Use map instead of array for all devices apis (#60)

server/http.go

@@ -58,16 +58,17 @@ func (h *Httpd) allDevicesHandler(
 ) func(http.ResponseWriter, *http.Request) {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		ids := h.mc.SortedIDs()
-		res := make([]apiData, 0)
+		res := make(map[string]apiData)
+
 		for _, id := range ids {
 			readings, err := readingsProvider(id)
 			if err != nil {
 				// Skip this meter, it will simply not be displayed
 				continue
 			}
 
-			data := apiData{device: id, readings: readings}
-			res = append(res, data)
+			data := apiData{readings: readings}
+			res[id] = data
 		}
 
 		if len(res) == 0 {
@@ -102,7 +103,7 @@ func (h *Httpd) singleDeviceHandler(
 			return
 		}
 
-		data := apiData{device: id, readings: readings}
+		data := apiData{readings: readings}
 
 		w.WriteHeader(http.StatusOK)
 		if err := json.NewEncoder(w).Encode(data); err != nil {

server/json.go

@@ -7,17 +7,15 @@ import (
 	"sort"
 )
 
-// apiData combines readings with associated device id for JSON encoding
-// using kvslice it ensured order export of the readings map
+// apiData combines readings with timestamps and uses
+// kvslice to ensure ordered export of the readings map
 type apiData struct {
-	device   string
 	readings *Readings
 }
 
 // MarshalJSON creates device api json for export
 func (d apiData) MarshalJSON() ([]byte, error) {
 	res := kvslice{
-		{"Device", d.device},
 		{"Timestamp", d.readings.Timestamp},
 		{"Unix", d.readings.Timestamp.Unix()},
 	}