MQTT Storage Read Transfer Object
The MQTT Storage Read Transfer Object is used to read MQTT messages that were previously stored using the MQTT Data Storage feature of the MQTT plug-in.
Before configuring the transfer object, ensure that the MQTT plug-in is configured correctly and that the Enable MQTT Data Storage option is enabled. Only then can this transfer object be used.
Basic Settings
After double-clicking the transfer object, configure the following properties:
| Property | Description |
|---|---|
| Broker Connection | Select the configured MQTT broker connection whose MQTT Data Storage is to be read. |
| Topic | Specify the topic or a topic pattern for which stored messages are to be read. Wildcards are allowed. |
| Dynamic Topic | Enable this option if the topic to be read is to be specified at runtime via an input value. |
You can then further refine the output using optional include and exclude filters.
Within a filter list, an OR operator applies. A match in Include includes a record in the result set, while a match in Exclude excludes it.
Filters
Field Filter
| Field | Description |
|---|---|
| Topic | The filter value is applied to the topics stored in memory. |
| Payload | The filter value is applied to the stored message contents. |
| QoS | The filter value is applied to the stored Quality of Service values. |
| Direction | The filter value is applied to the stored message direction. |
| Timestamp | The filter value is applied to the stored timestamps. |
Direction
| Direction | Description |
|---|---|
| Published | The last message content stored in memory on a topic was published by this instance. |
| Received | The most recent message content stored in memory on a topic was received from another source. |
Filter Type
| Type | Description |
|---|---|
| Contains | The filter value appears anywhere in the selected filter field. |
| Matches | The filter value must exactly match the content of the selected filter field. |
| Regex | The filter value is interpreted as a regular expression. |
Filter Value
| Property | Description |
|---|---|
| Value | The comparison value used to apply the configured filter. |
Timestamp Filter Value
| Local | Format |
|---|---|
| de_DE | [dd.MM.YYYY HH:mm:ss:fff] |
Behavior When No Results Are Found
Finally, specify how the transfer object should behave if no matching data is found.
| Behavior | Description |
|---|---|
| Error | The transfer object reports an error and further execution of the connection is terminated. |
| Abort | The transfer object reports that no data could be read, and execution of the connection continues. |
| Ignore | The transfer object reports successful execution, even if no data was read. |
Confirm your entries by clicking “OK”.