README

Database-backed feature flag provider for Yii3 applications. Implements the FlagProvider interface from rasuvaeff/yii3-feature-flags and reads flag configuration from a database table in a single query.

Using an AI coding assistant? llms.txt contains a compact API reference you can ingest in your prompt context.

Requirements

• PHP 8.3+
• rasuvaeff/yii3-feature-flags ^1.0
• yiisoft/db ^2.0
• yiisoft/db-migration ^2.0 (ships the table migration)
• yiisoft/definitions ^3.0 (DI Reference for WritableFlagProvider)
• a PSR-16 cache implementation — required transitively by yiisoft/db 2.0 (e.g. yiisoft/cache)

Installation

composer require rasuvaeff/yii3-feature-flags-db

With Yii3 config-plugin this package binds both FlagProvider and WritableFlagProvider to the same instance — do not also bind either key in your application or another backend, or yiisoft/config reports a Duplicate key error.

Database schema

Create the feature_flags table (adjust types for your RDBMS):

CREATE TABLE feature_flags (
    name        VARCHAR(190) PRIMARY KEY,
    enabled     BOOLEAN      NOT NULL DEFAULT TRUE,
    salt        VARCHAR(190) NOT NULL DEFAULT '',
    rollout     SMALLINT     NOT NULL DEFAULT 100,
    kill_switch BOOLEAN      NOT NULL DEFAULT FALSE,
    environments TEXT        NOT NULL DEFAULT '[]'
);

Migration

The package ships a migration (migrations/) for yiisoft/db-migration. Register the source path in your app's config/params.php:

'yiisoft/db-migration' => [
    'sourcePaths' => [
        dirname(__DIR__) . '/vendor/rasuvaeff/yii3-feature-flags-db/migrations',
    ],
],

Then apply and revert it with Yii Console:

./yii migrate:up
./yii migrate:down --limit=1

The table name defaults to feature_flags and must match the table argument of DbFlagProvider. To use a custom name, bind the migration constructor argument:

M260605000000CreateFeatureFlagsTable::class => [
    '__construct()' => ['table' => 'my_feature_flags'],
],

Usage

Basic DB provider

use Rasuvaeff\Yii3FeatureFlags\FeatureFlags;
use Rasuvaeff\Yii3FeatureFlagsDb\DbFlagProvider;

$provider = new DbFlagProvider(
    db: $connection,          // yiisoft/db ConnectionInterface
    table: 'feature_flags',   // optional, default is 'feature_flags'
);

$featureFlags = new FeatureFlags(provider: $provider);

if ($featureFlags->isEnabled('new-checkout')) {
    // new checkout flow
}

With PSR-16 caching

use Rasuvaeff\Yii3FeatureFlagsDb\CachedFlagProvider;

$cached = new CachedFlagProvider(
    inner: $provider,
    cache: $psr16Cache,       // PSR-16 CacheInterface
    ttl: 60,                  // seconds
);

$featureFlags = new FeatureFlags(provider: $cached);

Clear cache

$cached->clear();             // removes cached flags, next call reloads from DB

Writing flags

DbFlagProvider and CachedFlagProvider both implement WritableFlagProvider. Use them for programmatic CRUD or an admin UI.

use Rasuvaeff\Yii3FeatureFlags\Flag;
use Rasuvaeff\Yii3FeatureFlags\WritableFlagProvider;

/** @var WritableFlagProvider $provider */
$provider->save(flag: new Flag(
    name: 'new-checkout',
    enabled: true,
    rollout: 25,
    environments: ['production'],
));

$provider->remove(name: 'old-checkout');

• save() is an upsert keyed by name (insert or replace).
• remove() is idempotent: deleting a missing name is a no-op.
• CachedFlagProvider is write-through: after a successful save()/remove() it clears its cache before returning, so the next read reflects the change. When the inner provider is read-only (e.g. ConfigFlagProvider), write calls are silent no-ops — wrap a config provider safely without exceptions.
• Salt is normalized: Flag::__construct() replaces an empty salt with the flag name. On write the row stores '' whenever salt === name so the round-trip read keeps the same invariant (emptySaltFallsBackToName).
• Environments are encoded through FlagRowMapper::encodeEnvironments() and decoded through extractEnvironments(). Round-trip is guaranteed.

Writable DI binding

config/di.php binds WritableFlagProvider to the same instance as FlagProvider via Yiisoft\Definitions\Reference:

use Rasuvaeff\Yii3FeatureFlags\WritableFlagProvider;
use Yiisoft\Definitions\Reference;

return [
    // ...FlagProvider::class closure omitted for brevity...
    WritableFlagProvider::class => Reference::to(FlagProvider::class),
];

Inject WritableFlagProvider in write paths and FlagProvider in read paths; both resolve to the same object.

API reference

Security

• Kill switch, rollout hash logic, and environment targeting remain in the core package — the DB adapter is only a configuration source.
• Invalid row data (missing columns, malformed JSON, wrong types, out-of-range rollout, invalid flag name) throws InvalidFlagRowException instead of silently enabling features. Core validation errors are wrapped, so callers only need to catch InvalidFlagRowException.
• No SQL injection risk: table name is quoted via yiisoft/db quoter.

Examples

See examples/ for runnable scripts.

Development

composer build          # full gate: validate + normalize + cs + psalm + test
composer cs:fix         # auto-fix code style
composer psalm          # static analysis
composer test           # run tests

License

BSD-3-Clause. See LICENSE.md.