AlterDatabaseToMultiByteCharset.php

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<?php

namespace Elgg\Upgrades;

use Elgg\Upgrade\AsynchronousUpgrade;
use Elgg\Upgrade\Result;

class AlterDatabaseToMultiByteCharset extends AsynchronousUpgrade {

    private $utf8mb4_tables = [
        // InnoDB
        'access_collection_membership',
        'access_collections',
        'annotations',
        'api_users',
        'config',
        'entities',
        'entity_relationships',
        'metadata',
        'private_settings',
        'queue',
        'river',
        'system_log',
        'users_remember_me_cookies',
        'users_sessions',
        // MEMORY
        'hmac_cache',
        'users_apisessions',
    ];

    // Columns with utf8 encoding and utf8_general_ci collation
    // $table => [
    //   $column => $index
    // ]

    private $non_mb4_columns = [
        'config' => [
            'name' => [
                'primary' => true,
                'name' => 'name',
                'unique' => false,
            ],
        ],
        'entities' => [
            'subtype' => [
                'primary' => false,
                'name' => 'subtype',
                'unique' => false,
            ],
        ],
        'queue' => [
            'name' => [
                'primary' => false,
                'name' => "name",
                'unique' => false,
            ],
        ],
        'users_sessions' => [
            'session' => [
                'primary' => true,
                'name' => 'session',
                'unique' => false,
            ],
        ],
        'hmac_cache' => [
            'hmac' => [
                'primary' => true,
                'name' => 'hmac',
                'unique' => false,
            ],
        ],
        'system_log' => [
            'object_class' => [
                'primary' => false,
                'name' => 'object_class',
                'unique' => false,
            ],
            'object_type' => [
                'primary' => false,
                'name' => 'object_type',
                'unique' => false,
            ],
            'object_subtype' => [
                'primary' => false,
                'name' => 'object_subtype',
                'unique' => false,
            ],
            'event' => [
                'primary' => false,
                'name' => 'event',
                'unique' => false,
            ],
            'river_key' => [
                'primary' => false,
                'name' => 'river_key',
                'unique' => false,
                'columns' => ['object_type', 'object_subtype', 'event']
            ],
        ]
    ];

    public function getVersion(): int {
        return 2017080900;
    }

    public function needsIncrementOffset(): bool {
        return false;
    }

    public function shouldBeSkipped(): bool {

        $config = _elgg_services()->dbConfig->getConnectionConfig();
        $rows = _elgg_services()->db->getConnection('read')->executeQuery("SHOW TABLE STATUS FROM `{$config['database']}`");

        $prefixed_table_names = array_map(function ($t) use ($config) {
            return "{$config['prefix']}{$t}";
        }, $this->utf8mb4_tables);

        foreach ($rows->fetchAllAssociative() as $row) {
            $row = (object) $row;
            if (in_array($row->Name, $prefixed_table_names) && $row->Collation !== 'utf8mb4_general_ci') {
                return false;
            }
        }

        return true;
    }

    public function countItems(): int {
        return 1;
    }

    public function run(Result $result, $offset): Result {

        $config = _elgg_services()->dbConfig->getConnectionConfig();

        try {
            // check if we need to change a global variable
            $db_result = _elgg_services()->db->getConnection('read')->executeQuery("SHOW GLOBAL VARIABLES LIKE 'innodb_large_prefix'");
            $rows = $db_result->fetchAllAssociative();
            
            if (empty($rows) || $rows[0]['Value'] === 'OFF') {
                // required to allow bigger index sizes required for utf8mb4
                _elgg_services()->db->getConnection('write')->executeStatement("SET GLOBAL innodb_large_prefix = 'ON'");
            }
        } catch (\Exception $e) {
            // something went wrong, maybe database permissions, or version
            $result->addFailures();
            $result->addError("Failure to set 'innodb_large_prefix'. Ask your database administrator for more information.");
            $result->addError("Alternatively ask the database administrator to (temporarily) set 'innodb_large_prefix' to 'ON'.");
            $result->addError($e->getMessage());
            
            return $result;
        }
        
        try {
            // alter table structure
            $connection = _elgg_services()->db->getConnection('write');
            $connection->executeStatement("
                ALTER DATABASE
                `{$config['database']}`
                CHARACTER SET = utf8mb4
                COLLATE = utf8mb4_unicode_ci
            ");

            foreach ($this->utf8mb4_tables as $table) {
                if (!empty($this->non_mb4_columns[$table])) {
                    foreach ($this->non_mb4_columns[$table] as $column => $index) {
                        if ($index) {
                            if ($index['primary']) {
                                $connection->executeStatement("
                                    ALTER TABLE {$config['prefix']}{$table}
                                    DROP PRIMARY KEY
                                ");
                            } else {
                                $connection->executeStatement("
                                    ALTER TABLE {$config['prefix']}{$table}
                                    DROP KEY {$index['name']}
                                ");
                            }
                        }
                    }
                }

                $connection->executeStatement("
                    ALTER TABLE {$config['prefix']}{$table}
                    ROW_FORMAT=DYNAMIC
                ");

                $connection->executeStatement("
                    ALTER TABLE {$config['prefix']}{$table}
                    CONVERT TO CHARACTER SET utf8mb4
                    COLLATE utf8mb4_general_ci
                ");

                if (!empty($this->non_mb4_columns[$table])) {
                    foreach ($this->non_mb4_columns[$table] as $column => $index) {
                        if (empty($index['columns'])) {
                            // Alter table only if the key is not composite
                            $connection->executeStatement("
                                ALTER TABLE {$config['prefix']}{$table}
                                MODIFY $column VARCHAR(255)
                                CHARACTER SET utf8
                                COLLATE utf8_unicode_ci
                            ");
                        }

                        if (!$index) {
                            continue;
                        }

                        $sql = "ADD";
                        if ($index['unique']) {
                            $sql .= " UNIQUE ({$index['name']})";
                        } else if ($index['primary']) {
                            $sql .= " PRIMARY KEY ({$index['name']})";
                        } else {
                            $key_columns = elgg_extract('columns', $index, [$column]);
                            $key_columns = implode(',', $key_columns);
                            $sql .= " KEY {$index['name']} ($key_columns)";
                        }

                        $connection->executeStatement("
                            ALTER TABLE {$config['prefix']}{$table}
                            $sql
                        ");
                    }
                }
            }
        } catch (\Exception $e) {
            $result->addFailures();
            $result->addError($e->getMessage());
            
            return $result;
        }

        $result->addSuccesses();

        return $result;
    }
}