使用 goftp 列出 FTP 个文件

Question

我正在尝试编写一个连接到 FTP 服务器的简单 Go 程序，列出指定目录中的文件并拉取它们。

代码是这样的：

package main

import (
    "bytes"
    "fmt"
    "github.com/secsy/goftp"
    "io/ioutil"
    "log"
    "os"
    "path"
    "time"
)

func main() {
    config := goftp.Config{
        User:               "anonymous",
        Password:           "root@local.me",
        ConnectionsPerHost: 21,
        Timeout:            10 * time.Second,
        Logger:             os.Stderr,
    }

    // Connecting to the server
    client, dailErr := goftp.DialConfig(config, "ftp.example.com")

    if dailErr != nil {
        log.Fatal(dailErr)
        panic(dailErr)
    }
    // setting the search directory
    dir := "/downloads/"
    files, err := client.ReadDir(dir)

    if err != nil {
        for _, file := range files {
            if file.IsDir() {
                path.Join(dir, file.Name())
            } else {
                fmt.Println("the file is %s", file.Name())
            }
        }
    }
    // this section works , I am setting a file name and I can pull it
    // if I mark the search part
    ret_file := "example.PDF"

    fmt.Println("Retrieving file: ", ret_file)
    buf := new(bytes.Buffer)
    fullPathFile := dir + ret_file
    rferr := client.Retrieve(fullPathFile, buf)

    if rferr != nil {
        panic(rferr)
    }

    fmt.Println("writing data to file", ret_file)

    fmt.Println("Opening file", ret_file, "for writing")
    w, _ := ioutil.ReadAll(buf)
    ferr := ioutil.WriteFile(ret_file, w, 0644)

    if ferr != nil {
        log.Fatal(ferr)
        panic(ferr)
    } else {
        fmt.Println("Writing", ret_file, " completed")
    }
}

出于某种原因，我在 ReadDir 函数上遇到错误。我需要获取文件名以便下载它们。

Answer 1

当 ReadDir() returns 出错时，您正试图循环 files。这永远行不通，因为任何时候返回错误 files 都是 nil.

这是非常标准的行为，可以通过阅读 the implementation of ReadDir().

来确认

我猜你可能用过 the example from the project used to demonstrate ReadDir() as a starting point. Within the example, the error handling is involved because it's deciding whether or not to continue walking the directory tree. However, note that when ReadDir() returns an error that doesn't result in stopping the program, the subsequent for loop is a no-op，因为 files 是 nil。

这是一个小程序，它以直接的方式成功地使用了 Readdir() 的结果：

package main

import (
    "fmt"
    "github.com/secsy/goftp"
)

const (
    ftpServerURL = "ftp.us.debian.org"
    ftpServerPath = "/debian/"
)

func main() {
    client, err := goftp.Dial(ftpServerURL)
    if err != nil {
        panic(err)
    }
    files, err := client.ReadDir(ftpServerPath)
    if err != nil {
        panic(err)
    }
    for _, file := range files {
        fmt.Println(file.Name())
    }
}

它输出（匹配 http://ftp.us.debian.org/debian/ 的当前列表）：

$ go run goftp-test.go
README
README.CD-manufacture
README.html
README.mirrors.html
README.mirrors.txt
dists
doc
extrafiles
indices
ls-lR.gz
pool
project
tools
zzz-dists

使用 goftp 列出 FTP 个文件

List FTP files with goftp

ftp

ftp-client

go