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grav-db-kit

Shared database, migration, job queue and event infrastructure for Grav plugins by Trilby Media: a PDO wrapper with SQLite, MySQL and PostgreSQL dialects, an upgrade-only migrator, a database-backed job queue with an inline drain, an event sink backbone, a rate limiter and a key/value store.

It is a Composer package, not a Grav plugin, and it has no Grav dependency. Each plugin bundles its own copy, namespace-prefixed with Strauss, so plugins update it in their own releases and never need another plugin installed.

The code is extracted from KahunaCart's newer database layer and Forum Pro's services. KahunaCart (1.3), Forum Pro (1.0.10) and Helpdesk Pro all bundle it now; Switching an existing plugin records what changed when the first two moved over.

Requirements

• PHP 8.3 or newer with ext-pdo
• pdo_sqlite for SQLite (the default engine), pdo_mysql for MySQL 8+ / MariaDB 10.6+, pdo_pgsql for PostgreSQL 14+

Until the package is on Packagist, plugins use a Composer path repository pointing at ../grav-db-kit.

What is in it

The Testing classes ship in the package (they have no PHPUnit dependency) so plugin test suites can use them.

Connections

ConnectionFactory::sqlite() turns on WAL, foreign_keys, busy_timeout=5000 and synchronous=NORMAL, creates the directory when it is missing and puts a deny-all .htaccess and an empty index.html in it, because stock Grav web server rules do not block a .sqlite download from under user/. mysql() takes host/port or unix_socket, plus dbname, username and password. pgsql() also takes sslmode. fromPdo($pdo, 'sqlite'|'mysql'|'pgsql') wraps a PDO someone else opened (a grav-plugin-database named connection, a test fixture). mysqlIsStrict($db) tells a status page whether the server silently truncates data.

Connection is a thin PDO wrapper:

Runtime SQL written against a Connection has to stay in the portable subset the three engines share: identifiers unquoted (validated names) or through Dialect::quoteIdentifier(), every value bound as a parameter, LIMIT/OFFSET on SELECT only, no RETURNING/ON CONFLICT/ON DUPLICATE outside the dialect, times as UTC epoch BIGINT, booleans as INTEGER 0/1.

The dialect gives migrations their DDL fragments (primaryKey(), textLong(), tableOptions()) and idempotency probes (tableExists, columnExists, createIndexIfMissing, dropIndexIfExists, renameTableIfExists), and gives Connection its engine-specific writes and error classification (isRetryableError, isUniqueViolation).

Table names and options

Nothing in the kit writes a table name inline. KitTables names every table the kit itself touches:

Every name is validated as a plain SQL identifier when the object is built. toArray() lists them.

KitOptions holds the rest:

Pass the same KitOptions to ConnectionFactory and every class that takes one. Classes that take a Connection and no options use the connection's.

Migrations

A migration is a file named NNNN_snake_name.php that returns an instance of Migration:

Steps run in array order and are recorded one at a time (MySQL commits DDL implicitly, so a crash can land between steps), which is why every step has to be idempotent.

• Upgrade only: there are no down migrations; recovery is a backup.
• Several directories run in the order given, files sorted by name within each. That is how an add-on brings its tables into the same database and tracking table. Two files claiming one migration name is an error, and a missing directory contributes nothing.
• bootstrap() creates the migrations and locks tables with CREATE TABLE IF NOT EXISTS, so it is harmless on a database that already has them.
• migrate() holds a Lease named migrate for KitOptions::$lockTtl seconds and throws when another process holds it.
• Migrator::fingerprint($paths) is the name, size and mtime of every migration file, without reading any of them.
• Each migration file is required once per process and remembered by path, mtime and size. Migration files are anonymous classes, and PHP never frees a compiled anonymous class, so a process that builds many migrators (a test suite, a long worker) would otherwise grow by every migration's compiled code each time. Migrator::forgetLoadedFiles() clears the cache.

SchemaGuard

SchemaGuard::ensure(Migrator $migrator, SchemaStateStore $state, string $policy): array is the per-request "is the schema current?" check. It returns ['policy' => …, 'pending' => int, 'applied' => int].

When the store remembers the current fingerprint, it answers at once with nothing pending. Otherwise it asks the migrator, applies pending steps if the policy allows, and records the fingerprint once nothing is pending. Adding, removing or editing a migration file, or an add-on bringing its directory in, changes the fingerprint, so the full check runs once more.

An unknown policy throws InvalidArgumentException rather than quietly behaving like manual. SchemaGuard::normalizePolicy() and SchemaGuard::allows($policy, $engine) are public for plugins that want to check a setting early.

