Twig, the flexible, fast, and secure template language for Codeigniter 4

Twig is a template language for PHP.

Twig uses a syntax similar to the Django and Jinja template languages which inspired the Twig runtime environment.

v3.0.0 Highlights

Major architectural refactor (internal) with backward‑compatible public API:

• Extracted modular services:
  • TemplateDiscovery – template enumeration & in-process caching
  • TemplateCacheManager – compile index (compile-index.json) & compiled state tracking
  • DynamicRegistry – runtime registration of functions & filters
  • TemplateInvalidator – single/batch/namespace cache invalidation
• New listing filters: namespace + glob/pattern (e.g. @admin/*, emails/user_*).
• Optimized batch invalidation (single directory scan for multiple templates).
• Warmup now persists & reuses a compile index; skipping already compiled templates is faster.
• Structured logging normalized: event=twig.* key=value pairs (update log parsers if any).
• Namespace-specific autoescape strategy mapping (setAutoescapeForNamespace).
• Twig facade slimmed; internal arrays removed in favor of service classes.

Service Architecture Guide: See docs/SERVICES.md for an in-depth explanation of the new modular internal services (Discovery, CacheManager, DynamicRegistry, Invalidator) and advanced usage patterns.

Upgrade Notes:

• No breaking changes for typical usage (render/display/registerFunction/registerFilter/warmup/invalidate APIs preserved).
• If you accessed internal properties like $compiledTemplates directly, migrate to the public methods (warmup, listTemplates, invalidate*).
• Log format changed; adjust any monitoring tools expecting old message text.
• Version bumped to v3 to reflect the internal restructuring & new operational capabilities rather than surface API breaks.

Current Behavior

Discovery snapshot, preload and APCu acceleration are automatic in the default profile (leanMode = false). In Lean Mode they are disabled unless explicitly re-enabled with enableDiscoverySnapshot.

v3.x Runtime Capability Model

Runtime features are governed by a profile (Full vs Lean) plus nullable overrides:

Capability	Full (leanMode = false)	Lean (leanMode = true)	Override null	Override true	Override false
Discovery Snapshot (persist + preload + APCu)	ON	OFF	Inherit profile	Force ON	Force OFF
Warmup Summary Persistence	ON	OFF	Inherit profile	Force ON	Force OFF
Invalidation History (last + cumulative)	ON	OFF	Inherit profile	Force ON	Force OFF
Dynamic Metrics (function/filter counts)	ON	OFF	Inherit profile	Force ON	Force OFF
Extended Diagnostics (names lists, static counts)	ON	OFF	Inherit profile	Force ON	Force OFF

null significa “hereda el perfil base”. Establecer explícitamente true / false domina siempre al modo (Full / Lean).

Automatic Cache Backend Detection

El sistema siempre invoca service('cache'):

• Si el handler es FileHandler (clase contiene File) => modo filesystem usando la ruta cachePath (por defecto WRITEPATH/cache/twig).
• Cualquier otro handler => modo service (se envuelve en CICacheAdapter para compilados Twig e índices).

Diagnóstico (getDiagnostics()['cache']):

{
    "enabled": true,
    "path": "/var/www/app/writable/cache/twig",   // null cuando mode=service
    "mode": "filesystem" | "service",
    "service_class": "CodeIgniter\\Cache\\Handlers\\RedisHandler", // sólo en service
    "prefix": "twig_",    // derivado de Config\Cache::$prefix + 'twig_'
    "ttl": 0,              // 0 = sin expiración (habitual para compilados)
    "compiled_templates": 42,
    "reconstructed_index": false
}

Cache Key Prefix (Simplified)

The prefix strategy was further simplified: we no longer embed the textual global cache prefix into Twig keys. Instead only two possibilities exist:

• Global Config\Cache::$prefix ends with _ (non-empty) ⇒ prefix used: _twig_
• Otherwise ⇒ prefix used: twig_

The previous form (<global> + '_') . 'twig_' was removed to avoid accidental duplication and shorten keys. The removed per-Twig cachePrefix override remains removed.

Examples:

• '' → twig_
• 'app' → twig_
• 'app_' → _twig_
• 'mediaprous_' → _twig_

Applies uniformly to compiled templates, compile index, discovery snapshot, warmup summary & invalidation history.

Diagnostics expose the resolved value at diagnostics['cache']['prefix'].

Persistence Medium Map (diagnostics['persistence'])

Claves posibles: compile_index, discovery_snapshot, warmup, invalidations.

