52 lines
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2.3 KiB
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52 lines
No EOL
2.3 KiB
Markdown
---
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obj: concept
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wiki: https://en.wikipedia.org/wiki/MQTT
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website: https://mqtt.org/
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---
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# MQTT
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MQTT is an OASIS standard messaging protocol for the Internet of Things (IoT). It is designed as an extremely lightweight publish/subscribe messaging transport that is ideal for connecting remote devices with a small code footprint and minimal network bandwidth. MQTT today is used in a wide variety of industries, such as automotive, manufacturing, telecommunications, oil and gas, etc.
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## Concepts
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### 1. **Publisher-Subscriber Model:**
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MQTT follows a publish-subscribe communication model, where clients (publishers) send messages to topics, and other clients (subscribers) receive messages from those topics.
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### 2. **Broker:**
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The MQTT broker is a server that receives published messages from clients and delivers them to the appropriate subscribers.
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### 3. **Topics:**
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Topics act as channels or categories to which messages are published. Subscribers express interest in specific topics to receive relevant messages.
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## MQTT Components
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### 1. **Publisher:**
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- A client that sends messages to a specific topic.
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### 2. **Subscriber:**
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- A client that expresses interest in a specific topic and receives messages published to that topic.
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### 3. **Broker:**
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- The server that handles message routing between publishers and subscribers.
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## Topics and Subscriptions
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Each message is inside a topic allowing for organizing them.
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### 1. **Topics:**
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- Hierarchical and structured, topics enable flexible message routing.
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### 2. **Wildcards:**
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- MQTT supports wildcards (`+` and `#`) for subscribing to multiple topics.
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## Real-world Use Case
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### 1. **IoT (Internet of Things):**
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- MQTT is widely used in IoT scenarios for efficient communication between devices.
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### 2. **Home Automation:**
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- Smart homes leverage MQTT for controlling and monitoring devices. For example [zigbee2mqtt](../applications/web/zigbee2mqtt.md) with [Home Assistant](../applications/web/Home%20Assistant.md).
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### 3. **Messaging in Remote Locations:**
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- Suitable for scenarios with low bandwidth, high latency, or unreliable connections.
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## Docker Compose
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To use MQTT with mosquitto as a broker:
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```yaml
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version: "3"
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mqtt:
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image: eclipse-mosquitto:2.0
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restart: unless-stopped
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volumes:
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- "./mosquitto:/mosquitto"
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ports:
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- "1883:1883"
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``` |