server-go/client.go

package server

import (
	"crypto/tls"
	"fmt"
	"net"
	"time"
)

type Client struct {
	Name string

	Network          string
	Address          string
	TLSConfig        *tls.Config
	HandshakeTimeout time.Duration
	KeepAlive        time.Duration
	LocalAddress     net.Addr

	MaxConnections int
}

func (c *Client) Dial() (net.Conn, error) {
	if err := c.Validate(); nil != err {
		return nil, err
	}

	var deadline time.Time
	if 0 != c.HandshakeTimeout {
		deadline = time.Now().Add(c.HandshakeTimeout)
	}

	d := &net.Dialer{
		KeepAlive: c.KeepAlive,
		Deadline:  deadline,
		LocalAddr: c.LocalAddress,
	}

	conn, err := d.Dial(c.Network, c.Address)
	if nil != err {
		return nil, err
	}

	if nil != c.TLSConfig {
		cfg := c.TLSConfig.Clone()
		tlsConn := tls.Client(conn, cfg)
		if err := tlsConn.Handshake(); err != nil {
			tlsConn.Close()
			return nil, err
		}
		if !cfg.InsecureSkipVerify {
			if err := tlsConn.VerifyHostname(cfg.ServerName); err != nil {
				return nil, err
			}
		}
		conn = tlsConn
	}

	return conn, nil
}

func (c *Client) Validate() error {
	if "" == c.Name {
		c.Name = "Client"
	}

	if "" == c.Network {
		return fmt.Errorf("Client: Network is not valid")
	}

	if "" == c.Address {
		return fmt.Errorf("Client: Address is not valid")
	}

	if 0 >= c.MaxConnections {
		c.MaxConnections = 1
	}

	if 0 >= c.KeepAlive {
		c.KeepAlive = DefaultKeepAlive
	}
	if 0 >= c.HandshakeTimeout {
		c.HandshakeTimeout = DefaultHandshakeTimeout
	}

	return nil
}