return proper json

server/handler/fallback.go

@@ -3,6 +3,7 @@ package handler
 import (
 	"bytes"
 	"encoding/json"
+	"fmt"
 	"io"
 	"net/http"
 )
@@ -20,7 +21,12 @@ func (h *Handler) Fallback(w http.ResponseWriter, r *http.Request) {
 	// Pretty-print JSON to console
 	var prettyJSON bytes.Buffer
 	if err := json.Indent(&prettyJSON, body, "", "  "); err != nil {
-		http.Error(w, "Invalid JSON", http.StatusBadRequest)
+		w.Header().Set("Content-Type", "application/json")
+		w.WriteHeader(http.StatusBadRequest)
+		json.NewEncoder(w).Encode(map[string]string{
+			"status":  "ERROR",
+			"message": fmt.Sprintf("Invalid JSON received. Visit /about for more info."),
+		})
 		return
 	}