MSAL4JSample startup exception in authFilter

Question

From tomcat deployment:

27-Aug-2021 14:22:01.726 SEVERE [localhost-startStop-2] org.apache.catalina.core.StandardContext.filterStart Exception starting filter [authFilter]
java.lang.AbstractMethodError
at org.apache.catalina.core.ApplicationFilterConfig.initFilter(ApplicationFilterConfig.java:281)
at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:110)
at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4538)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5181)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:743)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:719)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:705)
at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:970)
at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1840)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)

• OR - from IDE:

2021-08-27 14:17:23.079 ERROR 19656 --- [ost-startStop-1] o.a.c.c.C.[.[.[/msal-web-sample] : Exception starting filter [authFilter]

java.lang.AbstractMethodError: null
at org.apache.catalina.core.ApplicationFilterConfig.initFilter(ApplicationFilterConfig.java:283) ~[catalina.jar:8.5.46]
at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:112) ~[catalina.jar:8.5.46]
at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4546) [catalina.jar:8.5.46]
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5191) [catalina.jar:8.5.46]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) [catalina.jar:8.5.46]
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1412) [catalina.jar:8.5.46]
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1402) [catalina.jar:8.5.46]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) [na:1.8.0_212]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_212]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_212]
at java.lang.Thread.run(Thread.java:748) [na:1.8.0_212]

Answer 1

I have fixed several issues with the sample code and it is now working for me. I ended up creating a fresh spring boot application from https://start.spring.io/

Issue 1:

The @SprintBootApplication annotation in the main application file did not seem to be scanning the java package for other classes marked with @Component and @Xbox One X etc. To fix I had to also add e.g. @ComponentScan("org.example.msal4jsample")

Use the package name for your project.

Issue 2:

The @RequestMapping annotations on the routes in the PageController file are incorrect and I had to shorten them to just "/", "/secure/aad", "/sign_out", "/graph/me"

Issue 3:

An exception occurs as posted above from the AuthFilter class since it implements javax.servlet.FIlter. I had to add the following lines to correct:

	@Override  
	public void init(FilterConfig config) {}  
	  
	@Override  
	public void destroy() {}  

Issue 4:

In the getAuthResulteByAuthCode function in the AuthHelper class -> the URI passed in parameters to acquireToken must have the full redirectUriSignin from config rather that the currentUri passed from the AuthFilter class.

Answer 2

Tacking on to GregoryKnott-6972 answer:

Another issue that could be going on is with Spring Filter registration. Instead of simply dropping a filter into your app, you might need to register it in Spring. This requires that it extend one of Spring's FilterBeans. In my case (i had this same issue), i extended GenericFilterBean in a separate class and then registered the bean in a different class. See below:

FILTER

public class VaryHeaderFilter extends GenericFilterBean {

    @Override
    public void destroy(){}

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException{
        chain.doFilter(request, new HttpServletResponseWrapper((HttpServletResponse) response){

            @Override
            public void addHeader(String name, String value){
                ...do some stuff
            }

            @Override
            public void setHeader(String name, String value){
                 .. do some stuff
            }
        });
    }

FILTER REGISTRATION

@Configuration
public class FilterConfig {

    @Bean
    public FilterRegistrationBean<VaryHeaderFilter> filterFilterRegistrationBean(){
        FilterRegistrationBean<VaryHeaderFilter> filterBean = new FilterRegistrationBean<>();
        VaryHeaderFilter filter = new VaryHeaderFilter();
        filterBean.setFilter(filter);
        return filterBean;
    }

}