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发表于 2016-11-8 15:14:00
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OleFileIO Module
The OleFileIO module reads Microsoft OLE2 files (also called Structured Storage or Microsoft Compound Document File Format), such as Microsoft Office documents, Image Composer and FlashPix files, and Outlook messages.
This module is the OleFileIO_PL project by Philippe Lagadec, v0.42, merged back into Pillow.
How to use this module
For more information, see also the file PIL/OleFileIO.py, sample code at the end of the module itself, and docstrings within the code.
About the structure of OLE files
An OLE file can be seen as a mini file system or a Zip archive: It contains streams of data that look like files embedded within the OLE file. Each stream has a name. For example, the main stream of a MS Word document containing its text is named “WordDocument”.
An OLE file can also contain storages. A storage is a folder that contains streams or other storages. For example, a MS Word document with VBA macros has a storage called “Macros”.
Special streams can contain properties. A property is a specific value that can be used to store information such as the metadata of a document (title, author, creation date, etc). Property stream names usually start with the character ‘05’.
For example, a typical MS Word document may look like this:
\x05DocumentSummaryInformation (stream)
\x05SummaryInformation (stream)
WordDocument (stream)
Macros (storage)
PROJECT (stream)
PROJECTwm (stream)
VBA (storage)
Module1 (stream)
ThisDocument (stream)
_VBA_PROJECT (stream)
dir (stream)
ObjectPool (storage)
Test if a file is an OLE container
Use isOleFile to check if the first bytes of the file contain the Magic for OLE files, before opening it. isOleFile returns True if it is an OLE file, False otherwise.
assert OleFileIO.isOleFile('myfile.doc')
Open an OLE file from disk
Create an OleFileIO object with the file path as parameter:
ole = OleFileIO.OleFileIO('myfile.doc')
Open an OLE file from a file-like object
This is useful if the file is not on disk, e.g. already stored in a string or as a file-like object.
ole = OleFileIO.OleFileIO(f)
For example the code below reads a file into a string, then uses BytesIO to turn it into a file-like object.
data = open('myfile.doc', 'rb').read()
f = io.BytesIO(data) # or StringIO.StringIO for Python 2.x
ole = OleFileIO.OleFileIO(f)
How to handle malformed OLE files
By default, the parser is configured to be as robust and permissive as possible, allowing to parse most malformed OLE files. Only fatal errors will raise an exception. It is possible to tell the parser to be more strict in order to raise exceptions for files that do not fully conform to the OLE specifications, using the raise_defect option:
ole = OleFileIO.OleFileIO('myfile.doc', raise_defects=DEFECT_INCORRECT)
When the parsing is done, the list of non-fatal issues detected is available as a list in the parsing_issues attribute of the OleFileIO object:
print('Non-fatal issues raised during parsing:')
if ole.parsing_issues:
for exctype, msg in ole.parsing_issues:
print('- %s: %s' % (exctype.__name__, msg))
else:
print('None')
Syntax for stream and storage path
Two different syntaxes are allowed for methods that need or return the path of streams and storages:
Either a list of strings including all the storages from the root up to the stream/storage name. For example a stream called “WordDocument” at the root will have [‘WordDocument’] as full path. A stream called “ThisDocument” located in the storage “Macros/VBA” will be [‘Macros’, ‘VBA’, ‘ThisDocument’]. This is the original syntax from PIL. While hard to read and not very convenient, this syntax works in all cases.
Or a single string with slashes to separate storage and stream names (similar to the Unix path syntax). The previous examples would be ‘WordDocument’ and ‘Macros/VBA/ThisDocument’. This syntax is easier, but may fail if a stream or storage name contains a slash.
Both are case-insensitive.
Switching between the two is easy:
slash_path = '/'.join(list_path)
list_path = slash_path.split('/')
Get the list of streams
listdir() returns a list of all the streams contained in the OLE file, including those stored in storages. Each stream is listed itself as a list, as described above.
print(ole.listdir())
Sample result:
[['\x01CompObj'], ['\x05DocumentSummaryInformation'], ['\x05SummaryInformation']
, ['1Table'], ['Macros', 'PROJECT'], ['Macros', 'PROJECTwm'], ['Macros', 'VBA',
'Module1'], ['Macros', 'VBA', 'ThisDocument'], ['Macros', 'VBA', '_VBA_PROJECT']
, ['Macros', 'VBA', 'dir'], ['ObjectPool'], ['WordDocument']]
As an option it is possible to choose if storages should also be listed, with or without streams:
ole.listdir (streams=False, storages=True)
Test if known streams/storages exist:
exists(path) checks if a given stream or storage exists in the OLE file.
if ole.exists('worddocument'):
print("This is a Word document.")
if ole.exists('macros/vba'):
print("This document seems to contain VBA macros.")