Valor: { "medium": "file" | "ci" } donde ci representa uso de cache service (cualquier handler no-file). Ejemplo:

"persistence": {
    "compile_index": { "medium": "ci" },
    "discovery_snapshot": { "medium": "ci" },
    "warmup": { "medium": "ci" },
    "invalidations": { "medium": "ci" }
}

Reconstructed Index

Si tras leer el índice (compile-index.json o clave remota) la lista está vacía pero se detectan ficheros PHP compilados (upgrade / copia manual), se crea un índice sintético con nombres unknown_N. Campo reconstructed_index = true advierte de esta situación; haz un warmup para regenerar un índice “real”.

Lean vs Full Diagnostics Output

Lean elimina secciones completas (no aparecen las claves) para minimizar payload. Ejemplo (lean + sin overrides) sólo contiene: renders, last_render_view, environment_resets, cache, performance, capabilities, persistence (y discovery si forzado). Cualquier override true reintroduce su sección concreta.

Debug Toolbar Tuning

Para instalaciones grandes o páginas con mucho JavaScript, el panel de Twig puede añadir latencia si renderiza todas las secciones (discovery, dynamics, templates) en cada request. Se proveen flags para reducir el trabajo de renderizado directamente (no existe ya modo diferido / fetch asincrónico; fue retirado por simplicidad y evitar recursiones de rutas).

Flags de configuración (en Config\\Twig):

Flag	Default	Efecto
toolbarMinimal	false	Si true sólo Core + Cache + Performance; omite Discovery, Warmup, Invalidations, Dynamics, Templates, Capabilities, Persistence.
toolbarShowTemplates	true	Muestra/oculta la tabla de plantillas. Ignorado si toolbarMinimal=true.
toolbarMaxTemplates	50	Límite de filas en la tabla de plantillas.
toolbarShowCapabilities	true	Muestra sección de capabilities. Ignorado si minimal.
toolbarShowPersistence	true	Muestra mediums de persistencia. Ignorado si minimal.

Ejemplo para máximo rendimiento en desarrollo (vista muy ligera):

$config->toolbarMinimal = true; // Sólo métricas esenciales

Perfil intermedio sin tabla de plantillas pero con capabilities y persistence:

$config->toolbarMinimal = false;
$config->toolbarShowTemplates = false;

Estrategia sugerida:

1. Empieza con toolbarMinimal=true si sólo depuras conteos y cache.
2. Añade secciones puntualmente: desactiva minimal y activa sólo lo que necesitas (toolbarShowTemplates=false para omitir la tabla, reduce toolbarMaxTemplates).
3. Usa Lean Mode para reducir también el tamaño de la estructura JSON interna si consumes diagnostics externamente.

Notas:

• Todas las secciones se renderizan inline; no hay peticiones secundarias.
• Sin dependencias de JavaScript para cargar contenido dinámico del panel.
• Las optimizaciones se centran en no construir HTML innecesario.

Ejemplos Rápidos

Forzar snapshot en Lean:

$config->leanMode = true;
$config->enableDiscoverySnapshot = true; // sólo snapshot; warmupSummary, invalidations, metrics siguen OFF

Listar plantillas con estado de compilación:

$twig->listTemplates(true); // [['name'=>'welcome','compiled'=>true], ...]

Warmup y ver resumen:

$twig->warmup(['welcome']);
print_r($twig->getDiagnostics()['warmup']);

Installation via composer

Use the package with composer install

> composer require daycry/twig

Configuration

Run command:

> php spark twig:publish

This command will copy a config file to your app namespace. Then you can adjust it to your needs. By default file will be present in app/Config/Twig.php.

Configuration Quick Start

$config = new \Daycry\Twig\Config\Twig();

// Optional: enable strict variables (throw on undefined)
$config->strictVariables = true;

// Optional: Lean Mode (disable non-essential persistence & diagnostics)
$config->leanMode = true;                      // minimal overhead
$config->enableDiscoverySnapshot = true;       // re-enable snapshot in lean if you have many templates

// Custom template paths (optionally with namespace)
$config->paths = [APPPATH.'Module/Views', [APPPATH.'Admin/Views','admin']];

// Create instance
$twig = new \Daycry\Twig\Twig($config);

Profiles Summary:

• Full (default): snapshot + preload + APCu (if available) + all diagnostics.
• Lean: minimal persistence; selectively re-add capabilities via nullable overrides.

