MySQL

Async MySQL database client for ReactPHP.

This is a MySQL database driver for ReactPHP. It implements the MySQL protocol and allows you to access your existing MySQL database. It is written in pure PHP and does not require any extensions.

Table of contents

Quickstart example
Usage
- Factory
  - createConnection()
  - createLazyConnection()
- ConnectionInterface
  - query()
  - queryStream()
  - ping()
  - quit()
  - close()
  - Events
Install
Tests
License

Quickstart example

This example runs a simple SELECT query and dumps all the records from a book table:

$loop = React\EventLoop\Factory::create();
$factory = new Factory($loop);

$uri = 'test:test@localhost/test';
$connection = $factory->createLazyConnection($uri);

$connection->query('SELECT * FROM book')->then(
    function (QueryResult $command) {
        print_r($command->resultFields);
        print_r($command->resultRows);
        echo count($command->resultRows) . ' row(s) in set' . PHP_EOL;
    },
    function (Exception $error) {
        echo 'Error: ' . $error->getMessage() . PHP_EOL;
    }
);

$connection->quit();

$loop->run();

See also the examples.

Usage

Factory

The Factory is responsible for creating your ConnectionInterface instance. It also registers everything with the main EventLoop.

$loop = \React\EventLoop\Factory::create();
$factory = new Factory($loop);

If you need custom connector settings (DNS resolution, TLS parameters, timeouts, proxy servers etc.), you can explicitly pass a custom instance of the ConnectorInterface:

$connector = new \React\Socket\Connector($loop, array(
    'dns' => '127.0.0.1',
    'tcp' => array(
        'bindto' => '192.168.10.1:0'
    ),
    'tls' => array(
        'verify_peer' => false,
        'verify_peer_name' => false
    )
));

$factory = new Factory($loop, $connector);

createConnection()

The createConnection(string $url): PromiseInterface<ConnectionInterface, Exception> method can be used to create a new ConnectionInterface.

It helps with establishing a TCP/IP connection to your MySQL database and issuing the initial authentication handshake.

$factory->createConnection($url)->then(
    function (ConnectionInterface $connection) {
        // client connection established (and authenticated)
    },
    function (Exception $e) {
        // an error occured while trying to connect or authorize client
    }
);

The method returns a Promise that will resolve with a ConnectionInterface instance on success or will reject with an Exception if the URL is invalid or the connection or authentication fails.

The returned Promise is implemented in such a way that it can be cancelled when it is still pending. Cancelling a pending promise will reject its value with an Exception and will cancel the underlying TCP/IP connection attempt and/or MySQL authentication.

$promise = $factory->createConnection($url);

$loop->addTimer(3.0, function () use ($promise) {
    $promise->cancel();
});

The $url parameter must contain the database host, optional authentication, port and database to connect to:

$factory->createConnection('user:secret@localhost:3306/database');

You can omit the port if you're connecting to default port 3306:

$factory->createConnection('user:secret@localhost/database');

If you do not include authentication and/or database, then this method will default to trying to connect as user root with an empty password and no database selected. This may be useful when initially setting up a database, but likely to yield an authentication error in a production system:

$factory->createConnection('localhost');

This method respects PHP's default_socket_timeout setting (default 60s) as a timeout for establishing the connection and waiting for successful authentication. You can explicitly pass a custom timeout value in seconds (or use a negative number to not apply a timeout) like this:

$factory->createConnection('localhost?timeout=0.5');

createLazyConnection()

Creates a new connection.

It helps with establishing a TCP/IP connection to your MySQL database and issuing the initial authentication handshake.

$connection = $factory->createLazyConnection($url);

$connection->query(…);

This method immediately returns a "virtual" connection implementing the ConnectionInterface that can be used to interface with your MySQL database. Internally, it lazily creates the underlying database connection only on demand once the first request is invoked on this instance and will queue all outstanding requests until the underlying connection is ready. Additionally, it will only keep this underlying connection in an "idle" state for 60s by default and will automatically end the underlying connection when it is no longer needed.

From a consumer side this means that you can start sending queries to the database right away while the underlying connection may still be outstanding. Because creating this underlying connection may take some time, it will enqueue all oustanding commands and will ensure that all commands will be executed in correct order once the connection is ready. In other words, this "virtual" connection behaves just like a "real" connection as described in the ConnectionInterface and frees you from having to deal with its async resolution.

If the underlying database connection fails, it will reject all outstanding commands and will return to the initial "idle" state. This means that you can keep sending additional commands at a later time which will again try to open a new underlying connection. Note that this may require special care if you're using transactions that are kept open for longer than the idle period.

