Add an APT source

This source follows the same flow apt itself uses to check for a
package's version, so it can be used to check for any APT repository
(not necessarily Debian or Ubuntu).

docs/usage.rst

@@ -610,6 +610,32 @@ host
 
 This source returns tags and supports :ref:`list options`.
 
+Check APT repository
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+::
+
+  source = "apt"
+
+This enables you to track the update of an arbitary APT repository, without needing of apt and an updated local APT database.
+
+apt
+  Name of the APT package.
+
+mirror
+  URL of the repository (defaults to http://ftp.debian.org/debian/)
+
+suite
+  Name of the APT repository release (jessie, wheezy, etc, defaults to sid)
+
+repo
+  Name of the APT repository (main, contrib, etc, defaults to main)
+
+arch
+  Architecture of the repository (i386, amd64, etc, defaults to amd64)
+
+strip_release
+  Strip the release part.
+
 Manually updating
 ~~~~~~~~~~~~~~~~~
 ::

nvchecker_source/apt.py

@@ -0,0 +1,52 @@
+# MIT licensed
+# Copyright (c) 2020 Felix Yan <felixonmars@archlinux.org>, et al.
+
+from nvchecker.api import session, GetVersionError
+
+APT_RELEASE_URL = "%s/dists/%s/Release"
+APT_PACKAGES_PATH = "%s/binary-%s/Packages%s"
+APT_PACKAGES_URL = "%s/dists/%s/%s"
+APT_PACKAGES_SUFFIX_PREFER = (".xz", ".gz", "")
+
+async def get_url(url):
+  res = await session.get(url)
+  data = res.body
+
+  if url.endswith(".xz"):
+    import lzma
+    data = lzma.decompress(data)
+  elif url.endswith(".gz"):
+    import gzip
+    data = gzip.decompress(data)
+
+  return data.decode('utf-8')
+
+async def get_version(name, conf, *, cache, **kwargs):
+  pkg = conf.get('apt') or name
+  mirror = conf.get('mirror', "http://ftp.debian.org/debian/")
+  suite = conf.get('suite', 'sid')
+  repo = conf.get('repo', 'main')
+  arch = conf.get('arch', 'amd64')
+  strip_release = conf.get('strip_release', False)
+
+  apt_release = await cache.get(APT_RELEASE_URL % (mirror, suite), get_url)
+  for suffix in APT_PACKAGES_SUFFIX_PREFER:
+    packages_path = APT_PACKAGES_PATH % (repo, arch, suffix)
+    if " " + packages_path in apt_release:
+      break
+  else:
+    raise GetVersionError('Packages file not found in APT repository')
+
+  apt_packages = await cache.get(APT_PACKAGES_URL % (mirror, suite, packages_path), get_url)
+
+  pkg_found = False
+  for line in apt_packages.split("\n"):
+    if line == "Package: " + pkg:
+      pkg_found = True
+    if pkg_found and line.startswith("Version: "):
+      version = line[9:]
+      if strip_release:
+        version = version.split("-")[0]
+      return version
+
+  raise GetVersionError('package not found in APT repository')

tests/test_apt.py

@@ -0,0 +1,28 @@
+# MIT licensed
+# Copyright (c) 2020 lilydjwg <lilydjwg@gmail.com>, et al.
+# Copyright (c) 2017 Felix Yan <felixonmars@archlinux.org>, et al.
+
+from flaky import flaky
+import pytest
+pytestmark = [pytest.mark.asyncio, pytest.mark.needs_net]
+
+@flaky(max_runs=10)
+async def test_apt(get_version):
+    assert await get_version("sigrok-firmware-fx2lafw", {
+        "source": "apt",
+    }) == "0.1.7-1"
+
+@flaky(max_runs=10)
+async def test_apt_strip_release(get_version):
+    assert await get_version("sigrok-firmware-fx2lafw", {
+        "source": "apt",
+        "strip_release": 1,
+    }) == "0.1.7"
+
+@flaky(max_runs=10)
+async def test_apt_deepin(get_version):
+    assert await get_version("sigrok-firmware-fx2lafw", {
+        "source": "apt",
+        "mirror": "https://community-packages.deepin.com/deepin",
+        "suite": "apricot",
+    }) == "0.1.6-1"