Fix: module did not expose __version__ (#75)

Solution: declare `__version__` in `__init__.py` and parse the file with a regex to determine the version in `setup.py`.

aleph_message/__init__.py

@@ -1,3 +1,4 @@
 from .models import MessagesResponse, parse_message
 
 __all__ = ["parse_message", "MessagesResponse"]
+__version__ = "0.4.0"

setup.py

@@ -4,38 +4,60 @@
 """
 
 import os
+import re
+
+
+def get_version():
+    version_file = os.path.join("aleph_message", "__init__.py")
+    initfile_lines = open(version_file, "rt").readlines()
+    version = r"^__version__ = ['\"]([^'\"]*)['\"]"
+
+    for line in initfile_lines:
+        mo = re.search(version, line, re.M)
+        if mo:
+            return mo.group(1)
+    raise RuntimeError(f"Unable to find version string in {version_file}.")
+
 
 from setuptools import setup
 
 # allow setup.py to be run from any path
 os.chdir(os.path.normpath(os.path.join(os.path.abspath(__file__), os.pardir)))
 
-with open('README.md') as file:
+with open("README.md") as file:
     long_description = file.read()
 
-setup(name='aleph-message',
-      version='0.4.0',
-      description='Aleph.im message specification ',
-      long_description=long_description,
-      long_description_content_type='text/markdown',
-      author='Hugo Herter',
-      author_email='[email protected]',
-      url='https://github.com/aleph-im/aleph-message',
-      packages=['aleph_message', 'aleph_message.models', 'aleph_message.models.execution'],
-      package_data={"aleph_message": ["py.typed"],
-                    "aleph_message.models": ["py.typed"],
-                    "aleph_message.models.execution": ["py.typed"]},
-      data_files=[],
-      install_requires=[
-          'pydantic~=1.10.5',
-          'typing_extensions~=4.5.0',
-      ],
-      license='MIT',
-      platform='any',
-      keywords="aleph.im message validation specification",
-      classifiers=['Development Status :: 5 - Production/Stable',
-                   'Programming Language :: Python :: 3',
-                   'Intended Audience :: Developers',
-                   'Topic :: System :: Distributed Computing',
-                   ],
-      )
+setup(
+    name="aleph-message",
+    version=get_version(),
+    description="Aleph.im message specification ",
+    long_description=long_description,
+    long_description_content_type="text/markdown",
+    author="Hugo Herter",
+    author_email="[email protected]",
+    url="https://github.com/aleph-im/aleph-message",
+    packages=[
+        "aleph_message",
+        "aleph_message.models",
+        "aleph_message.models.execution",
+    ],
+    package_data={
+        "aleph_message": ["py.typed"],
+        "aleph_message.models": ["py.typed"],
+        "aleph_message.models.execution": ["py.typed"],
+    },
+    data_files=[],
+    install_requires=[
+        "pydantic~=1.10.5",
+        "typing_extensions~=4.5.0",
+    ],
+    license="MIT",
+    platform="any",
+    keywords="aleph.im message validation specification",
+    classifiers=[
+        "Development Status :: 5 - Production/Stable",
+        "Programming Language :: Python :: 3",
+        "Intended Audience :: Developers",
+        "Topic :: System :: Distributed Computing",
+    ],
+)