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“Windchill” is beyond a simple PLM, it is a technology stack consisting of Identity Management, Token Management, Single-sign on Session Management, Database Management, Organization Management, and, behind all that, Product Management.

Windchill delegates Oauth2 authentication for a subset of its API routes to Apache HTTPd, Tomcat Servlet Engine, Ping Federate, LDAP, and a Tomcat Spring Bean.

It is the Tomcat Spring Bean which is responsible for receiving an incoming HTTP Request from Apache HTTPd via AJP and Tomcat that has an HTTP Authorization Bearer token and for then performing the token introspection with the Ping Federate service to determine if the token is valid and to extract the effective Windchill user identity from the token before forwarding that HTTP Request on into the Windchill application.

PTC delivers their technology stack as a complex and complicated collection of template deployments, property files, XML configuration files, and Ant scripts.

During installation of the Windchill stack, the installing administrator executes several ant scripts to weave configuration properties into the template files to yield the eventual effective configuration files which inform the running HTTPd and Tomcat services.

A Tomcat servlet ecosystem consists of a web server (like Apache HTTPd) and one or more Tomcat “engines” (or instances) each of which may have multiple “hosts” where each “host” runs multiple “contexts”. Each “context” can be configured to offer service from multiple servlet contexts.

(Modern microservices developers can think of a “servlet context” as a “microservice” - except for the difference that modern microservices are supposed to be more pure in limiting their scope than was the practice for servlets.)

The Windchill PDMLink application is a Tomcat servlet context that is found in <WINDCHILL<WINDCHILL_DRIVE>DRIVE>/Windchill/codebase/WEB-INF .

The servlet filter in this servlet context that is responsible to receive an Oauth2-token-bearing HTTP Request, to extract the token, to verify the token with the Token Server (PingFederate), to extract the effective Windchill user id, and to forward the request into Windchill is found in the security folder of this WEB-INF directory. There is a securityContext.xml file and a securityContext.properties file.

Because PTC does not assume that all its customers will offer OAuth2 access for their Windchill APIs, the servlet’s Context’s configuration file, web.xml, does not include the necessary filter, filter-mapping, servlet, and servlet-mapping elements.

Installation involves adding the necessary property strings to the securityContext.properties file and then adding the missing XML fragments to the web.xml file in the right locations to assure that incoming HTTP requests flow through the right filter chains and are routed to the right servlets by the right servlet-mapping elements.

PTC documentation states how to configure the Windchill servlet context for OAuth2 authentication. (The advice above merely explains which Tomcat configuration to modify and is intended to explain why the modifications are made).