Here is an example article that explains how to send transactions from your Metamask wallet using a Node.js backend application with the MetaMask API:
Sending Metamask Transactions Using PHP and Node.js
In this article, we will walk you through how to create a simple API in the backend of your Node.js application that allows you to send transactions from your Metamask wallet to other wallets.
Prerequisites:
- Install Node.js and MetaMask on your computer.
- Create a local PHP development environment (e.g. Laravel or Express).
- Create an account with MetaMask to test the API.
Project structure:
»bash
metamask-api/
app.php
config/
database.php
public/
controls/
index.php
services/
TransactionService.php
routes/
api.php
vendor/
autoload.php
App.js (backend PHP file)
php
use Illuminate\Support\Facades\DB;
// Connect to the database
$connection = DB::connect(‘mysql’, [
‘host’ => ‘localhost’,
‘user’ => ‘your_username’,
‘password’ => ‘your_password’,
]);
// Define a new transaction service
Class TransactionService {
public function createTransaction($data) {
// Validate input data
if (!isset($data[‘to’]) || !isset($data[‘amount’])) {
return false;
}
try {
// Execute the transaction
$result = DB::insert(‘transactions’, [
‘user_id’ => auth()->id(),
‘wallet_id’ => auth()->id(),
‘amount’ => floatval($data[‘amount’]),
‘tx_hash’ => hash(‘sha256’, uniqid()) // generate a unique transaction tx_hash
]);
if ($result) {
return true;
} else {
throw new Exception(‘Transaction failed’);
}
} catch (exception $e) {
return false;
}
}
}
// Create a new TransactionService instance
$transactionService = new TransactionService();
// Define a function to send transactions from the Metamask wallet
function sendTransaction($to, $amount) {
$data = [
‘to’ => $to,
‘amount’ => $amount
];
if (!$transactionService->createTransaction($data)) {
return false;
}
// Return true to indicate a successful transaction
return true;
}
index.php (controller file)
php
use Illuminate\Http\Request;
// Handle incoming requests from the Metamask wallet
$to = Request::input(‘to’);
$amount = Request::input(‘amount’);
if (!isset($to)) {
return response()->json([‘error’ => ‘Invalid address’]);
}
if (!isset($amount)) {
return response()->json([‘error’ => ‘Invalid amount’]);
}
// Send the transaction using the sendTransaction function
$response = sendTransaction($to, $amount);
return response()->json($response);
api.php (route file)
php
use Illuminate\Http\Request;
use App\Http\Controllers\TransactionService;
// Define a new transaction sending route
Route::post(‘/sendTransaction’, [
‘name’ => ‘Send transaction’,
‘uses’ => function(Request $request) {
return TransactionService::sendTransaction($request->input(‘to’), $request->input(‘amount’));
},
‘methods’ => [‘POST’]
]);
«
Explanation:
- In the "app.php" file, we define a new transaction service using the Laravel IoC container (Iloquent ORM).
- The "createTransaction" method validates the input data and executes the transaction in the database.
- In the "sendTransaction" function, we get the Metamask wallet address and amount from the request parameters. Then we call the "createTransaction" method of the transaction service to send the transaction.
- Finally, in the route file/api/sendTransaction’, we define a new route for sending transactions using the Laravel route builder.
