PHP ResourceBundle::create() Method: Usage and Examples

When working with localized application data, ResourceBundle::create() is useful because it opens an ICU resource bundle for a locale and bundle identifier.

Resource bundles store ICU localization data that can vary by locale and installed ICU version.

What Is ResourceBundle::create()?

Opens an ICU resource bundle for a locale and bundle identifier.

Its method signature is:

public static function create(?string $locale, ?string $bundle, bool $fallback = true): ?ResourceBundle

The arguments select the ICU locale and resource bundle, or the key/index to read. A fallback setting controls how ICU handles missing locale-specific entries.

Return value: ?ResourceBundle

Requirements: The PHP intl extension and corresponding ICU resource bundles must be installed.

Example 1: Inspect the basic behavior

Start with a self-contained PHP declaration and inspect the method result.

<?php

declare(strict_types=1);

$result = ResourceBundle::create("en", null);
echo $result instanceof ResourceBundle ? "bundle opened" : "bundle unavailable";

This example illustrates the call and required setup. Execution needs the PHP version or extension noted above.

Explanation: Opens an ICU resource bundle for a locale and bundle identifier.

Example 2: Compare a second case

Next, change the reflected declaration or parameter to observe a related situation.

<?php

declare(strict_types=1);

$result = ResourceBundle::create("fr", null);
echo $result instanceof ResourceBundle ? "bundle opened" : "bundle unavailable";

// Check the returned value type before using the result.
echo "\nResult type: " . get_debug_type($result);

This example illustrates the call and required setup. Execution needs the PHP version or extension noted above.

Explanation: Requires the intl extension and suitable ICU resource data; missing bundles can return null.

Practical Example: Apply the operation in context

This final case shows how the same API can be used when inspecting application definitions.

<?php

declare(strict_types=1);

$result = ResourceBundle::create("de", null);
echo $result instanceof ResourceBundle ? "bundle opened" : "bundle unavailable";

// Use the reflection result in a simple decision.
if (is_bool($result)) {
    echo "\nStatus: " . ($result ? "yes" : "no");
} elseif (is_array($result)) {
    echo "\nEntries: " . count($result);
} elseif ($result === null) {
    echo "\nNo value returned";
} else {
    echo "\nReflection result available";
}

This example illustrates the call and required setup. Execution needs the PHP version or extension noted above.

Explanation: ResourceBundle::get accesses an entry from an opened bundle.

Important Behavior and Edge Cases

• Requires the intl extension and suitable ICU resource data; missing bundles can return null.
• ResourceBundle::get accesses an entry from an opened bundle.
• Reflection describes declarations and runtime state; requesting metadata does not automatically validate or sanitize application input.

Comparison With Related Approaches

Common Beginner Mistakes

Key Takeaways

• Opens an ICU resource bundle for a locale and bundle identifier.
• Requires the intl extension and suitable ICU resource data; missing bundles can return null.
• ResourceBundle::get accesses an entry from an opened bundle.

Use ResourceBundle::create() when you need the precise metadata or behavior demonstrated above. Keep the target declaration and relevant PHP version in mind when adapting the examples.