Php Codeigniter：自动连接到Neo4J数据库

我一直在我的一个个人项目中使用codeigniter 2.x。数据库是MySql，但我决定迁移到Neo4J

我使用了我安装的名为GraphAware的库。到目前为止，它按预期运行。我的测试代码如下：

$user       = 'neo4j';
$password   = 'mypass';
$host       = 'myhost:7474';
$myDB       = 'mydb';

$client = ClientBuilder::create()
        ->addConnection('default','http://'.$user.':'.$password.'@'.$host.'/'.$myDB)
        ->build();

$query = "MATCH (n:user) RETURN n.username";

$result = $client->run($query);

到目前为止还不错

我的问题如下：如何在页面创建时自动连接到neo4j数据库，这样就不必每次都手动创建连接

在我看来，上面的代码会变成这样：

$db = $this->db->load('neo4j');

$query = "MATCH (n:user) RETURN n.username";

$result = $db->run($query);

我一直在codeigniter中搜索，由于缺乏对一些核心概念的理解，我似乎找不到解决方案

你知道如何进行吗

谢谢

---

Loïc.

我的目标是在每次页面加载时自动连接到Neo4J数据库，而不必在每次需要访问数据库时手动连接到数据库。我还担心不修改任何codeigniter系统文件

编辑：更新的解决方案。我的第一个解决方案是有问题的，因为它需要模型调用控制器来获取DB对象。这是不切实际的，并且违反了MVC工作流，在MVC工作流中，应该由控制器调用模型，而不是相反

更新的解决方案：

对于此解决方案，我们需要创建两个方面：

• 新的图书馆课程
• 一个新的控制器类

此外，可选但建议：

• 修改配置文件并插入数据库详细信息和凭据

1）在应用程序/库中创建新的库类

我们希望创建一个库类，它将由我们的新控制器加载和初始化，然后由我们的模型访问

此库仅包含2个函数：

• connect（）：执行到数据库的连接，并将数据库对象保存在私有类变量$neo4j中
• get_db（）：返回保存在函数connect（）中的数据库对象

application/libraries/neo4j.php

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed'); 
require_once 'vendor/autoload.php';
use GraphAware\Neo4j\Client\ClientBuilder;

class Neo4j {
    private $neo4j;

    //connect to the neo4j database
    public function connect(){
        //load CI to access config files 
        $CI = & get_instance();

        //Get database details from the config file.
        $user       = $CI->config->item('username');
        $password   = $CI->config->item('password');
        $host       = $CI->config->item('hostname');
        $port       = $CI->config->item('port');
        $database   = $CI->config->item('database');

        //build connection to db
        $client = ClientBuilder::create()
                ->addConnection('default', 'http://'.$user.':'.$password.'@'.$host.':'.$port)
                ->build();

        //save the connection object in a private class variable
        $this->neo4j    = $client;
    }

    //Returns the connection object to the neo4j database
    public function get_db(){
        return $this->neo4j;
    }
}

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

class Neo4j_controller extends TNK_Controller{

    //connect to neo4j db on instantiation
    function __construct(){
        parent::__construct();
        //load the neo4j library that we created
        $this->load->library('neo4j');
        //connect to the db
        $this->neo4j->connect();
    }
}

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');

$config['hostname'] = 'test.mysite.me';
$config['username'] = 'neo4j';
$config['password'] = 'my_password';
$config['database'] = 'mygraphdb';
$config['port']     = '7474';

/* End of file neo4jDatabase.php */
/* Location: ./application/config/neo4jDatabase.php */

require_once 'vendor/autoload.php';
use GraphAware\Neo4j\Client\ClientBuilder;

class Neo4j_controller extends Your_Normal_Controller{

    private $neo4j;

    //connect to db on instantiation
    function __construct(){
        parent::__construct();

        $this->connect();
    }

    //Connect to the neo4j db
    private function connect(){
       //I'll get these from config file later on
       $user       = 'neo4j';
       $password   = 'mypass';
       $host       = 'myhost:7474';
       $myDB       = 'mydb';

       //build connect to db 
       $client = ClientBuilder::create()
                ->addConnection('default', 'http://'.$user.':'.$password.'@'.$host.'/'.$myDB)
                ->build();
        //save the connection object in a private class variable
        $this->neo4j    = $client;
    }

    //Returns the connection object to the neo4j database
    public function get_db(){
        return $this->neo4j;
    }
}

4）修改配置文件（可选）

我对此有意见。最后，我创建了自己的配置文件neo4jDatabase.php

如果您在创建自己的配置文件或修改当前配置文件时也遇到问题，您仍然可以在neo4j库文件中硬编码数据库数据。这是一个坏习惯，但当它必须起作用时，它必须起作用

neo4jDatabase.php

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed'); 
require_once 'vendor/autoload.php';
use GraphAware\Neo4j\Client\ClientBuilder;

class Neo4j {
    private $neo4j;

