Added has_env() twig function to test if environmental variable is defined

CHANGELOG.md

@@ -4,6 +4,7 @@
 1. [](#new)
     * Added `FileInterface::touch()` method
     * Added optional `$field` parameter to `FlexMediaTrait::deleteMediaFile()` method
+    * Added `has_env()` twig function to test if environmental variable is defined
 2. [](#improved)
     * By default, add media to only pages which have been initialized in pages loop
 3. [](#bugfix)

system/src/Grav/Common/Twig/Extension/GravExtension.php

@@ -222,6 +222,7 @@ class GravExtension extends AbstractExtension implements GlobalsInterface
             new TwigFunction('svg_image', [$this, 'svgImageFunction']),
             new TwigFunction('xss', [$this, 'xssFunc']),
             new TwigFunction('unique_id', [$this, 'uniqueId']),
+            new TwigFunction('has_env', [$this, 'hasEnv']),
 
             // Translations
             new TwigFunction('t', [$this, 'translate'], ['needs_environment' => true]),
@@ -707,6 +708,15 @@ class GravExtension extends AbstractExtension implements GlobalsInterface
         return Utils::uniqueId($length, $options);
     }
 
+    /**
+     * @param $string
+     * @return bool
+     */
+    public function hasEnv($string): bool
+    {
+        return is_string($string) && getenv($string) !== false;
+    }
+
     /**
      * @param string $string
      * @return string