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Posted to users@tomcat.apache.org by Paul Yunusov <py...@rogers.com> on 2002/12/01 16:02:27 UTC
"Servlet unavailable" discussion
Hello,
I was wondering what, in general, can cause a servlet to be "unavailable" as
reported by a StandardWrapperValve of Tomcat 4.1.12.
Thanks,
Paul
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Re: "Servlet unavailable" discussion
Posted by Paul Yunusov <py...@rogers.com>.
Thanks, Tim. Makes a lot of sense now.
Paul
On Sunday 01 December 2002 03:01 pm, Tim Funk wrote:
> Its a security hole. Look at the archives for a more in depth explanation.
>
> Personally, I hate the invoker servlet because
> - it exposes the class name being used. Much harder to refactor your
> system. - Doesn't require explicit definition of servlets. This makes
> maintenance very hard because there is no roadmap of servlet
> definitions. web.xml is nice for this.
> - The absense of explicit declaration allows forgetful lazy programmers
> to keep old servlets around allowing for security leaks.
> - Doesn't require explicit definition of servlets. Its worth saying a
> second time because I hate it that much.
>
> -Tim
>
> Paul Yunusov wrote:
> > On Sunday 01 December 2002 01:55 pm, anywhere-info wrote:
> >>could you be you dint un-comment the invoker servlet in web.xml of ur
> >>tomcat
> >>
> >>Paul Yunusov wrote:
> >>>Hello,
> >>>
> >>>I was wondering what, in general, can cause a servlet to be
> >>> "unavailable" as reported by a StandardWrapperValve of Tomcat 4.1.12.
> >>>Thanks,
> >>>Paul
> >>>
> >>>--
> >>>To unsubscribe, e-mail:
> >>><ma...@jakarta.apache.org> For additional
> >>>commands, e-mail: <ma...@jakarta.apache.org>
> >
> > Thanks for the comment. Are you refering to this entry in web.xml?
> >
> > <servlet-mapping>
> > <servlet-name>invoker</servlet-name>
> > <url-pattern>/servlet/*</url-pattern>
> > </servlet-mapping>
> >
> > Individual mapping of the "/servlet/*" pattern to the invoker servlet for
> > every application seems to have been the default behavior in 4.0.x. Can
> > anyone explain, please, why it's changed to optional now?
> > Paul
> >
> > --
> > To unsubscribe, e-mail:
> > <ma...@jakarta.apache.org> For additional
> > commands, e-mail: <ma...@jakarta.apache.org>
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Re: "Servlet unavailable" discussion
Posted by Tim Funk <fu...@joedog.org>.
Its a security hole. Look at the archives for a more in depth explanation.
Personally, I hate the invoker servlet because
- it exposes the class name being used. Much harder to refactor your system.
- Doesn't require explicit definition of servlets. This makes
maintenance very hard because there is no roadmap of servlet
definitions. web.xml is nice for this.
- The absense of explicit declaration allows forgetful lazy programmers
to keep old servlets around allowing for security leaks.
- Doesn't require explicit definition of servlets. Its worth saying a
second time because I hate it that much.
-Tim
Paul Yunusov wrote:
> On Sunday 01 December 2002 01:55 pm, anywhere-info wrote:
>
>>could you be you dint un-comment the invoker servlet in web.xml of ur
>>tomcat
>>
>>Paul Yunusov wrote:
>>
>>>Hello,
>>>
>>>I was wondering what, in general, can cause a servlet to be "unavailable"
>>>as reported by a StandardWrapperValve of Tomcat 4.1.12.
>>>Thanks,
>>>Paul
>>>
>>>--
>>>To unsubscribe, e-mail:
>>><ma...@jakarta.apache.org> For additional
>>>commands, e-mail: <ma...@jakarta.apache.org>
>>
>
> Thanks for the comment. Are you refering to this entry in web.xml?
>
> <servlet-mapping>
> <servlet-name>invoker</servlet-name>
> <url-pattern>/servlet/*</url-pattern>
> </servlet-mapping>
>
> Individual mapping of the "/servlet/*" pattern to the invoker servlet for
> every application seems to have been the default behavior in 4.0.x. Can
> anyone explain, please, why it's changed to optional now?
> Paul
>
> --
> To unsubscribe, e-mail: <ma...@jakarta.apache.org>
> For additional commands, e-mail: <ma...@jakarta.apache.org>
>
>
>
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Re: "Servlet unavailable" discussion
Posted by Paul Yunusov <py...@rogers.com>.
On Sunday 01 December 2002 01:55 pm, anywhere-info wrote:
> could you be you dint un-comment the invoker servlet in web.xml of ur
> tomcat
>
> Paul Yunusov wrote:
> >Hello,
> >
> >I was wondering what, in general, can cause a servlet to be "unavailable"
> > as reported by a StandardWrapperValve of Tomcat 4.1.12.
> >Thanks,
> >Paul
> >
> >--
> >To unsubscribe, e-mail:
> > <ma...@jakarta.apache.org> For additional
> > commands, e-mail: <ma...@jakarta.apache.org>
Thanks for the comment. Are you refering to this entry in web.xml?
