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Posted to users@tomcat.apache.org by David Wall <d....@computer.org> on 2015/08/28 20:47:39 UTC
Can filters be loaded more than once?
I'm using Tomcat 8.0.23, but wondered if a filter defined in the Tomcat
conf/web.xml as well as defined in my app's WEB-INF/web.xml file causes
the filter to be loaded twice or whether duplicate filters are ignored?
If duplicates are ignored, what makes it a "duplicate"? Just the name,
the filter-name and url-pattern combo? The filter-class?
Is the filter-name field can sensitive? Noted that Tomcat uses a
lowercase 's' for it's filter name.
In Tomcat's conf/web.xml:
<filter>
<filter-name>setCharacterEncodingFilter</filter-name>
<filter-class>org.apache.catalina.filters.SetCharacterEncodingFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>UTF-8</param-value>
</init-param>
<async-supported>true</async-supported>
</filter>
<filter-mapping>
<filter-name>setCharacterEncodingFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
In my webapp's WEB-INF/web.xml:
<filter>
<filter-name>SetCharacterEncodingFilter</filter-name>
<filter-class>
org.apache.catalina.filters.SetCharacterEncodingFilter
</filter-class>
<async-supported>true</async-supported> <!-- Enable if using Vaadin
PUSH -->
<init-param>
<param-name>encoding</param-name>
<param-value>UTF-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>SetCharacterEncodingFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
When using Atmosphere with Vaadin PUSH, I occasionally get an exception
that indicates an issue with async operations, and it shows my filter
twice in the stack trace:
*java.lang.IllegalStateException: A filter or servlet of the current
chain does not support asynchronous operations.**
* at
org.apache.catalina.connector.Request.startAsync(Request.java:1610)
at
org.apache.catalina.connector.RequestFacade.startAsync(RequestFacade.java:1037)
at
javax.servlet.ServletRequestWrapper.startAsync(ServletRequestWrapper.java:392)
at
org.atmosphere.cpr.AtmosphereRequest.startAsync(AtmosphereRequest.java:723)
at
org.atmosphere.container.Servlet30CometSupport.suspend(Servlet30CometSupport.java:93)
at
org.atmosphere.container.Servlet30CometSupport.service(Servlet30CometSupport.java:68)
at
org.atmosphere.cpr.AtmosphereFramework.doCometSupport(AtmosphereFramework.java:2075)
at
com.vaadin.server.communication.PushRequestHandler.handleRequest(PushRequestHandler.java:226)
at
com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1408)
at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:351)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
*at
org.apache.catalina.filters.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:108)*
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
*at
org.apache.catalina.filters.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:108)*
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:614)
at
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
at
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at
org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:617)
at
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
at
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
at
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:668)
Re: Can filters be loaded more than once?
Posted by David Wall <d....@computer.org>.
Thanks for the help, Chris. I did note that some of the webapp web.xml
files didn't include the async option. I've decided for now we'll use
Tomcat's conf/web.xml to set this basic filter and let our webapps not
have to think about it.
On 8/28/15 12:27 PM, Christopher Schultz wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA256
>
> David,
>
> On 8/28/15 2:47 PM, David Wall wrote:
>> I'm using Tomcat 8.0.23, but wondered if a filter defined in the
>> Tomcat conf/web.xml as well as defined in my app's WEB-INF/web.xml
>> file causes the filter to be loaded twice or whether duplicate
>> filters are ignored?
>>
>> If duplicates are ignored, what makes it a "duplicate"? Just the
>> name, the filter-name and url-pattern combo? The filter-class?
> I've never looked into this, but I would imagine that Tomcat does no
> checking for duplicate filter definitions. Otherwise, the above
> questions are raised :)
>
>> Is the filter-name field can sensitive?
> Almost certainly.
>
>> Noted that Tomcat uses a lowercase 's' for it's filter name.
>>
>> In Tomcat's conf/web.xml:
>>
>> <filter> <filter-name>setCharacterEncodingFilter</filter-name>
>> <filter-class>org.apache.catalina.filters.SetCharacterEncodingFilter</
> filter-class>
>> <init-param> <param-name>encoding</param-name>
>> <param-value>UTF-8</param-value> </init-param>
>> <async-supported>true</async-supported> </filter>
>>
>> <filter-mapping>
>> <filter-name>setCharacterEncodingFilter</filter-name>
>> <url-pattern>/*</url-pattern> </filter-mapping>
> Note that the above Filter is commented-out by default.
