Golang中支持会话恢复的FTPS有哪些可用包

在Go语言中，支持FTPS会话恢复的包确实有限。以下是几个可用的选项：

1. github.com/jlaffaye/ftp：这是最常用的FTP包，支持TLS/SSL，但会话恢复需要手动实现。
2. github.com/secsy/goftp：您已经在使用，它支持TLS，但会话恢复同样需要额外处理。

对于会话恢复，您需要在代码中实现重连和状态恢复的逻辑。以下是一个使用jlaffaye/ftp包实现会话恢复的示例：

package main

import (
    "crypto/tls"
    "fmt"
    "log"
    "net"
    "time"
    "github.com/jlaffaye/ftp"
)

type FTPSClient struct {
    conn     *ftp.ServerConn
    host     string
    username string
    password string
    tlsConfig *tls.Config
}

func NewFTPSClient(host, username, password string) *FTPSClient {
    return &FTPSClient{
        host:     host,
        username: username,
        password: password,
        tlsConfig: &tls.Config{
            InsecureSkipVerify: true, // 仅测试使用，生产环境应配置正确证书
        },
    }
}

func (c *FTPSClient) Connect() error {
    dialer := &net.Dialer{Timeout: 30 * time.Second}
    conn, err := ftp.Dial(c.host, ftp.DialWithDialer(dialer), ftp.DialWithTLS(c.tlsConfig))
    if err != nil {
        return err
    }
    
    err = conn.Login(c.username, c.password)
    if err != nil {
        return err
    }
    
    c.conn = conn
    return nil
}

func (c *FTPSClient) Reconnect() error {
    if c.conn != nil {
        c.conn.Quit()
    }
    return c.Connect()
}

func (c *FTPSClient) UploadFile(remotePath string, localPath string) error {
    // 尝试上传，如果失败则重连重试
    err := c.upload(remotePath, localPath)
    if err != nil {
        log.Println("Upload failed, reconnecting...")
        if reconnectErr := c.Reconnect(); reconnectErr != nil {
            return fmt.Errorf("reconnect failed: %v", reconnectErr)
        }
        // 重试上传
        return c.upload(remotePath, localPath)
    }
    return nil
}

func (c *FTPSClient) upload(remotePath string, localPath string) error {
    file, err := os.Open(localPath)
    if err != nil {
        return err
    }
    defer file.Close()
    
    return c.conn.Stor(remotePath, file)
}

func main() {
    client := NewFTPSClient("ftps.example.com:21", "username", "password")
    
    // 初始连接
    if err := client.Connect(); err != nil {
        log.Fatal(err)
    }
    defer client.conn.Quit()
    
    // 上传文件，支持会话恢复
    if err := client.UploadFile("/remote/path/file.txt", "./local/file.txt"); err != nil {
        log.Fatal(err)
    }
    
    log.Println("File uploaded successfully")
}

对于secsy/goftp包，您可以类似地实现重连逻辑：

package main

import (
    "crypto/tls"
    "fmt"
    "log"
    "time"
    "github.com/secsy/goftp"
)

func createClient(server, user, pass string) (*goftp.Client, error) {
    config := goftp.Config{
        User:     user,
        Password: pass,
        Timeout:  30 * time.Second,
        TLSConfig: &tls.Config{
            InsecureSkipVerify: true,
        },
        TLSMode: goftp.TLSExplicit,
    }
    
    return goftp.DialConfig(config, server)
}

func uploadWithRetry(client *goftp.Client, remotePath, localPath string, maxRetries int) error {
    var err error
    for i := 0; i < maxRetries; i++ {
        file, openErr := os.Open(localPath)
        if openErr != nil {
            return openErr
        }
        
        err = client.Store(remotePath, file)
        file.Close()
        
        if err == nil {
            return nil
        }
        
        log.Printf("Upload attempt %d failed: %v", i+1, err)
        
        // 重新创建客户端
        if i < maxRetries-1 {
            time.Sleep(2 * time.Second)
            client, err = createClient("ftps.example.com:21", "user", "pass")
            if err != nil {
                return fmt.Errorf("reconnect failed: %v", err)
            }
        }
    }
    return err
}

func main() {
    client, err := createClient("ftps.example.com:21", "user", "pass")
    if err != nil {
        log.Fatal(err)
    }
    
    err = uploadWithRetry(client, "/remote/file.txt", "./local/file.txt", 3)
    if err != nil {
        log.Fatal(err)
    }
    
    log.Println("File uploaded successfully")
}

这些示例展示了如何在Go中实现FTPS的会话恢复功能。需要注意的是，这些包本身不提供自动会话恢复，需要您在应用层实现重连和重试逻辑。