Read data from a stream
openstream(path) opens a stream as a file-like object.
The following example extracts the “Pictures” stream from a PPT file:
pics = ole.openstream('Pictures')
data = pics.read()
Get information about a stream/storage
Several methods can provide the size, type and timestamps of a given stream/storage:
get_size(path) returns the size of a stream in bytes:
s = ole.get_size('WordDocument')
get_type(path) returns the type of a stream/storage, as one of the following constants: STGTY_STREAM for a stream, STGTY_STORAGE for a storage, STGTY_ROOT for the root entry, and False for a non existing path.
t = ole.get_type('WordDocument')
get_ctime(path) and get_mtime(path) return the creation and modification timestamps of a stream/storage, as a Python datetime object with UTC timezone. Please note that these timestamps are only present if the application that created the OLE file explicitly stored them, which is rarely the case. When not present, these methods return None.
c = ole.get_ctime('WordDocument')
m = ole.get_mtime('WordDocument')
The root storage is a special case: You can get its creation and modification timestamps using the OleFileIO.root attribute:
c = ole.root.getctime()
m = ole.root.getmtime()
Extract metadata
get_metadata() will check if standard property streams exist, parse all the properties they contain, and return an OleMetadata object with the found properties as attributes.
meta = ole.get_metadata()
print('Author:', meta.author)
print('Title:', meta.title)
print('Creation date:', meta.create_time)
# print all metadata:
meta.dump()
Available attributes include:
codepage, title, subject, author, keywords, comments, template,
last_saved_by, revision_number, total_edit_time, last_printed, create_time,
last_saved_time, num_pages, num_words, num_chars, thumbnail,
creating_application, security, codepage_doc, category, presentation_target,
bytes, lines, paragraphs, slides, notes, hidden_slides, mm_clips,
scale_crop, heading_pairs, titles_of_parts, manager, company, links_dirty,
chars_with_spaces, unused, shared_doc, link_base, hlinks, hlinks_changed,
version, dig_sig, content_type, content_status, language, doc_version
See the source code of the OleMetadata class for more information.
Parse a property stream
get_properties(path) can be used to parse any property stream that is not handled by get_metadata. It returns a dictionary indexed by integers. Each integer is the index of the property, pointing to its value. For example in the standard property stream ‘05SummaryInformation’, the document title is property #2, and the subject is #3.
p = ole.getproperties('specialprops')
By default as in the original PIL version, timestamp properties are converted into a number of seconds since Jan 1,1601. With the option convert_time, you can obtain more convenient Python datetime objects (UTC timezone). If some time properties should not be converted (such as total editing time in ‘05SummaryInformation’), the list of indexes can be passed as no_conversion:
p = ole.getproperties('specialprops', convert_time=True, no_conversion=[10])
Close the OLE file
Unless your application is a simple script that terminates after processing an OLE file, do not forget to close each OleFileIO object after parsing to close the file on disk.
ole.close()
Use OleFileIO as a script
OleFileIO can also be used as a script from the command-line to display the structure of an OLE file and its metadata, for example:
PIL/OleFileIO.py myfile.doc
You can use the option -c to check that all streams can be read fully, and -d to generate very verbose debugging information.
How to contribute
The code is available in a Mercurial repository on bitbucket. You may use it to submit enhancements or to report any issue.
If you would like to help us improve this module, or simply provide feedback, please contact me. You can help in many ways:
test this module on different platforms / Python versions
find and report bugs
improve documentation, code samples, docstrings
write unittest test cases
provide tricky malformed files
How to report bugs
To report a bug, for example a normal file which is not parsed correctly, please use the issue reporting page, or if you prefer to do it privately, use this contact form. Please provide all the information about the context and how to reproduce the bug.
If possible please join the debugging output of OleFileIO. For this, launch the following command :
PIL/OleFileIO.py -d -c file >debug.txt
Classes and Methods
class PIL.OleFileIO.OleFileIO(filename=None, raise_defects=40, write_mode=False, debug=False, path_encoding='utf-8')
Bases: object
OLE container object
This class encapsulates the interface to an OLE 2 structured storage file. Use the listdir() and openstream() methods to access the contents of this file.
Object names are given as a list of strings, one for each subentry level. The root entry should be omitted. For example, the following code extracts all image streams from a Microsoft Image Composer file:
ole = OleFileIO("fan.mic")
for entry in ole.listdir():
if entry[1:2] == "Image":
fin = ole.openstream(entry)
fout = open(entry[0:1], "wb")
while True:
s = fin.read(8192)
if not s:
break
fout.write(s)
You can use the viewer application provided with the Python Imaging Library to view the resulting files (which happens to be standard TIFF files).
close()
close the OLE file, to release the file object
dumpdirectory()
Dump directory (for debugging only)
dumpfat(fat, firstindex=0)
Displays a part of FAT in human-readable form for debugging purpose
dumpsect(sector, firstindex=0)
Displays a sector in a human-readable form, for debugging purpose.
exists(filename)
Test if given filename exists as a stream or a storage in the OLE container. Note: filename is case-insensitive.
