我需要从Canada Government的公共地理数据库中在我的PC（Windows操作系统）上的“C：\ DEMDownload”文件夹中下载几个（数字地球模型）zip文件。
当我在ftp.retrbinary('RETR %s' %file, open(local_file, 'wb').write)行运行我的代码时，我收到以下错误消息
Traceback (most recent call last):
File "<input>", line 1, in <module>
File "C:\Python27\lib\ftplib.py", line 414, in retrbinary
conn = self.transfercmd(cmd, rest)
File "C:\Python27\lib\ftplib.py", line 376, in transfercmd
return self.ntransfercmd(cmd, rest)[0]
File "C:\Python27\lib\ftplib.py", line 339, in ntransfercmd
resp = self.sendcmd(cmd)
File "C:\Python27\lib\ftplib.py", line 249, in sendcmd
return self.getresp()
File "C:\Python27\lib\ftplib.py", line 224, in getresp
raise error_perm, resp
error_perm: 550 Failed to open file.
二。是否可以避免编写available_days列表并创建要下载的所有zip文件的列表
import os, ftplib
destdir='C:\DEMDownload'
ftp = ftplib.FTP('ftp2.cits.rncan.gc.ca')
ftp.login('anonymous', '')
available_days= ['001k11.zip',
'001k12.zip',
'001k13.zip',
'001k14.zip',
'001k15.zip',
'001l13.zip',
'001l14.zip',
'001l16.zip',
'001m01.zip',
'001m02.zip',
'001m03.zip',
'001m04.zip',
'001m05.zip',
'001m06.zip',
'001m07.zip',
'001m08.zip',
'001m09.zip',
'001m10.zip',
'001m11.zip',
'001m12.zip',
'001m13.zip',
'001m14.zip',
'001m15.zip',
'001m16.zip',
'001n02.zip',
'001n03.zip',
'001n04.zip',
'001n05.zip',
'001n06.zip',
'001n07.zip',
'001n10.zip',
'001n11.zip',
'001n12.zip',
'001n13.zip',
'001n14.zip',
'001n15.zip']
hdfs = list()
for day in available_days :
file = available_days[available_days.index(day)]
print 'file=', file
local_file = os.path.join(destdir, file)
ftp.retrbinary('RETR %s' %file, open(local_file, 'wb').write)
hdfs.append(os.path.abspath(local_file))
ftp.cwd('..')
ftp.quit()
答案 0 :(得分：2)
我能够使用您的给定网址成功下载zip文件：
# connect to ftp
url = urlparse.urlparse("http://ftp2.cits.rncan.gc.ca/pub/geobase/official/cded/50k_dem/")
ftp = ftplib.FTP(url.netloc)
ftp.login()
ftp.cwd(ftp_dirname)
with open(filename, 'w') as fobj:
ftp.retrbinary('RETR %s' % basename, fobj.write)
您可以通过遍历ftp目录来避免使用硬编码的目录/文件名，类似于使用ftplib.FTP.dir()
以下完整代码：
url = 'http://ftp2.cits.rncan.gc.ca/pub/geobase/official/cded/50k_dem/'
url = urlparse.urlparse(url)
local_root = os.path.expanduser("~/ftp_download") # change this to wherever you want to download to
def download(ftp, ftp_path, filename, check_cwd=True):
"""
Using the given ftp connection, download from ftp_path to
filename.
If check_cwd is False, assume the ftp connection is already
in the correct current working directory (cwd)
"""
basename = posixpath.basename(ftp_path)
dirname = os.path.dirname(filename)
if not os.path.exists(dirname):
os.makedirs(dirname)
if check_cwd:
ftp_dirname = posixpath.dirname(ftp_path)
if ftp_dirname != ftp.pwd():
ftp.cwd(ftp_dirname)
with open(filename, 'w') as fobj:
ftp.retrbinary('RETR %s' % basename, fobj.write)
def ftp_dir(ftp):
"""
Given a valid ftp connection, get a list of 2-tuples of the
files in the ftp current working directory, where the first
element is whether the file is a directory and the second
element is the filename.
"""
# use a callback to grab the ftp.dir() output in a list
dir_listing = []
ftp.dir(lambda x: dir_listing.append(x))
return [(line[0].upper() == 'D', line.rsplit()[-1]) for line in dir_listing]
# connect to ftp
ftp = ftplib.FTP(url.netloc)
ftp.login()
# recursively walk through the directory and download each file, depth first
stack = [url.path]
while stack:
path = stack.pop()
ftp.cwd(path)
# add all directories to the queue
children = ftp_dir(ftp)
dirs = [posixpath.join(path, child[1]) for child in children if child[0]]
files = [posixpath.join(path, child[1]) for child in children if not child[0]]
stack.extend(dirs[::-1]) # add dirs reversed so they are popped out in order
# download all files in the directory
for filepath in files:
download(ftp, filepath, os.path.join(local_root, filepath.split(url.path,1)[-1]),
check_cwd=False)
# logout
ftp.quit()