📘 C# Blog Series – Blog 52 **“C# REST API + GPS Tracking — Device Data को API के Through कैसे Serve करें?

📘 C# Blog Series – Blog 52

**“C# REST API + GPS Tracking — Device Data को API के Through कैसे Serve करें?

(Real-Life Example: Live Location, History, Alerts, Device List APIs)”**

WebSocket से live updates मिलते हैं,
लेकिन REST APIs के बिना कोई भी GPS platform complete नहीं होता।

Mobile App, Web Dashboard, Reports, Admin Panel —
सब REST APIs से ही data लेते हैं।

आज हम सीखेंगे:

✔ REST API क्या है
✔ ASP.NET Core Web API basics
✔ GPS tracking के real API endpoints
✔ GET / POST / PUT / DELETE
✔ DTOs & clean responses
✔ Security basics (token)
✔ Performance tips

---

🟦 1. REST API क्या होता है? (Simple Definition)

REST API =
HTTP के ज़रिये data को structured तरीके से provide करना

Client (App/Web) → HTTP Request
Server (API) → JSON Response

Example:

GET /api/devices

Response:

[
  { "imei": "8611...", "lat": 26.85, "lon": 80.94 }
]

---

🟢 2. GPS System में REST API कहाँ use होती है?

✔ Device list दिखाने के लिए
✔ Current location fetch
✔ Route history
✔ Alerts history
✔ Reports (daily/weekly)
✔ Settings save
✔ User management

Live movement → WebSocket
Static / On-demand data → REST API

---

⭐ 3. ASP.NET Core Web API Project Setup

Create project:

dotnet new webapi -n GpsApi

Folder structure (recommended):

Controllers/
Services/
Models/
DTOs/
Repositories/

---

🌟 4. GPSDevice Model (Simple)

public class GPSDevice
{
    public string IMEI { get; set; }
    public double Latitude { get; set; }
    public double Longitude { get; set; }
    public int Speed { get; set; }
    public int Battery { get; set; }
    public DateTime LastUpdated { get; set; }
}

---

🟠 5. Device Controller (Core API)

[ApiController]
[Route("api/devices")]
public class DevicesController : ControllerBase
{
    private readonly IDeviceService _service;

    public DevicesController(IDeviceService service)
    {
        _service = service;
    }
}

---

🔵 6. GET: All Devices List

[HttpGet]
public IActionResult GetAll()
{
    var devices = _service.GetAllDevices();
    return Ok(devices);
}

API:

GET /api/devices

Used in:
✔ Dashboard list
✔ Admin panel

---

🟣 7. GET: Single Device Live Location

[HttpGet("{imei}")]
public IActionResult GetByImei(string imei)
{
    var device = _service.GetByImei(imei);
    if(device == null) return NotFound();

    return Ok(device);
}

API:

GET /api/devices/861128068064267

Used in:
✔ Map load
✔ Device detail page

---

🔥 8. GET: Device Route History

[HttpGet("{imei}/history")]
public IActionResult GetHistory(string imei,
    [FromQuery] DateTime from,
    [FromQuery] DateTime to)
{
    var data = _service.GetHistory(imei, from, to);
    return Ok(data);
}

API:

GET /api/devices/8611/history?from=2025-12-01&to=2025-12-02

Used in:
✔ Playback
✔ Reports

---

🧠 9. POST: Save Device Settings

[HttpPost("{imei}/settings")]
public IActionResult SaveSettings(string imei, DeviceSettingsDto dto)
{
    _service.SaveSettings(imei, dto);
    return Ok(new { status = "saved" });
}

Used in:
✔ Geo-fence
✔ Speed limit
✔ Alerts config

---

📌 10. DTOs (Best Practice)

Never expose DB models directly.

public class DeviceDto
{
    public string IMEI { get; set; }
    public double Lat { get; set; }
    public double Lon { get; set; }
    public int Speed { get; set; }
}

Return lightweight data → faster API.

---

🛡 11. API Security (Basic Token Example)

[Authorize]
[HttpGet]
public IActionResult GetAll()
{
    ...
}

Client sends:

Authorization: Bearer TOKEN

GPS APIs without auth = dangerous.

---

⚡ 12. Performance Tips (GPS APIs)

✔ Always use async

public async Task<IActionResult> GetAll()

✔ Index IMEI column
✔ Cache device list in memory
✔ Don’t join heavy tables
✔ Paginate history data
✔ Use DTOs only

---

🧪 13. API + WebSocket Together (Perfect Combo)

Pattern used by all GPS companies:

• REST API → initial data load

• WebSocket → live movement

Flow:

Page Load → GET /api/devices
Live Update → WebSocket push

---

⚠ Common Mistakes (Avoid)**

❌ Returning huge JSON
❌ Blocking DB calls
❌ No pagination
❌ No authentication
❌ Using entity models directly
❌ Mixing business logic in controller

---

🔚 Conclusion

REST API आपके GPS platform को बनाता है:

✔ Structured
✔ Scalable
✔ Secure
✔ App-friendly
✔ Report-ready
✔ Industry standard

GPS Tracking =
TCP (device) + WebSocket (live) + REST API (data)
तीनों मिलकर complete system बनाते हैं।