Apache and 302 redirect issues - apache

Question

I want to temporary bypass a 302 browser redirect by configuring Apache to rewrite all incoming HTTP requests from an external to an internal address before proxy-ing the request to a tomcat server listening on localhost. Reason being that the internal address is not exposed to the user environment. Ultimately the problem should be solved by reconfiguring the application to not redirect the initial browser request to an internal URL for authentication (the OPENAM XUI login page) but for now a workaround is needed.
My first attempt to achieve this was by using the standard ProxyPass and ProxyPassReverse directives but it seems that a 302 redirect request causes the client to break out of the proxy. My hope is now that that with help of the mod_rewrite engine I can make the redirect request not happening by configuring an internal-to-external http-request "translator". Unfortunately all my attempts to achieve such a setup have failed.
Question: is it possible to rewrite all incoming http requests from "https://external.app-server.com/app1/" to "https://internal.app-server.com/app1/" before the request is proxied to a localhost tomcat instance?
My currrently (not working) Apache config:
RewriteEngine On
RewriteCond %{HTTP_HOST} !^https://internal\.app-server\.com
RewriteRule "^/app1(.\*)" http://localhost:8080/app1$1
RewriteRule "^/openam(.\*)" https://localhost:8081/openam$1
SSLProxyEngine on
ProxyPreserveHost off
# ProxyPass /app1 http://localhost:8080/app1/
ProxyPassReverse /app1 http://localhost:8080/app1/
# ProxyPass /openam http://localhost:8081/openam
ProxyPassReverse /openam http://localhost:8081/openam

Answer 1

You will need 2 VirtualHost configurations.
Scenario:
users connect to https://external.example.com/app1
this proxies to https://internal.example.com/app1
this proxies to Tomcat at localhost:PORT
Your Apache configuration could look like:
Listen 443
# Responds to external.example.com requests
<VirtualHost *:443>
ServerName external.example.com
CustomLog "logs/external.access.log" common
ErrorLog "logs/external.error.log"
LogLevel debug
# TODO SSL directives
ProxyPass "/app1" "https://internal.example.com:8080/app1"
ProxyPassReverse "/app1" "https://internal.example.com:8080/app1"
</VirtualHost>
# Responds to internal.example.com requests
<VirtualHost *:443>
ServerName internal.example.com
CustomLog "logs/internal.access.log" common
ErrorLog "logs/internal.error.log"
LogLevel debug
# TODO SSL directives
ProxyPass "/app1" "http://localhost:8080/"
ProxyPassReverse "/app1" "http://localhost:8080/"
</VirtualHost>
Note: modify the port with the real Tomcat port you are using (instead of 8080).
Note 2: split your logs, it makes debugging must easier.
Note 3: can be used in HTML files, not apache configuration.
Note 4: to comment out a configuration line, put #. I do not know what \# does...
OR
If the server that responds to external.example.com and internal.example.com is the same, you can proxy both to tomcat directly.
You would do it like this:
Listen 443
# Responds to external.example.com requests
<VirtualHost *:443>
ServerName external.example.com
CustomLog "logs/external.access.log" common
ErrorLog "logs/external.error.log"
LogLevel debug
# TODO SSL directives
ProxyPass "/app1" "http://localhost:8080/"
ProxyPassReverse "/app1" "http://localhost:8080/"
</VirtualHost>
# Responds to internal.example.com requests
<VirtualHost *:443>
ServerName internal.example.com
CustomLog "logs/internal.access.log" common
ErrorLog "logs/internal.error.log"
LogLevel debug
# TODO SSL directives
ProxyPass "/app1" "http://localhost:8080/"
ProxyPassReverse "/app1" "http://localhost:8080/"
</VirtualHost>