EM-Gateway JavaScript SDK

Client library for the EM-Gateway fuel inventory management API.

The SDK accepts the API encryption key as either 64 hexadecimal characters (the format returned by EM-Gateway) or a 32-character UTF-8 string.

Installation

npm install em-gateway-sdk

Usage

Setup

const EMGatewayClient = require('em-gateway-sdk');

const client = new EMGatewayClient({
  baseUrl: 'http://your-api-host:3000',
  clientId: 'your-client-id',
  clientSecret: 'your-client-secret',
});

OAuth2 Token Flow

// Step 1: Get authorization URL
const authUrl = client.getAuthorizationUrl({
  redirectUri: 'http://localhost:3000',
  scope: 'tank_id storage_name remaining_fuel',
});
console.log('Visit:', authUrl);

// Step 2: After user authorizes, exchange code for token
const token = await client.exchangeAuthorizationCode({
  code: 'authorization-code-from-redirect',
  redirectUri: 'http://localhost:3000',
});

// Step 3: Set the token
client.setBearerToken(token.access_token);

Submit Fuel Data (Encrypted)

const testData = {
  code: 'FUEL-001',
  tank_id: 'TANK-001',
  storage_name: 'Storage A',
  storage_owner: 'Owner',
  storage_type: 'Type',
  fuel_type: 'Diesel',
  tank_capacity: 50000,
  dead_stock: 100,
  remaining_fuel: 25000,
  source: 1,
};

const result = await client.submitEncryptedFuelInventory(
  testData,
  'encryption-key-32-characters!!!',
  {
    clientId: 'your-client-id',
    count: 1,
  }
);
console.log(result);
// { success: true, message: '...', count: 1 }

Dry-Run Mode (Test Without Saving)

Test your data submission without writing to the database. The API decrypts and validates your data, then returns a preview — useful for testing before going live.

const result = await client.submitEncryptedFuelInventory(
  testData,
  'encryption-key-32-characters!!!',
  {
    clientId: 'your-client-id',
    count: 1,
    dryRun: true, // ← enables dry-run mode
  }
);

if (result.dry_run) {
  console.log('✅ Validation passed!');
  console.log('Preview:', result.preview);
  // No data was saved to database
}

Dry-Run Response (Success)

{
  "success": true,
  "dry_run": true,
  "message": "ข้อมูลผ่านการตรวจสอบทั้งหมด 1 รายการ (Dry-Run — ไม่ได้บันทึกลงฐานข้อมูล)",
  "count": 1,
  "preview": [
    {
      "code": "FUEL-001",
      "tank_id": "TANK-001",
      "storage_name": "Storage A",
      "remaining_fuel": 25000
    }
  ]
}

Dry-Run Response (Validation Error)

{
  "success": false,
  "dry_run": true,
  "message": "ข้อมูลไม่ผ่านการตรวจสอบ (Dry-Run)",
  "validation_errors": [
    { "index": 1, "missing_fields": ["tank_id", "fuel_type"] }
  ],
  "total_records": 1,
  "error_count": 1,
  "valid_count": 0
}

Master Data

const provinces = await client.request('/api/master/getProvince', {
  method: 'POST',
  body: {},
});

const regions = await client.request('/api/master/getRegion', {
  method: 'POST',
  body: {},
});

const tanks = await client.getStorageLocationTank({});

Health Check

const health = await client.health();
// { status: 'healthy', service: 'api-gateway', timestamp: '...' }

API Methods

| Method | Description | |--------|-------------| | getAuthorizationUrl(opts) | Generate OAuth2 authorization URL | | exchangeAuthorizationCode(opts) | Exchange auth code for token | | exchangeClientCredentials(opts) | Get token via client credentials | | setBearerToken(token) | Set the JWT access token | | submitFuelInventory(payload) | Submit raw fuel data (POST) | | submitEncryptedFuelInventory(data, key, opts) | Submit encrypted fuel data | | encryptFuelPayload(data, key) | Encrypt data with AES-256-CBC | | getStorageLocationTank(payload) | Get storage location tanks | | health() | Server health check | | request(path, opts) | Generic API request |

Environment Variables

EM_GATEWAY_URL=http://your-api-host:3000
EM_GATEWAY_CLIENT_ID=your-client-id
EM_GATEWAY_CLIENT_SECRET=your-client-secret