Hi André and Dan,
Thanks a lot, this solved my problem!
Just one question Dan.Sorry for my ignorance, but could you explain why that is obvious?
>Apache will (in the default configuration) redirect /SEDO to /SEDO/ (if 'SEDO' is a directory). If you're proxying back, Apache won't >know that obviously, but you can use a rewrite rule to simulate this:
I'm just getting started with the proxy stuff and now and then I still get confused.
Thanks again, it's greatly appreciated!
2008/11/18 Dan Udey <dan@xxxxxxxxxxxxxxx>You could also, in order to keep the URLs pretty and SEO and whatnot, just add an extra / on the end.
Apache will (in the default configuration) redirect /SEDO to /SEDO/ (if 'SEDO' is a directory). If you're proxying back, Apache won't know that obviously, but you can use a rewrite rule to simulate this:
RewriteRule ^/([^/]+)$ $1/ [R=301,L]
So /<anything> will be redirected to /<anything>/ automatically, and then browsers will know to look for /<anything>/image.gif - in this case <anything> is any string without a slash anywhere in it
If your URLs only have alphanumeric characters in them, you can pretty up the rule like so:
RewriteRule /([a-zA-Z0-9]+)$ $1/ [R=301,L]
Which is still not pretty, but is somewhat less ugly. Either way, it fixes the problem in question.
On 17-Nov-08, at 3:36 PM, André Warnier wrote:
André Warnier wrote:
Bocalinda wrote:
Yes, that would be /SEDO/index.jspOk, now a simple test :
When, instead of requesting
http://yourserversip/SEDO
if you request in your browser
http://yourserversip/SEDO/index.jsp
then your relative image links are working, right ?
(provided the images are really there)
Now replying to my own previous post, because I want to go to bed and so you would not have to wait for the conclusion :
My reasoning is that the browser does what it does, and what it does is right : if it sees the link <img src="" in a page that it received when it requested
http://server/SEDO
the it will request
http://server/image.gif
for the image.
So far, ok for the browser, but that does not resolve your problem.
To resolve your problem, the browser must known that when it requested
http://server/SEDO
what it really got was
http://server/SEDO/index.jsp
so that it can interpret the link <img src="" as the request URL
http://server/SEDO/image.gif
The way to tell the browser that, would be that when it requests
http://server/SEDO
it receives a response from the server saying "no no, that's not there, but it's here instead" :
http://server/SEDO/index.jsp
That is called a re-direct, or a 301/302 response.
The browser, when it receives this, will (automatically and transparently) request again the resource, but this time as
http://server/SEDO/index.jsp
and following that, it will correctly interpret <img src="" as
http://server/SEDO/image.gif
(or http://server/SEDO_NEW/image.gif as the case may be)
which URLs will be proxied to Tomcat and thus properly load-balanced.
CQFD
So now, the trick consists in having your server, upon request of
http://server/SEDO
to send back a re-direct to
http://server/SEDO/index.jsp
and that is probably a matter for mod_rewrite, or maybe just a configuration directive in Apache.
(See the Redirect* directives)
Note : in the URL to "redirect to", make sure that you specify it with a leading "http://server", because otherwise Apache may get smart and do an internal re-direct, which would not be known by your browser, and thus defeat the above logic.
Hope this helps, as they say.
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2008/11/17 André Warnier <aw@xxxxxxxxxx>
Bocalinda wrote:
Hi André.Let's forget for the time being about "image.gif". It is the step before
I'm glad we managed to understand eachother :)
Sorry, maybe I did not use the correct example before, but that is wrong.
If you original request isThat's what I tried before. But the thing is that I don't know where to
http://172,18.0.1/SEDO
and from there, your browser receives an html page (wherever it came
from),
and that html page contains a link <img href="" then the
browser
will request
http://172,18.0.1/SEDO/image.gif
wait a minute.. maybe it won't. Because it would remove the "SEDO", for
being the last path component, and replace it by "image.gif".
Now I think I get it.
The browser would have to know that it is not really getting "SEDO", but
/SEDO/something.
Hmmm.
I guess that the only way to make this work (if you cannot change the
<img>
links in the pages), would be to force a re-direct to the real thing,
when
the browser requests "SEDO".
redirect to, because:
a. I don't know whether image.gif belongs to SEDO or SEDO-NEW
b. I don't want to hardcode a Tomcat URL, because that server could be
down.
What is the resource that the browser really obtains when it requests
http://172,18.0.1/SEDO ?The resource in the browser remains http://172.18.0.1/SEDO all the time.
(this must be something on your Tomcats)
While I see the following in my apache error logs:
No such file or folder /htdocs/image.gif (More or less, I'm not behind
that
computer right now).
I'm puzzled.
I think it may have to do with ProxyPassReverse not being set properly.
Wait. I repeat :
What is the resource that the browser *really* obtains when it requests
http://172.18.0.1/SEDO ?
(this must be something on your Tomcats)
that, which interests me.
When the browser requests "http://172.18.0.1/SEDO", it first gets an html
page. That page is probably defined as being your "Welcome document" for
that directory in Tomcat. What is that document ?
Put another way, which equivalent URL could be used to get the same page
from Tomcat ?
(Maybe "index.jsp" or something ?)
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