Parameters: filename – path of stream in storage tree. (see openstream for syntax)
Returns: True if object exist, else False.
get_metadata()
Parse standard properties streams, return an OleMetadata object containing all the available metadata. (also stored in the metadata attribute of the OleFileIO object)
new in version 0.25
get_rootentry_name()
Return root entry name. Should usually be ‘Root Entry’ or ‘R’ in most implementations.
get_size(filename)
Return size of a stream in the OLE container, in bytes.
Parameters:
filename – path of stream in storage tree (see openstream for syntax)
Returns:
size in bytes (long integer)
Raises:
IOError – if file not found
TypeError – if this is not a stream.
get_type(filename)
Test if given filename exists as a stream or a storage in the OLE container, and return its type.
Parameters: filename – path of stream in storage tree. (see openstream for syntax)
Returns: False if object does not exist, its entry type (>0) otherwise:
STGTY_STREAM: a stream
STGTY_STORAGE: a storage
STGTY_ROOT: the root entry
getctime(filename)
Return creation time of a stream/storage.
Parameters: filename – path of stream/storage in storage tree. (see openstream for syntax)
Returns: None if creation time is null, a python datetime object otherwise (UTC timezone)
new in version 0.26
getmtime(filename)
Return modification time of a stream/storage.
Parameters: filename – path of stream/storage in storage tree. (see openstream for syntax)
Returns: None if modification time is null, a python datetime object otherwise (UTC timezone)
new in version 0.26
getproperties(filename, convert_time=False, no_conversion=None)
Return properties described in substream.
Parameters:
filename – path of stream in storage tree (see openstream for syntax)
convert_time – bool, if True timestamps will be converted to Python datetime
no_conversion – None or list of int, timestamps not to be converted (for example total editing time is not a real timestamp)
Returns:
a dictionary of values indexed by id (integer)
getsect(sect)
Read given sector from file on disk.
Parameters: sect – int, sector index
Returns: a string containing the sector data.
listdir(streams=True, storages=False)
Return a list of streams and/or storages stored in this file
Parameters:
streams – bool, include streams if True (True by default) - new in v0.26
storages – bool, include storages if True (False by default) - new in v0.26 (note: the root storage is never included)
Returns:
list of stream and/or storage paths
loaddirectory(sect)
Load the directory.
Parameters: sect – sector index of directory stream.
loadfat(header)
Load the FAT table.
loadfat_sect(sect)
Adds the indexes of the given sector to the FAT
Parameters: sect – string containing the first FAT sector, or array of long integers
Returns: index of last FAT sector.
loadminifat()
Load the MiniFAT table.
open(filename, write_mode=False)
Open an OLE2 file in read-only or read/write mode. Read and parse the header, FAT and directory.
Parameters:
filename –
string-like or file-like object, OLE file to parse
if filename is a string smaller than 1536 bytes, it is the path of the file to open. (bytes or unicode string)
if filename is a string longer than 1535 bytes, it is parsed as the content of an OLE file in memory. (bytes type only)
if filename is a file-like object (with read, seek and tell methods), it is parsed as-is.
write_mode – bool, if True the file is opened in read/write mode instead of read-only by default. (ignored if filename is not a path)
openstream(filename)
Open a stream as a read-only file object (BytesIO). Note: filename is case-insensitive.
Parameters: filename –
path of stream in storage tree (except root entry), either:
a string using Unix path syntax, for example: ‘storage_1/storage_1.2/stream’
or a list of storage filenames, path to the desired stream/storage. Example: [‘storage_1’, ‘storage_1.2’, ‘stream’]
Returns: file object (read-only)
Raises: IOError – if filename not found, or if this is not a stream.
raise_defect(defect_level, message, exception_type=<type 'exceptions.IOError'>)
This method should be called for any defect found during file parsing. It may raise an IOError exception according to the minimal level chosen for the OleFileIO object.
Parameters:
defect_level –
defect level, possible values are:
DEFECT_UNSURE : a case which looks weird, but not sure it’s a defect
DEFECT_POTENTIAL : a potential defect
DEFECT_INCORRECT : an error according to specifications, but parsing can go on
DEFECT_FATAL : an error which cannot be ignored, parsing is impossible
message – string describing the defect, used with raised exception.
exception_type – exception class to be raised, IOError by default
sect2array(sect)
convert a sector to an array of 32 bits unsigned integers, swapping bytes on big endian CPUs such as PowerPC (old Macs)
write_sect(sect, data, padding='\x00')
Write given sector to file on disk.
