ftp read() Memory Error in python

Question

i get an error 'Memory Error' when it open and reads a file larger than 500mb. if its less than 500mb it works perfectly.. im using the size for my progress bar's maxvalue

    self.ftp = FTP(hostname)
    self.ftp.login(user, password)
    self.f = open(self.filename,'rb')

    with open(self.filename,'rb') as filein:
        self.size = filein.read()

    self.size = len(self.size)

Answer 1

Don't use the read() method since it reads the whole file into a string. You should use the os.stat() function to get the the file metadata, which returns a stat structure with the member st_size. That's the size in bytes of the file. You don't have to read it all in first.

For sending, also read in and write out in chunks (say 16kB), in a loop.

Answer 2

So, filein.read() actually reads (i.e. downloads) the file and is consuming your memory.
You can instead use

self.size = self.ftp.size(self.filename)