Tell Router to use https for the protocol, when enabled.

Author: paulharris

include/crow/app.h

@@ -517,6 +517,7 @@ namespace crow
 #ifdef CROW_ENABLE_SSL
             if (ssl_used_)
             {
+                router_.using_ssl = true;
                 ssl_server_ = std::move(std::unique_ptr<ssl_server_t>(new ssl_server_t(this, bindaddr_, port_, server_name_, &middlewares_, concurrency_, timeout_, &ssl_context_)));
                 ssl_server_->set_tick_function(tick_interval_, tick_function_);
                 ssl_server_->signal_clear();

include/crow/routing.h

@@ -1266,7 +1266,9 @@ namespace crow // NOTE: Already documented in "crow/app.h"
     class Router
     {
     public:
-        Router()
+        bool using_ssl;
+
+        Router() : using_ssl(false)
         {}
 
         DynamicRule& new_rule_dynamic(const std::string& rule)
@@ -1467,7 +1469,7 @@ namespace crow // NOTE: Already documented in "crow/app.h"
                 }
                 else
                 {
-                    res.add_header("Location", "http://" + req.get_header_value("Host") + req.url + "/");
+                    res.add_header("Location", (using_ssl ? "https://" : "http://") + req.get_header_value("Host") + req.url + "/");
                 }
                 res.end();
                 return;
@@ -1715,7 +1717,7 @@ namespace crow // NOTE: Already documented in "crow/app.h"
                 }
                 else
                 {
-                    res.add_header("Location", "http://" + req.get_header_value("Host") + req.url + "/");
+                    res.add_header("Location", (using_ssl ? "https://" : "http://") + req.get_header_value("Host") + req.url + "/");
                 }
                 res.end();
                 return;