Fix swagger scheme (#2221)

A fixup up for #2217 to properly adjust the schemes defined in swagger.

Previously the X-Forwarded-Proto wasn't respected but now it is.

Author: kwk

main.go

@@ -411,21 +411,20 @@ func main() {
 		func(res http.ResponseWriter, req *http.Request, url url.Values) {
 			b, err := swagger.Asset("swagger.json")
 			if err != nil {
-				res.WriteHeader(404)
+				res.WriteHeader(http.StatusNotFound)
 				return
 			}
 
 			s := string(b)
 			// replace swagger host with host from request
-			newHost := rest.AbsoluteURL(req, "")
-			newHost = strings.Replace(newHost, "http://", "", -1)
-			newHost = strings.Replace(newHost, "https://", "", -1)
-			s = strings.Replace(s, `"host":"openshift.io"`, `"host":"`+newHost+`"`, -1)
-
-			// replace schemes in swagger with the current URL scheme
-			if req.URL != nil && strings.ToLower(req.URL.Scheme) == "https" {
-				s = strings.Replace(s, `"schemes":["http"]`, `"schemes":["https"]`, -1)
+			u, err := rest.AbsoluteURLAsURL(req, "")
+			if err != nil {
+				res.WriteHeader(http.StatusInternalServerError)
+				res.Write([]byte(err.Error()))
+				return
 			}
+			s = strings.Replace(s, `"host":"openshift.io"`, `"host":"`+u.Host+`"`, -1)
+			s = strings.Replace(s, `"schemes":["http"]`, `"schemes":["`+u.Scheme+`"]`, -1)
 
 			res.Header().Set("Access-Control-Allow-Origin", "*")
 			res.Header().Set("Access-Control-Allow-Methods", "GET")

rest/url.go

@@ -6,6 +6,7 @@ import (
 	"io"
 	"io/ioutil"
 	"net/http"
+	"net/url"
 	"strings"
 
 	"github.com/fabric8-services/fabric8-wit/errors"
@@ -24,6 +25,12 @@ func AbsoluteURL(req *http.Request, relative string) string {
 	return fmt.Sprintf("%s://%s%s", scheme, req.Host, relative)
 }
 
+// AbsoluteURLAsURL returns the result of AbsoluteURL parsed into a URL
+// structure and a potential parsing error.
+func AbsoluteURLAsURL(req *http.Request, relative string) (*url.URL, error) {
+	return url.Parse(AbsoluteURL(req, relative))
+}
+
 // ReplaceDomainPrefix replaces the last name in the host by a new name. Example: api.service.domain.org -> sso.service.domain.org
 func ReplaceDomainPrefix(host string, replaceBy string) (string, error) {
 	split := strings.SplitN(host, ".", 2)