base-golang/pkg/downloader/controller/controller.go

package controller

import (
	"golang.org/x/net/proxy"
	"net"
	"net/http"
	"net/url"
	"os"
	"time"
)

type Controller interface {
	Touch(name string, size int64) (file *os.File, err error)
	Open(name string) (file *os.File, err error)
	Write(name string, offset int64, buf []byte) (int, error)
	Close(name string) error
	ContextDialer() (proxy.Dialer, error)
	ContextCookie() http.CookieJar
	ContextTimeout() time.Duration
	ContextProxy() func(*http.Request) (*url.URL, error)
}

type Option func(*option)

type option struct {
	CookieJar http.CookieJar
	Timeout   time.Duration
	Dialer    proxy.Dialer
	Proxy     func(*http.Request) (*url.URL, error)
}

func WithCookie(cookieJar http.CookieJar) Option {
	return func(opt *option) {
		opt.CookieJar = cookieJar
	}
}

func WithTimeout(timeout time.Duration) Option {
	return func(opt *option) {
		opt.Timeout = timeout
	}
}

func WithDialer(dialer proxy.Dialer) Option {
	return func(opt *option) {
		opt.Dialer = dialer
	}
}

func WithProxy(fn func(*http.Request) (*url.URL, error)) Option {
	return func(opt *option) {
		opt.Proxy = fn
	}
}

type DefaultController struct {
	*option
	Files map[string]*os.File
}

func NewController(options ...Option) *DefaultController {
	opt := new(option)
	for _, f := range options {
		f(opt)
	}
	if opt.Timeout == 0 {
		opt.Timeout = time.Second * 30
	}
	if opt.Dialer == nil {
		opt.Dialer = proxy.FromEnvironment()
	}
	return &DefaultController{
		Files:  make(map[string]*os.File),
		option: opt,
	}
}

func (c *DefaultController) Touch(name string, size int64) (file *os.File, err error) {
	file, err = os.Create(name)
	if size > 0 {
		err = os.Truncate(name, size)
		if err != nil {
			return nil, err
		}
	}
	if err == nil {
		c.Files[name] = file
	}
	return
}

func (c *DefaultController) Open(name string) (file *os.File, err error) {
	file, err = os.OpenFile(name, os.O_RDWR, os.ModePerm)
	if err == nil {
		c.Files[name] = file
	}
	return
}

func (c *DefaultController) Write(name string, offset int64, buf []byte) (int, error) {
	return c.Files[name].WriteAt(buf, offset)
}

func (c *DefaultController) Close(name string) error {
	err := c.Files[name].Close()
	delete(c.Files, name)
	return err
}

func (c *DefaultController) ContextDialer() (proxy.Dialer, error) {
	return &DialerWarp{dialer: c.Dialer}, nil
}

func (c *DefaultController) ContextCookie() http.CookieJar {
	return c.CookieJar
}

func (c *DefaultController) ContextTimeout() time.Duration {
	return c.Timeout
}

func (c *DefaultController) ContextProxy() func(*http.Request) (*url.URL, error) {
	return c.Proxy
}

type DialerWarp struct {
	dialer proxy.Dialer
}

type ConnWarp struct {
	conn net.Conn
}

func (c *ConnWarp) Read(b []byte) (n int, err error) {
	return c.conn.Read(b)
}

func (c *ConnWarp) Write(b []byte) (n int, err error) {
	return c.conn.Write(b)
}

func (c *ConnWarp) Close() error {
	return c.conn.Close()
}

func (c *ConnWarp) LocalAddr() net.Addr {
	return c.conn.LocalAddr()
}

func (c *ConnWarp) RemoteAddr() net.Addr {
	return c.conn.RemoteAddr()
}

func (c *ConnWarp) SetDeadline(t time.Time) error {
	return c.conn.SetDeadline(t)
}

func (c *ConnWarp) SetReadDeadline(t time.Time) error {
	return c.conn.SetReadDeadline(t)
}

func (c *ConnWarp) SetWriteDeadline(t time.Time) error {
	return c.conn.SetWriteDeadline(t)
}

func (d *DialerWarp) Dial(network, addr string) (c net.Conn, err error) {
	conn, err := d.dialer.Dial(network, addr)
	if err != nil {
		return nil, err
	}
	return &ConnWarp{conn: conn}, nil
}