idpSSOFederate.jsp works on the identity provider side to receive and parse authentication requests from the service provider and generate a Response containing an assertion. The endpoint for this JSP is protocol://host:port/service-deploy-uri/idpSSOFederate. idpSSOFederate.jsp takes the following parameters:
SAMLRequest: This required parameter takes as a value the XML blob that contains the AuthnRequest.
metaAlias: This optional parameter takes as a value the metaAlias set in the identity provider's extended metadata configuration file.
RelayState: This optional parameter takes as a value the target URL of the request.