>
>> In my webapp's WEB-INF/web.xml:
>>
>> <filter> <filter-name>SetCharacterEncodingFilter</filter-name>
>> <filter-class>
>> org.apache.catalina.filters.SetCharacterEncodingFilter
>> </filter-class> <async-supported>true</async-supported> <!-- Enable
>> if using Vaadin PUSH --> <init-param>
>> <param-name>encoding</param-name> <param-value>UTF-8</param-value>
>> </init-param> </filter>
>>
>> <filter-mapping>
>> <filter-name>SetCharacterEncodingFilter</filter-name>
>> <url-pattern>/*</url-pattern> </filter-mapping>
>>
>> When using Atmosphere with Vaadin PUSH, I occasionally get an
>> exception that indicates an issue with async operations, and it
>> shows my filter twice in the stack trace:
>>
>> *java.lang.IllegalStateException: A filter or servlet of the
>> current chain does not support asynchronous operations.** *
>> at
>> org.apache.catalina.connector.Request.startAsync(Request.java:1610)
> Boy,
> it would be nice if Tomcat told you which Filter of or Servlet of
> the current change didn't support asynchronous operations. I don't
> immediately see a good way of getting that information from the
> Request object. :(
>
> - -chris
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Re: Can filters be loaded more than once?
Posted by Christopher Schultz <ch...@christopherschultz.net>.
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256
David,
On 8/28/15 2:47 PM, David Wall wrote:
> I'm using Tomcat 8.0.23, but wondered if a filter defined in the
> Tomcat conf/web.xml as well as defined in my app's WEB-INF/web.xml
> file causes the filter to be loaded twice or whether duplicate
> filters are ignored?
>
> If duplicates are ignored, what makes it a "duplicate"? Just the
> name, the filter-name and url-pattern combo? The filter-class?
I've never looked into this, but I would imagine that Tomcat does no
checking for duplicate filter definitions. Otherwise, the above
questions are raised :)
> Is the filter-name field can sensitive?
Almost certainly.
> Noted that Tomcat uses a lowercase 's' for it's filter name.
>
> In Tomcat's conf/web.xml:
>
> <filter> <filter-name>setCharacterEncodingFilter</filter-name>
> <filter-class>org.apache.catalina.filters.SetCharacterEncodingFilter</
filter-class>
>
> <init-param> <param-name>encoding</param-name>
> <param-value>UTF-8</param-value> </init-param>
> <async-supported>true</async-supported> </filter>
>
> <filter-mapping>
> <filter-name>setCharacterEncodingFilter</filter-name>
> <url-pattern>/*</url-pattern> </filter-mapping>
Note that the above Filter is commented-out by default.
> In my webapp's WEB-INF/web.xml:
>
> <filter> <filter-name>SetCharacterEncodingFilter</filter-name>
> <filter-class>
> org.apache.catalina.filters.SetCharacterEncodingFilter
> </filter-class> <async-supported>true</async-supported> <!-- Enable
> if using Vaadin PUSH --> <init-param>
> <param-name>encoding</param-name> <param-value>UTF-8</param-value>
> </init-param> </filter>
>
> <filter-mapping>
> <filter-name>SetCharacterEncodingFilter</filter-name>
> <url-pattern>/*</url-pattern> </filter-mapping>
>
> When using Atmosphere with Vaadin PUSH, I occasionally get an
> exception that indicates an issue with async operations, and it
> shows my filter twice in the stack trace:
>
> *java.lang.IllegalStateException: A filter or servlet of the
> current chain does not support asynchronous operations.** *
> at
> org.apache.catalina.connector.Request.startAsync(Request.java:1610)
Boy,
>
it would be nice if Tomcat told you which Filter of or Servlet of
the current change didn't support asynchronous operations. I don't
immediately see a good way of getting that information from the
Request object. :(
- -chris
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Comment: GPGTools - http://gpgtools.org
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