MXS-1220: Add self links to all resources

A self link to the resource itself provides a convenient way for the
client to request a resource, modify it and call the self link to update
it. This removes some of the burden on the client to keep track of the
resource links by placing these in the resource itself.

server/core/httprequest.cc

@@ -19,6 +19,11 @@
 using std::string;
 using std::deque;
 
+#define HTTP_HOST_HEADER "Host"
+
+const std::string HttpRequest::HTTP_PREFIX = "http://";
+const std::string HttpRequest::HTTPS_PREFIX = "https://";
+
 /** TODO: Move this to a C++ string utility header */
 namespace maxscale
 {
@@ -93,7 +98,9 @@ HttpRequest::HttpRequest(struct MHD_Connection *connection, string url, string m
     m_connection(connection)
 {
     process_uri(url, m_resource_parts);
-    m_hostname = get_header("Host");
+    // TODO: Add https support
+    m_hostname = HttpRequest::HTTP_PREFIX;
+    m_hostname += get_header(HTTP_HOST_HEADER);
 }
 
 HttpRequest::~HttpRequest()