zipremove 0.8.0

Extend `zipfile` with `remove`-related functionalities

This package extends zipfile with remove-related functionalities.

API

• ZipFile.remove(zinfo_or_arcname)

  Removes a member entry from the archive's central directory. zinfo_or_arcname may be the full path of the member or a ZipInfo instance. If multiple members share the same full path and the path is provided, only one of them is removed.

  The archive must be opened with mode 'w', 'x' or 'a'.

  Returns the removed ZipInfo instance.

  Calling remove on a closed ZipFile will raise a ValueError.

  Note: This method only removes the member's entry from the central directory, making it inaccessible to most tools. The member's local file entry, including content and metadata, remains in the archive and is still recoverable using forensic tools. Call repack afterwards to completely remove the member and reclaim space.

• ZipFile.repack(removed=None, *, strict_descriptor=False[, chunk_size])

  Rewrites the archive to remove unreferenced local file entries, shrinking its file size. The archive must be opened with mode 'a'.

  If removed is provided, it must be a sequence of ZipInfo objects representing the recently removed members, and only their corresponding local file entries will be removed. Otherwise, the archive is scanned to locate and remove local file entries that are no longer referenced in the central directory.

  When scanning, setting strict_descriptor=True disables detection of any entry using an unsigned data descriptor (a format deprecated by the ZIP specification since version 6.3.0, released on 2006-09-29, and used only by some legacy tools), which is significantly slower to scan—around 100 to 1000 times in the worst case. This does not affect performance on entries without such feature.

  chunk_size may be specified to control the buffer size when moving entry data (default is 1 MiB).

  Calling repack on a closed ZipFile will raise a ValueError.

  Note: The scanning algorithm is heuristic-based and assumes that the ZIP file is normally structured—for example, with local file entries stored consecutively, without overlap or interleaved binary data. Prepended binary data, such as a self-extractor stub, is recognized and preserved unless it happens to contain bytes that coincidentally resemble a valid local file entry in multiple respects—an extremely rare case. Embedded ZIP payloads are also handled correctly, as long as they follow normal structure. However, the algorithm does not guarantee correctness or safety on untrusted or intentionally crafted input. It is generally recommended to provide the removed argument for better reliability and performance.

• ZipFile.copy(zinfo_or_arcname, new_arcname[, chunk_size])

  Copies a member zinfo_or_arcname to new_arcname in the archive. zinfo_or_arcname may be the full path of the member or a ZipInfo instance.

  chunk_size may be specified to control the buffer size when copying entry data (default is 1 MiB).

  The archive must be opened with mode 'w', 'x' or 'a', and the underlying stream must be seekable.

  Returns the original version of the copied ZipInfo instance.

  Calling copy on a closed ZipFile will raise a ValueError.

Examples

Remove entries and reclaim space

Call repack after removes to reclaim the space of the removed entries:

import os
import zipremove as zipfile

with zipfile.ZipFile('archive.zip', 'w') as zh:
    zh.writestr('file1', 'content1')
    zh.writestr('file2', 'content2')
    zh.writestr('file3', 'content3')
    zh.writestr('file4', 'content4')

print(os.path.getsize('archive.zip'))  # 398

with zipfile.ZipFile('archive.zip', 'a') as zh:
    zh.remove('file1')
    zh.remove('file2')
    zh.remove('file3')
    zh.repack()

print(os.path.getsize('archive.zip'))  # 116 (would be 245 without `repack`)

Alternatively, pass the ZipInfo objects of the removed entries, for better performance and error-proofing:

import os
import zipremove as zipfile

with zipfile.ZipFile('archive.zip', 'w') as zh:
    zh.writestr('file1', 'content1')
    zh.writestr('file2', 'content2')
    zh.writestr('file3', 'content3')
    zh.writestr('file4', 'content4')

print(os.path.getsize('archive.zip'))  # 398

with zipfile.ZipFile('archive.zip', 'a') as zh:
    zinfos = []
    zinfos.append(zh.remove('file1'))
    zinfos.append(zh.remove('file2'))
    zinfos.append(zh.remove('file3'))
    zh.repack(zinfos)

print(os.path.getsize('archive.zip'))  # 116 (would be 245 without `repack`)

Move entries under a folder and reclaim space

Moving entries in a ZIP file must be done as a combination of copy, remove, and optionally repack, because every local file entry contains the filename and requires rewriting.

import os
import zipremove as zipfile

with zipfile.ZipFile('archive.zip', 'w') as zh:
    zh.writestr('file0', 'content0')
    zh.writestr('folder1/file1', 'content1')
    zh.writestr('folder1/file2', 'content2')
    zh.writestr('folder1/file3', 'content3')

print(os.path.getsize('archive.zip'))  # 446

with zipfile.ZipFile('archive.zip', 'a') as zh:
    for n in zh.namelist():
        if n.startswith('folder1/'):
            n2 = 'folder2/' + n[len('folder1/'):]
            zh.copy(n, n2)
            zh.remove(n)
    zh.repack()

print(os.path.getsize('archive.zip'))  # 446 (would be 599 without `repack`)

Similarly, pass the ZipInfo objects of the copied/removed entries for better performance and error-proofing:

import os
import zipremove as zipfile

with zipfile.ZipFile('archive.zip', 'w') as zh:
    zh.writestr('file0', 'content0')
    zh.writestr('folder1/file1', 'content1')
    zh.writestr('folder1/file2', 'content2')
    zh.writestr('folder1/file3', 'content3')

print(os.path.getsize('archive.zip'))  # 446

with zipfile.ZipFile('archive.zip', 'a') as zh:
    zinfos = []
    for n in zh.namelist():
        if n.startswith('folder1/'):
            n2 = 'folder2/' + n[len('folder1/'):]
            zinfos.append(zh.remove(zh.copy(n, n2)))
    zh.repack(zinfos)

print(os.path.getsize('archive.zip'))  # 446 (would be 599 without `repack`)