How to update one file inside zip file?

Question

I have this zip file structure.

zipfile name = filename.zip

filename>    images>
             style.css
             default.js
             index.html

I want to update just index.html. I tried to update index.html, but then it contains only index.html file in 1.zip file and other files are removed.

This is the code which I tried:

import zipfile

msg = 'This data did not exist in a file before being added to the ZIP file'
zf = zipfile.ZipFile('1.zip', 
                     mode='w',
                     )
try:
    zf.writestr('index.html', msg)
finally:
    zf.close()
    
print zf.read('index.html')

So how can I update only index.html file using Python?

What have you tried so far? Show us your code and describe what does and what doesn't work. — , Sep 09 '14 at 07:05

sebdelsol · Answer 1 · 2014-09-09T12:15:07.867

Updating a file in a ZIP is not supported. You need to rebuild a new archive without the file, then add the updated version.

import os
import zipfile
import tempfile

def updateZip(zipname, filename, data):
    # generate a temp file
    tmpfd, tmpname = tempfile.mkstemp(dir=os.path.dirname(zipname))
    os.close(tmpfd)

    # create a temp copy of the archive without filename            
    with zipfile.ZipFile(zipname, 'r') as zin:
        with zipfile.ZipFile(tmpname, 'w') as zout:
            zout.comment = zin.comment # preserve the comment
            for item in zin.infolist():
                if item.filename != filename:
                    zout.writestr(item, zin.read(item.filename))

    # replace with the temp archive
    os.remove(zipname)
    os.rename(tmpname, zipname)

    # now add filename with its new data
    with zipfile.ZipFile(zipname, mode='a', compression=zipfile.ZIP_DEFLATED) as zf:
        zf.writestr(filename, data)

msg = 'This data did not exist in a file before being added to the ZIP file'
updateZip('1.zip', 'index.html', msg)

Note that you need contextlib with Python 2.6 and earlier, since ZipFile is also a context manager only since 2.7.

You might want to check if your file actually exists in the archive to avoid an useless archive rebuild.

I do the management of temporary files a little bit differently: first, `from tempfile import NamedTemporaryFile` then to use the temp file I simply put the rest of the function in `with NamedTemporaryFile() as tmp_file:` and get the name: `tmpname = os.path.basename(tmp_file.name)`. In the end, instead of `os.rename(...)` I do `shutil.copyfile(tmpname, filename)`. The temp file is handled and closed in the end by the context manager. — zezollo, Jul 15 '20 at 14:58

score 5 · Answer 2 · edited May 23 '17 at 12:18

It is not possible to update an existing file. You will need to read the file you want to edit and create a new archive including the file that you edited and the other files that were originally present in the original archive.

Below are some of the questions that might help.

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2 Answers2

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