reading MetadataAPI attributes value

Question

I'm calling MetadataAPI as the code below and it's returning getBody() with a very long string as shown below, please scroll horizontal to see it and for brevity purpose I cut short.

HttpRequest req = new HttpRequest();
    req.setMethod( 'POST' );
    req.setHeader( 'Content-Type', 'text/xml; charset=utf-8' );
    req.setHeader( 'SOAPAction', 'readMetadata' );
    req.setEndpoint( URL.getOrgDomainUrl().toExternalForm() + '/services/Soap/m/48.0' );
    req.setBody( soapMessage );

    HttpResponse res = new Http().send( req );
    res.getBody();

Here is the debug output

<?xml version="1.0" encoding="UTF-8"?><soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns="http://soap.sforce.com/2006/04/metadata" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><soapenv:Body><readMetadataResponse><result><records xsi:type=\"Profile\"><fullName>Employee</fullName><applicationVisibilities><application>My_Awesome_App</application><default>false</default><visible>false</visible></applicationVisibilities><applicationVisibilities><application>standard__AppLauncher</application><default>......{removed}..... <objectPermissions><allowCreate>true</allowCreate><allowDelete>false</allowDelete><allowEdit>true</allowEdit><allowRead>true</allowRead><modifyAllRecords>false</modifyAllRecords><object>employee__c</object><viewAllRecords>false</viewAllRecords></objectPermissions>......</soapenv:Body></soapenv:Envelope>

My question is: How to extract the values from <objectPermissions> that getBody() is rendering? or any other attributes. for an example, if I want to read the value of objectPermissions or object how would I go after?

Answer 1

Generally speaking, you parse it with the XmlNode class:

Dom.Document doc = new Dom.Document();
doc.load(res.getBody());
Dom.XmlNode body = doc.getRootElement().getChildElement('Body','soapenv').getChildElement('readMetadataResponse',null);
for(Dom.XmlNode resultNode: body.getChildElements()) {
  ...
}

This is cumbersome if you want to parse it this way, but it can be done.

You can also use the XmlStreamReader, but I find it more troublesome than even the above, since you also need to build a "state machine".

Finally, you convert the entire mess to an untyped Map, as I demonstrate in my very own XmlToJson parser. It has a convenient "half-way" point where you can get an object that you can then process as if it were a JSON.deserializeUntyped result, which I find incredibly useful (but, be aware that you'll be using inordinate amount of CPU and heap). If you can handle it, and it's rare, this might be useful for you.

Finally, consider researching a REST API alternative. The Metadata API is restricted to System Administrators, while the REST API can be used by almost any user. I make no assumptions as to your use case, but you may want to research this if you haven't already.