Parameters:
sect – int, sector index
data – bytes, sector data
padding – single byte, padding character if data < sector size
write_stream(stream_name, data)
Write a stream to disk. For now, it is only possible to replace an existing stream by data of the same size.
Parameters:
stream_name –
path of stream in storage tree (except root entry), either:
a string using Unix path syntax, for example: ‘storage_1/storage_1.2/stream’
or a list of storage filenames, path to the desired stream/storage. Example: [‘storage_1’, ‘storage_1.2’, ‘stream’]
data – bytes, data to be written, must be the same size as the original stream.
class PIL.OleFileIO.OleMetadata
Bases: object
class to parse and store metadata from standard properties of OLE files.
Available attributes: codepage, title, subject, author, keywords, comments, template, last_saved_by, revision_number, total_edit_time, last_printed, create_time, last_saved_time, num_pages, num_words, num_chars, thumbnail, creating_application, security, codepage_doc, category, presentation_target, bytes, lines, paragraphs, slides, notes, hidden_slides, mm_clips, scale_crop, heading_pairs, titles_of_parts, manager, company, links_dirty, chars_with_spaces, unused, shared_doc, link_base, hlinks, hlinks_changed, version, dig_sig, content_type, content_status, language, doc_version
Note: an attribute is set to None when not present in the properties of the OLE file.
References for SummaryInformation stream: - http://msdn.microsoft.com/en-us/library/dd942545.aspx - http://msdn.microsoft.com/en-us/library/dd925819%28v=office.12%29.aspx - http://msdn.microsoft.com/en-us/library/windows/desktop/aa380376%28v=vs.85%29.aspx - http://msdn.microsoft.com/en-us/library/aa372045.aspx - http://sedna-soft.de/summary-information-stream/ - http://poi.apache.org/apidocs/org/apache/poi/hpsf/SummaryInformation.html
References for DocumentSummaryInformation stream: - http://msdn.microsoft.com/en-us/library/dd945671%28v=office.12%29.aspx - http://msdn.microsoft.com/en-us/library/windows/desktop/aa380374%28v=vs.85%29.aspx - http://poi.apache.org/apidocs/org/apache/poi/hpsf/DocumentSummaryInformation.html
new in version 0.25
DOCSUM_ATTRIBS = ['codepage_doc', 'category', 'presentation_target', 'bytes', 'lines', 'paragraphs', 'slides', 'notes', 'hidden_slides', 'mm_clips', 'scale_crop', 'heading_pairs', 'titles_of_parts', 'manager', 'company', 'links_dirty', 'chars_with_spaces', 'unused', 'shared_doc', 'link_base', 'hlinks', 'hlinks_changed', 'version', 'dig_sig', 'content_type', 'content_status', 'language', 'doc_version']
SUMMARY_ATTRIBS = ['codepage', 'title', 'subject', 'author', 'keywords', 'comments', 'template', 'last_saved_by', 'revision_number', 'total_edit_time', 'last_printed', 'create_time', 'last_saved_time', 'num_pages', 'num_words', 'num_chars', 'thumbnail', 'creating_application', 'security']
dump()
Dump all metadata, for debugging purposes.
parse_properties(olefile)
Parse standard properties of an OLE file, from the streams “SummaryInformation” and “DocumentSummaryInformation”, if present. Properties are converted to strings, integers or python datetime objects. If a property is not present, its value is set to None.
PIL.OleFileIO.debug(msg)
PIL.OleFileIO.debug_pass(msg)
PIL.OleFileIO.debug_print(msg)
PIL.OleFileIO.filetime2datetime(filetime)
convert FILETIME (64 bits int) to Python datetime.datetime
PIL.OleFileIO.i16(c, o=0)
Converts a 2-bytes (16 bits) string to an integer.
c: string containing bytes to convert o: offset of bytes to convert in string
PIL.OleFileIO.i32(c, o=0)
Converts a 4-bytes (32 bits) string to an integer.
c: string containing bytes to convert o: offset of bytes to convert in string
PIL.OleFileIO.i8(c)
PIL.OleFileIO.isOleFile(filename)
Test if a file is an OLE container (according to the magic bytes in its header).
Parameters: filename –
string-like or file-like object, OLE file to parse
if filename is a string smaller than 1536 bytes, it is the path of the file to open. (bytes or unicode string)
if filename is a string longer than 1535 bytes, it is parsed as the content of an OLE file in memory. (bytes type only)
if filename is a file-like object (with read and seek methods), it is parsed as-is.
Returns: True if OLE, False otherwise.
PIL.OleFileIO.set_debug_mode(debug_mode)
Set debug mode on or off, to control display of debugging messages. :param mode: True or False |
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