RestProxy fails to proxy queries through a reverse-proxied remote Attivio instance

[voutilad]

If configuring searchui to proxy queries to a remote host that's front-ended with a reverse-proxy service, it generates proxy queries that may result in 404 errors due to bad HTTP headers even though the url generated is valid with the environment.

The RestProxy controller needs to drop the original Host header from the searchui-frontend React client to resolve this issue at least with IIS 8.5 performing SSL termination and reverse proxying of HTTP requests.

I have a fix, but don't know the appropriate way to share it.

My current environment looks similar to:

                                                                 Remote Machine
+---------------------------------+            +---------------------------------------------------+
|  Tomcat 9                       |            | +---------------+       +----------------------+  |
|                                 |            | |               |       |                      |  |
|   +---------------------------+ |            | |               |       |     Attivio AIE      |  |
|   | searchui servlet          | |            | |  IIS w/       |       |     v5.5             |  |
|   |    +-------------------+  | |            | |  reverse proxy|       |                      |  |
|   |    |                   |  | |  HTTPS     | |  rules &      | http  |                      |  |
|   |    | RestProxy       +-------------------->+  https       +----------->                   |  |
|   |    | controller        |  | |            | |  termination  |       |                      |  |
|   |    +----------^--------+  | |            | |               |       |                      |  |
|   |               |           | |            | |               |       |                      |  |
|   +---------------------------+ |            | +---------------+       +----------------------+  |
+---------------------------------+            +---------------------------------------------------+
                    |
                    |http
                    |
+---------------------------------+
| Local Machine     |             |
|   +---------------------------+ |
|   | Browser       |           | |
|   |   +-----------+---------+ | |
|   |   |                     | | |
|   |   | searchui client     | | |
|   |   |                     | | |
|   |   |                     | | |
|   |   +---------------------+ | |
|   +---------------------------+ |
+---------------------------------+