Dynamic XML generation

Stewart Burchell

Thank for your reply. Please find below details :

Use Case : To generate XML dynamically from data in database.

XML Format : Plese refere belw schema

What is going to be consuming data : A variable which will be used to send this on MQ

There is a parent child tags and few levels of casting . We have already tried using toXML() and it would need around 10-15 CDTs.

Can we have another way to creae it?

Below is the sample schema :

<?xml version="1.0" encoding="utf-8"?><BaExchReq xmlns:xc=""> 
<Envelope> <TransactionRef>##</TransactionRef> 
 <MsgId>##</MsgId> 
 <CreationTime>##</CreationTime> 
 <Requestor>##</Requestor>
 <Responder>c##</Responder> 
 <Service>##</Service> 
 <RequestType>##</RequestType> 
</Envelope> 
<Payload> 
 <AppHdr xmlns=""> 
  <MsgRef>##</MsgRef> 
  <CrDate>##</CrDate> 
 </AppHdr> 
 <Document xmlns="##"> 
  <SbcptOrdrV03> 
   <MsgId> 
    <Id>##</Id> 
    <CreDtTm>##</CreDtTm> 
   </MsgId> 
   <MltplOrdrDtls> 
    <InvstmtAcctDtls> 
     <AcctId> 
      <Prtry> <Id>##</Id> </Prtry> 
     </AcctId> 
    </InvstmtAcctDtls> 
    <IndvOrdrDtls> 
     <OrdrRef>##</OrdrRef> 
      <FinInstrmDtls> 
       <Id> 
        <ISIN>##</ISIN>     
       </Id>  
      </FinInstrmDtls> 
      <GrssAmt Ccy="">##</GrssAmt>
      <PhysDlvryInd>##</PhysDlvryInd> 
      <ReqdSttlmCcy>##</ReqdSttlmCcy>
    </IndvOrdrDtls> 
   </MltplOrdrDtls> 
  </SbcptOrdrV03> 
 </Document> 
</Payload> 
</BaExchReq>

It won't be elegant but you could assemble the message by providing a template of the message with a set of 'tokens' embedded in it that you want to be substituted with the values from your database. I don't know what the data looks like when you've retrieved it from the database but if you can coerce it into the format that I use in the following example this is how I would approach it:

Here's the XML message as a template with just the first 3 data items set as tags:

<?xml version="1.0" encoding="utf-8"?><BaExchReq xmlns:xc=""> 
<Envelope> <TransactionRef>###TransactionRef###</TransactionRef> 
 <MsgId>###MsgId###</MsgId> 
 <CreationTime>###CreationTime###</CreationTime> 
 <Requestor>##</Requestor>
 <Responder>c##</Responder> 
 <Service>##</Service> 
 <RequestType>##</RequestType> 
</Envelope> 
<Payload> 
 <AppHdr xmlns=""> 
  <MsgRef>##</MsgRef> 
  <CrDate>##</CrDate> 
 </AppHdr> 
 <Document xmlns="##"> 
  <SbcptOrdrV03> 
   <MsgId> 
    <Id>##</Id> 
    <CreDtTm>##</CreDtTm> 
   </MsgId> 
   <MltplOrdrDtls> 
    <InvstmtAcctDtls> 
     <AcctId> 
      <Prtry> <Id>##</Id> </Prtry> 
     </AcctId> 
    </InvstmtAcctDtls> 
    <IndvOrdrDtls> 
     <OrdrRef>##</OrdrRef> 
      <FinInstrmDtls> 
       <Id> 
        <ISIN>##</ISIN>     
       </Id>  
      </FinInstrmDtls> 
      <GrssAmt Ccy="">##</GrssAmt>
      <PhysDlvryInd>##</PhysDlvryInd> 
      <ReqdSttlmCcy>##</ReqdSttlmCcy>
    </IndvOrdrDtls> 
   </MltplOrdrDtls> 
  </SbcptOrdrV03> 
 </Document> 
</Payload> 
</BaExchReq>

And here's the code that takes that template a substitutes the tags for the corresponding values:

a!localVariables(
  local!parameters: {
    {tag: "###TransactionRef###", value: "ABC123"},
    {tag: "###MsgId###", value: "123a4fc4g4aa1204"},
    {tag: "###CreationTime###", value: "28-08-2020 09:03"}
  },
  fn!reduce(
    fn!substitute(
      _,
      _
    ),
    ri!xmlTemplate,
    fn!merge(
      fn!index(local!parameters,"tag"),
      fn!index(local!parameters,"value")
    )
  )
)

fn!reduce() is a loop that starts with an initial value - the template - and, for a provided list, runs a function - in this case fn!substitute -  on that value and then takes the result and passes that to the next iteration of the provided function.

fn!merge() takes a set of lists and makes a list of those lists - in this case, takes the list of tags and list of values and pairs them up.

