Document Details

   using System;
   using System.Collections.Generic;
   using System.IO;
   using System.Text;
   using System.Threading.Tasks;
   using Microsoft.Azure.Devices.Client;
   using Microsoft.Azure.WebJobs;
   using Microsoft.Azure.WebJobs.Extensions.EdgeHub;
   using Microsoft.Azure.WebJobs.Host;
   using Microsoft.Extensions.Logging;
   using Newtonsoft.Json;
   using Sql = System.Data.SqlClient;

   namespace Functions.Samples
   {
       public static class sqlFunction
       {
           [FunctionName("sqlFunction")]
           public static async Task FilterMessageAndSendMessage(
               [EdgeHubTrigger("input1")] Message messageReceived,
               [EdgeHub(OutputName = "output1")] IAsyncCollector<Message> output,
               ILogger logger)
           {
               const int temperatureThreshold = 20;
               byte[] messageBytes = messageReceived.GetBytes();
               var messageString = System.Text.Encoding.UTF8.GetString(messageBytes);

               if (!string.IsNullOrEmpty(messageString))
               {
                   logger.LogInformation("Info: Received one non-empty message");
                   // Get the body of the message and deserialize it.
                   var messageBody = JsonConvert.DeserializeObject<MessageBody>(messageString);

                   //Store the data in SQL db
                   const string str = "<sql connection string>";
                   using (Sql.SqlConnection conn = new Sql.SqlConnection(str))
                   {
                       conn.Open();
                       var insertMachineTemperature = "INSERT INTO MeasurementsDB.dbo.TemperatureMeasurements VALUES (CONVERT(DATETIME2,'" + messageBody.timeCreated + "', 127), 'machine', " + messageBody.machine.temperature + ");";
                       var insertAmbientTemperature = "INSERT INTO MeasurementsDB.dbo.TemperatureMeasurements VALUES (CONVERT(DATETIME2,'" + messageBody.timeCreated + "', 127), 'ambient', " + messageBody.ambient.temperature + ");";
                       using (Sql.SqlCommand cmd = new Sql.SqlCommand(insertMachineTemperature + "\n" + insertAmbientTemperature, conn))
                       {
                           //Execute the command and log the # rows affected.
                           var rows = await cmd.ExecuteNonQueryAsync();
                           logger.LogInformation($"{rows} rows were updated");
                       }
                   }

                   if (messageBody != null && messageBody.machine.temperature > temperatureThreshold)
                   {
                       // Send the message to the output as the temperature value is greater than the threshold.
                       using (var filteredMessage = new Message(messageBytes))
                       {
                            // Copy the properties of the original message into the new Message object.
                            foreach (KeyValuePair<string, string> prop in messageReceived.Properties)
                            {filteredMessage.Properties.Add(prop.Key, prop.Value);}
                            // Add a new property to the message to indicate it is an alert.
                            filteredMessage.Properties.Add("MessageType", "Alert");
                            // Send the message.
                            await output.AddAsync(filteredMessage);
                            logger.LogInformation("Info: Received and transferred a message with temperature above the threshold");
                       }
                   }
               }
           }
       }
       //Define the expected schema for the body of incoming messages.
       class MessageBody
       {
           public Machine machine {get; set;}
           public Ambient ambient {get; set;}
           public string timeCreated {get; set;}
       }
       class Machine
       {
           public double temperature {get; set;}
           public double pressure {get; set;}
       }
       class Ambient
       {
           public double temperature {get; set;}
           public int humidity {get; set;}
       }
   }