Now that we have the basic code for the web service, let’s move on and clean this channel up. The results will be ready for day-to-day operations, and much easier to maintain.

Before You Start

Let’s start from scratch with a new channel:

1. From the Dashboard, create a new channel with the following components:
   • Source = From LLP
   • Destination = To Channel
   • Filter = disabled
2. From the To Channel destination component, open the Translator and import this project code: SoaUI_Final_Cut_Filter.zip
3. Commit your first milestone.

How It Works

This section explains the adjustments we made to the original code:

1. It was important that we cleaned up and streamlined the main() function. The result has a much tidier layout where the steps are self explanatory and where errors are easily handled:

   require 'node'
   require 'webserviceX'
   
   TempF = 'degreeFahrenheit'
   TempC = 'degreeCelsius'
   DegreesF = '°F'
   DegreesC = '°C'
   
   local function trace(a,b,c,d) return end
   
   function main(Data)
   
      local X = webserviceX.ConvertTemp(Data, TempF, TempC)
   
      if webserviceX.IsFault(X) then     
         -- Ooops!! Something happened so lets get the 
         -- fault message to determine what went wrong
         webserviceX.GetFault(X)     
      else
         -- Everyting is OK so lets create an       
         -- out message and push it to the queue 
         local Out = webserviceX.CreateOutMsg(Data, X, TempC):S()
         queue.push{data=Out}      
      end 
   
   end

2. We also created a webserviceX module that contains additional functionality for error handling (along with our original web service logic). We’ve also taken the logical steps and placed them in their own functions. This results in much more manageable chunks of code.

   local function trace(a,b,c,d) return end
   
   function GetHL7Message(HL7)
      -- Lets begin by brininging in some sample data
      local Orig = hl7.parse{vmd='HL7_2.5.1.vmd',data=HL7}
      local Out = hl7.message{vmd='HL7_2.5.1.vmd',name=Orig:nodeName()}   
      Out:mapTree(Orig)
      return Out
   end
   
   function MakeRequest(HL7, TempFrom, TempTo)
   
      local P = xml.parse{data=D}
   
      P["soapenv:Envelope"]["soapenv:Body"]
      ["web:ConvertTemp"]["web:Temperature"][1]=
      HL7.PATIENT_RESULT[1].ORDER_OBSERVATION[1].OBSERVATION[2].OBX[5][1]
   
      P["soapenv:Envelope"]["soapenv:Body"]
      ["web:ConvertTemp"]["web:FromUnit"][1]=TempFrom
   
      P["soapenv:Envelope"]["soapenv:Body"]
      ["web:ConvertTemp"]["web:ToUnit"][1]=TempTo
   
      return P
   end
   
   function webserviceX.ConvertTemp(HL7,TempFrom, TempTo)
   
      local Msg = GetHL7Message(HL7)
      local P = MakeRequest(Msg, TempFrom, TempTo)
   
      -- Call the convert temperature web service 
      -- and save the result to a local variable  
      local R,C,D = net.http.post{url=Url.. 'ConvertTemperature.asmx', 
         headers={['Content-type']='text/xml;charset=UTF-8', 
            SOAPAction=SoapAction.. 'ConvertTemp'}, 
         body=P:S(),
         live=true}
   
      trace(C,D,R)
   
      -- Create variable "X" that points to our parsed soap response and 
      -- populate our outbound message with the converted temperature
      -- and units of measure
      return xml.parse{data=R} 
   
   end
   
   -- Returns nil if we do not have a SOAP fault response
   function webserviceX.IsFault(X)
      return X["soap:Envelope"]["soap:Body"]["soap:Fault"]   
   end
   
   -- Extracts the response message from a non fault response
   function GetResponse(X)
      return X["soap:Envelope"]["soap:Body"].
       ConvertTempResponse.ConvertTempResult[1]
   end
   
   -- Extracts the error message from a fault response
   function webserviceX.GetFault(X)
      return X["soap:Envelope"]["soap:Body"]
              ["soap:Fault"].faultstring[1]:S()
   end
   
   -- Create a message that will be sent to the destination endpoint
   function webserviceX.CreateOutMsg(HL7, X, TempTo)
      local Out = GetHL7Message(HL7)
   
      local TempValue
   
      if TempTo == TempC then
         TempValue = DegreesC
      else
         TempValue = DegreesF     
      end
   
      Out.PATIENT_RESULT[1].ORDER_OBSERVATION[1].OBSERVATION[2].OBX[5][1]=GetResponse(X)
      Out.PATIENT_RESULT[1].ORDER_OBSERVATION[1].OBSERVATION[2].OBX[6][2]=TempValue
   
      return Out
   end