我可以使用 Python 将内存中的对象上传到 FTP 吗?

2022-01-09 00:00:00 python object ftp ftplib upload

问题描述

这是我现在正在做的事情:

Here's what I'm doing now:

mysock = urllib.urlopen('http://localhost/image.jpg')
fileToSave = mysock.read()
oFile = open(r"C:image.jpg",'wb')
oFile.write(fileToSave)
oFile.close
f=file('image.jpg','rb')
ftp.storbinary('STOR '+os.path.basename('image.jpg'),f)
os.remove('image.jpg')

将文件写入磁盘然后立即删除它们似乎是系统上应该避免的额外工作.我可以使用 Python 将内存中的对象上传到 FTP 吗?

Writing files to disk and then imediately deleting them seems like extra work on the system that should be avoided. Can I upload an object in memory to FTP using Python?

解决方案

因为 duck-typing，文件对象(代码中的f)只需要支持.read(blocksize)调用就可以使用storbinary.当遇到这样的问题时，我会去源头，在本例中是 lib/python2.6/ftplib.py:

Because of duck-typing, the file object (f in your code) only needs to support the .read(blocksize) call to work with storbinary. When faced with questions like this, I go to the source, in this case lib/python2.6/ftplib.py:

def storbinary(self, cmd, fp, blocksize=8192, callback=None):
    """Store a file in binary mode.  A new port is created for you.

    Args:
      cmd: A STOR command.
      fp: A file-like object with a read(num_bytes) method.
      blocksize: The maximum data size to read from fp and send over
                 the connection at once.  [default: 8192]
      callback: An optional single parameter callable that is called on
                on each block of data after it is sent.  [default: None]

    Returns:
      The response code.
    """
    self.voidcmd('TYPE I')
    conn = self.transfercmd(cmd)
    while 1:
        buf = fp.read(blocksize)
        if not buf: break
        conn.sendall(buf)
        if callback: callback(buf)
    conn.close()
    return self.voidresp()

正如评论，它只需要一个类文件对象，实际上它甚至不是特别像文件，它只需要 read(n).StringIO 提供了这样的内存文件"服务.

As commented, it only wants a file-like object, indeed it not even be particularly file-like, it just needs read(n). StringIO provides such "memory file" services.

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