Pw Url Routing

ProcessWire URL/Path Hooks Skill

When to Use This Skill

Use this skill when you need to:

• Create custom API endpoints (e.g., returning JSON data).
• Handle specific URLs without creating physical pages, templates, or fields in the admin.
• Create virtual routes, short URLs, or SEO-friendly URL segments dynamically.
• Intercept existing paths before ProcessWire issues a 404 response.

[!IMPORTANT] CRITICAL DOCUMENTATION RULE: Before writing any ProcessWire code or using its API, you MUST consult the local API documentation located at .agents/docs/index.md. You MUST NOT hallucinate API methods. ALL code, documentation, and file contents MUST strictly be written in English. Ensure inner code strings are always in English and wrapped in ProcessWire translation functions ($this->_('English String') or __('English String', __FILE__)) so they can localized if needed.

Fundamentals

URL hooks are defined during the ProcessWire boot process, typically in site/init.php (recommended) or site/ready.php, or inside a module's init() method.

Basic Routing

To output a string directly:

$wire->addHook('/api/hello', function($event) {
    return 'Hello World';
});

To output HTML and prevent further ProcessWire output, return true:

$wire->addHook('/api/hello', function($event) {
    echo '<h1>Hello World</h1>';
    return true;
});

Rendering an Existing Page

You can return a Page object to map a custom URL directly to an existing page. ProcessWire will make this the active $page and render it normally:

$wire->addHook('/special-offer', function($event) {
    return $event->pages->get('/about/contact/');
});

Advanced Routing Patterns

Named Arguments (Variables)

You can extract values from the URL into arguments.

• Simple Named Arguments: {argument_name}

$wire->addHook('/hello/{planet}', function($event) {
    // You can access it via arguments or directly
    $planet = $event->arguments('planet');
    // or $event->planet;

    // Validate or return false for a 404 response
    if (!in_array($planet, ['earth', 'mars'])) {
        return false;
    }

    return "Hello " . $planet;
});

• Pattern Matching Named Arguments: (name:pattern)

$wire->addHook('/hello/(planet:earth|mars|jupiter)', function($event) {
    return "Hello " . $event->planet;
});

Wildcards & Regular Expressions

If the path structure is complex, you can use full PCRE regex patterns. Remembering portions of the matched URL without named arguments uses $event->arguments(1).

$wire->addHook('(/.*)/json', function($event) {
    $path = $event->arguments(1);
    $page = $event->pages->findOne($path);

    if (!$page->id || !$page->viewable()) {
        return false;
    }

    // Returning an array automatically outputs as JSON with proper Content-Type
    return [
        'id' => $page->id,
        'title' => $page->title
    ];
});

Important Behaviors & Constraints

[!WARNING] Trailing Slashes: ProcessWire strictly enforces trailing slashes. /foo/bar/ definition will 301 redirect /foo/bar to /foo/bar/. To accept both without redirecting: $wire->addHook('/foo/bar/?', ...)

[!NOTE] Pagination: URL hooks ignore numbered pagination by default (/foo/bar/page2). To support pagination, append {pageNum} strictly as the last segment without a trailing slash: $wire->addHook('/foo/bar/{pageNum}', ...) The page number can be accessed via $event->pageNum.

Return Values Reference

1. String: Output string directly.
2. Array: Converted automatically to JSON with application/json header.
3. Page Object: ProcessWire renders the page and sets it as the active $page.
4. true: Tells ProcessWire you output the data manually (via echo).
5. false or null: Instructs ProcessWire to return a standard 404 response.

Conditional Registration

Instead of checking request types inside the hook callback, conditionally wrap the hook registration to save memory and process cycles:

if ($input->is('POST')) {
    $wire->addHook('/api/submit', function($event) { /* Handle POST */ });
}