Feature: #86409 - Allow usage of environment variables in site configuration

See Issue #86409

Description

To enable environment variable based configuration the TYPO3 Core Yaml loader has been adjusted to be able to resolve environment variables. Resolving of variables in the loader can be enabled or disabled via flags. When editing the site configuration through the backend interface the resolving of environment variables needs to be disabled to be able to add environment configuration through the interface.

The format for environment variables is %env(ENV_NAME)%. Environment variables may be used to replace complete values or parts of a value.

Impact

In site configuration environment variables can be used. One common example would be the base url that can now be configured via an environment variable.

Additionally, the Yaml Loader class has two new flags: PROCESS_PLACEHOLDERS and PROCESS_IMPORTS.

  • PROCESS_PLACEHOLDERS decides whether or not placeholders (%abc%) will be resolved.
  • PROCESS_IMPORTS decides whether or not imports (imports key) will be resolved.

Example usage in site configuration:

base: 'https://%env(BASE_DOMAIN)%/'