// NewRemoteRPCClient returns a RPC client which connects to a running geth instance.
// Depending on the given context this can either be a IPC or a HTTP client.
func NewRemoteRPCClient(ctx *cli.Context) (rpc.Client, error) {
	if ctx.Args().Present() {
		endpoint := ctx.Args().First()
		return NewRemoteRPCClientFromString(endpoint)
	}
	// use IPC by default
	return rpc.NewIPCClient(node.DefaultIPCEndpoint())
}
// NewRemoteRPCClientFromString returns a RPC client which connects to the given
// endpoint. It must start with either `ipc:` or `rpc:` (HTTP).
func NewRemoteRPCClientFromString(endpoint string) (rpc.Client, error) {
	if strings.HasPrefix(endpoint, "ipc:") {
		return rpc.NewIPCClient(endpoint[4:])
	}
	if strings.HasPrefix(endpoint, "rpc:") {
		return rpc.NewHTTPClient(endpoint[4:])
	}
	if strings.HasPrefix(endpoint, "http://") {
		return rpc.NewHTTPClient(endpoint)
	}
	if strings.HasPrefix(endpoint, "ws:") {
		return rpc.NewWSClient(endpoint)
	}
	return nil, fmt.Errorf("invalid endpoint")
}