问题描述
我想检索存储在 FTP 服务器上的压缩 gz 文件中的数据，而不将文件写入本地存档.
I would like to retrieve the data inside a compressed gz file stored on an FTP server, without writing the file to the local archive.
目前我已经完成了
from ftplib import FTP
import gzip
ftp = FTP('ftp.server.com')
ftp.login()
ftp.cwd('/a/folder/')
fileName = 'aFile.gz'
localfile = open(fileName,'wb')
ftp.retrbinary('RETR '+fileName, localfile.write, 1024)
f = gzip.open(localfile,'rb')
data = f.read()
然而，这会将文件localfile"写入当前存储.
This, however, writes the file "localfile" on the current storage.
我试图改变这个
from ftplib import FTP
import zlib
ftp = FTP('ftp.server.com')
ftp.login()
ftp.cwd('/a/folder/')
fileName = 'aFile.gz'
data = ftp.retrbinary('RETR '+fileName, zlib.decompress, 1024)
但是，ftp.retrbinary 不输出其回调的输出.有没有办法做到这一点?
but, ftp.retrbinary does not output the output of its callback.
Is there a way to do this?
推荐答案
一个简单的实现是:
将文件下载到内存中类似文件的对象，例如
BytesIO;
将其传递给 fileobj 参数noreferrer">GzipFile 构造函数.
pass that to fileobj parameter of GzipFile constructor.
import gzip
from io import BytesIO
import shutil
from ftplib import FTP
ftp = FTP('ftp.example.com')
ftp.login('username', 'password')
flo = BytesIO()
ftp.retrbinary('RETR /remote/path/archive.tar.gz', flo.write)
flo.seek(0)
with open('archive.tar', 'wb') as fout, gzip.GzipFile(fileobj = flo) as gzip:
shutil.copyfileobj(gzip, fout)
<小时>
以上将整个 .gz 文件加载到内存中.对于大文件来说什么是低效的.更智能的实现将改为流式传输数据.但这可能需要实现一个智能的自定义类文件对象.
The above loads whole .gz file to a memory. What can be inefficient for large files. A smarter implementation would stream the data instead. But that would probably require implementing a smart custom file-like object.
另请参阅在 FTP 服务器上的 zip 文件中获取文件名，而无需下载整个存档.
这篇关于从 FTP 服务器上的 gz 文件中检索数据而不在本地写入的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持跟版网！