add format for dial proxy command

Author: wzshiming

dial.go

@@ -7,7 +7,7 @@ import (
 
 type DialProxyCommand []string
 
-func (p *DialProxyCommand) DialContext(ctx context.Context, network string, address string) (net.Conn, error) {
+func (p *DialProxyCommand) Format(network string, address string) ([]string, error) {
 	host, port, err := net.SplitHostPort(address)
 	if err != nil {
 		return nil, err
@@ -22,6 +22,14 @@ func (p *DialProxyCommand) DialContext(ctx context.Context, network string, addr
 	for i := range proxy {
 		proxy[i] = ReplaceEscape(proxy[i], m)
 	}
+	return proxy, nil
+}
+
+func (p *DialProxyCommand) DialContext(ctx context.Context, network string, address string) (net.Conn, error) {
+	proxy, err := p.Format(network, address)
+	if err != nil {
+		return nil, err
+	}
 	cp := ProxyCommand(ctx, proxy[0], proxy[1:]...)
 	return cp.Stdio()
 }