Note that creating the underlying connection will be deferred until the first request is invoked. Accordingly, any eventual connection issues will be detected once this instance is first used. You can use the quit() method to ensure that the "virtual" connection will be soft-closed and no further commands can be enqueued. Similarly, calling quit() on this instance when not currently connected will succeed immediately and will not have to wait for an actual underlying connection.

Depending on your particular use case, you may prefer this method or the underlying createConnection() which resolves with a promise. For many simple use cases it may be easier to create a lazy connection.

The $url parameter must contain the database host, optional authentication, port and database to connect to:

$factory->createLazyConnection('user:secret@localhost:3306/database');

You can omit the port if you're connecting to default port 3306:

$factory->createLazyConnection('user:secret@localhost/database');

If you do not include authentication and/or database, then this method will default to trying to connect as user root with an empty password and no database selected. This may be useful when initially setting up a database, but likely to yield an authentication error in a production system:

$factory->createLazyConnection('localhost');

This method respects PHP's default_socket_timeout setting (default 60s) as a timeout for establishing the underlying connection and waiting for successful authentication. You can explicitly pass a custom timeout value in seconds (or use a negative number to not apply a timeout) like this:

$factory->createLazyConnection('localhost?timeout=0.5');

By default, this method will keep "idle" connection open for 60s and will then end the underlying connection. The next request after an "idle" connection ended will automatically create a new underlying connection. This ensure you always get a "fresh" connection and as such should not be confused with a "keepalive" or "heartbeat" mechanism, as this will not actively try to probe the connection. You can explicitly pass a custom idle timeout value in seconds (or use a negative number to not apply a timeout) like this:

$factory->createLazyConnection('localhost?idle=0.1');

ConnectionInterface

The ConnectionInterface represents a connection that is responsible for communicating with your MySQL server instance, managing the connection state and sending your database queries.

query()

The query(string $query, array $params = array()): PromiseInterface method can be used to perform an async query.

This method returns a promise that will resolve with a QueryResult on success or will reject with an Exception on error. The MySQL protocol is inherently sequential, so that all queries will be performed in order and outstanding queries will be put into a queue to be executed once the previous queries are completed.

$connection->query('CREATE TABLE test ...');
$connection->query('INSERT INTO test (id) VALUES (1)');

If this SQL statement returns a result set (such as from a SELECT statement), this method will buffer everything in memory until the result set is completed and will then resolve the resulting promise. This is the preferred method if you know your result set to not exceed a few dozens or hundreds of rows. If the size of your result set is either unknown or known to be too large to fit into memory, you should use the queryStream() method instead.

$connection->query($query)->then(function (QueryResult $command) {
    if (isset($command->resultRows)) {
        // this is a response to a SELECT etc. with some rows (0+)
        print_r($command->resultFields);
        print_r($command->resultRows);
        echo count($command->resultRows) . ' row(s) in set' . PHP_EOL;
    } else {
        // this is an OK message in response to an UPDATE etc.
        if ($command->insertId !== 0) {
            var_dump('last insert ID', $command->insertId);
        }
        echo 'Query OK, ' . $command->affectedRows . ' row(s) affected' . PHP_EOL;
    }
}, function (Exception $error) {
    // the query was not executed successfully
    echo 'Error: ' . $error->getMessage() . PHP_EOL;
});

You can optionally pass an array of $params that will be bound to the query like this:

$connection->query('SELECT * FROM user WHERE id > ?', [$id]);

The given $sql parameter MUST contain a single statement. Support for multiple statements is disabled for security reasons because it could allow for possible SQL injection attacks and this API is not suited for exposing multiple possible results.

queryStream()

The queryStream(string $sql, array $params = array()): ReadableStreamInterface method can be used to perform an async query and stream the rows of the result set.

This method returns a readable stream that will emit each row of the result set as a data event. It will only buffer data to complete a single row in memory and will not store the whole result set. This allows you to process result sets of unlimited size that would not otherwise fit into memory. If you know your result set to not exceed a few dozens or hundreds of rows, you may want to use the query() method instead.

$stream = $connection->queryStream('SELECT * FROM user');
$stream->on('data', function ($row) {
    echo $row['name'] . PHP_EOL;
});
$stream->on('end', function () {
    echo 'Completed.';
});

You can optionally pass an array of $params that will be bound to the query like this:

$stream = $connection->queryStream('SELECT * FROM user WHERE id > ?', [$id]);

This method is specifically designed for queries that return a result set (such as from a SELECT or EXPLAIN statement). Queries that do not return a result set (such as a UPDATE or INSERT statement) will not emit any data events.

