proxy.golang.org : github.com/kisielk/og-rek

Package ogórek(*) is a library for decoding/encoding Python's pickle format. Use Decoder to decode a pickle from input stream, for example: Use Encoder to encode an object as pickle into output stream, for example: The following table summarizes mapping of basic types in between Python and Go: For dicts there are two modes. In the first, default, mode Python dicts are decoded into standard Go map. This mode tries to use builtin Go type, but cannot mirror py behaviour fully because e.g. int(1), big.Int(1) and float64(1.0) are all treated as different keys by Go, while Python treats them as being equal. It also does not support decoding dicts with tuple used in keys: With PyDict=y mode, however, Python dicts are decoded as ogórek.Dict which mirrors behaviour of Python dict with respect to keys equality, and with respect to which types are allowed to be used as keys. For strings there are also two modes. In the first, default, mode both py2/py3 str and py2 unicode are decoded into string with py2 str being considered as UTF-8 encoded. Correspondingly for protocol ≤ 2 Go string is encoded as UTF-8 encoded py2 str, and for protocol ≥ 3 as py3 str / py2 unicode. ogórek.ByteString can be used to produce bytestring objects after encoding even for protocol ≥ 3. This mode tries to match Go string with str type of target Python depending on protocol version, but looses information after decoding/encoding cycle: However with StrictUnicode=y mode there is 1-1 mapping in between py2 unicode / py3 str vs Go string, and between py2 str vs ogórek.ByteString. In this mode decoding/encoding and encoding/decoding operations are always identity with respect to strings: For bytes, unconditionally to string mode, there is direct 1-1 mapping in between Python and Go types: Python classes and instances are mapped to Class and Call, for example: In particular on Go side it is thus by default safe to decode pickles from untrusted sources(^). Over the time the pickle stream format was evolving. The original protocol version 0 is human-readable with versions 1 and 2 extending the protocol in backward-compatible way with binary encodings for efficiency. Protocol version 2 is the highest protocol version that is understood by standard pickle module of Python2. Protocol version 3 added ways to represent Python bytes objects from Python3(~). Protocol version 4 further enhances on version 3 and completely switches to binary-only encoding. Protocol version 5 added support for out-of-band data(%). Please see https://docs.python.org/3/library/pickle.html#data-stream-format for details. On decoding ogórek detects which protocol is being used and automatically handles all necessary details. On encoding, for compatibility with Python2, by default ogórek produces pickles with protocol 2. Bytes thus, by default, will be unpickled as str on Python2 and as bytes on Python3. If an earlier protocol is desired, or on the other hand, if Bytes needs to be encoded efficiently (protocol 2 encoding for bytes is far from optimal), and compatibility with pure Python2 is not an issue, the protocol to use for encoding could be explicitly specified, for example: See EncoderConfig.Protocol for details. Pickle was originally created for serialization in ZODB (http://zodb.org) object database, where on-disk objects can reference each other similarly to how one in-RAM object can have a reference to another in-RAM object. When a pickle with such persistent reference is decoded, ogórek represents the reference with Ref placeholder similarly to Class and Call. However it is possible to hook into decoding and process such references in application specific way, for example loading the referenced object from the database: Similarly, for encoding, an application can hook into serialization process and turn pointers to some in-RAM objects into persistent references. Please see DecoderConfig.PersistentLoad and EncoderConfig.PersistentRef for details. On Python two different objects with different types can represent essentially the same entity. For example 1 (int) and 1L (long) represent integer number one via two different types and are decoded by ogórek into Go types int64 and big.Int correspondingly. However on the Python side those two representations are often used interchangeably and programs are usually expected to handle both with the same effect. To help handling decoded values with such differences ogórek provides utilities that bring objects to common type irregardless of which type variant was used in the pickle stream. For example AsInt64 tries to represent unpickled value as int64 if possible and errors if not. For strings the situation is similar, but a bit different. On Python3 strings are unicode strings and binary data is represented by bytes type. However on Python2 strings are bytestrings and could contain both text and binary data. In the default mode py2 strings, the same way as py2 unicode, are decoded into Go strings. However in StrictUnicode mode py2 strings are decoded into ByteString - the type specially dedicated to represent them on Go side. There are two utilities to help programs handle all those bytes/string data in the pickle stream in uniform way: Using the helpers fits into Python3 strings/bytes model but also allows to handle the data generated from under Python2. Similarly Dict considers ByteString to be equal to both string and Bytes with the same underlying content. This allows programs to access Dict via string/bytes keys following Python3 model, while still being able to handle dictionaries generated from under Python2. -------- (*) ogórek is Polish for "pickle". (~) bytes can be produced only by Python3 or zodbpickle (https://pypi.org/project/zodbpickle), not by standard Python2. Respectively, for protocol ≤ 2, what ogórek produces is unpickled as bytes by Python3 or zodbpickle, and as str by Python2. (^) contrary to Python implementation, where malicious pickle can cause the decoder to run arbitrary code, including e.g. os.system("rm -rf /"). (%) ogórek currently does not support out-of-band data.

Registry - Source - Documentation - JSON - codemeta.json
purl: pkg:golang/github.com/kisielk/og-rek
Keywords: go , pickle
License: MIT
Latest release: 9 months ago
First release: over 7 years ago
Namespace: github.com/kisielk
Dependent packages: 11
Dependent repositories: 19
Stars: 60 on GitHub
Forks: 16 on GitHub
Docker dependents: 4
Docker downloads: 2,144,872
See more repository details: repos.ecosyste.ms
Last synced: 14 days ago

• Readme
• Versions 4
• Dependent Packages 11
• Maintainers 0