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tut:mqtt [2018-07-20 11:04] jk [Subscription Wildcard Examples] |
tut:mqtt [2018-07-20 18:31] jk |
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| ... see [[https://www.hivemq.com/blog/mqtt-essentials-part-1-introducing-mqtt]] | ... see [[https://www.hivemq.com/blog/mqtt-essentials-part-1-introducing-mqtt]] | ||
| + | |||
| + | ... see [[https://blog.doubleslash.de/mqtt-fuer-dummies/]] | ||
| ===== MQTT Data Flow by Examples ===== | ===== MQTT Data Flow by Examples ===== | ||
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| {{ :tut:mqtt:mqtt1.svg?600x0 }} | {{ :tut:mqtt:mqtt1.svg?600x0 }} | ||
| - | If Client X publishes any data with Topic 1 and nobody is listening (nobody has subscribed Topic 1) the data is lost. | + | If Client X publishes any data with Topic 1 and nobody is listening (nobody has subscriped Topic 1) the data is lost. |
| (Exception: see Topics with Retain Flag) | (Exception: see Topics with Retain Flag) | ||
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| * Client A connected | * Client A connected | ||
| - | * Client B connected and subscribes Topic 2 | + | * Client B connected and subscripes Topic 2 |
| {{ :tut:mqtt:mqtt2.svg?600x0 |}} | {{ :tut:mqtt:mqtt2.svg?600x0 |}} | ||
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| * Client A, C, E connected | * Client A, C, E connected | ||
| - | * Client B connected and subscribes Topic 2 | + | * Client B connected and subscripes Topic 2 |
| - | * Client F connected and subscribes Topic 3 | + | * Client F connected and subscripes Topic 3 |
| {{ :tut:mqtt:mqtt3.svg?600x0 }} | {{ :tut:mqtt:mqtt3.svg?600x0 }} | ||
| - | Any Client can publish any data with any Topic at anytime. The subscriping Clients are notified instantly about change of the Topics they subscripes and only that. | + | Any Client can publish any data with any Topic at anytime. The subscribing Clients are notified instantly about change of the Topics they subscripes and only that. |
| ==== Example: Many Publisher, 1 Subscriber with Wildcard ==== | ==== Example: Many Publisher, 1 Subscriber with Wildcard ==== | ||
| * Client A, C, E connected | * Client A, C, E connected | ||
| - | * Client D connected and subscribes Topic with '#' | + | * Client D connected and subscripes Topic with '#' |
| {{ :tut:mqtt:mqtt4.svg?600x0 }} | {{ :tut:mqtt:mqtt4.svg?600x0 }} | ||
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| ==== Example: Request and Answer ==== | ==== Example: Request and Answer ==== | ||
| - | * Client E connected and subscribes Topic 4 | + | * Client E connected and subscripes Topic 4 |
| - | * Client F connected and subscribes Topic 3 | + | * Client F connected and subscripes Topic 3 |
| {{ :tut:mqtt:mqtt5.svg?600x0 }} | {{ :tut:mqtt:mqtt5.svg?600x0 }} | ||
| - | Every Client can be publisher and subscriper. For sneding a request/command one Topic can be used. For the answer an other Topic is used. | + | Every Client can be publisher and subscriber. For sneding a request/command one Topic can be used. For the answer an other Topic is used. |
| Note: This can be solved with only one Tpoic but the publisher would receive his own request/command. | Note: This can be solved with only one Tpoic but the publisher would receive his own request/command. | ||
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| * Client G connected | * Client G connected | ||