Usage Loading Library

$twig = new \Daycry\Twig\Twig();
$twig->display( 'file.html', [] );

Usage as a Service

$twig = \Config\Services::twig();
$twig->display( 'file.html', [] );

Usage as a Helper

In your BaseController - $helpers array, add an element with your helper filename.

protected $helpers = [ 'twig_helper' ];

And then you can use the helper

$twig = twig_instance();
$twig->display( 'file.html', [] );

Add Globals

$twig = new \Daycry\Twig\Twig();

$session = \Config\Services::session();
$session->set( array( 'name' => 'Daycry' ) );
$twig->addGlobal( 'session', $session );
$twig->display( 'file.html', [] );

File Example

<!DOCTYPE html>
<html lang="es">  
    <head>    
        <title>Example</title>    
        <meta charset="UTF-8">
        <meta name="title" content="Example">
        <meta name="description" content="Example">   
    </head>  
    <body>
        <h1>Hi {{ name }}</h1>
        {{ dump( session.get( 'name' ) ) }}
    </body>  
</html>

Collector

If you want to debug the data in twig templates.

Toolbar.php file

    use Daycry\Twig\Debug\Toolbar\Collectors\Twig;
    
    public array $collectors = [
        ...
        //Views::class,
        Twig::class
    ];

Advanced Features

Caching & Persistence Overview

This integration implements a multi-layer caching architecture covering:

1. Compiled template classes (auto-detected backend: CI cache service if available, otherwise filesystem)
2. Compile index (logical template -> compiled flag)
3. Template discovery stats + optional snapshot (with fingerprint & APCu acceleration)
4. Warmup summary persistence
5. Invalidation state (last + cumulative)

Backend selection is automatic (CI cache service if available, otherwise filesystem). Prefix derives from global cache config; TTL normally unlimited.

Discovery snapshot, preload and APCu acceleration are now automatic in the full profile (leanMode = false). Use enableDiscoverySnapshot when in Lean Mode to opt back in.

Warm all templates once after deployment:

php spark twig:warmup --all

Clear everything (compiled + persisted artifacts):

php spark twig:clear-cache --reinit

See full details, key layout, and troubleshooting in docs/CACHING.md.

Further Reading

• docs/SERVICES.md – Modular internal services (Discovery, CacheManager, DynamicRegistry, Invalidator)
• docs/PERFORMANCE.md – Warmup strategy, discovery tuning, invalidation efficiency, diagnostics interpretation

Lean Mode (Low-Overhead Profile)

Enable Lean Mode to minimize persistence & diagnostic overhead:

$config->leanMode = true; // disables warmup summary, invalidation history, discovery snapshot, dynamic & extended diagnostics

Re-enable selected capabilities while staying in Lean:

$config->leanMode = true;
$config->enableDiscoverySnapshot = true;   // keep snapshot for faster discovery
$config->enableWarmupSummary = true;       // record last warmup result

If leanMode = false (default) all capabilities are active automatically (snapshot always on now).

See docs/CACHING.md (section "Lean Mode & Capability Overrides") and docs/PERFORMANCE.md for rationale & cost matrix.

Custom Loader Injection

Replace the internal loader (e.g. use an in-memory ArrayLoader for tests):

use Twig\\Loader\\ArrayLoader;
use Daycry\\Twig\\Twig;

$twig = new Twig();
$twig->withLoader(new ArrayLoader([
    'hello.twig' => 'Hello {{ name }}'
]));

echo $twig->render('hello', ['name' => 'World']);

Strict Variables

Enable strict mode (undefined variables throw a RuntimeError):

$config = new \\Daycry\\Twig\\Config\\Twig();
$config->strictVariables = true;
$twig = new Twig($config);

Dynamic Registration (Functions & Filters)

Register functions or filters at runtime, even before the first render. Items queued before initialization are applied automatically.

Supports:

1. Boolean shorthand (backward compatible) → safe HTML when true.
2. Array options mirroring native Twig options (is_safe, needs_environment, needs_context, etc.).

// Boolean shorthand
$twig->registerFunction('hello_fn', fn(string $n) => 'Hello ' . $n);             // escaped by default
$twig->registerFunction('raw_html', fn() => '<b>Bold</b>', true);                // mark as safe HTML

// Array options (new)
$twig->registerFunction('upper_env',
    function(\Twig\Environment $env, string $v) { return strtoupper($v); },
    ['needs_environment' => true]
);

// Filters
$twig->registerFilter('exclaim', fn(string $v) => $v . '!', ['is_safe' => ['html']]);
$twig->registerFilter('italic', fn(string $v) => '<i>'.$v.'</i>', []);           // will be escaped

Usage in templates:

