Forward hostname and path in proxy - spring

Question

I have an external service:
https://domainx.com/path/a/to/my/app
Via proxies and webservices it ends-up in my Spring (Data Rest) application on a tomcat server, exposed under:
http://mytomcatserver:8080/this/is/my/app
This app returns a HAL-JSON response with in it a _links section, pointing to itself and other resources. For example:
{
"id": "a_resource_001",
"_links": {
"self": {
"href": "http://mytomcatserver:8080/this/is/my/app/res/a_resource_001"
}
}
}
On the consuming side this link won't mean anything of course.
This was solved: on the consuming side, somewhere a header is added:
X-Forwarded-Host=domainx.com
Then the result became (automatically thanks to the framework):
{
"id": "a_resource_001",
"_links": {
"self": {
"href": "https://domainx.com/this/is/my/app/res/a_resource_001"
}
}
}
The link is improved, but still the path / context-root doesn't match:
/path/a/to/my/app != /this/is/my/app.
So, I thought, is there a X-Forwarded-Path or something like that. Some header that is picked up by my application framework (Tomcat, or Spring, or Spring Data Rest) and used to build the url in the JSON response.
But no, didn't find it.
Does somebody know how to solve such issues. It seems to me I'm not the first dealing with this stuff.
O yeah, using the same path is not an option in this case. (Of course, if I would expose my application's context-root as /path/to/my/app, it would work. not an option in this case)
I imagine there is a solution in Tomcat/Spring where some headers might influence the links.
But I also think that this can be solved in the web-server (apache) or proxy settings.

Answer 1

I had same issues with this.
While you're using a spring application, the easiest way is to set the context path the same to the proxy.
There is also the option to get the x-forwarded-for information. Those has to be sent from proxy.
On application side you can use (in this case application.properties)
server.use-forward-headers=true
server.servlet.context-path=/my/custom/context/path