Python – Extract files from zip file and retain mod date

extractionpythonzip

I'm trying to extract files from a zip file using Python 2.7.1 (on Windows, fyi) and each of my attempts shows extracted files with Modified Date = time of extraction (which is incorrect).

import os,zipfile
outDirectory = 'C:\\_TEMP\\'
inFile = 'test.zip'
fh = open(os.path.join(outDirectory,inFile),'rb') 
z = zipfile.ZipFile(fh)
for name in z.namelist():
    z.extract(name,outDirectory)
fh.close()

I also tried using the .extractall method, with the same results.

import os,zipfile
outDirectory = 'C:\\_TEMP\\'
inFile = 'test.zip'
zFile = zipfile.ZipFile(os.path.join(outDirectory,inFile))        
zFile.extractall(outDirectory)

Can anyone tell me what I'm doing wrong?

I'd like to think this is possible without having to post-correct the modified time per How do I change the file creation date of a Windows file?.

Best Answer

Well, it does take a little post-processing, but it's not that bad:

import os
import zipfile
import time

outDirectory = 'C:\\TEMP\\'
inFile = 'test.zip'
fh = open(os.path.join(outDirectory,inFile),'rb') 
z = zipfile.ZipFile(fh)

for f in z.infolist():
    name, date_time = f.filename, f.date_time
    name = os.path.join(outDirectory, name)
    with open(name, 'wb') as outFile:
        outFile.write(z.open(f).read())
    date_time = time.mktime(date_time + (0, 0, -1))
    os.utime(name, (date_time, date_time))

Okay, maybe it is that bad.

Related Solutions

Python – How to get file creation & modification date/times in Python

Getting some sort of modification date in a cross-platform way is easy - just call os.path.getmtime(path) and you'll get the Unix timestamp of when the file at path was last modified.

Getting file creation dates, on the other hand, is fiddly and platform-dependent, differing even between the three big OSes:

On Windows, a file's ctime (documented at https://msdn.microsoft.com/en-us/library/14h5k7ff.aspx) stores its creation date. You can access this in Python through os.path.getctime() or the .st_ctime attribute of the result of a call to os.stat(). This won't work on Unix, where the ctime is the last time that the file's attributes or content were changed.
On Mac, as well as some other Unix-based OSes, you can use the .st_birthtime attribute of the result of a call to os.stat().
On Linux, this is currently impossible, at least without writing a C extension for Python. Although some file systems commonly used with Linux do store creation dates (for example, ext4 stores them in st_crtime) , the Linux kernel offers no way of accessing them; in particular, the structs it returns from stat() calls in C, as of the latest kernel version, don't contain any creation date fields. You can also see that the identifier st_crtime doesn't currently feature anywhere in the Python source. At least if you're on ext4, the data is attached to the inodes in the file system, but there's no convenient way of accessing it.

The next-best thing on Linux is to access the file's mtime, through either os.path.getmtime() or the .st_mtime attribute of an os.stat() result. This will give you the last time the file's content was modified, which may be adequate for some use cases.

Putting this all together, cross-platform code should look something like this...

import os
import platform

def creation_date(path_to_file):
    """
    Try to get the date that a file was created, falling back to when it was
    last modified if that isn't possible.
    See http://stackoverflow.com/a/39501288/1709587 for explanation.
    """
    if platform.system() == 'Windows':
        return os.path.getctime(path_to_file)
    else:
        stat = os.stat(path_to_file)
        try:
            return stat.st_birthtime
        except AttributeError:
            # We're probably on Linux. No easy way to get creation dates here,
            # so we'll settle for when its content was last modified.
            return stat.st_mtime

Python – Importing files from different folder

Note: This answer was intended for a very specific question. For most programmers coming here from a search engine, this is not the answer you are looking for. Typically you would structure your files into packages (see other answers) instead of modifying the search path.

By default, you can't. When importing a file, Python only searches the directory that the entry-point script is running from and sys.path which includes locations such as the package installation directory (it's actually a little more complex than this, but this covers most cases).

However, you can add to the Python path at runtime:

# some_file.py
import sys
# insert at 1, 0 is the script path (or '' in REPL)
sys.path.insert(1, '/path/to/application/app/folder')

import file

Best Answer

Related Solutions

Python – How to get file creation & modification date/times in Python

Python – Importing files from different folder

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