Two stores:

• new KvSchemaState(new KvStore($db, $tables), 'migrations.complete') keeps the fingerprint in the plugin's KV table (Forum Pro's arrangement). The answer lives in the database it describes, and a missing KV table on a fresh database reads as "not recorded".
• new CallbackSchemaState($get, $set) hands it to two closures (KahunaCart keeps it in Grav's cache so bin/grav clear forces a recheck). Fold the database target into the cache key, or a site pointed at a fresh database would trust an answer about the old one.

Call ensure() outside any open transaction.

InfraTables

InfraTables::kv|jobs|rateLimits(Dialect $d, KitTables $t) return migration step closures that create the tables the kit's classes use, under the names in KitTables:

• kv: kv_key VARCHAR(64) primary key, kv_value TEXT NULL, updated_at BIGINT.
• jobs: id, type, payload_json, run_after, attempts, max_attempts, locked_at, locked_by, completed_at, last_error, created_at, cancel_requested_at, cancelled_at, dedupe_key, with indexes ix_{jobs}_pending (completed_at, run_after) and ix_{jobs}_dedupe (dedupe_key, completed_at). This is KahunaCart's kahunacart_jobs after its migrations 0001, 0049 and 0077, without the store scope. On a table that already exists in an older layout it adds the missing columns and indexes in place.
• rateLimits: id, bucket VARCHAR(64), rl_key VARCHAR(190), window_start BIGINT, hits, UNIQUE (bucket, rl_key, window_start) and ix_{table}_window (window_start). An existing table in another layout is left alone (see switching).

The migrations and locks tables are not here, because the migrator creates them before it runs anything.

Lease

A named, expiring lock held as one row in the locks table. It replaces the four copies of the same code in KahunaCart and Forum Pro.

An expired row is taken over in place, so a process that died holding a lease blocks others for at most its TTL. Every acquisition gets its own owner string (the configured owner plus a random tail), and release() only deletes the row this object took, so two leases in one request never release each other's. No step depends on catching a failed insert, which keeps a lease usable inside an open PostgreSQL transaction and lets real errors (a deadlock) reach the caller instead of reading as "busy".

KvStore, RateLimiter, UnsubscribeSigner, Clock

KvStore($db, $tables, $clock) holds installation-scoped values: get, set, delete and remember($key, $create). remember writes insert-if-absent and reads back, so two first requests agree on one value (a secret that changed under a link already sent would break the link). Keys are 1 to 64 bytes; a longer one is refused rather than cut.

RateLimiter($db, $tables, $pruneOdds = 50, $clock) is KahunaCart's fixed-window limiter:

hit(bucket, key, limit, window, ?now) returns a RateLimitResult (allowed, remaining, retryAfter). Windows are aligned to the epoch; a denied call still counts; a limit of zero or less turns the bucket off and costs no queries. One row per bucket and key is rolled forward from window to window, and old rows in the calling bucket are swept on roughly one call in $pruneOdds (0 turns that off). A bucket has one window length, because the sweep works out its cutoff from the calling window. prune($before, ?$bucket) drops windows that started before a time, in one bucket or in all of them. Keys longer than 190 bytes are stored as their SHA-256. anonymize($value) hashes an IP or email for use as a key.

UnsubscribeSigner($kv, $secretKey = 'unsubscribe_secret') signs one-click unsubscribe links: sign(string $subject, string $scope) and verify($subject, $scope, $token). The token is an HMAC-SHA256 over {subject}|{scope} with a secret created once in the KV store. A scope may not contain |.

Clock is one method, now(): int. SystemClock is time(). Every class that decides by time takes an optional Clock, and tests pass Testing\FrozenClock.

Events

EventSink::emit(string $event, array $payload): void receives domain events after the write's transaction commits. Names are dotted (ticket.created), payloads flat, and a sink must never throw.

CompositeSink fans one emission out to several sinks. A sink that throws is caught and the others still run. withErrorReporter(fn (Throwable $e, string $event, EventSink $sink) => $log->error(…)) returns a copy that reports those failures (a reporter that throws is ignored too). add($sink) appends one. NullSink discards everything.

