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-rw-r--r--core/application.php5
-rw-r--r--core/migrations.php43
-rw-r--r--core/namespace/Application.php14
-rw-r--r--core/namespace/Migrator.php182
4 files changed, 244 insertions, 0 deletions
diff --git a/core/application.php b/core/application.php
index 21ab203..d6c9bd0 100644
--- a/core/application.php
+++ b/core/application.php
@@ -142,6 +142,11 @@ $Language = Application::getLanguage();
$Database = Application::getDatabase();
#===============================================================================
+# Include migration detection
+#===============================================================================
+require 'migrations.php';
+
+#===============================================================================
# Check if "304 Not Modified" and ETag header should be sent
#===============================================================================
if(Application::get('CORE.SEND_304') === TRUE AND !defined('ADMINISTRATION')) {
diff --git a/core/migrations.php b/core/migrations.php
new file mode 100644
index 0000000..f2c9714
--- /dev/null
+++ b/core/migrations.php
@@ -0,0 +1,43 @@
+<?php
+#===============================================================================
+# Get Migrator singleton
+#===============================================================================
+$Migrator = Application::getMigrator();
+
+#===============================================================================
+# Check for outstanding database schema migrations
+#===============================================================================
+if($Migrator->isMigrationNeeded()) {
+ @session_start();
+
+ Application::set('TEMPLATE.NAME', Application::get('ADMIN.TEMPLATE'));
+ Application::set('TEMPLATE.LANG', Application::get('ADMIN.LANGUAGE'));
+ Application::getLanguage(TRUE); // Force recreation of Language object
+
+ if(HTTP::issetPOST(['token' => Application::getSecurityToken()], 'run')) {
+ if(!$migrated = $Migrator->runMigrations()) {
+ Application::exit('CONFUSED: No migrations were performed?!');
+ }
+ }
+
+ $Template = Template\Factory::build('migration');
+ $Template->set('MIGRATION', [
+ 'LIST' => $Migrator->getMigrations(),
+ 'SUCCESSFUL' => $migrated ?? [],
+ 'SCHEMA_VERSION' => [
+ 'DATABASE' => $Migrator->getVersionFromTable(),
+ 'CODEBASE' => $Migrator::CURRENT_SCHEMA_VERSION
+ ],
+ ]);
+
+ Application::exit($Template);
+}
+
+#===============================================================================
+# Check for an unsupported downgrade attempt
+#===============================================================================
+else if($Migrator->isDowngradeAttempt()) {
+ throw new Exception('MIGRATOR: The schema version used by *your* database is
+ higher than the schema version defined in the codebase. It is officially
+ not supported to automatically downgrade the database schema version!');
+}
diff --git a/core/namespace/Application.php b/core/namespace/Application.php
index 3cecf3b..829f758 100644
--- a/core/namespace/Application.php
+++ b/core/namespace/Application.php
@@ -6,6 +6,7 @@ class Application {
#===============================================================================
private static $Database;
private static $Language;
+ private static $Migrator;
private static $repositories = [];
#===============================================================================
@@ -81,6 +82,19 @@ class Application {
}
#===============================================================================
+ # Return singleton Migrator instance
+ #===============================================================================
+ public static function getMigrator(): Migrator {
+ if(!self::$Migrator instanceof Migrator) {
+ $Migrator = new Migrator(self::getDatabase());
+ $Migrator->setMigrationsDir(ROOT.'core/db/migrations/');
+ self::$Migrator = $Migrator;
+ }
+
+ return self::$Migrator;
+ }
+
+ #===============================================================================
# Return singleton repository instance
#===============================================================================
public static function getRepository(string $namespace): Repository {
diff --git a/core/namespace/Migrator.php b/core/namespace/Migrator.php
new file mode 100644
index 0000000..3096862
--- /dev/null
+++ b/core/namespace/Migrator.php
@@ -0,0 +1,182 @@
+<?php
+class Migrator {
+ private $Database;
+ private $version;
+ private $directory;
+ private $migrations = [];
+
+ const CURRENT_SCHEMA_VERSION = 4;
+
+ #===============================================================================
+ # Fetch on-disk schema version from migration table
+ #===============================================================================
+ public function __construct(Database $Database) {
+ $this->Database = $Database;
+
+ try {
+ $Statement = $Database->query('SELECT schema_version FROM migration');
+
+ if(!$this->version = $Statement->fetchColumn()) {
+ throw new Exception('The migration table does exist, but there is
+ no row containing the currently used on-disk schema version!');
+ }
+ } catch(PDOException $Exception) {
+ if($Exception->getCode() === '42S02') /* Table not found */ {
+ $this->version = $this->determineFallbackSchemaVersion();
+ $this->createMigrationTable($this->version);
+ } else {
+ throw $Exception;
+ }
+ }
+ }
+
+ #===============================================================================
+ # Specify the directory which contains the migration files
+ #===============================================================================
+ public function setMigrationsDir(string $directory): void {
