add error handler for unreachable destination

astar.go

@@ -98,7 +98,7 @@ func (b *Bifrost) RouteOnlyTimeIndependent(rounds *Rounds, origins []SourceKey,
 
 	_, ok := rounds.EarliestArrivals[destKey]
 	if !ok {
-		panic("destination unreachable")
+		panic(NoRouteError(true))
 	}
 
 	journey := b.ReconstructJourney(destKey, 1, rounds)

errors.go

@@ -0,0 +1,9 @@
+package bifrost
+
+import "fmt"
+
+type NoRouteError bool
+
+func (e NoRouteError) Error() string {
+	return fmt.Sprintf("no route found")
+}

raptor.go

@@ -220,7 +220,7 @@ func (b *Bifrost) RouteTransit(rounds *Rounds, origins []SourceKey, destKey uint
 
 	_, ok = rounds.EarliestArrivals[destKey]
 	if !ok {
-		return nil, fmt.Errorf("destination unreachable")
+		return nil, NoRouteError(true)
 	}
 
 	journey := b.ReconstructJourney(destKey, lastRound, rounds)

server/main.go

@@ -115,13 +115,24 @@ func main() {
 
 func handle(c *gin.Context, b *bifrost.Bifrost) {
 	defer func() {
-		if r := recover(); r != nil {
-			fmt.Println("Recovered in f", r)
+		r := recover()
 
-			debug.PrintStack()
+		if r == nil {
+			return
+		}
 
-			c.String(500, "Internal server error: %v", r)
+		if _, ok := r.(bifrost.NoRouteError); ok {
+			c.JSON(404, gin.H{
+				"error": "no route found",
+			})
+			return
 		}
+
+		fmt.Println("Recovered in f", r)
+
+		debug.PrintStack()
+
+		c.String(500, "Internal server error: %v", r)
 	}()
 
 	req := &JourneyRequest{}