The underscore is a way of 'deferring' the actual value to be passed to run-time and maps the inputs to fn!substitute() to the items that follow in fn!reduce() in the order they appear.

I know: it's not intuitive but it is effective.

Note: I am assuming that the example you've provided to me is 'static' - that is, there are not any repeating elements, although the name 'MltplOrdrDtls' does suggest there may be repeating elements within it, which will be a different challenge.

It won't be elegant but you could assemble the message by providing a template of the message with a set of 'tokens' embedded in it that you want to be substituted with the values from your database. I don't know what the data looks like when you've retrieved it from the database but if you can coerce it into the format that I use in the following example this is how I would approach it:

Here's the XML message as a template with just the first 3 data items set as tags:

<?xml version="1.0" encoding="utf-8"?><BaExchReq xmlns:xc=""> 
<Envelope> <TransactionRef>###TransactionRef###</TransactionRef> 
 <MsgId>###MsgId###</MsgId> 
 <CreationTime>###CreationTime###</CreationTime> 
 <Requestor>##</Requestor>
 <Responder>c##</Responder> 
 <Service>##</Service> 
 <RequestType>##</RequestType> 
</Envelope> 
<Payload> 
 <AppHdr xmlns=""> 
  <MsgRef>##</MsgRef> 
  <CrDate>##</CrDate> 
 </AppHdr> 
 <Document xmlns="##"> 
  <SbcptOrdrV03> 
   <MsgId> 
    <Id>##</Id> 
    <CreDtTm>##</CreDtTm> 
   </MsgId> 
   <MltplOrdrDtls> 
    <InvstmtAcctDtls> 
     <AcctId> 
      <Prtry> <Id>##</Id> </Prtry> 
     </AcctId> 
    </InvstmtAcctDtls> 
    <IndvOrdrDtls> 
     <OrdrRef>##</OrdrRef> 
      <FinInstrmDtls> 
       <Id> 
        <ISIN>##</ISIN>     
       </Id>  
      </FinInstrmDtls> 
      <GrssAmt Ccy="">##</GrssAmt>
      <PhysDlvryInd>##</PhysDlvryInd> 
      <ReqdSttlmCcy>##</ReqdSttlmCcy>
    </IndvOrdrDtls> 
   </MltplOrdrDtls> 
  </SbcptOrdrV03> 
 </Document> 
</Payload> 
</BaExchReq>

And here's the code that takes that template a substitutes the tags for the corresponding values:

a!localVariables(
  local!parameters: {
    {tag: "###TransactionRef###", value: "ABC123"},
    {tag: "###MsgId###", value: "123a4fc4g4aa1204"},
    {tag: "###CreationTime###", value: "28-08-2020 09:03"}
  },
  fn!reduce(
    fn!substitute(
      _,
      _
    ),
    ri!xmlTemplate,
    fn!merge(
      fn!index(local!parameters,"tag"),
      fn!index(local!parameters,"value")
    )
  )
)

fn!reduce() is a loop that starts with an initial value - the template - and, for a provided list, runs a function - in this case fn!substitute -  on that value and then takes the result and passes that to the next iteration of the provided function.

fn!merge() takes a set of lists and makes a list of those lists - in this case, takes the list of tags and list of values and pairs them up.

The underscore is a way of 'deferring' the actual value to be passed to run-time and maps the inputs to fn!substitute() to the items that follow in fn!reduce() in the order they appear.

I know: it's not intuitive but it is effective.

Note: I am assuming that the example you've provided to me is 'static' - that is, there are not any repeating elements, although the name 'MltplOrdrDtls' does suggest there may be repeating elements within it, which will be a different challenge.