See also ReadableStreamInterface for more details about how readable streams can be used in ReactPHP. For example, you can also use its pipe() method to forward the result set rows to a WritableStreamInterface like this:

$connection->queryStream('SELECT * FROM user')->pipe($formatter)->pipe($logger);

Note that as per the underlying stream definition, calling pause() and resume() on this stream is advisory-only, i.e. the stream MAY continue emitting some data until the underlying network buffer is drained. Also notice that the server side limits how long a connection is allowed to be in a state that has outgoing data. Special care should be taken to ensure the stream is resumed in time. This implies that using pipe() with a slow destination stream may cause the connection to abort after a while.

The given $sql parameter MUST contain a single statement. Support for multiple statements is disabled for security reasons because it could allow for possible SQL injection attacks and this API is not suited for exposing multiple possible results.

ping()

The ping(): PromiseInterface<void, Exception> method can be used to check that the connection is alive.

This method returns a promise that will resolve (with a void value) on success or will reject with an Exception on error. The MySQL protocol is inherently sequential, so that all commands will be performed in order and outstanding command will be put into a queue to be executed once the previous queries are completed.

$connection->ping()->then(function () {
    echo 'OK' . PHP_EOL;
}, function (Exception $e) {
    echo 'Error: ' . $e->getMessage() . PHP_EOL;
});

quit()

The quit(): PromiseInterface<void, Exception> method can be used to quit (soft-close) the connection.

This method returns a promise that will resolve (with a void value) on success or will reject with an Exception on error. The MySQL protocol is inherently sequential, so that all commands will be performed in order and outstanding commands will be put into a queue to be executed once the previous commands are completed.

$connection->query('CREATE TABLE test ...');
$connection->quit();

close()

The close(): void method can be used to force-close the connection.

Unlike the quit() method, this method will immediately force-close the connection and reject all oustanding commands.

$connection->close();

Forcefully closing the connection will yield a warning in the server logs and should generally only be used as a last resort. See also quit() as a safe alternative.

Events

Besides defining a few methods, this interface also implements the EventEmitterInterface which allows you to react to certain events:

error event

The error event will be emitted once a fatal error occurs, such as when the connection is lost or is invalid. The event receives a single Exception argument for the error instance.

$connection->on('error', function (Exception $e) {
    echo 'Error: ' . $e->getMessage() . PHP_EOL;
});

This event will only be triggered for fatal errors and will be followed by closing the connection. It is not to be confused with "soft" errors caused by invalid SQL queries.

close event

The close event will be emitted once the connection closes (terminates).

$connecion->on('close', function () {
    echo 'Connection closed' . PHP_EOL;
});

See also the close() method.

Install

The recommended way to install this library is through Composer. New to Composer?

This will install the latest supported version:

$ composer require react/mysql:^0.5

See also the CHANGELOG for details about version upgrades.

This project aims to run on any platform and thus does not require any PHP extensions and supports running on legacy PHP 5.4 through current PHP 7+ and HHVM. It's highly recommended to use PHP 7+ for this project.

Tests

To run the test suite, you first need to clone this repo and then install all dependencies through Composer:

$ composer install

The test suite contains a number of functional integration tests that send actual test SQL queries against your local database and thus rely on a local MySQL test database with appropriate write access. The test suite creates and modifies a test table in this database, so make sure to not use a production database! You can change your test database credentials by passing these ENV variables:

$ export DB_HOST=localhost
$ export DB_PORT=3306
$ export DB_USER=test
$ export DB_PASSWD=test
$ export DB_DBNAME=test

For example, to create an empty test database, you can also use a temporary mysql Docker image like this:

$ docker run -it --rm --net=host \
    -e MYSQL_RANDOM_ROOT_PASSWORD=yes -e MYSQL_DATABASE=test \
    -e MYSQL_USER=test -e MYSQL_PASSWORD=test mysql

To run the test suite, go to the project root and run:

$ php vendor/bin/phpunit

License

MIT, see LICENSE file.

This is a community project now managed by @friends-of-reactphp. The original implementation was created by @bixuehujin starting in 2013 and has been migrated to @friends-of-reactphp in 2018 to help with maintenance and upcoming feature development.

The original implementation was made possible thanks to the following projects:

phpdaemon: the MySQL protocol implementation is based on code of this project (with permission).
node-mysql: the API design is inspired by this project.

License

friends-of-reactphp/mysql

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