[Solved] Given this Python code snippet using Paho MQTT client: client.publish('home/livingroom', 'light=on', qos=1) What is the expected behavior of this publish call? | Raspberry Pi

Raspberry Pi - MQTT for IoT

Given this Python code snippet using Paho MQTT client:

client.publish('home/livingroom', 'light=on', qos=1)

What is the expected behavior of this publish call?

AThe message is queued until the client reconnects.

BThe message is sent once without confirmation.

CThe message is sent with a four-step handshake to guarantee exactly once delivery.

DThe message is sent and the client waits for acknowledgment to ensure delivery at least once.

Step-by-Step Solution

Solution:

Step 1: Understand QoS 1 behavior
QoS 1 guarantees the message is delivered at least once, using acknowledgment from the broker.
Step 2: Match behavior with code
The publish call with qos=1 waits for PUBACK to confirm delivery.
Final Answer:
The message is sent and the client waits for acknowledgment to ensure delivery at least once. -> Option D
Quick Check:
QoS 1 = at least once delivery with ACK [OK]

Quick Trick: QoS 1 waits for PUBACK to confirm delivery [OK]

Common Mistakes:

MISTAKES

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