Direct download url for the latest PyCharm Community Edition.

pycharm_community_url.py

#!/usr/bin/env python

"""
The JetBrains Toolbox app fetches (xz-compressed) json feeds inside ASN.1 signedData.
Retrieve the feed and locate the direct download url for the latest PyCharm Community Edition.
"""

from __future__ import print_function

import json
import platform
from distutils.version import LooseVersion

from pyasn1.codec.der.decoder import decode as der_decoder
from pyasn1_modules.rfc2315 import ContentInfo, contentTypeMap, signedData, data

try:
    import lzma
except ImportError:
    from backports import lzma

try:
    from urllib.request import urlopen
except ImportError:
    from urllib2 import urlopen


# This constant is hardcoded in "JetBrains Toolbox.app"
PUBLIC_FEED = 'https://download.jetbrains.com/toolbox/feeds/v1/public-feed.feed.xz.signed'
RELEASE_FEED = 'release.feed'
CURRENT_PLATFORM = {'Windows': 'windows', 'Linux': 'linux', 'Darwin': 'mac'}[platform.system()]


def asn1_to_signed_data(filelikeobject):
    contentInfo, rest_of_input = der_decoder(filelikeobject.read(), asn1Spec=ContentInfo())

    # Signed Data
    contentType = contentInfo.getComponentByName('contentType')
    assert contentType == signedData

    contentInfo, leftover = der_decoder(
        contentInfo.getComponentByName('content'),
        asn1Spec=contentTypeMap[contentType]
    )

    # data
    data_contentInfo = contentInfo.getComponentByName("contentInfo")
    data_contentType = data_contentInfo.getComponentByName('contentType')
    assert data_contentType  == data

    raw_xz_data, leftover = der_decoder(
        data_contentInfo.getComponentByName('content'),
        asn1Spec=contentTypeMap[data_contentType]
    )

    # bytes
    return raw_xz_data._value


def decompress_xz_json(bytesequence):
    json_string = lzma.LZMADecompressor().decompress(bytesequence)
    return json.loads(json_string)


def locate_latest_package_url(d, platform_os=CURRENT_PLATFORM):
    available_packages = [n for n in d['entries'] if n['id'] == 'PyCharm-C' and n['package']['os'] == platform_os]
    newest_package = sorted(available_packages, key=lambda a: LooseVersion(a['version']), reverse=True)[0]
    return newest_package['package']['url']


def toolbox():
    keyfile = urlopen(PUBLIC_FEED)
    raw_xz_data = asn1_to_signed_data(keyfile)
    feed_url = [f['url'] for f in decompress_xz_json(raw_xz_data)['feeds'] if RELEASE_FEED in f['url']][0]

    keyfile = urlopen(feed_url)
    raw_xz_data = asn1_to_signed_data(keyfile)
    packages = decompress_xz_json(raw_xz_data)
    url = locate_latest_package_url(packages)
    return url

if __name__ == "__main__":
    print(toolbox())