Mongrel + mod_proxy URL issues

Rails
1

We have a Centos server with a number of virtual hosts, and my rails app
runs under one of those virtual hosts using mongrel_rails. The app lives
in /home/mydomain/railsapp where /home/mydomain/railsapp/public is the
rails root.

It runs under mongrel on port 8008, so to get to it users invoke the url
http://www.mydomain.com:8008/ - all is fine to this point.

Now I have some users whose firewalls forbid these semantics, so I went
and configured apache (v1.3) to have mod_proxy in an attempt to get the
:8008 out of the URLs the user submits.

With a simple rule like:

ProxyPass / http://mydomain.com:8008/
ProxyPassReverse / http://mydomain.com:8008/

It works beautifully when the user invokes http://www.mydomain.com. I
believe all my paths within the app are relative to the rails root. Now
here is the PROBLEM.

I cannot use ‘/’ for the proxy since mydomain.com needs to work for the
website that already predates the rails app, and in fact wants to offer
it to it’s users. So I changed the mod_proxy rules in apache to:

ProxyPass /myapp/ http://mydomain.com:8008/
ProxyPassReverse /myapp/ http://mydomain.com:8008/

I did this in hopes users could specify http://www.mydomain.com/myapp/

Well this works but the problem is that all the links I created using
the link_to method do not invoke
http://www.mydomain.com/tourney/controller/etc,
the merely are relative hrefs that look like
href=“/mycontroller/mymethod/etc”
and as a result do not go to the proper pages.

How do I fix this? Why is it different when I specify a subdir versus
just specifying ‘/’ in my proxy? I have tried using:

ActionController::AbstractRequest.relative_url_root = “/myapp” and it
just does not help. I am extremely confused and tired. I can’t help but
feel I’m getting close. It’s taken the last 2 days to get mod_proxy
working. Any help is appreciated.

2

Zed-

Thanks for the reply – I’ll be happy to try it, but if I have problems
how do I get back to the current version? Just do another install?

I’ll give it a shot this afternoon.

3

On Thu, 2006-07-27 at 01:23 +0200, Mike K. wrote:

ActionController::AbstractRequest.relative_url_root = “/myapp” and it
just does not help. I am extremely confused and tired. I can’t help but
feel I’m getting close. It’s taken the last 2 days to get mod_proxy
working. Any help is appreciated.

Try the current mongrel 0.3.13.4 pre-release:

sudo gem install mongrel --source=http://mongrel.rubyforge.org/releases/

And use the --prefix setting. That’ll do it. Let me know how it works
otherwise. I’ve got bugs in the queue to be fixed next week.

–
Zed A. Shaw

http://mongrel.rubyforge.org/
http://www.railsmachine.com/ – Need Mongrel support?

4

OK Zed I have the latest installed and everything runs fine as before in
the basic setup where I just run off http://www.mydomain.com:8008/

However I am confused as to how to use the URI. If I set the prefix to
anything when mongrel starts it says it is listening and available on
0.0.0.0:refix.

Should I be using my mod_proxy rules for dereferencing
http://www.mydomain.com/myapp into http://www.mydomain.com:8008/ and
still running mongrel on port 8008 as before?

If I set the prefix I cannot get to my app at all – I probably am not
using it properly. I need some direction.

Thanks in advance,
Mike

p.s. - pls feel free to communiate directly, I have been writing sys s/w
for 20+ years.

5

On Thu, 2006-07-27 at 11:04 +0200, Mike K. wrote:

Zed-

Thanks for the reply – I’ll be happy to try it, but if I have problems
how do I get back to the current version? Just do another install?

I’ll give it a shot this afternoon.

Yes, you should be able to do:

gem uninstall mongrel

And then tell it to uninstall all versions just to clear everything out.
Finally, just do:

gem install mongrel

–
Zed A. Shaw

http://mongrel.rubyforge.org/
http://www.railsmachine.com/ – Need Mongrel support?

6

Zed I mad some progress. I disabled all the mod_proxy business. I took
my app which was in /home/mydomain/test with
railsroot=/home/mydomain/test/public, and copied the whole tree over to
/home/mydomain/public_html – so now there is
/home/mydomain/public_html/test with the usual rails subdirs under it.

If I start up mongrel_rails start -prefix /test/public I can reference
the app by the URL http://www.mydomain.com/test/public. All my link-to’s
are fine.

I did find that anywhere in a view where I hand-coded html for an image
where I said did not work. However if I
recoded it to use <%= image_tag etc %> instead it found the images
properly.

I have one remaining problem - I use file column for images, and
everywhere I use image_tag(url_for_file_column(…)) I am getting the
prefix twice. That is the images are assigned to be at
http://www.mydomain.com/test/public/test/public/classname/images/imagenum
instead of
http://www.mydomain.com/test/public/classname/images/imagenum

I also have to confess things look noticeably slower with the prefix.