index.py

import hashlib
import os
from operator import attrgetter

from meta.common import polymc_path
from meta.model import MetaVersion, MetaPackage
from meta.model.index import MetaPackageIndex, MetaVersionIndex, MetaVersionIndexEntry, MetaPackageIndexEntry

PMC_DIR = polymc_path()


# take the hash type (like hashlib.md5) and filename, return hex string of hash
def hash_file(hash_fn, file_name):
    hash_instance = hash_fn()
    with open(file_name, "rb") as f:
        for chunk in iter(lambda: f.read(4096), b""):
            hash_instance.update(chunk)
    return hash_instance.hexdigest()


# ignore these files when indexing versions
ignore = {"index.json", "package.json", ".git", ".github"}

# initialize output structures - package list level
packages = MetaPackageIndex()

# walk thorugh all the package folders
for package in sorted(os.listdir(PMC_DIR)):
    if package in ignore:
        continue

    sharedData = MetaPackage.parse_file(os.path.join(PMC_DIR, package, "package.json"))
    recommendedVersions = set()
    if sharedData.recommended:
        recommendedVersions = set(sharedData.recommended)

    # initialize output structures - version list level
    versionList = MetaVersionIndex(uid=package, name=sharedData.name)

    # walk through all the versions of the package
    for filename in os.listdir(PMC_DIR + "/%s" % package):
        if filename in ignore:
            continue

        # parse and hash the version file
        filepath = PMC_DIR + "/%s/%s" % (package, filename)
        filehash = hash_file(hashlib.sha256, filepath)
        versionFile = MetaVersion.parse_file(filepath)
        is_recommended = versionFile.version in recommendedVersions

        versionEntry = MetaVersionIndexEntry.from_meta_version(versionFile, is_recommended, filehash)

        versionList.versions.append(versionEntry)

    # sort the versions in descending order by time of release
    versionList.versions = sorted(versionList.versions, key=attrgetter('release_time'), reverse=True)

    # write the version index for the package
    outFilePath = PMC_DIR + "/%s/index.json" % package
    versionList.write(outFilePath)

    # insert entry into the package index
    packageEntry = MetaPackageIndexEntry(
        uid=package,
        name=sharedData.name,
        sha256=hash_file(hashlib.sha256, outFilePath)
    )
    packages.packages.append(packageEntry)

packages.write(os.path.join(PMC_DIR, "index.json"))