Recently in one of my Laravel project, I had a situation where some of the tables are required to copy from one db server to other db server on real time basis.

First of all I thought about using binary logging but it, but my hosting provider refused to enable binary logging. Other option is to use federated storage engine. But hosting provider refused to enable it too. In fact the tech support team asked me a question that what is Fedarated storage engine? So I gave up the hope on them. Finally I implemented with the strategy that I am going to explain in this blog.

Using Laravel Observer and Eloquent

In Laravel we can use model observers to listen to the events on models and take actions. Here are steps you have to perform.

Step 1 : Create Observer

Create a new Class in App\Http\Observers folder and name is ModelObserver

Step 2 : Assign Observer to Model

In your model file add boot function as following.

public static function boot()
{
parent::boot();
YourModelName::observe(new \App\Http\Observers\ModelObserver);
}

Step 3 : Add Methods to Your Observer

In your ModelObserver class add following methods.

public function created($model)
{

}

public function updated($model)
{

}

Now when you insert or update record with Eloquent it will invoke created and updated method and will send model instance as param.

Replication to Other Server

Now next step is to implement replication strategy. For this we are going to create separate model and use remote server connection with that model.

Step 1 : Save Remote Host Connection

For this first of all create saparate MySql connection in your config/database.php file

‘replica’ => [
‘driver’ => ‘mysql’,
‘host’ => env(‘REPLICA_DB_HOST’, ‘remotehost’),
‘port’ => env(‘REPLICA_DB_PORT’, ‘3306’),
‘database’ => env(‘REPLICA_DB_NAME’, ‘your_db’),
‘username’ => env(‘REPLICA_DB_USERNAME’, ‘your_username’),
‘password’ => env(‘REPLICA_DB_PASSWORD’, ‘your_password’),
‘charset’ => ‘utf8’,
‘collation’ => ‘utf8_unicode_ci’,
‘prefix’ => ”,
‘strict’ => false,
‘engine’ => null,
]

Step 2 : Create Model to Connect to Remote Host

Now create a separate model and assign remote server connection to it.

<?php

namespace App\Http\Models;

use Illuminate\Database\Eloquent\Model;

class RemoteModel extends Model
{
protected $connection= ‘replica’;
protected $table = ‘remote_table’;
}

Step 3 : Replicate Model

Now inside your observer’s created method add following code.

if($model instanceOf \App\Http\Models\Model){
$modelArray = $model->toArray();
$newModel = new \App\Http\Models\RemoteModel;
foreach( $modelArray as $key => $value ){
if(gettype($modelArray[$key]) != ‘array’){
$newModel[$key] = $modelArray[$key];
}
}
$newModel->save();
}

As you can see in above code that we are checking first if model created is type of our Model Class and then creating object of RemoteModel and assigning values of Model to RemoteModel object and then finally call save method, this will create row in remote table on remote server.