从FTP服务器上的gz文件检索数据，而无需在本地写入 [英] Retrieve data from gz file on FTP server without writing it locally

问题描述

我想检索存储在FTP服务器上的gz压缩文件中的数据，而无需将该文件写入本地档案.

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

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()

但是，这会将文件"localfile"写入当前存储.

This, however, writes the file "localfile" on the current storage.

我试图在此更改

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. 有办法吗?

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:

• 将文件下载到类似文件的内存中对象，例如将其传递给fileobj参数rel ="nofollow noreferrer"> 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)
  

  ---

  以上将整个.gz文件加载到内存中.大型文件可能没有效率.一个更聪明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文件状对象.

  ---

  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.

  另请参见在FTP服务器上的zip文件中获取文件名，而无需下载整个存档文件.

  这篇关于从FTP服务器上的gz文件检索数据，而无需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IT屋！