    //connect to the neo4j database
    public function connect(){
        //load CI to access config files 
        $CI = & get_instance();

        //Get database details from the config file.
        $user       = $CI->config->item('username');
        $password   = $CI->config->item('password');
        $host       = $CI->config->item('hostname');
        $port       = $CI->config->item('port');
        $database   = $CI->config->item('database');

        //build connection to db
        $client = ClientBuilder::create()
                ->addConnection('default', 'http://'.$user.':'.$password.'@'.$host.':'.$port)
                ->build();

        //save the connection object in a private class variable
        $this->neo4j    = $client;
    }

    //Returns the connection object to the neo4j database
    public function get_db(){
        return $this->neo4j;
    }
}

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

class Neo4j_controller extends TNK_Controller{

    //connect to neo4j db on instantiation
    function __construct(){
        parent::__construct();
        //load the neo4j library that we created
        $this->load->library('neo4j');
        //connect to the db
        $this->neo4j->connect();
    }
}

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');

$config['hostname'] = 'test.mysite.me';
$config['username'] = 'neo4j';
$config['password'] = 'my_password';
$config['database'] = 'mygraphdb';
$config['port']     = '7474';

/* End of file neo4jDatabase.php */
/* Location: ./application/config/neo4jDatabase.php */

require_once 'vendor/autoload.php';
use GraphAware\Neo4j\Client\ClientBuilder;

class Neo4j_controller extends Your_Normal_Controller{

    private $neo4j;

    //connect to db on instantiation
    function __construct(){
        parent::__construct();

        $this->connect();
    }

    //Connect to the neo4j db
    private function connect(){
       //I'll get these from config file later on
       $user       = 'neo4j';
       $password   = 'mypass';
       $host       = 'myhost:7474';
       $myDB       = 'mydb';

       //build connect to db 
       $client = ClientBuilder::create()
                ->addConnection('default', 'http://'.$user.':'.$password.'@'.$host.'/'.$myDB)
                ->build();
        //save the connection object in a private class variable
        $this->neo4j    = $client;
    }

    //Returns the connection object to the neo4j database
    public function get_db(){
        return $this->neo4j;
    }
}

2）使您的普通控制器实例化Neo4j_控制器

class Test extends Neo4j_controller {...}

3） 在控制器（此处称为测试）中，创建一个函数，您将：

• 通过调用$this->Get_DB（）获取DB对象

• 使用该对象执行查询

在我们的测试控制器中创建的函数，用于向neo4j数据库发送查询：

public function db_query(){

    $db = $this->get_db();

    $query = "match (n:user) return n";

    print_r($db->run($query)->getRecords());
  }

调用函数db_query时，它返回用户节点，而不需要我们手动编写任何代码来连接neo4j数据库

---

Loïc.

我的目标是在每次页面加载时自动连接到Neo4J数据库，而不必在每次需要访问数据库时手动连接到数据库。我还担心不修改任何codeigniter系统文件

编辑：更新的解决方案。我的第一个解决方案是有问题的，因为它需要模型调用控制器来获取DB对象。这是不切实际的，并且违反了MVC工作流，在MVC工作流中，应该由控制器调用模型，而不是相反

更新的解决方案：

对于此解决方案，我们需要创建两个方面：

• 新的图书馆课程
• 一个新的控制器类

此外，可选但建议：

• 修改配置文件并插入数据库详细信息和凭据

1）在应用程序/库中创建新的库类

我们希望创建一个库类，它将由我们的新控制器加载和初始化，然后由我们的模型访问

此库仅包含2个函数：

• connect（）：执行到数据库的连接，并将数据库对象保存在私有类变量$neo4j中
• get_db（）：返回保存在函数connect（）中的数据库对象

application/libraries/neo4j.php

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed'); 
require_once 'vendor/autoload.php';
use GraphAware\Neo4j\Client\ClientBuilder;

class Neo4j {
    private $neo4j;

    //connect to the neo4j database
    public function connect(){
        //load CI to access config files 
        $CI = & get_instance();

        //Get database details from the config file.
        $user       = $CI->config->item('username');
        $password   = $CI->config->item('password');
        $host       = $CI->config->item('hostname');
        $port       = $CI->config->item('port');
        $database   = $CI->config->item('database');

        //build connection to db
        $client = ClientBuilder::create()
                ->addConnection('default', 'http://'.$user.':'.$password.'@'.$host.':'.$port)
                ->build();

        //save the connection object in a private class variable
        $this->neo4j    = $client;
    }

    //Returns the connection object to the neo4j database
    public function get_db(){
        return $this->neo4j;
    }
}

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

class Neo4j_controller extends TNK_Controller{

    //connect to neo4j db on instantiation
    function __construct(){
        parent::__construct();
        //load the neo4j library that we created
        $this->load->library('neo4j');
        //connect to the db
        $this->neo4j->connect();
    }
}