Testing helpers

• EngineProvider($envPrefix = 'GRAVDBKIT_TEST', $tablePrefixes = ['kit_'], $options) builds a fresh empty database for the engine the environment selects: {PREFIX}_ENGINE is sqlite (default), mysql or pgsql, and {PREFIX}_MYSQL_DSN/_USER/_PASS, {PREFIX}_PGSQL_DSN/_USER/_PASS reach the servers. On a server it drops every table under the given prefixes first. SQLite gets a new temporary file, removed at exit. sibling() opens a second connection to the same database for contention tests. Asking for a server engine without its DSN throws: a run meant to cover MySQL must not pass by covering nothing. available($engine) is there for tests that only want a server when one is configured.
• MigratedDatabase($paths, $tables, $engines, $options, $envPrefix) gives a migrated database per test. On SQLite it migrates once, snapshots the result as SQL and replays it into a new in-memory database for each call (milliseconds instead of a full migration run). On a server engine it drops and migrates every time. {PREFIX}_MIGRATE_EACH=1 skips the snapshot when a migration itself is under test.
• SpySink records events (of($event), names(), reset()), and $explode = true makes it throw.
• FrozenClock has set() and advance().

Running the kit's own tests

A local MariaDB whose root account uses unix_socket auth is reachable through its socket as your own OS user. CI runs all three engines on PHP 8.3 and 8.4.

tests/Integration/AdoptionTest.php needs real Forum Pro and KahunaCart databases. It looks for them under ~/workspace/grav-forum and ~/workspace/grav-kahunacart (override with GRAVDBKIT_ADOPT_FORUM_DB, GRAVDBKIT_ADOPT_FORUM_PLUGIN, GRAVDBKIT_ADOPT_KAHUNACART_DB, GRAVDBKIT_ADOPT_KAHUNACART_PLUGIN) and skips, saying where it looked, when they are missing. It only ever copies the originals.

Bundling with Strauss

Grav loads every plugin's autoloader into one process, so each plugin bundles its own copy of the kit under its own namespace prefix (TrilbyMedia\GravDbKit\… becomes, for example, Grav\Plugin\HelpdeskPro\Vendor\TrilbyMedia\GravDbKit\…). The kit is written so that works: no global state shared between copies, no class_exists() checks against its own unprefixed names, and no class names built from strings. Refer to kit classes with use statements and ::class, which Strauss rewrites, including in migration files.

The exact Strauss config, commands, .gitignore rules and verification steps are in docs/packaging.md; composer packaging-check runs the harness that proves two prefixed copies coexist.

Changes from the in-tree copies

Public class and method names follow KahunaCart's, with these differences:

• Connection::__construct(PDO, Dialect, ?KitOptions): the savepoint prefix comes from KitOptions and defaults to sp_ (KahunaCart hard-coded cp_sp_, Forum Pro fp_sp_). New inTransaction() and options().
• ConnectionFactory::create/sqlite/mysql/pgsql/fromPdo take a trailing ?KitOptions; mysql() also accepts unix_socket.
• Migrator::__construct(Connection, string|array $paths, ?KitTables, ?KitOptions): table names come from KitTables, the lock TTL from KitOptions (the private LOCK_TTL constant is gone), and the run-lock is a Lease, whose owner string carries a random tail per acquisition. New connection() and tables().
• RateLimiter moved from KahunaCart's Security namespace to Support. Its constructor is (Connection, ?KitTables, int $pruneOdds = 50, ?Clock), so pruneOdds: as a named argument still works but not as the second positional one. The TABLE constant is gone (use KitTables::$rateLimits), and the table stores bucket and key in two columns (bucket, rl_key) instead of one joined key. Its insert is an insert-if-absent rather than a caught duplicate.
• Forum Pro's RateLimiter::hit(string $key, int $window, int $max): bool becomes hit($bucket, $key, $limit, $window)->allowed, and prune() becomes prune(int $before, ?string $bucket = null).
• KvStore (Forum Pro's) takes ?KitTables and ?Clock, gains delete(), refuses keys over 64 bytes, and remember() no longer lets a second writer replace the first value.
• UnsubscribeSigner::sign(string $subject, string $scope) takes a string subject instead of Forum Pro's int $userId. The token for (string)$userId is byte-for-byte the one Forum Pro issued.
• CompositeSink gains withErrorReporter(), add() and sinks().
• SchemaGuard, Lease, KitTables, KitOptions, InfraTables and the Testing classes are new. KahunaCart's SettingsTable and money conventions stay in KahunaCart.

Switching an existing plugin

A plugin moves to the kit without moving any data: it passes the table names and savepoint prefix it already uses.

