Added support to NewJsonRpc to return an error as well as an interface

ethereal/ethereum.go

@@ -100,9 +100,13 @@ func main() {
 	}
 
 	if StartRpc {
-		ethereum.RpcServer = ethrpc.NewJsonRpcServer(ethpub.NewPEthereum(ethereum.StateManager(), ethereum.BlockChain(), ethereum.TxPool()))
+		ethereum.RpcServer, err = ethrpc.NewJsonRpcServer(ethpub.NewPEthereum(ethereum.StateManager(), ethereum.BlockChain(), ethereum.TxPool()))
+		if err != nil {
+			log.Println("Could not start RPC interface:", err)
+		} else {
 			go ethereum.RpcServer.Start()
 		}
+	}
 
 	log.Printf("Starting Ethereum GUI v%s\n", ethutil.Config.Ver)
 

ethereum/ethereum.go

@@ -133,9 +133,13 @@ func main() {
 		go console.Start()
 	}
 	if StartRpc {
-		ethereum.RpcServer = ethrpc.NewJsonRpcServer(ethpub.NewPEthereum(ethereum.StateManager(), ethereum.BlockChain(), ethereum.TxPool()))
+		ethereum.RpcServer, err = ethrpc.NewJsonRpcServer(ethpub.NewPEthereum(ethereum.StateManager(), ethereum.BlockChain(), ethereum.TxPool()))
+		if err != nil {
+			logger.Infoln("Could not start RPC interface:", err)
+		} else {
 			go ethereum.RpcServer.Start()
 		}
+	}
 
 	RegisterInterrupts(ethereum)