I haven't tested this, but this is what I'm suggesting. New part is colored blue.

XData BPL [ XMLNamespace = "http://www.intersystems.com/bpl" ]
{
<process language='objectscript' request='CUH.Mess.DCIQ.JsonIn' response='CUH.Mess.DCIQ.JsonOut' height='3400' width='2000' >
<context>
<property name='JsonObjectIn' type='CUH.Mess.DCIQ.JsonInObj' instantiate='1' />
<property name='HL7QRY' type='EnsLib.HL7.Message' instantiate='0' />
<property name='HL7ADR' type='EnsLib.HL7.Message' instantiate='0' />
<property name='JsonObjectOut' type='CUH.Mess.DCIQ.JsonOutObj' instantiate='1' />
<property name='RequestNumber' type='%String' initialexpression='""' instantiate='0' >
<parameters>
<parameter name='MAXLEN'  value='50' />
</parameters>
</property>
<property name='IsInteger' type='%Boolean' instantiate='0' />
<property name='ProcError' type='%String' initialexpression='""' instantiate='0' >
<annotation><![CDATA[Error message to be sent back in the Response.]]></annotation>
<parameters>
<parameter name='MAXLEN'  value='50' />
</parameters>
</property>
<property name='ValidOriginUrl' type='%String' instantiate='0' >
<parameters>
<parameter name='MAXLEN'  value='100' />
</parameters>
</property>
<property name='ValidContactType' type='%String' instantiate='0' >
<parameters>
<parameter name='MAXLEN'  value='50' />
</parameters>
</property>
<property name='ValidIDNumberType' type='%String' initialexpression='""' instantiate='0' >
<parameters>
<parameter name='MAXLEN'  value='50' />
</parameters>
</property>
<property name='ValidNHSCodeType' type='%String' initialexpression='""' instantiate='0' >
<parameters>
<parameter name='MAXLEN'  value='50' />
</parameters>
</property>
</context>
<sequence xend='200' yend='3500' >
<scope xpos='200' ypos='250' xend='200' yend='2850' >
<annotation><![CDATA[Handles all errors]]></annotation>
<code name='Initialize JSON request' xpos='200' ypos='350' >
<![CDATA[ set context.JsonObjectIn = ##class(CUH.Mess.DCIQ.JsonInObj).%New()
 do context.JsonObjectIn.%JSONImport(request.bodyJson)]]>
</code>
<if name='Is "data" an array?' condition='context.JsonObjectIn.data.%IsA("%DynamicArray")' xpos='200' ypos='450' xend='200' yend='700' >
<true>
<assign name="Make &quot;data&quot; a %DynamicObject" property="context.JsonObjectIn.data" value="context.JsonObjectIn.data.%Pop()" action="set" xpos='335' ypos='600' />
</true>
</if>
<assign name="Valid URL" property="context.ValidOriginUrl" value="##class(Ens.Util.FunctionSet).Lookup(&quot;CUH.DCIQToEpic.OriginUrl&quot;,$NAMESPACE,&quot;&quot;,3)" action="set" languageOverride="" xpos='200' ypos='800' >
<annotation><![CDATA[Environment specific]]></annotation>
</assign>
<assign name="Valid ContactType" property="context.ValidContactType" value="##class(Ens.Util.FunctionSet).Lookup(&quot;CUH.DCIQToEpic.ContactType&quot;,$NAMESPACE,&quot;&quot;,3)" action="set" languageOverride="" xpos='200' ypos='900' >
<annotation><![CDATA[Environment specific]]></annotation>
</assign>
<assign name="Valid IDNumberType" property="context.ValidIDNumberType" value="##class(Ens.Util.FunctionSet).Lookup(&quot;CUH.DCIQToEpic.IDNumberType&quot;,$NAMESPACE,&quot;&quot;,3)" action="set" languageOverride="" xpos='200' ypos='1000' >
<annotation><![CDATA[Environment specific]]></annotation>
</assign>
<assign name="Valid NHSCodeType" property="context.ValidNHSCodeType" value="##class(Ens.Util.FunctionSet).Lookup(&quot;CUH.DCIQToEpic.NHSCodeType&quot;,$NAMESPACE,&quot;&quot;,3)" action="set" languageOverride="" xpos='200' ypos='1100' >
<annotation><![CDATA[Environment specific]]></annotation>
</assign>
<if name='Check OriginUrl' condition='context.JsonObjectIn.meta."origin_url"=context.ValidOriginUrl' xpos='200' ypos='1200' xend='200' yend='2600' >
<true>
<if name='Check Contact Type' condition='(context.JsonObjectIn.data."0"."con_type"=context.ValidContactType)||(context.JsonObjectIn.data."con_type"=context.ValidContactType)' xpos='470' ypos='1350' xend='470' yend='2500' >
<true>
<if name='Check idNumber Type' condition='(context.JsonObjectIn.data.idNumbers.GetAt(1).type)=context.ValidIDNumberType' xpos='740' ypos='1500' xend='740' yend='2400' >
<true>
<assign name="Get Request Number" property="context.RequestNumber" value="context.JsonObjectIn.data.idNumbers.GetAt(1).number" action="set" languageOverride="" xpos='1010' ypos='1650' />
<code name='Integer pattern' xpos='1010' ypos='1750' >
<![CDATA[ set context.IsInteger = ((context.RequestNumber)?.N)]]>
</code>
<if name='Integer?' condition='context.IsInteger' xpos='1010' ypos='1850' xend='1010' yend='2300' >
<annotation><![CDATA[Checks if Requested Number sent is an Integer]]></annotation>
<true>
<transform name='Create HL7 query' class='CUH.Tran.GetDCIQJsonPatientToEpicQRYQ011' source='context.JsonObjectIn' target='context.HL7QRY' xpos='1280' ypos='2000' />
<call name='Send to MPIQueryHandler' target='MPI Query Handler' async='0' xpos='1280' ypos='2100' >
<request type='EnsLib.HL7.Message' >
<assign property="callrequest" value="context.HL7QRY" action="set" languageOverride="" />
</request>
<response type='EnsLib.HL7.Message' >
<assign property="context.HL7ADR" value="callresponse" action="set" languageOverride="" />
</response>
</call>
<transform name='Converts HL7 to JSON' class='CUH.Tran.EpicADRA19ToDCIQJsonPatient' source='context.HL7ADR' target='context.JsonObjectOut' xpos='1280' ypos='2200' />
</true>
<false>
<assign name="Error No Number" property="context.ProcError" value="&quot;MRN needs to be a positive numeric value&quot;" action="set" languageOverride="" xpos='1010' ypos='2000' />
</false>
</if>
</true>
<false>
<assign name="Error idNumber Type" property="context.ProcError" value="&quot;Invalid idNumber Type&quot;" action="set" languageOverride="" xpos='740' ypos='1650' />
</false>
</if>
</true>
<false>
<assign name="Error Contact Type" property="context.ProcError" value="&quot;Invalid Patient Contact Type&quot;" action="set" languageOverride="" xpos='470' ypos='1500' />
</false>
</if>
</true>
<false>
<assign name="Error Origin Url" property="context.ProcError" value="&quot;Origin URL not authorized!&quot;" action="set" languageOverride="" xpos='200' ypos='1350' />
</false>
</if>
<faulthandlers>
<catchall xpos='200' ypos='2700' xend='200' yend='350' >
<assign property="context.ProcError" value="&quot;Error in the Json/HL7 conversion/transformation block&quot;" action="set" languageOverride="" xpos='200' ypos='250' />
</catchall>
</faulthandlers>
</scope>
<assign name="Assign Error to Response" property="context.JsonObjectOut.errors" value="context.ProcError" action="set" languageOverride="" xpos='200' ypos='2950' />
<if condition='context.JsonObjectOut.errors&apos;=""' xpos='200' ypos='3050' xend='200' yend='3400' >
<annotation><![CDATA[Check if any errors]]></annotation>
<true>
<trace name='Log the Error' value='context.JsonObjectOut.errors' xpos='470' ypos='3200' />
<assign name="Returns {}" property="response.bodyJson" value="&quot;{}&quot;" action="set" languageOverride="" xpos='470' ypos='3300' />
</true>
<false>
<code name='Returns Valid Response' xpos='200' ypos='3200' >
<![CDATA[ set temp = ##class(CUH.Mess.DCIQ.JsonOut).%New()
 do context.JsonObjectOut.%JSONExportToString(.temp)
 set response.bodyJson = temp]]>
</code>
</false>
</if>
</sequence>
</process>
}