{{ hello_fn('World') }} {# Hello World #}
{{ raw_html() }}        {# <b>Bold</b> (not escaped) #}
{{ 'wow'|exclaim }}     {# wow! #}
{{ 'x'|italic }}        {# &lt;i&gt;x&lt;/i&gt; because unsafe #}

Cache Management

Specify a custom cache path via config:

$config = new \\Daycry\\Twig\\Config\\Twig();
$config->cachePath = WRITEPATH.'cache'.DIRECTORY_SEPARATOR.'twig_custom';
$twig = new Twig($config);

Clear compiled templates (optionally reinitializing the environment):

$removedFiles = $twig->clearCache();       // remove compiled files only
$removedFiles = $twig->clearCache(true);   // also reset Twig Environment
$cacheDir     = $twig->getCachePath();

Example: Combining Everything

$config = new \\Daycry\\Twig\\Config\\Twig();
$config->strictVariables = true;
$config->cachePath = WRITEPATH.'cache/twig_app';

$twig = new Twig($config);

$twig->registerFunction('link', fn(string $t, string $u) => '<a href="'.esc($u,'url').'">'.esc($t).'</a>', true);
$twig->registerFilter('reverse', fn(string $v) => strrev($v));

echo $twig->render('page', ['title' => 'My Page']);

If you change templates programmatically and need a fresh compile, call clearCache(true).

Dynamic Extension Registration

You can add Twig extensions at runtime:

use Daycry\Twig\Twig;
use App\Twig\MyExtension; // extends \Twig\Extension\AbstractExtension

$twig = new Twig();
$twig->registerExtension(MyExtension::class); // queued or immediate

CLI: Clear Twig Cache

After installing, you can clear compiled templates from the CLI:

php spark twig:clear-cache
php spark twig:clear-cache --reinit   # also recreates the Environment

Selective Template Invalidation

Remove cache for a single logical template name (without extension):

$twig->invalidateTemplate('emails/welcome');           // best-effort removal
$twig->invalidateTemplate('emails/welcome', true);     // remove + reinitialize environment

CLI variant:

php spark twig:invalidate emails/welcome
php spark twig:invalidate emails/welcome --reinit

Batch & Namespace Invalidation

Invalidate multiple logical template names in one call:

$summary = $twig->invalidateTemplates(['welcome','emails/welcome','admin/dashboard']);
/* $summary example:
[
    'removed'   => 3,        // total cache files removed
    'templates' => [         // per logical template details
        'welcome' => 1,
        'emails/welcome' => 1,
        'admin/dashboard' => 1,
    ],
    'reinit' => false,
]*/

// Force environment recreation after invalidation:
$twig->invalidateTemplates(['welcome'], true);

Invalidate by namespace (when using namespaced paths @namespace):

// Invalidate all templates under namespace '@admin'
$twig->invalidateNamespace('@admin');

// Invalidate all templates in the main (root) namespace
$twig->invalidateNamespace(null);

Warmup / Precompilation

Precompile templates to avoid first-hit latency. Two APIs:

// Specific templates (logical names without extension)
$summary = $twig->warmup(['welcome','emails/welcome']);
// All discovered templates under configured paths
$summaryAll = $twig->warmupAll();

/* Returned structure:
[
    'compiled' => 5,
    'skipped'  => 12, // already compiled
    'errors'   => 0,
]
*/

// Force recompilation ignoring existing compiled cache fingerprints
$twig->warmup(['welcome'], true);

CLI command:

php spark twig:warmup --all
php spark twig:warmup welcome emails/welcome
php spark twig:warmup welcome --force   # recompile even if cached

Warmup uses a heuristic hash check (md5 of logical name) to decide if a template seems compiled; --force bypasses this.

Logging

All logging now delegates entirely to CodeIgniter's native log_message() helper. No internal logger instance or setLogger() method exists anymore.

Log entries follow a normalized event=<name> key=value ... pattern for easier machine parsing. Representative events (levels vary: debug/info/error):

• twig.functions.start, twig.functions.ready
• twig.function.queued, twig.function.registered, twig.function.unregistered
• twig.filter.queued, twig.filter.registered, twig.filter.unregistered
• twig.extension.queued, twig.extension.registered, twig.extension.queued_recreate, twig.extension.unregistered
• twig.cache.enabled, twig.cache.disabled, twig.cache.cleared
• twig.template.invalidated, twig.templates.invalidated, twig.namespace.invalidated
• twig.warmup.compiled, twig.warmup.error
• twig.loader.replaced, twig.reset

Control verbosity via your global app/Config/Logger.php. No additional configuration is required inside Twig.

