Python ftplib，通过ftp获取最新文件

Question

我知道如何设置下载这样的文件，但是大多数文件的名称都不是最新的。 我将如何下载最新文件？

通过：

• 修改日期
• 时间戳记
• if version.current < version.new then download

这是我到目前为止的内容：

#!/usr/bin/env python

import ftplib
import os
import socket

HOST = 'ftp.site.org'
DIRN = 'dir/'
FILE = 'filename-LATEST.tar.gz'

def main():
    try:
    f = ftplib.FTP(HOST)
except (socket.error, socket.gaierror), e:
    print 'ERROR: cannot reach "%s"' % HOST
    return
print '*** Connected to host "%s"' % HOST

try:
    f.login()
except ftplib.error_perm:
    print 'ERROR:: cannot login anonymously'
    f.quit()
    return
print '*** Logged in as "anonymous"'

try:
    f.cwd(DIRN)
except ftplib.error_perm:
    print 'ERROR: cannot CD to "%s"' % DIRN
    f.quit()
    return
print '*** Changed to "%s" folder' % DIRN

try:
    f.retrbinary('RETR %s' % FILE, open(FILE, 'wb').write)
except ftplib.error_perm:
    print 'ERROR: cannot read file "%s"' % FILE
    os.unlink(FILE)
else:
    print '*** Downloaded "%s" to CWD' % FILE
f.quit()
return

if __name__ == '__main__':
main()

Answer 1

您必须像ftplib的文档中那样执行ftp.retrlines('LIST',callback)并解析结果

Answer 2

我的答案与ftplib无关。 其pexpect方式。 见下面的代码

#!/usr/bin/python -B

#Program to download latest file from a FTP directory specified

import sys
import os
import pexpect

if len(sys.argv)!=5:
    print "Usage:"
    print "\t",sys.argv[0],"<IP Address> <Username> <Password> <Directory-Path>"
    print "\t","Use \"\" if there is no password"
    sys.exit(1)

ip=str(sys.argv[1])
usr=str(sys.argv[2])
pswd=str(sys.argv[3])
path=str(sys.argv[4])
timeout=10
log_file=file("temp",'w')

try:
    try:
        child=pexpect.spawn("ftp "+ip)
    except:
        print "failed to connect "+sys.exc_function()
        sys.exit(1)

    x=child.expect(['Name',pexpect.EOF,pexpect.TIMEOUT],timeout)
    if x!=0:
        print "No \"Name\" prompt"
        sys.exit(1)

    child.sendline(usr)
    x=child.expect(["[pP]assword","[lL]ogin [sS]ucess","logged in",
            pexpect.EOF,pexpect.TIMEOUT],timeout)
    if x==0:
        child.sendline(pswd)   #Add case for no password
        y=child.expect(["[lL]ogin [sS]uccess","User "+usr+" logged in", 
        "[iI]correct [lLogin]",pexpect.EOF,pexpect.TIMEOUT],timeout) 
        if y!=0 and y!=1:
            print "Login Failed"
            sys.exit(1)
    elif x!=1 and x!=2:
        print "Authentication Timed Out!!"
        sys.exit(1) 

    child.sendline("cd "+path)
    x=child.expect(["[dD]irectory successfully changed","CWD command successful",
            pexpect.EOF,pexpect.TIMEOUT],timeout) 
    if x!=0 and x!=1:
        print "cd Failed!!!"
        sys.exit(1)

    child.logfile=log_file

    child.sendline("ls -lrt")
    x=child.expect(["[dD]irectory send OK","[tT]ransfer [cC]omplete",
            pexpect.EOF,pexpect.TIMEOUT],timeout)
    if x!=0 and x!=1:
        print "listing failed" 
        sys.exit(1)

    os.system("cat temp | grep '^-' |"+\
         "sed -n '$p' | awk '{print $NF}' > file_name") 

    fd=open("file_name","r")   #for loop is not needed here since there'll be only one line
    for line in fd:
        if line:
             latest_file=line.strip()
             break
        else:
             print "No file found"
             sys.exit(1)
    fd.close()
    child.logfile=sys.stdout
    os.system("rm temp file_name")

    child.sendline("bi")
    child.expect("ftp>")
    child.sendline("ha")
    child.expect("ftp>")

    child.sendline("get "+latest_file)
    x=child.expect(["[tT]ransfer [cC]omplete",
            pexpect.EOF,pexpect.TIMEOUT],200) #Add more error cases here
    if x!=0:
        print "Copy Failed" 
        sys.exit(1)

    child.close()
    sys.exit(0)
except KeyboardInterrupt:
    print "",

对于不同的ftp服务器， ftp提示将有所不同。 手动尝试一次，并expect代码中的相同。 您还可以添加更多错误情况。 我使用log_file是因为无法在ftp中通过管道ls -lrt的输出来直接提取文件名。

我知道我的代码效率不高。请在必要时进行编辑。 但是，这将工作！ 干杯