One thing you could do:
At the top of your BPL, add an <if> checking if "data" is an array or an object:

if context.JsonObjectIn.data.%IsA("%DynamicArray")

If it is, then use an assign to set context.JsonObjectIn.data to the last element of the array (%Pop() returns the last element of an array):

set context.JsonObjectIn.data = context.JsonObjectIn.data.%Pop()

After doing this, the rest of the actions should work the same for either input.

Note that this assumes that when "data" is an array that the array only has one item in it. If it can have multiple items then you'll need to add logic to choose the correct item.

As you noted, fromDao is in the HS.FHIRModel classes, but in the code you pasted you're actually using a class under HS.FHIR:

Set cls = $CLASSMETHOD("HS.FHIR.DTL.vR4.Model.Resource.Patient","fromDao",dao)

I think you want to do this instead:

Set cls = $CLASSMETHOD("HS.FHIRModel.R4.Patient","fromDao",dao)

https://docs.intersystems.com/irisforhealth20241/csp/documatic/%25CSP.Do...

Good question. In OAuth the response will include the expiration time, so that's what I was expecting here.

If the response doesn't include an expiration time does the vendor's documentation say anything about if tokens can be used for more than 1 request and if so how long it's valid for? If you know it's supposed to be valid for 60 minutes then you could just log the time when you requested the token and use that to track it.