is invoked only when the object it operates on is not null.?

Other Updates?

Additional support has been added for attributes, named arguments, and improvements to Unicode support. Previously, array unpacking only supported numeric keys; now, it extends to string keys as well.?

Tasks to Perform in PHP Code Following Server Upgrade, Modification, or Renaming?

• Incorporate the updated server name or IP address into the code, especially if conditional statements are dependent on server-specific information.?
• Ensure the creation of essential directories on the new server to prevent potential errors in PHP file operations such as fopen() and fwrite(). Failure to do so may lead to operational issues.?
• Transfer relevant data from the previous server to the new one, including but not limited to images, logos, cron jobs, and data stored in cloud storage.?
• Address potential memory issues, as exemplified by the PHP message: "PHP Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate 20480 bytes)."??

Implement the following strategies to resolve this problem: i) Optimize SQL queries by fetching only necessary columns and minimizing the use of joins. ii) Restrict the use of loops in the code to mitigate memory consumption. iii) Implement techniques such as loading limited data or employing lazy loading, especially when dealing with a large number of records that need to be fetched.?

What are the typical PHP errors that may arise after PHP migration from 7.0 to 8.1, and how can these issues be addressed??

1. Issue: Constructors with the same name as the classes are no longer treated as such.??

PHP 8.1 resolution: The use of the construct() method is now required. Review all constructors in class files, replacing instances of the class name with construct().?

1. Issue: The use of the [] operator for referencing arrays is no longer allowed.??

PHP 7.0 -> $cities[] = $city; (Example of variable declaration change in PHP 8.1)??

PHP 8.1 resolution -> Use array_push($cities, $city); An error in 8.1 -> [] operator not supported.?

3. Issue: The error mentioned in part 1 can result in a json_decode() error, as it interprets $cities as strings rather than an array without the PHP 8.1 fix. PHP 7.0 -> @json_decode($cities); (Example of function call change in PHP 8.1)??

PHP 8.1 resolution -> @json_decode(json_encode($cities)); An error in 8.1 -> json_decode(): Argument #1 ($json) must be of type string, array is given.?

4. Issue: The get_magic_quotes_gpc() method has been deprecated since PHP 7.4. An error occurred in 8.1: Uncaught Error: Call to undefined function get_magic_quotes_gpc();?

5. Issue: Deprecated variable and parameter declarations.??

PHP 8.1 resolutions -> i) Ensure function calls match function definitions and their parameter sequences. ii) In function definitions, assign default parameters from right to left. Example: function test_function(int $var1, int $var2='101', int $var3='abc')?

6. Error mentioned in the pt.2 PHP 7.0 version can lead to multiple errors in array functions. A few such array functions are listed below.? ? ? Error 1?

implode() -> Error occurred in 8.1 -> TypeError: implode(): Argument #2 ($array) must be of type array?

In PHP 8.1, the implode() function's second argument must be of type array. If you're passing a non-array argument, you need to ensure that it is converted to an array before passing it to implode().?

Before (PHP 7.0):?

phpCopy code?

$glue = ","; $result = implode($glue, $nonArray);??

After (PHP 8.1):?

phpCopy code?

$glue = ","; $result = implode($glue, (array) $nonArray);??

Error 2?

count() -> Error occurred in 8.1 -> TypeError: count(): Argument #1 ($value) must be of type Countable|array?

In PHP 8.1, the count() function's argument must be of type Countable or array. If you're passing a non-array or non-Countable argument, ensure that it is validated or converted appropriately.?

Before (PHP 7.0):?

phpCopy code?

$count = count($value);??

After (PHP 8.1):?

phpCopy code?

$count = is_countable($value) ? count($value) : 0; // or $count = count((array) $value);??

Error 3?

in_array() -> Error occurred in 8.1 -> TypeError: in_array(): Argument #2 ($haystack) must be of type array?

In PHP 8.1, the in_array() function's second argument ($haystack) must be of type array. Ensure that the variable you're passing is indeed an array.?

Before (PHP 7.0):?

phpCopy code?

$exists = in_array($needle, $nonArray);??

After (PHP 8.1):?

phpCopy code?

$exists = in_array($needle, (array) $nonArray);??

iv) array_keys() - TypeError: array_keys(): Argument #1 ($array) must be of type array?

?Error 4?

array_keys() -> Error occurred in 8.1 -> TypeError: array_keys(): Argument #1 ($array) must be of type array.? ?

In PHP 8.1, the array_keys() function's first argument ($array) must be of type array. Ensure that the variable you're passing is indeed an array.?

Before (PHP 7.0):?

phpCopy code?

$keys = array_keys($nonArray);??

After (PHP 8.1):?

phpCopy code?

$keys = array_keys((array) $nonArray);??

Additional Considerations:?

Check Variable Types: Double-check the types of variables you are working with to ensure they are appropriate for the functions you are using.?

Update Libraries and Dependencies: If you are using third-party libraries, make sure to update them to versions that are compatible with PHP 8.1.?

Review PHP 8.0 Changes: If you haven't already, review the changes introduced in PHP 8.0, as some of those changes might also impact your code during the migration to PHP 8.1.?

Remember to thoroughly test your code after making these changes to ensure that it functions correctly in the PHP 8.1 environment.?

Final Words:??

I trust this PHP migration guide will assist you in harnessing the advantages of the latest functionalities and enhancements. PHP 8.1 ensures security and reliability while introducing disruptive features that optimize the performance and safety of your PHP website. It is recommended to upgrade to PHP 8.1, simplifying the web development process, improving error handling, and streamlining maintenance post-deployment. It is crucial to emphasize that thorough code testing is necessary before deploying in production during the migration to avoid compatibility issues. Also, using the relevant PHP development tools is recommended.?