Is there a means to set the host & port for the Spring HATEOAS `ControllerLinkBuilder`?

Question

Spring HATEOAS provides the handy ControllerLinkBuilder to create links to controller methods, which will be added as hrefs in the JSON/XML returned to a client. For instance:

resource.add(linkTo(methodOn(FooController.class)
    .findFoo(entity.getClient().getId()))
    .withRel("show"));

... might generate JSON a bit like:

{
  "name":"foo", 
  "links":[
    {"rel":"show","href":"http://111.11.11.111:28080/foos/1"}
  ]
}

However...

I tend to access my services through a reverse proxy. Which I guess most people probably would. This lets me have multiple services running on different ports, but lets me access them all through the same base URL. Unfortunately, accessing through a proxy means that the URL being generated by Spring HATEOAS is not a URL which is valid for accessing the resource.

Now I could just hard-code the links, but that's rather fragile. Having the ControllerLinkBuilder generate URLs based on my controller @RequestMapping configuration is valuable to me, as it avoids the risk of my links getting out of sync with reality.

So I was wondering whether there's a property somewhere that I could use to force the host and port values. I'm using Spring Boot, so ideally a property that I could add to the application.properties file in each environment.

Note:

As this issue seems to be caused by a bug in Spring, I should probably point out that I'm using Spring Boot 1.0.2.RELEASE.

Answer 1

A pure answer to the question I originally posed seems to involve writing my own ControllerLinkBuilder implementation which has the option of building the URL based on environment variables that I set. I may do that.

However, the reason I was trying to force the URL is that there is a bug in the ControllerLinkBuilder. It's worth noting that this bug is a bug in code which was copied from ServletUriComponentsBuilder.

String scheme = request.getScheme();

// The port number retrieved here is the port set by server.port
int port = request.getServerPort();
String host = request.getServerName();

String header = request.getHeader("X-Forwarded-Host");

if (StringUtils.hasText(header)) {
    String[] hosts = StringUtils.commaDelimitedListToStringArray(header);
    String hostToUse = hosts[0];
    if (hostToUse.contains(":")) {
        String[] hostAndPort = StringUtils.split(hostToUse, ":");
        host  = hostAndPort[0];

        // Note that the port is set if there is a ":" in the address.
        port = Integer.parseInt(hostAndPort[1]);
    }
    else {
        host = hostToUse;
    }
}

ServletUriComponentsBuilder builder = new ServletUriComponentsBuilder();
builder.scheme(scheme);
builder.host(host);

// Here lies the bug...
if ((scheme.equals("http") && port != 80) || (scheme.equals("https") && port != 443)) {
    builder.port(port);
}

Basically, the port is only set when the server.port is not 80 or 443, rather than being based on the port used for the request. This means that if the X-Forwarded-Host is using a default port for the scheme (and therefore not having anything after the ":"), then the application port will be used instead of the default.