coder
diff --git a/‎coderd/httpapi/host.go
Lines changed: 20 additions & 0 deletions b/‎coderd/httpapi/host.go
Lines changed: 20 additions & 0 deletions
diff --git a/‎coderd/subdomain.go
Lines changed: 0 additions & 155 deletions b/‎coderd/subdomain.go
Lines changed: 0 additions & 155 deletions
diff --git a/‎coderd/subdomain_test.go
Lines changed: 0 additions & 116 deletions b/‎coderd/subdomain_test.go
Lines changed: 0 additions & 116 deletions
@@ -0,0 +1,20 @@
+package httpapi
+
+import "net/http"
+
+const (
+	// XForwardedHostHeader is a header used by proxies to indicate the
+	// original host of the request.
+	XForwardedHostHeader = "X-Forwarded-Host"
+)
+
+// RequestHost returns the name of the host from the request.  It prioritizes
+// 'X-Forwarded-Host' over r.Host since most requests are being proxied.
+func RequestHost(r *http.Request) string {
+	host := r.Header.Get(XForwardedHostHeader)
+	if host != "" {
+		return host
+	}
+
+	return r.Host
+}