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Differences between PHP 5.5 and PHP 7/8

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This page covers how to migrate your PHP 5.5 app to the PHP 7/8 runtime on the App Engine standard environment.

Compatibility issues between PHP 5.5 and PHP 7/8

The official PHP documentation provides information on migrating from different PHP versions:

Migrating your app.yaml file

You must place a front controller to handle all routing in your application. For more information, see Application startup.

The PHP 7/8 runtimes do not allow the script handler element to be customized. The only valid value is auto, because all traffic is served using the entrypoint command. All non-static URL handlers must include script: auto to deploy successfully.

The behavior of some elements in the app.yaml configuration file has been modified:

ElementChange typeDescription
entrypointAdded Optionally, use this field to specify the command that will run when your app starts.
threadsafeDeprecatedAll applications are presumed to be threadsafe, meaning an instance can handle multiple requests at the same time.
api_versionDeprecatedPreviously required but not needed in the PHP 7/8 runtimes.
librariesDeprecatedArbitrary third party dependencies can be installed using a composer.json metadata file.
  • The script field is optional and the only accepted value is auto. Use a web framework (like Laravel, Symfony, Slim, or a similar option) with in-app routing to execute a script when a request hits a specific route
  • The login field is not supported. Use Identity and Access Management (IAM) for user management.

If you use of any of the deprecated fields, there will be an error on app deployment.

For more information, see the app.yaml reference.

Reduced runtime restrictions

The PHP 7/8 runtimes have fewer restrictions compared to the PHP 5.5 runtime.

For more information, see the PHP 7/8 runtime environment documentation.

Migrating from the App Engine PHP SDK

To reduce runtime migration effort and complexity, the App Engine standard environment allows you to access many of legacy bundled services and APIs in the PHP 7/8 runtime, such as Memcache. Your PHP 7/8 app can call the bundled services APIs through the App Engine SDK for PHP 7/8, and access most of the same functionality as on the PHP 5 runtime. Not all the legacy bundled services available for PHP 5 have a corresponding service in PHP 7/8. For the full list of legacy bundled services APIs available for PHP 7/8, see the legacy bundled services API references documentation.

You also have the option to use Google Cloud products that offer similar functionality as the legacy bundled services. These Google Cloud products provide idiomatic Google Cloud CLI client library. For the legacy bundled services that are not available as separate products in Google Cloud, such as search, you can use third-party providers or other workarounds. To learn more about migrating to unbundled services, see Migrating from bundled services.

Running your application locally

To test your application and run it locally:

  1. Locally install a version of PHP that corresponds to one of the PHP 7/8 runtimes available on the App Engine standard environment.
  2. Install a web server and use this to serve your app locally.

For example, start the HTTP server by running the following command:

php -S localhost:8080

Then, view your application in your web browser at http://localhost:8080.