Handlers that handle proxy specific things, such as resolving a full url for outside use, or knowing if https

[apatrida]

A lot of people write common code to deal with things like:

"am I on secure connection?" (have to look at proxy / load balancer headers to know)

"I need a fully qualified link to one of my routes for an outside resource to use" (for example, giving an oauth service the callback URL and making it correct for the given server, protocol, host, etc)

[apatrida]

Yes, the auto redirects are to solve the issues that are common, for the common headers that load balancers / proxies use. Currently, everyone has to learn how to do that themselves or do some hacky way (config for what my root path of my app is, parse the URL, shove in the new part of the URL, redirect) which breaks down when you do more virtual hosts and more complicated scenarios.

For example, one framework I see does about this much work which is pretty standard that I would prefer everyone not try to figure out on their own:

open class RedirectResult(val url: String) : ActionResult {
    override fun writeResponse(context: ActionContext) {
        val scheme = context.request.getHeader("X-Forwarded-Proto") let { scheme ->
            val finalShceme = if (scheme.isNullOrBlank()) { context.request.getScheme() } else scheme
            finalScheme
        }
        val host = context.request.getHeader("X-Forwarded-Host") let {  host ->
            val hostWithPossiblePort = if (host.isNullOrBlank()) { context.request.getServerName() } else { host }
            hostWithPossiblePort.substringBefore(':')
        }
        val port = context.request.getHeader("X-Forwarded-Port") let  { port ->
            val tempPort = if (port.isNullOrBlank())  { context.request.getServerPort()  } else { port }
            val finalPort = if (scheme == "https" && tempPort == "443") { "" }
                            else if (scheme == "http" && tempPort == "80") { "" }
                            else ":$tempPort"
            finalPort
        }

        val finalUrl = if (url.startsWith("http://") || url.startsWith("https://")) {
            context.response.sendRedirect(url)
        }
        else if (url.startsWith("//")) {
            val goto = "$scheme:$url"
            context.response.sendRedirect(goto)
        } else if (url.startsWith("/")) {
            val goto = "$scheme://$host$port$url"
            context.response.sendRedirect(goto)
        } else {
            val oldUri = URI(context.request.getRequestURI())
            val newUri = oldUri.resolve(url)
            val builder = buildUri(newUri).setScheme(scheme).setHost(host)
            val newRedirect = builder.toString()
            context.response.sendRedirect(newRedirect)
        }
        finalUrl
    }
}

That is the minimal redirect, and makes assumptions that are likely correct for http https protocol URL's.

[apatrida]

And if your deployment has a root context (such as servlet base path) that has to be taken into account, etc.

[pmlopes]

@apartida if you could translate that to Java and submit a PR then it would help getting this into master as something like SecureUpgradeHandler or some better name...

[slayful]

Need some help with that?

[slayful]

Here's a non-working prototype: slayful@8cb7b74
Is this the right direction?

[pmlopes]

This has been fixed with: 136ff03 and other improvements.