Breaking change: previous ad-hoc message formats were replaced; if you had log parsers, update them to consume the new key=value style.

CLI Commands Overview

Command	Description	Common Options / Notes
php spark twig:publish	Publish the config file to app/Config/Twig.php.	Run once after install.
php spark twig:clear-cache	Delete compiled cache files.	--reinit recreate environment after clearing.
php spark twig:invalidate <template>	Invalidate a single logical template.	--reinit if removed. Name without extension.
php spark twig:invalidate:batch <t1> <t2> ...	Invalidate multiple logical templates.	--reinit if any removed.
php spark twig:warmup	Precompile specific templates.	Provide names or use --all; --force to ignore existing cache.
php spark twig:list	List discovered logical templates.	--status to include compiled flag.
php spark twig:stats	Show counts & cache information.	Reads compile index and cache directory.

Template Listing & Filtering

Use the listTemplates() API to enumerate logical names. You can filter by namespace and/or a glob-style pattern (* and ?).

// All templates
$all = $twig->listTemplates();

// All templates inside a namespace
$admin = $twig->listTemplates(false, '@admin');

// Pattern filtering (within namespace)
$adminDash = $twig->listTemplates(false, '@admin', 'dash*/index');

// With compiled status
$withStatus = $twig->listTemplates(true);

Patterns are case-insensitive. If a namespace is supplied, the pattern is matched against the path portion inside that namespace.

Template Discovery Cache

Discovered logical template names are cached per-process (context hash: loader class + paths + extension). The cache invalidates automatically when:

1. Loader is replaced (withLoader())
2. Environment reset (resetTwig()) This reduces filesystem traversal on repeated listing or namespace invalidation operations.

Changelog (recent additions)

Summary of notable enhancements (proposed release 0.3.0):

• Loader replacement via withLoader()
• Strict variables mode ($strictVariables config)
• Dynamic runtime registration & unregistration: registerFunction(), unregisterFunction(), registerFilter(), unregisterFilter(), registerExtension(), unregisterExtension()
• Cache utilities: getCachePath(), clearCache(), runtime toggles disableCache(), enableCache(), isCacheEnabled()
• Selective, batch, and namespace invalidation: invalidateTemplate(), invalidateTemplates(), invalidateNamespace() + CLI counterparts
• Warmup & precompilation: warmup(), warmupAll() with persisted compile index (compile-index.json)
• Listing & status: listTemplates() (with namespace/pattern filtering & compiled status)
• Namespace auto-escape strategy mapping: setAutoescapeForNamespace(), removeAutoescapeForNamespace()
• New CLI commands: twig:invalidate, twig:invalidate:batch, twig:warmup, twig:list, twig:stats, twig:clear-cache, twig:publish -- Unified structured logging (key=value)
• In-process discovery cache for logical template enumeration

Roadmap / Ideas

Potential future exploration:

• Template dependency graph (track includes/extends for smarter invalidation)
• Optional metrics hook (expose render times to an external profiler)
• Pluggable cache backend abstraction (filesystem vs memory)
• Enhanced auto-escape strategies (contextual by file pattern)
• Interactive CLI (prompt-driven) for template operations

New Features Documentation

Unregister Runtime Additions

Remove previously registered dynamic artifacts:

$twig->unregisterFunction('temp_fn');
$twig->unregisterFilter('brackets');
$twig->unregisterExtension(MyExtension::class);

Runtime Cache Toggle

Disable recompilation writing and force non-cached rendering (development convenience):

$twig->disableCache();          // turns off cache (does not delete existing by default)
$twig->disableCache(true);      // also removes existing compiled files
$twig->enableCache();           // re-enable with default path
$twig->enableCache('/custom/path');
if (!$twig->isCacheEnabled()) { /* ... */ }

Namespace Auto-Escape Mapping

Set different escaping strategies per Twig namespace (leading @ omitted when specifying):

$twig->setAutoescapeForNamespace('admin', 'html');
$twig->setAutoescapeForNamespace('rawmail', false);   // disable escaping
$twig->removeAutoescapeForNamespace('rawmail');

Persistent Compile Index & Listing

Warmup operations store compiled logical names into compile-index.json within the cache directory.

$twig->warmup(['welcome']);
$templates = $twig->listTemplates(true); // [['name' => 'welcome', 'compiled' => true], ...]

New CLI Commands

php spark twig:list             # list logical template names
php spark twig:list --status    # include compiled status (from index)
php spark twig:stats            # show counts & cache info
php spark twig:invalidate:batch welcome emails/welcome