Issue in applying routing query commands in IoT Hub Azure Portal

Question

Issue in applying routing query commands in IoT Hub Azure Portal

Athira Gopinath(UST,IN) 141

Hi, As part of my research, I want to filter out the data coming from IoT Hub based on certain conditions. For that purpose, I have tried out ""IoT Hub message routing query syntax" published by Azure(https://learn.microsoft.com/en-us/azure/iot-hub/iot-hub-devguide-routing-query-syntax) by giving different routing queries specified in the document. It is observed that, the routing queries are not working as expected. Please suggest a solution to solve this problem.

Matthijs van der Veer 4,376 Reputation points MVP Volunteer Moderator

2023-04-04T07:14:49.2066667+00:00

Hey Athira, it would be great to include what you're trying to do and what issues you're running into. Right now, all I can tell is that you're trying to do 'something', and it's not working.

If you can edit your question and include a minimal reproducible example, we can help you out!
Athira Gopinath(UST,IN) 141 Reputation points

2023-04-04T07:35:27.4233333+00:00

We have tried giving this routing query "$body.Weather.HistoricalData[0].Month = 'Feb'" under message routing in Azure Portal. Expecting the routing will pass the message body with these attributes. To fetch the filtered data, we are running azure consumer code . But not getting the data as expected. Along with this, we tried to filter the data with device id.

Then we are receiving the payload
Matthijs van der Veer 4,376 Reputation points MVP Volunteer Moderator

2023-04-04T07:53:45.57+00:00
Ok thanks for that. I see you're following the tutorial. Just to make sure, can you check if the device is sending data with the message ContentType set to application/json?

// Set message body type and content encoding message.contentEncoding = "utf-8"; message.contentType = "application/json";
Athira Gopinath(UST,IN) 141 Reputation points

2023-04-05T07:35:57.5933333+00:00

@Matthijs van der Veer and @Sander van de Velde | MVP Thanks for the quick reply. I have tried the same and it is working. But when I tried **$body.Weather.Temperature = 50 AND $body.Weather.IsEnabled,**it is not getting saved and updated. Please find the error while saving the query. If we are giving the same query like **$body.Weather.IsEnabled AND $body.Weather.Temperature = 50 ,**it is getting saved and it is working. Similarly, **$body.properties.desired.telemetryConfig.sendFrequency > 10,is_defined($body.properties.desired.telemetryConfig.sendFrequency) -(**since the filter is based on message body whether it will filter out twin properties), $twin.tags.deploymentLocation.floor = 1are also not working as mentioned in the document. All other sql queries are working as mentioned in the azure document.

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Matthijs van der Veer 4,376 Reputation points MVP Volunteer Moderator

2023-04-04T07:14:49.2066667+00:00

Hey Athira, it would be great to include what you're trying to do and what issues you're running into. Right now, all I can tell is that you're trying to do 'something', and it's not working.

If you can edit your question and include a minimal reproducible example, we can help you out!
Athira Gopinath(UST,IN) 141 Reputation points

2023-04-04T07:35:27.4233333+00:00

We have tried giving this routing query "$body.Weather.HistoricalData[0].Month = 'Feb'" under message routing in Azure Portal. Expecting the routing will pass the message body with these attributes. To fetch the filtered data, we are running azure consumer code . But not getting the data as expected. Along with this, we tried to filter the data with device id.

Then we are receiving the payload
Matthijs van der Veer 4,376 Reputation points MVP Volunteer Moderator

2023-04-04T07:53:45.57+00:00

Ok thanks for that. I see you're following the tutorial. Just to make sure, can you check if the device is sending data with the message ContentType set to application/json?

// Set message body type and content encoding message.contentEncoding = "utf-8"; message.contentType = "application/json";
Athira Gopinath(UST,IN) 141 Reputation points

2023-04-05T07:35:57.5933333+00:00

@Matthijs van der Veer and @Sander van de Velde | MVP Thanks for the quick reply. I have tried the same and it is working. But when I tried **$body.Weather.Temperature = 50 AND $body.Weather.IsEnabled,**it is not getting saved and updated. Please find the error while saving the query. If we are giving the same query like **$body.Weather.IsEnabled AND $body.Weather.Temperature = 50 ,**it is getting saved and it is working. Similarly, **$body.properties.desired.telemetryConfig.sendFrequency > 10,is_defined($body.properties.desired.telemetryConfig.sendFrequency) -(**since the filter is based on message body whether it will filter out twin properties), $twin.tags.deploymentLocation.floor = 1are also not working as mentioned in the document. All other sql queries are working as mentioned in the azure document.

Answer 1

Hello @Athira Gopinath(UST,IN), the IoT Hub supports routing messages to several kinds of endpoints based on routing rules. These rules can be filtered to filter incoming messages. Because the message body could be anything, it is passed as a byte array, the regular routing ignores the message body. In most cases, Azure resources assume that the body contains a JSON message but that is not the case this time. As @Matthijs van der Veer mentioned already you need to provide some extra content information

using (var message = new Message(messageBytes)) 
{ 
    // Set message body type and content encoding. 
    message.ContentEncoding = "utf-8"; 
    message.ContentType = "application/json"; 
 
    await deviceClient.SendEventAsync(message); 
}

This is the case with all IoT Devices SDKs (like C#, Javascript, Python) and even the non-SDK MQTT way of communication. Now, the IoT Hub knows the incoming byte array message can safely be decoded into JSON so the body properties can be read. If the response helped, do "Accept Answer". If it doesn't work, please let us know the progress. All community members with similar issues will benefit by doing so. Your contribution is highly appreciated.

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Issue in applying routing query commands in IoT Hub Azure Portal

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