@Override
            public MessageContext get() throws Throwable {
                val decoder = new HTTPSOAP11Decoder();
                decoder.setParserPool(configurationContext.getOpenSamlConfigBean().getParserPool());
                decoder.setHttpServletRequestSupplier(() -> request);

                val binding = new BindingDescriptor();
                binding.setId(getClass().getName());
                binding.setShortName(getClass().getName());
                binding.setSignatureCapable(true);
                binding.setSynchronous(true);

                decoder.setBindingDescriptor(binding);
                decoder.initialize();
                decoder.decode();
                return decoder.getMessageContext();
            }
Handle SAML2 exceptions.

@param req the req
@param ex  the ex
@return the model and view
support/cas-server-support-saml-idp-web/src/main/java/org/apereo/cas/support/saml/web/idp/profile/AbstractSamlIdPProfileHandlerController.java