ftp簡介
FTP(File Transfer Protocol)是文件傳輸協議的簡稱。用於Internet上的控制文件的雙向傳輸。同時，它也是一個應用程序（Application）。用戶可以通過它把自己的PC機與世界各地所有運行FTP協議的服務器相連，訪問服務器上的大量程序和信息。如果用戶需要將文件從自己的計算機上發送到另一臺計算機上，可使用FTP上傳（upload）或（put）操作，而更多種的情況是用戶使用FTP下載（download）或獲取（get）操作從FTP服務器上下載文件，python通過ftplib來實現其功能。
常用ftp命令與函數對應關係
| ftp命令 | 對應的FTP對象方法 | 備註 |
|---|---|---|
| ls | nlst([pathname]) | Return a list of file names as returned by the NLST command. |
| dir | dir([pathname]) | Produce a directory listing as returned by the LIST command, printing it to standard output. |
| rename | rename(fromname, toname) | Rename file fromname on the server to toname. |
| delete | delete(filename) | Remove the file named filename from the server. |
| cd | cwd(pathname) | Set the current directory on the server. |
| mkdir | mkd(pathname) | Create a new directory on the server. |
| pwd | pwd() | Return the pathname of the current directory on the server. |
| rmdir | rmd(dirname) | Remove the directory named dirname on the server. |
| size(filename) | Request the size of the file named filename on the server. | |
| quit | quit() | Send a QUIT command to the server and close the connection. |
| close | close() | Close the connection unilaterally. |
| put | storbinary(cmd, fp, blocksize=8192, callback=None, rest=None) | Store a file in binary transfer mode. |
| get | retrbinary(cmd, callback, blocksize=8192, rest=None) | Retrieve a file in binary transfer mode. |
實例
from ftplib import FTP
# 創建FTP對象，設置調試級別
ftp = FTP()
ftp.set_debuglevel(2)
# 連接FTP並打印出歡迎信息
ftp.connect("IP","port")
ftp.login("user","password")
print ftp.getwelcome()
# 進入遠程目錄
ftp.cmd("xxx/xxx")
# 設置的緩衝區大小
bufsize=1024
# 上傳文件
file_handler = open("file1.txt","rb")
ftp.storbinaly("STOR filename1.txt", file_handler, bufsize)
file_handler.close()
# 下載文件
file_handler = open("fil2.txt", "wb")
ftp.retrbinary("RETR file2.txt", file_handler.write, bufsize)
file_handler.close()
#關閉調試模式, 退出ftp
ftp.set_debuglevel(0)
ftp.quit()