+ if(!is_readable($this->directory = rtrim($directory, '/'))) {
+ throw new Exception('Migrator cannot read migration directory.');
+ };
+ }
+
+ #===============================================================================
+ # Check if new migrations needs to be applied
+ #===============================================================================
+ public function isMigrationNeeded(): bool {
+ $databaseSchema = $this->version;
+ $codebaseSchema = self::CURRENT_SCHEMA_VERSION;
+ return $databaseSchema < $codebaseSchema;
+ }
+
+ #===============================================================================
+ # Check if this is an unsupported downgrade attempt
+ #===============================================================================
+ public function isDowngradeAttempt(): bool {
+ $databaseSchema = $this->version;
+ $codebaseSchema = self::CURRENT_SCHEMA_VERSION;
+ return $databaseSchema > $codebaseSchema;
+ }
+
+ #===============================================================================
+ # Add a migration to the queue
+ #===============================================================================
+ private function enqueue(int $sequence, string $migration): void {
+ $this->migrations[$sequence] = $migration;
+ }
+
+ #===============================================================================
+ # Remove a migration from the queue
+ #===============================================================================
+ private function dequeue(int $sequence): void {
+ unset($this->migrations[$sequence]);
+ }
+
+ #===============================================================================
+ # Get the currently used on-disk schema version
+ #===============================================================================
+ public function getVersionFromTable(): int {
+ return $this->version;
+ }
+
+ #===============================================================================
+ # Get an array with all migration commands
+ #===============================================================================
+ public function getMigrations(): array {
+ $databaseSchema = $this->version;
+ $codebaseSchema = self::CURRENT_SCHEMA_VERSION;
+
+ if(!$this->isMigrationNeeded()) {
+ return [];
+ }
+
+ foreach(range($databaseSchema+1, $codebaseSchema) as $number) {
+ $file = sprintf("%s/%d.sql", $this->directory, $number);
+
+ if(!is_readable($file)) {
+ throw new Exception("Migrator cannot read migration file: »{$file}«");
+ }
+ $this->enqueue($number, file_get_contents($file));
+ }
+
+ return $this->migrations;
+ }
+
+ #===============================================================================
+ # Run migrations sequentially
+ #===============================================================================
+ public function runMigrations(): array {
+ foreach($this->getMigrations() as $sequence => $migration) {
+ try {
+ if($this->Database->query($migration)) {
+ $this->dequeue($sequence);
+ $this->updateMigrationTable($sequence);
+ $migrated[] = $sequence;
+ }
+ } catch(PDOException $Exception) {
+ $error = 'Migration from %d to %d failed with PDO error:<br>';
+ $error .= sprintf($error, $sequence-1, $sequence);
+ $error .= sprintf('<code>%s</code>', $Exception->getMessage());
+
+ if(!empty($migrated ?? [])) {
+ $error .= '<br>The following migrations were successful: ';
+ $error .= '<code>'.implode(', ', $migrated).'</code>';
+ }
+
+ throw new Exception($error);
+ }
+ }
+
+ return $migrated ?? [];
+ }
+
+ #===============================================================================
+ # Update the migration table with the specified schema version
+ #===============================================================================
+ private function updateMigrationTable(int $version): int {
+ $query = 'UPDATE migration SET schema_version = ?';
+ $Statement = $this->Database->prepare($query);
+
+ if($Statement->execute([$version])) {
+ return $this->version = $version;
+ }
+ }
+
+ #===============================================================================
+ # Create the migration table with the specified schema version
+ #===============================================================================
+ private function createMigrationTable(int $version): bool {
+ $create = 'CREATE TABLE migration (schema_version smallint(4) NOT NULL)
+ ENGINE=InnoDB DEFAULT CHARSET=utf8mb4';
+ $insert = 'INSERT INTO migration (schema_version) VALUES (?)';
+
+ $this->Database->query($create);
+ $Statement = $this->Database->prepare($insert);
+
+ return $Statement->execute([$version]);
+ }
+
+ #===============================================================================
+ # Determine on-disk schema version if migration table does not exist
+ #===============================================================================
+ private function determineFallbackSchemaVersion(): int {
+ # If the migration table does not yet exist, the user may have upgraded from
+ # an older release of the application and sits somewhere between 0 and 4. So
+ # we run some checks against the tables to determine the schema version.
+ $test[4] = 'SHOW COLUMNS FROM post WHERE Field = "argv" AND Type = "varchar(250)"';
+ $test[3] = 'SHOW INDEX FROM post WHERE Key_name = "search"';
+ $test[2] = 'SHOW INDEX FROM post WHERE Key_name = "time_insert"';
+ $test[1] = 'SHOW COLUMNS FROM post WHERE Field = "argv"';
+
+ foreach($test as $version => $query) {
+ try {
+ $Statement = $this->Database->query($query);
+
+ if ($Statement && $Statement->fetch()) {
+ return $version;
+ }
+ } catch(PDOException $Exception) {}
+ }
+
+ return 0;
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-21 22:42:08 +0000