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

Lists locale identifiers available inside a resource bundle.

The examples focus on the operation itself, including the important distinction: ResourceBundle::create opens a bundle; getLocales lists locales stored in it.

What It Does

Use the examples below to observe the behavior on a small dataset before extending it to application code.

Syntax and Return Value

ResourceBundle::getLocales(...) — requires the corresponding optional extension

The displayed signature describes the API or identifies any correction or optional dependency. When a parameter is optional, supply it only when the task requires it.

Example 1: Basic Use

Supply the directory containing compiled ICU resource files, not a PHP array of translations. Requires the intl extension.

<?php
$bundleRoot = __DIR__ . "/icu-bundles";
$locales = ResourceBundle::getLocales($bundleRoot);
if ($locales === false) {
    throw new RuntimeException("Resource bundle could not be inspected");
}
foreach ($locales as $locale) {
    echo $locale . PHP_EOL;
}

This example is meant for a configured application environment; output depends on the installed extension, external service, or database contents.

Example 2: Checking Behavior

Supply the directory containing compiled ICU resource files, not a PHP array of translations. Requires the intl extension. This version demonstrates a separate way of consuming the locale list.

<?php
$bundleRoot = __DIR__ . "/icu-bundles";
$locales = ResourceBundle::getLocales($bundleRoot);
if ($locales === false) {
    throw new RuntimeException("Resource bundle could not be inspected");
}
foreach ($locales as $locale) {
    if (str_starts_with($locale, "en")) { echo $locale . PHP_EOL; }
}

This example is meant for a configured application environment; output depends on the installed extension, external service, or database contents.

Example 3: Practical Example

Supply the directory containing compiled ICU resource files, not a PHP array of translations. Requires the intl extension. This version demonstrates a separate way of consuming the locale list.

<?php
$bundleRoot = __DIR__ . "/icu-bundles";
$locales = ResourceBundle::getLocales($bundleRoot);
if ($locales === false) {
    throw new RuntimeException("Resource bundle could not be inspected");
}
foreach ($locales as $locale) {
    echo strtolower($locale) . PHP_EOL;
}

This example is meant for a configured application environment; output depends on the installed extension, external service, or database contents.

Important Behavior and Edge Cases

Requires the intl extension and an ICU data bundle; an unavailable bundle or locale should be handled explicitly.

This API is supplied by an optional extension that is not installed in the local test runtime, or requires a different PHP version. The example must be verified in a matching environment.

Comparison with Related Approaches

Common Beginner Mistakes

Key Takeaways

• Lists locale identifiers available inside a resource bundle.
• Requires the intl extension and an ICU data bundle; an unavailable bundle or locale should be handled explicitly.
• ResourceBundle::create opens a bundle; getLocales lists locales stored in it.

Use ResourceBundle::getLocales when its documented behavior matches the problem. Test the relevant edge cases in your own runtime before deploying it.