Communication Paradigm — MQTT vs HTTP

Communication Paradigm:

• MQTT: It operates on a publish/subscribe model, where devices do not communicate directly with each other. When data is published, devices subscribing to that data receive the information.
• HTTP: It follows a request/response model, where devices send a request to a server, and the server responds. Each request establishes a new connection.

Connection State:

• MQTT: It can maintain a persistent connection, enabling continuous communication between devices.
• HTTP: Due to the request/response model, a new connection is established and closed for each request, not keeping a continuous connection open.

Data Size and Overhead:

• MQTT: It typically has smaller header sizes and less data overhead, making it more efficient.
• HTTP: Larger header and response data sizes may lead to increased bandwidth usage.

Power Consumption and Performance:

• MQTT: It tends to have lower power consumption and lower bandwidth usage, making it preferable for many IoT devices.
• HTTP: Because it establishes a new connection for each request, it may consume more energy and exhibit lower performance in applications requiring continuous connections.

Use Cases:

• MQTT: Ideal for scenarios where IoT devices require real-time data exchange, such as sensor data, telemetry, or instant updates.
• HTTP: Suited for situations where a device needs to request specific data from a server or send data updates intermittently, like making requests to a web API or updating a web page.

In summary, MQTT and HTTP serve different purposes in the IoT landscape. MQTT is favored for its real-time capabilities, lower power consumption, and continuous connection maintenance, while HTTP is suitable for intermittent data exchange and request-driven communication. The choice between them depends on the specific requirements and use cases of the IoT application.

MQTT Usage

import paho.mqtt.client as mqtt
import time

# MQTT broker'ına bağlanmak için gerekli bilgiler
broker_address = "mqtt.eclipse.org"
port = 1883
# MQTT client'ını oluştur
client = mqtt.Client("IoT_Device")
# Broker'a bağlan
client.connect(broker_address, port)
# IoT cihazından sensör verisi yayınla
def publish_sensor_data():
    while True:
        sensor_data = "Sensor data: XYZ"
        client.publish("iot/sensors", sensor_data)
        time.sleep(5)  # Örneğin, her 5 saniyede bir veri yayınla
# Veri yayınla
publish_sensor_data()

HTTP Usage

PYTHON

import requests
import time

# HTTP endpoint
api_url = "https://example.com/api/sensors"
# IoT cihazından sensör verisi gönder
def send_sensor_data():
    while True:
        sensor_data = {"data": "XYZ"}
        response = requests.post(api_url, json=sensor_data)
        
        if response.status_code == 200:
            print("Veri başarıyla gönderildi.")
        else:
            print(f"Hata! HTTP Status Code: {response.status_code}")
        time.sleep(5)  # Örneğin, her 5 saniyede bir veri gönder
# Veri gönder
send_sensor_data()

While HTTP is used to send sensor data to an API endpoint using a POST request. MQTT with its persistent connection and low data overhead is suitable for real-time data exchanges. HTTP, with its request/response model, is suitable for on-demand communication and integration with web-based APIs.