Question

I want to strip a SOAP envelope from a message to get at the XML in the body.

I attempted the following;

String strippedOfEnvelopedHeader = msg.replaceAll("(?s)(?i)<(.*):Envelope.*<\1:Body>", "");

I thought that this would stip out the SOAP envelope, specifically the header, from a message like;


<soapenv:Envelope xmlns:soapenv='http://schemas.xmlsoap.org/soap/envelope/'>
<env:Header xmlns:env='http://schemas.xmlsoap.org/soap/envelope/' xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance'/>
<soapenv:Body>
<myXML> stuff is here</myXML>
</soapenv:Body>
</soapenv:Envelope>


which should result in;


<myXML> stuff is here</myXML>
</soapenv:Body>
</soapenv:Envelope>


However, the group back-reference does not seem to work.

If I replace both the capture group and the back-reference the substitution works fine;

String strippedOfEnvelopeHeader = msg.replaceAll("(?i)(?s)<soapenv:Envelope.*<soapenv:Body>", "");

I think I can guess the problem, the capture group is being greedy and grabbing the entire message and thus failing the match.

But the solution evades me.

Any ideas?

Answer 1

Try 2 backslashes

"(?si)<(.*):Envelope.*<\\1:Body>"

You need 2 because \1 itself is already a special escape sequence to Java. Therefore it will be decoded into the character U+0001 before feeding to the regex engine. You need to protect it by adding one more backslash.

(And the usual “don’t parse XML with Regex” warning follows…)