<servlet-mapping>
<servlet-name>invoker</servlet-name>
<url-pattern>/servlet/*</url-pattern>
</servlet-mapping>
Individual mapping of the "/servlet/*" pattern to the invoker servlet for
every application seems to have been the default behavior in 4.0.x. Can
anyone explain, please, why it's changed to optional now?
Paul
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Re: "Servlet unavailable" discussion
Posted by anywhere-info <an...@netscape.net>.
could you be you dint un-comment the invoker servlet in web.xml of ur tomcat
Paul Yunusov wrote:
>Hello,
>
>I was wondering what, in general, can cause a servlet to be "unavailable" as
>reported by a StandardWrapperValve of Tomcat 4.1.12.
>Thanks,
>Paul
>
>--
>To unsubscribe, e-mail: <ma...@jakarta.apache.org>
>For additional commands, e-mail: <ma...@jakarta.apache.org>
>
>
>
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Re: "Servlet unavailable" discussion
Posted by Paul Yunusov <py...@rogers.com>.
On Sunday 01 December 2002 09:57 pm, Craig R. McClanahan wrote:
> On Sun, 1 Dec 2002, Paul Yunusov wrote:
> > Date: Sun, 1 Dec 2002 15:40:41 -0500
> > From: Paul Yunusov <py...@rogers.com>
> > Reply-To: Tomcat Users List <to...@jakarta.apache.org>,
> > pyunusov@rogers.com
> > To: Tomcat Users List <to...@jakarta.apache.org>
> > Subject: Re: "Servlet unavailable" discussion
> >
> > On Sunday 01 December 2002 10:02 am, Paul Yunusov wrote:
> > > Hello,
> > >
> > > I was wondering what, in general, can cause a servlet to be
> > > "unavailable" as reported by a StandardWrapperValve of Tomcat 4.1.12.
> > > Thanks,
> > > Paul
> >
> > The invoker servlet discussion was useful but it didn't really address
> > the question above. (Still, here is a good thread on the invoker servlet:
> > http://www.mail-archive.com/tomcat-user@jakarta.apache.org/msg75346.html)
> >
> > There is one answer so far: not reloading a context after changing a
> > class file in it. Any other observations on causes of "unavailable"
> > servlets?
>
> A couple of other ways to get this error (the Tomcat logs will generally
> include a stack trace of the original exception):
>
> * Throw an exception from the init() method of your servlet.
> (In particular, you can throw an UnavailableException that
> indicates the servlet is either permanently unavailable or
> unavailable only for a certain amount of time.
>
> * Throw an UnavailableException from the service() (or doGet/doPut)
> method of your servlet.
>
> * Specify a <servlet-class> that doesn't exist in your webapp.
>
> > Paul
>
> Craig
Great help, Craig. Thanks.
Paul
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Re: "Servlet unavailable" discussion
Posted by "Craig R. McClanahan" <cr...@apache.org>.
On Sun, 1 Dec 2002, Paul Yunusov wrote:
> Date: Sun, 1 Dec 2002 15:40:41 -0500
> From: Paul Yunusov <py...@rogers.com>
> Reply-To: Tomcat Users List <to...@jakarta.apache.org>,
> pyunusov@rogers.com
> To: Tomcat Users List <to...@jakarta.apache.org>
> Subject: Re: "Servlet unavailable" discussion
>
> On Sunday 01 December 2002 10:02 am, Paul Yunusov wrote:
> > Hello,
> >
> > I was wondering what, in general, can cause a servlet to be "unavailable"
> > as reported by a StandardWrapperValve of Tomcat 4.1.12.
> > Thanks,
> > Paul
>
> The invoker servlet discussion was useful but it didn't really address the
> question above. (Still, here is a good thread on the invoker servlet:
> http://www.mail-archive.com/tomcat-user@jakarta.apache.org/msg75346.html)
>
> There is one answer so far: not reloading a context after changing a class
> file in it. Any other observations on causes of "unavailable" servlets?
A couple of other ways to get this error (the Tomcat logs will generally
include a stack trace of the original exception):
* Throw an exception from the init() method of your servlet.
(In particular, you can throw an UnavailableException that
indicates the servlet is either permanently unavailable or
unavailable only for a certain amount of time.
* Throw an UnavailableException from the service() (or doGet/doPut)
method of your servlet.
* Specify a <servlet-class> that doesn't exist in your webapp.
> Paul
Craig
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Re: "Servlet unavailable" discussion
Posted by Paul Yunusov <py...@rogers.com>.
On Sunday 01 December 2002 10:02 am, Paul Yunusov wrote:
> Hello,
>
> I was wondering what, in general, can cause a servlet to be "unavailable"
> as reported by a StandardWrapperValve of Tomcat 4.1.12.
> Thanks,
> Paul
The invoker servlet discussion was useful but it didn't really address the
question above. (Still, here is a good thread on the invoker servlet:
http://www.mail-archive.com/tomcat-user@jakarta.apache.org/msg75346.html)
There is one answer so far: not reloading a context after changing a class
file in it. Any other observations on causes of "unavailable" servlets?
Paul
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