Issue #23252: Added support for writing ZIP files to unseekable streams.
diff --git a/Lib/zipfile.py b/Lib/zipfile.py
index 8c2950f..55afa08 100644
--- a/Lib/zipfile.py
+++ b/Lib/zipfile.py
@@ -667,6 +667,26 @@
self._file = None
self._close(fileobj)
+# Provide the tell method for unseekable stream
+class _Tellable:
+ def __init__(self, fp):
+ self.fp = fp
+ self.offset = 0
+
+ def write(self, data):
+ n = self.fp.write(data)
+ self.offset += n
+ return n
+
+ def tell(self):
+ return self.offset
+
+ def flush(self):
+ self.fp.flush()
+
+ def close(self):
+ self.fp.close()
+
class ZipExtFile(io.BufferedIOBase):
"""File-like object for reading an archive member.
@@ -994,6 +1014,7 @@
self.filename = getattr(file, 'name', None)
self._fileRefCnt = 1
self._lock = threading.RLock()
+ self._seekable = True
try:
if mode == 'r':
@@ -1002,13 +1023,24 @@
# set the modified flag so central directory gets written
# even if no files are added to the archive
self._didModify = True
- self.start_dir = self.fp.tell()
+ try:
+ self.start_dir = self.fp.tell()
+ except (AttributeError, OSError):
+ self.fp = _Tellable(self.fp)
+ self.start_dir = 0
+ self._seekable = False
+ else:
+ # Some file-like objects can provide tell() but not seek()
+ try:
+ self.fp.seek(self.start_dir)
+ except (AttributeError, OSError):
+ self._seekable = False
elif mode == 'a':
try:
# See if file is a zip file
self._RealGetContents()
# seek to start of directory and overwrite
- self.fp.seek(self.start_dir, 0)
+ self.fp.seek(self.start_dir)
except BadZipFile:
# file is not a zip file, just append
self.fp.seek(0, 2)
@@ -1415,7 +1447,8 @@
zinfo.file_size = st.st_size
zinfo.flag_bits = 0x00
with self._lock:
- self.fp.seek(self.start_dir, 0)
+ if self._seekable:
+ self.fp.seek(self.start_dir)
zinfo.header_offset = self.fp.tell() # Start of header bytes
if zinfo.compress_type == ZIP_LZMA:
# Compressed data includes an end-of-stream (EOS) marker
@@ -1436,6 +1469,8 @@
return
cmpr = _get_compressor(zinfo.compress_type)
+ if not self._seekable:
+ zinfo.flag_bits |= 0x08
with open(filename, "rb") as fp:
# Must overwrite CRC and sizes with correct data later
zinfo.CRC = CRC = 0
@@ -1464,17 +1499,24 @@
zinfo.compress_size = file_size
zinfo.CRC = CRC
zinfo.file_size = file_size
- if not zip64 and self._allowZip64:
- if file_size > ZIP64_LIMIT:
- raise RuntimeError('File size has increased during compressing')
- if compress_size > ZIP64_LIMIT:
- raise RuntimeError('Compressed size larger than uncompressed size')
- # Seek backwards and write file header (which will now include
- # correct CRC and file sizes)
- self.start_dir = self.fp.tell() # Preserve current position in file
- self.fp.seek(zinfo.header_offset, 0)
- self.fp.write(zinfo.FileHeader(zip64))
- self.fp.seek(self.start_dir, 0)
+ if zinfo.flag_bits & 0x08:
+ # Write CRC and file sizes after the file data
+ fmt = '<LQQ' if zip64 else '<LLL'
+ self.fp.write(struct.pack(fmt, zinfo.CRC, zinfo.compress_size,
+ zinfo.file_size))
+ self.start_dir = self.fp.tell()
+ else:
+ if not zip64 and self._allowZip64:
+ if file_size > ZIP64_LIMIT:
+ raise RuntimeError('File size has increased during compressing')
+ if compress_size > ZIP64_LIMIT:
+ raise RuntimeError('Compressed size larger than uncompressed size')
+ # Seek backwards and write file header (which will now include
+ # correct CRC and file sizes)
+ self.start_dir = self.fp.tell() # Preserve current position in file
+ self.fp.seek(zinfo.header_offset)
+ self.fp.write(zinfo.FileHeader(zip64))
+ self.fp.seek(self.start_dir)
self.filelist.append(zinfo)
self.NameToInfo[zinfo.filename] = zinfo
@@ -1504,11 +1546,8 @@
zinfo.file_size = len(data) # Uncompressed size
with self._lock:
- try:
+ if self._seekable:
self.fp.seek(self.start_dir)
- except (AttributeError, io.UnsupportedOperation):
- # Some file-like objects can provide tell() but not seek()
- pass
zinfo.header_offset = self.fp.tell() # Start of header data
if compress_type is not None:
zinfo.compress_type = compress_type
@@ -1557,11 +1596,8 @@
try:
if self.mode in ("w", "a") and self._didModify: # write ending records
with self._lock:
- try:
+ if self._seekable:
self.fp.seek(self.start_dir)
- except (AttributeError, io.UnsupportedOperation):
- # Some file-like objects can provide tell() but not seek()
- pass
self._write_end_record()
finally:
fp = self.fp