程式扎記: [Python Std Library] Data Compress/Archive : zipfile — Work with ZIP archives

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2012年6月5日 星期二

[Python Std Library] Data Compress/Archive : zipfile — Work with ZIP archives


來源自 這裡
Preface :
New in version 1.6.
The ZIP file format is a common archive and compression standard. This module provides tools to create, read, write, append, and list a ZIP file. Any advanced use of this module will require an understanding of the format, as defined in PKZIP Application Note.

This module does not currently handle multi-disk ZIP files. It can handle ZIP files that use the ZIP64 extensions (that is ZIP files that are more than 4 GByte in size). It supports decryption of encrypted files in ZIP archives, but it currently cannot create an encrypted file. Decryption is extremely slow as it is implemented in native Python rather than C.

The module defines the following items :
- exception zipfile.BadZipfile
The error raised for bad ZIP files (old name: zipfile.error).

- exception zipfile.LargeZipFile
The error raised when a ZIP file would require ZIP64 functionality but that has not been enabled.

- class zipfile.ZipFile
The class for reading and writing ZIP files.

- class zipfile.PyZipFile
Class for creating ZIP archives containing Python libraries.

- class zipfile.ZipInfo([filename[, date_time]])
Class used to represent information about a member of an archive. Instances of this class are returned by the getinfo() and infolist() methods of ZipFile objects. Most users of the zipfile module will not need to create these, but only use those created by this module. filename should be the full name of the archive member, and date_time should be a tuple containing six fields which describe the time of the last modification to the file; the fields are described in section ZipInfo Objects.

Supported APIs in this module :
zipfile.is_zipfile(filename)
Changed in version 2.7: Support for file and file-like objects.
Returns True if filename is a valid ZIP file based on its magic number, otherwise returns Falsefilename may be a file or file-like object too.

Constants in this module :
zipfile.ZIP_STORED
The numeric constant for an uncompressed archive member.

zipfile.ZIP_DEFLATED
The numeric constant for the usual ZIP compression method. This requires the zlib module. No other compression methods are currently supported.

ZipFile Objects :
- class zipfile.ZipFile(file[, mode[, compression[, allowZip64]]])
Changed in version 2.6: If mode is a and the file does not exist at all, it is created.
New in version 2.7: Added the ability to use ZipFile as a context manager.

Open a ZIP file, where file can be either a path to a file (a string) or a file-like object. The mode parameter should be 'r' to read an existing file, 'w' to truncate and write a new file, or 'a' to append to an existing file. If mode is 'a' and file refers to an existing ZIP file, then additional files are added to it. If file does not refer to a ZIP file, then a new ZIP archive is appended to the file. This is meant for adding a ZIP archive to another file.

compression is the ZIP compression method to use when writing the archive, and should be ZIP_STORED or ZIP_DEFLATED; unrecognized values will causeRuntimeError to be raised. If ZIP_DEFLATED is specified but the zlib module is not available, RuntimeError is also raised. The default is ZIP_STORED. If allowZip64 is True zipfile will create ZIP files that use the ZIP64 extensions when the zipfile is larger than 2 GB. If it is false (the defaultzipfile will raise an exception when the ZIP file would require ZIP64 extensions. ZIP64 extensions are disabled by default because the default zip and unzip commands on Unix (the InfoZIP utilities) don’t support these extensions.

ZipFile is also a context manager and therefore supports the with statement. In the example, myzip is closed after the with statement’s suite is finished—even if an exception occurs :
  1. with ZipFile('spam.zip''w') as myzip:  
  2.     myzip.write('eggs.txt')  

ZipFile.close()
Close the archive file. You must call close() before exiting your program or essential records will not be written.

ZipFile.getinfo(name)
Return a ZipInfo object with information about the archive member name. Calling for a name not currently contained in the archive will raise a KeyError.

ZipFile.infolist()
Return a list containing a ZipInfo object for each member of the archive. The objects are in the same order as their entries in the actual ZIP file on disk if an existing archive was opened.

