more file structure

api/resource/common/handler.go

@@ -0,0 +1,43 @@
+package common
+
+import (
+	"fmt"
+	"net"
+	"net/http"
+)
+
+// Display some information about this API for the default page
+// TODO - static fileserver with docs
+func HomeLink(w http.ResponseWriter, r *http.Request) {
+	//w.WriteHeader(http.StatusNotImplemented)
+	fmt.Fprintf(w, "VM Chargeback Tracking Program. API interface only. See Nathan Coad (nathan.coad@dell.com) for further details. ")
+}
+
+// Display error message for invalid requests
+func HandleNotFound(w http.ResponseWriter, r *http.Request) {
+	ip, err := IPFromRequest(r)
+	if err != nil {
+		fmt.Println("Error", err)
+		http.Error(w, "VM Chargeback Tracking Program.. Invalid Path Specified.", http.StatusNotFound)
+		return
+	}
+
+	fmt.Printf("Request from IP %s\n", ip.String())
+	http.Error(w, "VM Chargeback Tracking Program. Invalid Path Specified.", http.StatusNotFound)
+	// TODO - investigate rate limiting for invalid requests
+}
+
+// IPFromRequest extracts the user IP address from req, if present.
+// @see https://blog.golang.org/context/userip/userip.go
+func IPFromRequest(req *http.Request) (net.IP, error) {
+	ip, _, err := net.SplitHostPort(req.RemoteAddr)
+	if err != nil {
+		return nil, fmt.Errorf("userip: %q is not IP:port", req.RemoteAddr)
+	}
+
+	userIP := net.ParseIP(ip)
+	if userIP == nil {
+		return nil, fmt.Errorf("userip: %q is not IP:port", req.RemoteAddr)
+	}
+	return userIP, nil
+}