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');

$config['hostname'] = 'test.mysite.me';
$config['username'] = 'neo4j';
$config['password'] = 'my_password';
$config['database'] = 'mygraphdb';
$config['port']     = '7474';

/* End of file neo4jDatabase.php */
/* Location: ./application/config/neo4jDatabase.php */

require_once 'vendor/autoload.php';
use GraphAware\Neo4j\Client\ClientBuilder;

class Neo4j_controller extends Your_Normal_Controller{

    private $neo4j;

    //connect to db on instantiation
    function __construct(){
        parent::__construct();

        $this->connect();
    }

    //Connect to the neo4j db
    private function connect(){
       //I'll get these from config file later on
       $user       = 'neo4j';
       $password   = 'mypass';
       $host       = 'myhost:7474';
       $myDB       = 'mydb';

       //build connect to db 
       $client = ClientBuilder::create()
                ->addConnection('default', 'http://'.$user.':'.$password.'@'.$host.'/'.$myDB)
                ->build();
        //save the connection object in a private class variable
        $this->neo4j    = $client;
    }

    //Returns the connection object to the neo4j database
    public function get_db(){
        return $this->neo4j;
    }
}

4）修改配置文件（可选）

我对此有意见。最后，我创建了自己的配置文件neo4jDatabase.php

如果您在创建自己的配置文件或修改当前配置文件时也遇到问题，您仍然可以在neo4j库文件中硬编码数据库数据。这是一个坏习惯，但当它必须起作用时，它必须起作用

neo4jDatabase.php

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed'); 
require_once 'vendor/autoload.php';
use GraphAware\Neo4j\Client\ClientBuilder;

class Neo4j {
    private $neo4j;

    //connect to the neo4j database
    public function connect(){
        //load CI to access config files 
        $CI = & get_instance();

        //Get database details from the config file.
        $user       = $CI->config->item('username');
        $password   = $CI->config->item('password');
        $host       = $CI->config->item('hostname');
        $port       = $CI->config->item('port');
        $database   = $CI->config->item('database');

        //build connection to db
        $client = ClientBuilder::create()
                ->addConnection('default', 'http://'.$user.':'.$password.'@'.$host.':'.$port)
                ->build();

        //save the connection object in a private class variable
        $this->neo4j    = $client;
    }

    //Returns the connection object to the neo4j database
    public function get_db(){
        return $this->neo4j;
    }
}

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

class Neo4j_controller extends TNK_Controller{

    //connect to neo4j db on instantiation
    function __construct(){
        parent::__construct();
        //load the neo4j library that we created
        $this->load->library('neo4j');
        //connect to the db
        $this->neo4j->connect();
    }
}

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');

$config['hostname'] = 'test.mysite.me';
$config['username'] = 'neo4j';
$config['password'] = 'my_password';
$config['database'] = 'mygraphdb';
$config['port']     = '7474';

/* End of file neo4jDatabase.php */
/* Location: ./application/config/neo4jDatabase.php */

require_once 'vendor/autoload.php';
use GraphAware\Neo4j\Client\ClientBuilder;

class Neo4j_controller extends Your_Normal_Controller{

    private $neo4j;

    //connect to db on instantiation
    function __construct(){
        parent::__construct();

        $this->connect();
    }

    //Connect to the neo4j db
    private function connect(){
       //I'll get these from config file later on
       $user       = 'neo4j';
       $password   = 'mypass';
       $host       = 'myhost:7474';
       $myDB       = 'mydb';

       //build connect to db 
       $client = ClientBuilder::create()
                ->addConnection('default', 'http://'.$user.':'.$password.'@'.$host.'/'.$myDB)
                ->build();
        //save the connection object in a private class variable
        $this->neo4j    = $client;
    }

    //Returns the connection object to the neo4j database
    public function get_db(){
        return $this->neo4j;
    }
}

2）使您的普通控制器实例化Neo4j_控制器

class Test extends Neo4j_controller {...}

3） 在控制器（此处称为测试）中，创建一个函数，您将：

• 通过调用$this->Get_DB（）获取DB对象

• 使用该对象执行查询

在我们的测试控制器中创建的函数，用于向neo4j数据库发送查询：

public function db_query(){

    $db = $this->get_db();

    $query = "match (n:user) return n";

    print_r($db->run($query)->getRecords());
  }

调用函数db_query时，它返回用户节点，而不需要我们手动编写任何代码来连接neo4j数据库

---

Loïc.

通常，您会创建一个neo4j服务，该服务将创建一次连接，并在需要时注入该服务。也许在谷歌上寻找Codigniter+DependencyInjection。我是GraphAware客户端的维护者，但我没有CI方面的经验。谢谢你的帮助Christophe，但我知道