Write an update archive with only the files changed since the last publish

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
2026-10-24 01:07:47 +00:00
parent c6eb1355a8
commit ae37e0be53
2 changed files with 104 additions and 7 deletions
@@ -0,0 +1,77 @@
+#!/usr/bin/env python3
+"""Archives the files of a publish folder that differ from the previous archive.
+
+usage: publish-update.py <previous archive> <folder> <output archive>
+
+The previous archive is the full one the last publish left behind (.zip or
+.tar.gz). A file goes into the output when it is new or its content changed;
+files the new publish no longer has are listed but cannot be removed by
+unpacking over the old install. The archive keeps the folder name as its top
+directory, like the full one. Prints nothing and writes nothing when no file
+changed.
+"""
+import hashlib
+import os
+import sys
+import tarfile
+import zipfile
+
+
+def digest(data):
+    return hashlib.sha256(data).hexdigest()
+
+
+def read_previous(path):
+    """Maps each file's path inside the archive to a hash of its content."""
+    hashes = {}
+    if path.endswith(".zip"):
+        with zipfile.ZipFile(path) as archive:
+            for info in archive.infolist():
+                if not info.is_dir():
+                    hashes[info.filename] = digest(archive.read(info))
+    else:
+        with tarfile.open(path) as archive:
+            for member in archive.getmembers():
+                if member.isfile():
+                    hashes[member.name] = digest(archive.extractfile(member).read())
+    return hashes
+
+
+def main(previous, folder, output):
+    root = os.path.basename(os.path.normpath(folder))
+    old = read_previous(previous)
+    changed = []
+    current = set()
+    for directory, _, names in os.walk(folder):
+        for name in sorted(names):
+            full = os.path.join(directory, name)
+            inside = root + "/" + os.path.relpath(full, folder).replace(os.sep, "/")
+            current.add(inside)
+            with open(full, "rb") as file:
+                if old.get(inside) != digest(file.read()):
+                    changed.append((full, inside))
+    removed = sorted(set(old) - current)
+
+    if os.path.exists(output):
+        os.remove(output)
+    if not changed:
+        print("no file changed since the previous archive")
+        return
+    changed.sort(key=lambda pair: pair[1])
+    if output.endswith(".zip"):
+        with zipfile.ZipFile(output, "w", zipfile.ZIP_DEFLATED) as archive:
+            for full, inside in changed:
+                archive.write(full, inside)
+    else:
+        with tarfile.open(output, "w:gz") as archive:
+            for full, inside in changed:
+                archive.add(full, inside, recursive=False)
+    print(f"{output}: {len(changed)} changed of {len(current)} files")
+    for gone in removed:
+        print(f"  no longer in the publish: {gone}")
+
+
+if __name__ == "__main__":
+    if len(sys.argv) != 4:
+        sys.exit(__doc__)
+    main(*sys.argv[1:])