python - 如何使用Python查找debian软件包信息

Question

我想使用 python 以编程方式查找 debian 软件包的最新可用版本。我环顾四周，但找不到合适的关键字来消除所有“python”“parse”“package”“index”碰巧翻过来的噪音。

有谁知道加载和解析这样的包索引的方法吗？
这是示例的 URL，我无法用 yaml 或 json 完全解析它: http://packages.osrfoundation.org/gazebo/ubuntu/dists/trusty/main/binary-amd64/ http://packages.osrfoundation.org/gazebo/ubuntu/dists/trusty/main/binary-amd64/Packages

我看过apt_pkg ，但我不确定如何将其处理为我需要的在线索引。

谢谢!

Answer 1

您可以使用subprocess要运行的模块 apt-cache policy <app> :

from subprocess import check_output

out = check_output(["apt-cache", "policy","python"])
print(out)

输出:

python:
  Installed: 2.7.5-5ubuntu3
  Candidate: 2.7.5-5ubuntu3
  Version table:
 *** 2.7.5-5ubuntu3 0
        500 http://ie.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages
        100 /var/lib/dpkg/status

您可以传递您尝试获取使用函数的信息的任何应用程序:

from subprocess import check_output,CalledProcessError
def apt_cache(app):
    try:
        return check_output(["apt-cache", "policy",app])
    except CalledProcessError as e:
        return e.output

print(apt_cache("python"))

或者使用 *args 并运行您喜欢的任何命令:

from subprocess import check_output,CalledProcessError
def apt_cache(*args):
    try:
        return check_output(args)
    except CalledProcessError as e:
        return e.output

print(apt_cache("apt-cache","showpkg ","python"))

如果你想解析输出，你可以使用 re:

import  re
from subprocess import check_output,CalledProcessError
def apt_cache(*args):
    try:
        out = check_output(args)
        m = re.search("Candidate:.*",out)
        return m.group() if m else "No match"
    except CalledProcessError as e:
        return e.output

print(apt_cache("apt-cache","policy","python"))
Candidate: 2.7.5-5ubuntu3

或者获取已安装的和候选的:

def apt_cache(*args):
    try:
        out = check_output(args)
        m = re.findall("Candidate:.*|Installed:.*",out)
        return "{}\n{}".format(*m) if m else "No match"
    except CalledProcessError as e:
        return e.output
 print(apt_cache("apt-cache","policy","python"))

输出:

Installed: 2.7.5-5ubuntu3
Candidate: 2.7.5-5ubuntu3