1. Require getgrav/grav-db-kit and set up the Strauss prefix.
2. Build the connection through the kit's ConnectionFactory with the plugin's KitOptions, and pass the plugin's KitTables to the Migrator, Lease, KvStore, RateLimiter and job queue.
3. In every migration file, point the three use lines at the kit (…\Database\Connection, …\Database\Dialect\Dialect, …\Database\Migration). Nothing else in a migration file changes, and no step re-runs: the tracking rows are keyed by migration and step name, which stay the same.
4. Point every other use …\Database\Connection (repositories, services, tests) at the kit, and delete the in-tree classes/Database (except anything plugin-specific, such as KahunaCart's SettingsTable).
5. Replace the in-tree lease code and ensureMigrated()/autoMigrate() with Lease and SchemaGuard::ensure().
6. If the plugin uses the kit's job queue, append a step with InfraTables::jobs($d, $tables), which brings an older jobs table forward in place. If it uses the kit's RateLimiter, replace its rate-limit table as described below.

AdoptionTest checks steps 2 and 3 against copies of real databases. For each plugin, the kit's migrator reports exactly the pending steps the plugin's own migrator reports, applies exactly those, and reports zero pending on a database the plugin itself brought current, without re-running anything.

Forum Pro

• KitTables(migrations: 'forum_migrations', locks: 'forum_locks', kv: 'forum_kv', jobs: 'forum_jobs', rateLimits: 'forum_rate_limits') and KitOptions(savepointPrefix: 'fp_sp_').
• 26 migration files change their three use lines. About 77 files in classes/, forum-pro.php and tests/ import Grav\Plugin\ForumPro\Database\….
• ForumPro::ensureMigrated() becomes SchemaGuard::ensure($migrator, new KvSchemaState(new KvStore($db, $tables)), $policy). The same migrations.complete row is used; Forum Pro's stored value is a different hash, so the first request after the switch runs the full check once (and finds nothing to do).
• forum_jobs predates the dedupe and cancellation columns. A new step with InfraTables::jobs() adds them.
• forum_rate_limits has no bucket column and its unique key is (rl_key, window_start), so it cannot be upgraded in place. Most rows are counters that expire within minutes, but ViewCounter also buffers unflushed topic view counts there under views:topic:* keys. The switching migration should rename the old table, create the new one with InfraTables::rateLimits(), copy the views:% rows across as bucket views (or flush them first), and drop the old table. ViewCounter then reads and writes bucket = 'views', and every hit('prefix:…', $window, $max) call becomes hit('prefix', '…', $max, $window)->allowed. The kit's prune() has no exception for view rows, so ViewCounter must flush before rows age out, or keep its own prune.
• Unsubscribe links already sent keep verifying: pass the user id as a string.

KahunaCart

• KitTables::withPrefix('kahunacart') and KitOptions(savepointPrefix: 'cp_sp_'). KahunaCart has no KV table, so it keeps its Grav-cache schema state through CallbackSchemaState, and needs InfraTables::kv() only if it adopts KvStore.
• 83 migration files change their three use lines. Migration 0061 also calls Grav\Plugin\KahunaCart\Database\SettingsTable::upsert(), which stays in KahunaCart and must type-hint the kit's Connection. About 149 files in classes/ and kahunacart.php import Grav\Plugin\KahunaCart\Database\….
• Add-ons are the largest part of the switch. Their migration files implement KahunaCart's Migration interface and their code type-hints KahunaCart's Connection: bookings (24 files), dummy (4), licenses (20), newsletters (65), rentals (10), shipping (14), subscriptions (24). Once KahunaCart bundles the kit under its Strauss prefix, those names change, so the add-ons must be released in step with KahunaCart. KahunaCart 1.3 decouples them with class_alias() shims for the old Database\*, Jobs\* and Security\RateLimitResult names pointing at the bundled kit classes, registered all at once (see "Switching Forum Pro and KahunaCart later" in docs/packaging.md for why not lazily), plus thin wrappers for Migrator and RateLimiter, whose old constructors add-on tests still call. Add-ons run unchanged.
• The catalog index drain (IndexBuilder) and the refund lock (TransactionRepository::withOrderLock) become Lease calls. The refund lock keeps throwing its own RefundLocked on acquire() === false.
• kahunacart_rate_limits keeps bucket and key joined in one key primary key. Its rows are pure counters, so the switching migration can drop it and recreate it with InfraTables::rateLimits(). Callers change from Security\RateLimiter to Support\RateLimiter with the same hit() arguments.
• kahunacart_jobs already has every column InfraTables::jobs() creates (plus store_id, which the kit leaves alone).

License

MIT, Copyright (c) 2026 Trilby Media, LLC. See LICENSE.