php - Symfony:动态更改数据库

Question

假设我有 3 个数据库:

• prefix_db1
• prefix_db2
• prefix_db3
  

我想从这样的 url 动态连接到它们 http://localhost/my-project/web/app_dev.php/db1/books 所以我知道要连接到哪个数据库来自 url(在本例中为 prefix_db1)
基本上，我们的想法是准备一个监听器，它将随每个 http 请求 一起触发，从 url 中获取数据库名称，然后覆盖 doctrin 的参数，如下所示:
在 services.yml 中:

dynamic_connection:
        class: AppBundle\service\DynamicDBConnector
        arguments:  ['@request_stack']
        calls:
            - [ setDoctrineConnection, ['@doctrine.dbal.default_connection'] ]
        tags:
            - { name: kernel.event_listener, event: kernel.request, method: onKernelRequest }

我的听众:

<?php    
namespace AppBundle\service;

use Doctrine\DBAL\Connection;
use Symfony\Component\HttpFoundation\RequestStack;
use Exception;

class DynamicDBConnector
{
    /**
     * @var Connection
     */
    private $connection;

    /*
     * @var Request
     */
    private $request;


    public function __construct(RequestStack $requestStack)
    {
        $this->request = $requestStack->getCurrentRequest();

    }

    /**
     * Sets the DB Name prefix to use when selecting the database to connect to
     *
     * @param  Connection       $connection
     * @return DynamicDBConnector $this
     */
    public function setDoctrineConnection(Connection $connection)
    {
        $this->connection = $connection;
        return $this;
    }

    public function onKernelRequest()
    {
        if ($this->request->attributes->has('_company')) {

            $connection = $this->connection;
            $params     = $this->connection->getParams();

            $companyName = $this->request->get('_company');
            // I did the concatenation here because in paramaters.yml I just put the prefix (database_name: prefix_) so after the concatenation I get the whole database name "prefix_db1"
            $params['dbname'] = $params['dbname'] . $companyName;

            // Set up the parameters for the parent
            $connection->__construct(
                $params,
                $connection->getDriver(),
                $connection->getConfiguration(),
                $connection->getEventManager()
            );

            try {
                $connection->connect();
            } catch (Exception $e) {
                // log and handle exception
            }
        }

        return $this;
    }
}

现在效果很好，我已经使用一个简单的书籍列表对其进行了测试，每次更改 url 时，我都会获得与每个数据库相关的列表:

http://localhost/my-project/web/app_dev.php/db1/books // I get books of database prefix_db1

http://localhost/my-project/web/app_dev.php/db2/books // I get books of database prefix_db2

现在让我们开始讨论问题吧:):
现在的问题是，当我使用身份验证系统保护我的项目并尝试使用此 url http://localhost/my-project/web 登录(当然每个数据库都有 user 表)时/app_dev.php/db1/login我得到这个异常:

An exception occured in driver: SQLSTATE[HY000] [1049] Base 'prefix_' unknown

如你所见，symfony 尝试使用 parameters.yml 中声明的 database_name 登录用户，这意味着 symfony 的 security_checker 具有在我的听众之前和覆盖 Doctrine 的 params 之前被解雇。

我的问题:
有没有办法在任何其他 http 请求监听器之前触发我的监听器？或者可能是一种替代解决方案，以确保对数据库的任何请求都必须使用正确的数据库名称。
很抱歉发了这么长的帖子。

编辑:
来自symfony的官方文档:
https://symfony.com/doc/2.3/cookbook/event_dispatcher/event_listener.html

The other optional tag attribute is called priority, which defaults to 0 and it controls the order in which listeners are executed (the highest the priority, the earlier a listener is executed). This is useful when you need to guarantee that one listener is executed before another. The priorities of the internal Symfony listeners usually range from -255 to 255 but your own listeners can use any positive or negative integer.

我将监听器的优先级设置为 10000:

tags:
    - { name: kernel.event_listener, event: kernel.request, method: onKernelRequest, priority: 10000 }

但问题依然存在，在 symfony 之前仍然无法触发我的监听器!

Answer 1

我找到了解决办法
这个想法是更改 symfony 用来创建数据库连接的默认 Connection 类:

doctrine:
    dbal:
        connections:
            default:
                wrapper_class: AppBundle\Doctrine\DynamicConnection
                driver: pdo_mysql
                host: '%database_host%'
                port: '%database_port%'
                dbname: '%database_name%'
                user: '%database_user%'
                password: '%database_password%'
                charset: UTF8

之后我们可以在构造函数中更改给定的参数:

use Doctrine\DBAL\Connection;
use Doctrine\DBAL\Driver;

class DynamicConnection extends Connection
{
    public function __construct(array $params, Driver $driver, $config, $eventManager)
    {
        $params['dbname'] = 'teqsdqsdqst';
        parent::__construct($params, $driver, $config, $eventManager);
    }
}

现在我们只需要从 url 中获取参数并在 $params['dbname'] 中设置即可。
通过这种方式，我们确保 symfony 将始终使用此类来创建连接，并且我们不再需要使用 http requestes

触发监听器