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From André Warnier>
Subject Re: linking (limiting???)
Date Wed, 18 Dec 2013 13:55:43 GMT
Ray Holme wrote:
>> Hmm . . . . Lots of speculation here. How are the files referenced in 
> your application? It seems that if the physical files are available, 
> then the application works fine. If the physical files are not 
> available, then the database has problems (firebird under xinetd, 
> perhaps?) and you get 404 errors. Does the application scan a directory 
> and populate the database on startup? Does the database need to know 
> where the files are? Does the database need read access to the files?
>  I have spent the night thinking about this. As I said before, these files have NOTHING
to do with the database (located elsewhere and outside of the webapp, of course).
> They are accessed by either HTTPD or Apache/Tomcat (WHICH?). And therein may be the rub.
Perhaps if the file is accessed by Apache/Tomcat (port 8080), they would be fine. Perhaps
if HTTPD (port 80) tries to get them using /var/www/html/myApplication (a symbolic link to
/opt/apache/webapps/MyApplication) it fails. If this makes sense (and it might), then it depends
on how the file is going to be picked up - is there any write-up to figure out how this httpd
VS apache/tomcat link works (I have no idea what does except pass things back and
forth between the two  :: totally needed in Linux but not on a deployed application in MS-XP
using port 8080 - perhaps exclusively without using  port 80). If this does NOT make sense,
then making the application run as tomcat (not root) does not make sense for improving this
particular situation (agreed that I should do this and will immediately, but root -> tomcat
should not change the link behavior - in any
>  of the three scenarios (link, alias, virtual directory)).
> Once I get the tomcat user to run everrything, I will try again and post the results.

I believe that you may be confused by this "Tomcat user" aspect of things, and you should

maybe look at the issue from the other end.

The application (presumably) generates HTML pages, which are sent to a browser.
In these pages, there are links to the "files" (images or whatever).
What do those links look like in the HTML received by the browser ? (use : "view page 
source" or "copy link location").
And (to compare), what does a link look like, which points to some "executable" part of 
the application (a real java webapp servlet/jsp page) ?

Next, tell us how the browser accesses the application.  Which hostname/port is it using ?
And which server-side software answers to such links ? (does this link directly to Tomcat,

or to Apache httpd which then forwards some (or all) requests to Tomcat ?)

Even if this is not really a Tomcat issue, people on this list may be able/willing to help

you, but you have to provide precise and comprehensive information first, so that they do

not have the impression of wasting their time following dead-ends.

Note that in any case, it is almost always a bad idea to allow an Apache httpd front-end 
to access any part of a Tomcat webapps directory directly (or via filesystem links).
That is because then, it can completely bypass the Tomcat builtin access security 
mechanisms. (It is also not portable if some day you decide to run Apache httpd and Tomcat

on separate hosts).

But it is certainly possible - and perhaps much easier in your case - to have Apache httpd

only forward *some* links to Tomcat, and serve other documents (like your files or images)

directly from within the Apache httpd DocumentRoot file structure.
Which would remove the need to have these files hosted under the Tomcat webapps dir, which

seems to be your ultimate goal if I have followed this correctly.

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