My Host

John_Hinnegan · February 10, 2012, 6:00pm

I need to get some absolute redirects working – basically I set callback hooks to external services, but I want these hooks to use my configured CNAME’s. I’m trying to find a way so that my app doesn’t have to know about these CNAME’s. So I’m looking at the request in the controller to try and get the base URL where I’m running.

To test, I’m using localtunnel. I have found what I’m looking for in 3 places, and I’m wondering if one is better than another or if one is more reliably set than another.

request.env[“SERVER_NAME”]

request.host

request.env[“HTTP_HOST”]

All three of these have the value I’m looking for (e.g. “3eym.localtunnel.com”) . Is there any difference between them? Should I favor one over another?

Philip_Hallstrom · February 10, 2012, 7:17pm

I need to get some absolute redirects working -- basically I set callback hooks to external services, but I want these hooks to use my configured CNAME's. I'm trying to find a way so that my app doesn't have to know about these CNAME's. So I'm looking at the request in the controller to try and get the base URL where I'm running.

To test, I'm using localtunnel. I have found what I'm looking for in 3 places, and I'm wondering if one is better than another or if one is more reliably set than another.

request.env["SERVER_NAME"] request.host request.env["HTTP_HOST"]

All three of these have the value I'm looking for (e.g. "3eym.localtunnel.com") . Is there any difference between them? Should I favor one over another?

I'd use request.host...

That calls raw_host_with_port (and trims the port). raw_host_with_port looks like this:

def raw_host_with_port if forwarded = env["HTTP_X_FORWARDED_HOST"] forwarded.split(/,\s?/).last else env['HTTP_HOST'] || "#{env['SERVER_NAME'] || env['SERVER_ADDR']}:#{env['SERVER_PORT']}" end end

So does some extra checking for you...

github.com

rails/rails/blob/5f67cfeda116f2b932ef72781420aa37e62437ca/actionpack/lib/action_dispatch/http/url.rb#L92


      
          def url
            protocol + host_with_port + fullpath
          end
          
          # Returns 'https://' if this is an SSL request and 'http://' otherwise.
          def protocol
            @protocol ||= ssl? ? 'https://' : 'http://'
          end
          
          # Returns the \host for this request, such as "example.com".
          def raw_host_with_port
            if forwarded = env["HTTP_X_FORWARDED_HOST"]
              forwarded.split(/,\s?/).last
            else
              env['HTTP_HOST'] || "#{env['SERVER_NAME'] || env['SERVER_ADDR']}:#{env['SERVER_PORT']}"
            end
          end
          
          # Returns the host for this request, such as example.com.
          def host
            raw_host_with_port.sub(/:\d+$/, '')

-philip

John_Hinnegan · February 10, 2012, 11:23pm

thank you