From 38cc67385fb1b36aa0881bc5982bc58d75dac464 Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?Luk=C3=A1=C5=A1=20Hr=C3=A1zk=C3=BD?= <lhrazky@redhat.com>

Date: Wed, 11 Nov 2020 18:45:11 +0100

Subject: [PATCH] Package: add a get_header() method (RhBug:1876606)

Adds get_header() method to the Package class, which returns the rpm

header of an installed package.

= changelog =

msg: Add get_header() method to the Package class

type: enhancement

resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1876606

---

 dnf/package.py        | 24 ++++++++++++++++++++++++

 tests/test_package.py | 12 ++++++++++++

 2 files changed, 36 insertions(+)

diff --git a/dnf/package.py b/dnf/package.py

index baef04fa5b..836e0e4989 100644

--- a/dnf/package.py

+++ b/dnf/package.py

@@ -26,11 +26,13 @@

 from dnf.i18n import _

 import binascii

+import dnf.exceptions

 import dnf.rpm

 import dnf.yum.misc

 import hawkey

 import logging

 import os

+import rpm

 logger = logging.getLogger("dnf")

@@ -95,6 +97,11 @@ def from_repo(self):

     @property

     def _header(self):

+        """

+        Returns the header of a locally present rpm package file. As opposed to

+        self.get_header(), which retrieves the header of an installed package

+        from rpmdb.

+        """

         return dnf.rpm._header(self.localPkg())

     @property

@@ -164,6 +171,23 @@ def debugsource_name(self):

         src_name = self.source_name if self.source_name is not None else self.name

         return src_name + self.DEBUGSOURCE_SUFFIX

+    def get_header(self):

+        """

+        Returns the rpm header of the package if it is installed. If not

+        installed, returns None. The header is not cached, it is retrieved from

+        rpmdb on every call. In case of a failure (e.g. when the rpmdb changes

+        between loading the data and calling this method), raises an instance

+        of PackageNotFoundError.

+        """

+        if not self._from_system:

+            return None

+

+        try:

+            # RPMDBI_PACKAGES stands for the header of the package

+            return next(self.base._ts.dbMatch(rpm.RPMDBI_PACKAGES, self.rpmdbid))

+        except StopIteration:

+            raise dnf.exceptions.PackageNotFoundError("Package not found when attempting to retrieve header", str(self))

+

     @property

     def source_debug_name(self):

         # :api

diff --git a/tests/test_package.py b/tests/test_package.py

index cd4872e631..514e5bf099 100644

--- a/tests/test_package.py

+++ b/tests/test_package.py

@@ -68,6 +68,18 @@ def fn_getter():

             with self.assertRaises(IOError):

                 pkg._header

+    # rpm.hdr() is not easy to construct with custom data, we just return a string

+    # instead, as we don't actually need an instance of rpm.hdr for the test

+    @mock.patch("rpm.TransactionSet.dbMatch", lambda self, a, b: iter(["package_header_test_data"]))

+    def test_get_header(self):

+        pkg = self.sack.query().installed().filter(name="pepper")[0]

+        header = pkg.get_header()

+        self.assertEqual(header, "package_header_test_data")

+

+        pkg = self.sack.query().available().filter(name="pepper")[0]

+        header = pkg.get_header()

+        self.assertEqual(header, None)

+

     @mock.patch("dnf.package.Package.rpmdbid", long(3))

     def test_idx(self):

         """ pkg.idx is an int. """