Question

I have a number of pre-generated, static xml files containing soap requests. I can read them, send the request, and get back and answer from the server. I would like to get some advice on how to create a dynamic process:

<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
  <soap:Body>
    <getProject xmlns="http://myserver/">
      <atr1>string</atr1>
      <atr2>string</atr2>
    </getProject>
  </soap:Body>
</soap:Envelope>

So, I want to be able to read these xml files, change the values of the nodes , etc. to real values gathered from user input at run-time. What would be the best way to go: read the xml file line by line and use a regex to replace value, or maybe make a temp copy of the xml file, use sax to replace the node value, then send the new xml, or completely discard the pre-generated xml files and instead create them on-the-fly, or how? Any suggestions would be appreciated.

Answer 1

• Using regexes would be fragile, because the formatting of the XML could change in ways you’re not expecting, and still be well-formed and valid XML, but not fit your regexes. In general it’s not recommended to use regexes to parse XML.
• Using SAX to read in the XML file (why make a temp copy?), copy all nodes to the output, modifying certain ones to put in the user-supplied values. That sounds like a good, workable solution.
• Create the XML from scratch: that does sound simpler, if you know their structure in advance, and it’s not too big. One way to do this would be to use an XSLT stylesheet, and pass in the user-supplied values as parameters.