java-manifest-py
Encode/decode Java's META-INF/MANIFEST.MF in Python.
Installation
To install the latest release on PyPI, run:
$ pip install java-manifestUsage
A MANIFEST is represented by a list of dictionaries, where each dictionary
corresponds to an empty-line delimited section of the MANIFEST and each
dictionary has str keys and either str or bool values.
java_manifest.loads takes a string containing MANIFEST-formatted data and
returns a list of dictionaries, where each dictionary is a section in the
MANIFEST. java_manifest.load does the same, using any typing.TextIO
readable object.
>>> import java_manifest
>>> manifest_str = """
... Name: README-Example-1
... Long-Line: aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
... aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
...
... Name: README-Example-2
... Foo: Bar
... """
>>> manifest = java_manifest.loads(manifest_str)
>>> print(manifest)
[{'Name': 'README-Example-1', 'Long-Line': 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'}, {'Name': 'README-Example-2', 'Foo': 'Bar'}]Similarly, java_manifest.dumps returns a string of MANIFEST-formatted data
from a list of dictionaries, where each dictionary is a section in the
MANIFEST. java_manifest.dump does the same, writing into any typing.TextIO
writable object.
>>> import java_manifest
>>> manifest = [
... {
... "Name": "README-Example",
... "Some-Str": "Some random string",
... },
... ]
>>> manifest_str = java_manifest.dumps(manifest)
>>> print(manifest_str)
Name: README-Example
Some-Str: Some random string
<BLANKLINE>There is also a from_jar function that finds the META-INF/MANIFEST.MF file
within the jar and java_manifest.loads that.
>>> import java_manifest
>>> manifest = java_manifest.from_jar("test_files/simple.jar")Custom Encoders/Decoders
Because Java's manifest file format doesn't deal with structured values within
a section, specific uses of the format create ad-hoc encoding/decoding rules
that can convert some structured data into a basic string so it can be encoded
into a manifest and vice versa. The encoder and decoder arguments for
dumping and loading respectively are responsible for handling this. An encoder
and decoder both take in a key-value pair. However, an encoder receives
potentially structured data as the value and returns plain string, while a
decode receives string values and returns potentially structured data.
As we have already see, the default encoder and decoder does no transformation and prevents you from attempting to dump non-string data.
>>> import java_manifest
>>> print(java_manifest.dumps([{"foo": "bar"}]))
foo: bar
>>> print(java_manifest.dumps([{"int": 1}]))
Traceback (most recent call last):
...
ValueError: key 'int' has type <class 'int'> value, expected strYou can however describe more custom encoders that support for example lists of strings.
>>> def encode(key, val):
... if isinstance(val, list):
... return ",".join(val)
... return val
>>> print(java_manifest.dumps([{"foo": "bar", "names": ["alice", "bob", "charlie"]}], encoder=encode))
foo: bar
names: alice,bob,charlie
<BLANKLINE>Similarly for custom decoders.
>>> import java_manifest
>>> def decode(key, val):
... # In reality you'd probably want to target only specific keys, to avoid
... # messing up random strings containing commas. This is just an example.
... vals = val.split(",")
... if len(vals) == 1:
... return val
... else:
... return vals
>>> manifest = java_manifest.loads("foo: bar\r\nnames: alice,bob,charlie", decoder=decode)
>>> print(manifest)
[{'foo': 'bar', 'names': ['alice', 'bob', 'charlie']}]