| - | * Client H connected and subscribes Topic 5 with QoS | + | * Client H connected and subscripes Topic 5 with QoS |
| {{ :tut:mqtt:mqtt6.svg?600x0 }} | {{ :tut:mqtt:mqtt6.svg?600x0 }} | ||
| Line 75: | Line 77: | ||
| |2|garantee that data arrives only once| | |2|garantee that data arrives only once| | ||
| - | Note: Each publisher and each subscriper can user the QoS flag without affecting the others. | + | Note: Each publisher and each subscriber can user the QoS flag without affecting the others. |
| ==== Example: Remain-Flag ==== | ==== Example: Remain-Flag ==== | ||
| * Client Y was connected long time ago | * Client Y was connected long time ago | ||
| - | * Client Z connects now and subscribes Topic 6 | + | * Client Z connects now and subscripes Topic 6 |
| {{ :tut:mqtt:mqtt7.svg?600x0 }} | {{ :tut:mqtt:mqtt7.svg?600x0 }} | ||
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| ==== Exact Match ==== | ==== Exact Match ==== | ||
| - | On subscriping **"/MyHome/Kitchen/Temperature"** you get: | + | On subscribing **"/MyHome/Kitchen/Temperature"** you get: |
| * **/MyHome/Kitchen/Temperature** | * **/MyHome/Kitchen/Temperature** | ||
| * <del>/MyHome/Kitchen/Humity</del> | * <del>/MyHome/Kitchen/Humity</del> | ||
| Line 131: | Line 133: | ||
| ==== # Wildcard ==== | ==== # Wildcard ==== | ||
| - | On subscriping **"/#"** you get: | + | On subscribing **"/#"** you get: |
| * /MyHome/Kitchen/Temperature | * /MyHome/Kitchen/Temperature | ||
| * /MyHome/Kitchen/Humity | * /MyHome/Kitchen/Humity | ||
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| * /MyGarden/Pool/Temperature | * /MyGarden/Pool/Temperature | ||
| - | On subscriping **"/MyHome/#"** you get: | + | On subscribing **"/MyHome/#"** you get: |
| * **/MyHome/**Kitchen/Temperature | * **/MyHome/**Kitchen/Temperature | ||
| * **/MyHome/**Kitchen/Humity | * **/MyHome/**Kitchen/Humity | ||
| Line 149: | Line 151: | ||
| * <del>/MyGarden/Pool/Temperature</del> | * <del>/MyGarden/Pool/Temperature</del> | ||
| - | On subscriping **"/MyHome/Kitchen/#"** you get: | + | On subscribing **"/MyHome/Kitchen/#"** you get: |
| * **/MyHome/Kitchen/**Temperature | * **/MyHome/Kitchen/**Temperature | ||
| * **/MyHome/Kitchen/**Humity | * **/MyHome/Kitchen/**Humity | ||
| Line 160: | Line 162: | ||
| ==== + Wildcard ==== | ==== + Wildcard ==== | ||
| - | On subscriping **"/MyHome/+/Temperature"** you get: | + | On subscribing **"/MyHome/+/Temperature"** you get: |
| * **/MyHome/**Kitchen**/Temperature** | * **/MyHome/**Kitchen**/Temperature** | ||
| * <del>/MyHome/Kitchen/Humity</del> | * <del>/MyHome/Kitchen/Humity</del> | ||
| Line 169: | Line 171: | ||
| * <del>/MyGarden/Pool/Temperature</del> | * <del>/MyGarden/Pool/Temperature</del> | ||
| - | On subscriping **"/+/+/Temperature"** you get: | + | On subscribing **"/+/+/Temperature"** you get: |
| * /MyHome/Kitchen**/Temperature** | * /MyHome/Kitchen**/Temperature** | ||
| * <del>/MyHome/Kitchen/Humity</del> | * <del>/MyHome/Kitchen/Humity</del> | ||
| Line 178: | Line 180: | ||
| * /MyGarden/Pool**/Temperature** | * /MyGarden/Pool**/Temperature** | ||
| - | On subscriping **"/+/+/+/Temperature"** you get: | + | On subscribing **"/+/+/+/Temperature"** you get: |
| * <del>/MyHome/Kitchen/Temperature</del> | * <del>/MyHome/Kitchen/Temperature</del> | ||
| * <del>/MyHome/Kitchen/Humity</del> | * <del>/MyHome/Kitchen/Humity</del> | ||
