Bug 55855

Summary:	Unexpected WsFilter is configured in a webapp that does not use WebSocket
Product:	Tomcat 7	Reporter:	Konstantin Kolinko <knst.kolinko>
Component:	Catalina	Assignee:	Tomcat Developers Mailing List <dev>
Status:	RESOLVED FIXED
Severity:	enhancement
Priority:	P2
Version:	7.0.47
Target Milestone:	---
Hardware:	PC
OS:	All

Description Konstantin Kolinko 2013-12-07 00:38:18 UTC

Reproducible in Tomcat 7 on 7.0.47 and on the current 7.0.x (@ r1548765).
I have not tested Tomcat 8.

Steps to reproduce:
1. Create the file webapps/ROOT/test.jsp in the default ROOT web application.
[[[
<% throw new RuntimeException(); %>
]]]

2. Configure JAVA_HOME to point to a Java 7 JRE (7u45).
3. Start Tomcat
4. Browse http://localhost:8080/test.jsp
The following stacktrace is printed on the error page and into the log files:
[[[
org.apache.jasper.JasperException: An exception occurred processing JSP page /test.jsp at line 1

1: <% throw new RuntimeException(); %>


Stacktrace:
	org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:568)
	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:470)
	org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
]]]


The "WsFilter" in the stacktrace is unexpected, as the default ROOT web application does not use WebSockets.

Comment 1 Mark Thomas 2013-12-07 19:00:29 UTC

This is not really that different from saying that a web application that doesn't use JSPs still has a JspServlet instance or a web application that doesn't use sessions still has a session manager.

As discussed on the users list we could add a attribute to the Context to specify a regular expression for SCI implementation classes that should be ignored. I'm changing this to an enhancement request to do exactly that.

Comment 2 Mark Thomas 2013-12-16 21:06:08 UTC

I have patched 8.0.x and 7.0.x so the filter is only added if a web application has active WebSocket Endpoints. I think there is still merit in disabling the SCI since that will remove the need for the annotation scan.

Comment 3 Mark Thomas 2014-01-15 12:24:53 UTC

A new option, containerSciFilter, has been added to the Context in 8.0.x and will be included in 8.0.0 onwards.

Comment 4 Mark Thomas 2014-01-15 13:36:53 UTC

The option has been back-ported to 7.0.x and will be included in 7.0.51 onwards.

Comment 5 Konstantin Kolinko 2015-07-01 12:14:23 UTC

Historical notes:

(In reply to Mark Thomas from comment #2)
> I have patched 8.0.x and 7.0.x so the filter is only added if a web
> application has active WebSocket Endpoints. I think there is still merit in
> disabling the SCI since that will remove the need for the annotation scan.

1. The change described above was later reverted because of a regression: it broke programmatic configuration of endpoints.

The regression was reported in "[VOTE] Release Apache Tomcat 8.0.0-RC9" thread.

http://tomcat.markmail.org/thread/2zmfqvveg3xhegwq

This is the reason why the WsFilter installation cannot be skipped in a web application that uses websockets.

The change: r1551356
Reverting the change: r1552076


2. As part of review for this issue, performance of WsFilter was improved in r1552083. Change log message: "Don't do the expensive 'Is this a WebSocket upgrade request check' if no endpoints have been registered"

(In reply to Mark Thomas from comment #3)
> A new option, containerSciFilter, has been added to the Context in 8.0.x and
> will be included in 8.0.0 onwards.


3. Note, that "containerSciFilter" option can be used to explicitly disable WebSocket support for a selected web application (or globally via the default context configuration file).

http://tomcat.apache.org/tomcat-8.0-doc/config/context.html

http://wiki.apache.org/tomcat/HowTo/FasterStartUp