Reading in XML from webserivce request using HttpRequest

Question

I have seen multiple posts online talking about how to read in XML data from a web request using HttpRequest, but I cannot seem to make it work or find any documentation on it. The closest I have gotten is to making it work is to enclose the xml in

< request >....< /request >

which is not acceptable for my case.

Is there anyway to send a raw string of xml to salesforce for manual parsing and not having to alter or encapsulate that string?

edit.

    < B:Envelope xmlns:B="http://schemas.xmlsoap.org/soap/envelope/" xmlns:A="theircustomuri" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
       < SOAP:Header xmlns:SOAP="http://schemas.xmlsoap.org/soap/envelope/" xmlns:SOAP-SEC="http://schemas.xmlsoap.org/soap/security/2000-12">
          < SOAP-SEC:Signature SOAP:mustUnderstand="1">
             < Signature xmlns="http://www.w3.org/2000/09/xmldsig#" xmlns:C="theircustomuri" xmlns:wsse="http://schemas.xmlsoap.org/ws/2002/07/secext">
                < SignedInfo>
                   < CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#" />
                   < SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1" />
                   < Reference URI="#Body">
                      < Transforms>
                         < Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#" />
                      < /Transforms>
                      < DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1" />
                      < DigestValue>xxxxxxxxxxxxxxxxx< /DigestValue>
                   < /Reference>
                < /SignedInfo>
                < SignatureValue>xxxxxxxxxxxxxxxxx< /SignatureValue>
                < KeyInfo>
                   < X509Data>
                      < X509Certificate />
                      < X509IssuerSerial>
                         < X509IssuerName>Oxxxxxxxxxxxxxxxxxxx< /X509IssuerName>
                         < X509SerialNumber>xxxxxxxxxxxxxxxxx< /X509SerialNumber>
                      < /X509IssuerSerial>
                   < /X509Data>
                < /KeyInfo>
             < /Signature>
          < /SOAP-SEC:Signature>
       < /SOAP:Header>
       < B:Body id="Body">
          < B:Fault>
             < B:faultcode>Client.invalidData< /B:faultcode>
             < B:faultstring>invalidData< /B:faultstring>
             < B:detail>
                < faultdetails>detailed info< /faultdetails>
             < /B:detail>
          < /B:Fault>
          < A:AdditionalInfo version="2.0">
             < A:SenderID>FS000< /A:SenderID>
             < A:TargetID>F000BK< /A:TargetID>
          < /A:AdditionalInfo>
       < /B:Body>
    < /B:Envelope>

Answer 1

The answer to this is as @sfdcfox suggested. You can just create a rest endpoint without parameters (so salesforce doesn't try to automatically deserialize).

 @HttpPost
global static String doPost() {
    String soapRequestBody = RestContext.request.requestBody.toString();
    RestResponse res = RestContext.response;
    res.statusCode = 200;
    res.responseBody = Blob.valueOf('OK');
    return 'OK';
}