dashboard: handle correctly baseurl option

On the first public.html GET, load the index.html file, as Go
Template.

dashboard/static.go

@@ -1,8 +1,13 @@
 package main
 
 import (
+	"bytes"
 	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
 	"net/http"
+	"os"
 	"path"
 	"strings"
 	"time"
@@ -14,16 +19,37 @@ import (
 	"github.com/julienschmidt/httprouter"
 )
 
+var BaseURL = "/"
 var forwarder *string = nil
 var fwdPublicJson = false
 
+var indexTmpl []byte
+
+func getIndexHtml(w io.Writer) {
+	if len(indexTmpl) == 0 {
+		if file, err := os.Open(path.Join(StaticDir, "index.html")); err != nil {
+			log.Println("Unable to open index.html: ", err)
+		} else {
+			defer file.Close()
+
+			if indexTmpl, err = ioutil.ReadAll(file); err != nil {
+				log.Println("Cannot read whole index.html: ", err)
+			} else {
+				indexTmpl = bytes.Replace(indexTmpl, []byte("{{.urlbase}}"), []byte(path.Clean(path.Join(BaseURL+"/", "nuke"))[:len(path.Clean(path.Join(BaseURL+"/", "nuke")))-4]), -1)
+			}
+		}
+	}
+
+	w.Write(indexTmpl)
+}
+
 func init() {
 	api.Router().GET("/", func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
-		http.ServeFile(w, r, path.Join(StaticDir, "index.html"))
+		http.Redirect(w, r, "public0.html", http.StatusFound)
 	})
 	for i := 0; i <= 9; i++ {
 		api.Router().GET(fmt.Sprintf("/public%d.html", i), func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
-			http.ServeFile(w, r, path.Join(StaticDir, "index.html"))
+			getIndexHtml(w)
 		})
 	}