ZipFile.namelist()
Return a list of archive members by name :
>>> import zipfile
>>> zipFile = zipfile.ZipFile('test.zip')
>>> zipFile.namelist()
['Crawer-2-10-1.JPG', 'Crawer-2-11-1.JPG', 'Crawer-2-11-2.JPG', 'Crawer-2-12-1.JPG', 'Crawer-2-12-2.JPG', 'Crawer.pptx']

ZipFile.open(name[, mode[, pwd]])
New in version 2.6.
Extract a member from the archive as a file-like object (ZipExtFile). name is the name of the file in the archive, or a ZipInfo object. The mode parameter, if included, must be one of the following: 'r' (the default), 'U', or 'rU'. Choosing 'U' or 'rU' will enable universal newline support in the read-only object. pwd is the password used for encrypted files. Calling on a closed ZipFile will raise a RuntimeError :

ZipFile.extract(member[, path[, pwd]])
New in version 2.6.
Extract a member from the archive to the current working directory; member must be its full name or a ZipInfo object. Its file information is extracted as accurately as possible. path specifies a different directory to extract to. member can be a filename or a ZipInfo object. pwd is the password used for encrypted files.


ZipFile.extractall([path[, members[, pwd]]])
New in version 2.6.
Extract all members from the archive to the current working directory. path specifies a different directory to extract to. members is optional and must be a subset of the list returned by namelist()pwd is the password used for encrypted files :

ZipFile.printdir()
Print a table of contents for the archive to sys.stdout :

ZipFile.setpassword(pwd)
New in version 2.6.
Set pwd as default password to extract encrypted files.

ZipFile.read(name[, pwd])
Changed in version 2.6pwd was added, and name can now be a ZipInfo object.
Return the bytes of the file name in the archive. name is the name of the file in the archive, or a ZipInfo object. The archive must be open for read or append. pwd is the password used for encrypted files and, if specified, it will override the default password set with setpassword(). Calling on a closed ZipFile will raise aRuntimeError.

ZipFile.testzip()
Read all the files in the archive and check their CRC’s and file headers. Return the name of the first bad file, or else return None. Calling on a closed ZipFile will raise a RuntimeError.

ZipFile.write(filename[, arcname[, compress_type]])
Write the file named filename to the archive, giving it the archive name arcname (by default, this will be the same as filename, but without a drive letter and with leading path separators removed). If given, compress_type overrides the value given for the compression parameter to the constructor for the new entry. The archive must be open with mode 'w' or 'a' – calling on a ZipFile created with mode 'r' will raise a RuntimeError. Calling on a closed ZipFile will raise a RuntimeError.

ZipFile.writestr(zinfo_or_arcname, bytes[, compress_type])
Changed in version 2.7: The compression_type argument.
Write the string bytes to the archive; zinfo_or_arcname is either the file name it will be given in the archive, or a ZipInfo instance. If it’s an instance, at least the filename, date, and time must be given. If it’s a name, the date and time is set to the current date and time. The archive must be opened with mode 'w' or 'a' – calling on a ZipFile created with mode 'r' will raise a RuntimeError. Calling on a closed ZipFile will raise a RuntimeError.

If given, compress_type overrides the value given for the compression parameter to the constructor for the new entry, or in the zinfo_or_arcname (if that is a ZipInfoinstance).

The following data attributes are also available :
ZipFile.debug
The level of debug output to use. This may be set from 0 (the default, no output) to 3 (the most output). Debugging information is written to sys.stdout.

ZipFile.comment
The comment text associated with the ZIP file. If assigning a comment to a ZipFile instance created with mode ‘a’ or ‘w’, this should be a string no longer than 65535 bytes. Comments longer than this will be truncated in the written archive when ZipFile.close() is called.

ZipInfo Objects :
Instances of the ZipInfo class are returned by the getinfo() and infolist() methods of ZipFile objects. It stores information about a single member of the ZIP archive. Instances have the following attributes :
ZipInfo.filename
Name of the file in the archive.

ZipInfo.date_time
The time and date of the last modification to the archive member. This is a tuple of six values :

ZipInfo.compress_type
Type of compression for the archive member.

ZipInfo.comment
Comment for the individual archive member.

ZipInfo.extra
Expansion field data. The PKZIP Application Note contains some comments on the internal structure of the data contained in this string.

ZipInfo.create_system
System which created ZIP archive.

ZipInfo.create_version
PKZIP version which created ZIP archive.

ZipInfo.extract_version
PKZIP version needed to extract archive.

ZipInfo.volume
Volume number of file header.

ZipInfo.internal_attr
Internal attributes.

ZipInfo.external_attr
External file attributes.

ZipInfo.header_offset
Byte offset to the file header.

ZipInfo.CRC
CRC-32 of the uncompressed file.

ZipInfo.compress_size
Size of the compressed data.

ZipInfo.file_size
Size of the uncompressed file.
This message was edited 35 times. Last update was at 05/06/2012 16:50:33

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