Azure Function (v2, .NET Core): Deserialize Event Hub input coming from Stream Analytics Job

Question

I have an Azure Stream Analytics job that outputs events as "Line separated" and encoded in UTF8.

I created an Azure Function (v2, .NET Core) that gets triggered by events on the Event Hub. In this context I process the events in batches:

public static async Task Run(
    [EventHubTrigger(
        "xxx",
        Connection = "xxx",
        ConsumerGroup = "xxx")
    ] EventData[] events, 
    ILogger log)

My goal is to deserialize the input into a POCO class based object. What I currently always get is an error of "Unexpected character...".

What is the correct way of deserialization in that context?

Answer 1

Finally the following approach worked:

private static List<a> DeserializeInput(EventData[] events, ILogger log)
{ 
    try
    {
        List<a> inputsDeserializedAsList = new List<a>();

        foreach (EventData eventData in events)
        {
            // Deserialize Input
            string payload = Encoding.UTF8.GetString(eventData.Body);
            log.LogInformation($"DeserializeInput: payload retrieved: {payload}...");

            DateTime enqueuedTimeUtc = (DateTime)eventData.SystemProperties.EnqueuedTimeUtc;

            using (StringReader reader = new StringReader(payload))
            {
                List<a> inputEventsAsList = new List<a>();

                string line;
                while ((line = reader.ReadLine()) != null)
                {
                    a parsedData = JsonConvert.DeserializeObject<a>(line);
                    parsedData.EventEnqueuedUtcTime = enqueuedTimeUtc;
                    inputEventsAsList.Add(parsedData);
                }
                inputsDeserializedAsList.AddRange(inputEventsAsList);
            }
        }

        return inputsDeserializedAsList;
    }
    catch (Exception e) {
        throw new Exception("DeserializeInput: failed deserializing input...", e);
    }
}