源码阅读笔记-pip-pop
想让代码更加pythonic，最好的方法就是阅读源码，边阅读边实践。推荐知乎Python之美。这里先读一读pip-pop项目源码
这是一个很简单的单文件项目 我是源码pip-pop，用来对比、处理requirements.txt文件–python依赖包文件
整个源码介绍如下，包括看项目的过程，先读文件，再读文件夹
.gitignore
/.tox # 不懂
/*.egg-info # 部署该工具的文件
*.pyc
自建的ignore文件，没有使用github的自带python-ignore模板
.travis.yml
sudo: false # 是否需要sudo权限
language: python # bin文件的执行语言
python: # 支持的python版本
- "2.7"
- "3.4"
- "3.5"
- "pypy"
cache: pip # 缓存，不太懂
install: # 安装改工具的方法
- pip install -r requirements.txt
script: # 不懂
- tox # 这是啥？
目前还不知道用处，好像是用来配置pip-pop工具用的
LICENSE
mit
README.rst
同 README.md
requirements.txt
依赖
docopt==0.6.2
tox==2.3.1
setup.py
配置
"""
pip-pop manages your requirements files.
"""
import sys
from setuptools import setup
setup(
name='pip-pop', # 库名
version='0.1.0', # 版本
url='https://github.com/kennethreitz/pip-pop', # 源码地址
license='MIT', # license
author='Kenneth Reitz', # 作者
author_email='me@kennethreitz.org', # 邮箱
description=__doc__.strip('\n'), # 库描述文档，疑问：为什么去掉\n?
#packages=[], # 不懂
scripts=['bin/pip-diff', 'bin/pip-grep'], # 不懂
#include_package_data=True, # 不懂
zip_safe=False, # 不懂
platforms='any', # 可运行平台
install_requires=['docopt', 'pip>=1.5.0'], # 依赖包
tests_require=['tox'], # 测试依赖
classifiers=[ # 参考：元信息
# As from https://pypi.python.org/pypi?%3Aaction=list_classifiers
#'Development Status :: 1 - Planning', # 计划中
#'Development Status :: 2 - Pre-Alpha',
#'Development Status :: 3 - Alpha', # 内测试
'Development Status :: 4 - Beta', # 对外测试版本
#'Development Status :: 5 - Production/Stable', # 稳定版本
#'Development Status :: 6 - Mature', # 干啥用？
#'Development Status :: 7 - Inactive', # 干啥用？
'Programming Language :: Python', # 依赖环境
'Programming Language :: Python :: 2',
'Programming Language :: Python :: 2.7',
'Programming Language :: Python :: 3',
'Programming Language :: Python :: 3.4',
'Programming Language :: Python :: 3.5',
'Programming Language :: Python :: Implementation :: CPython',
'Programming Language :: Python :: Implementation :: PyPy',
'Intended Audience :: Developers',
'Intended Audience :: System Administrators',
'License :: OSI Approved :: BSD License',
'Operating System :: OS Independent',
'Topic :: System :: Systems Administration',
]
)
bin/pip-diff
主要源码
#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""Usage: # docopt命令行
pip-diff (--fresh | --stale) <reqfile1> <reqfile2> [--exclude <package>...]
pip-diff (-h | --help)
Options:
-h --help Show this screen.
--fresh List newly added packages. # 新增加的包
--stale List removed packages. # 移除的包
"""
import os
from docopt import docopt
from pip.req import parse_requirements
from pip.index import PackageFinder
from pip._vendor.requests import session
requests = session()
class Requirements(object):
def __init__(self, reqfile=None):
super(Requirements, self).__init__()
self.path = reqfile
self.requirements = []
if reqfile:
self.load(reqfile)
def __repr__(self):
return '<Requirements \'{}\'>'.format(self.path)
def load(self, reqfile): # 同pip-grep文件中的这个函数， 将指定文件的依赖包解析并加载到self
if not os.path.exists(reqfile):
raise ValueError('The given requirements file does not exist.')
finder = PackageFinder([], [], session=requests)
for requirement in parse_requirements(reqfile, finder=finder, session=requests):
if requirement.req: # req是啥？
if not getattr(requirement.req, 'name', None):
# Prior to pip 8.1.2 the attribute `name` did not exist.
requirement.req.name = requirement.req.project_name
self.requirements.append(requirement.req)
def diff(self, requirements, ignore_versions=False, excludes=None): # 为什么不用set来实现？
r1 = self # 对象1，包含多个依赖包
r2 = requirements # 对象2，包含多个依赖包
results = {'fresh': [], 'stale': []} # 记录对比结果
# Generate fresh packages.
other_reqs = ( # 如果忽略版本，则只保存名字，否则保存整个对象
[r.name for r in r1.requirements]
if ignore_versions else r1.requirements
)
for req in r2.requirements: # 对于新的reqirement
r = req.name if ignore_versions else req #处理成与other_reqs相同类型的变量
if r not in other_reqs and r not in excludes: # 新增加的包，并且不在白名单中，则加入fresh
results['fresh'].append(req)
# Generate stale packages.
other_reqs = ( # 既然fresh和stale是分开写的，那么这个变量命名方式就不好，不应该跟上面相同，不容易理解
[r.name for r in r2.requirements]
if ignore_versions else r2.requirements
)
for req in r1.requirements: # 对于旧的reqirement
r = req.name if ignore_versions else req
if r not in other_reqs and r not in excludes: # 如果不是在新列表里，并且不在白名单里，则加入stale
results['stale'].append(req)
return results
def diff(r1, r2, include_fresh=False, include_stale=False, excludes=None):
include_versions = True if include_stale else False # 版本号只在有stale包时才用
excludes = excludes if len(excludes) else [] # 规范为列表
try:
r1 = Requirements(r1)
r2 = Requirements(r2)
except ValueError:
print('There was a problem loading the given requirements files.')
exit(os.EX_NOINPUT)
results = r1.diff(r2, ignore_versions=True, excludes=excludes)
if include_fresh:
for line in results['fresh']:
print(line.name if include_versions else line) # 只打印名字 耦合性太强了
if include_stale:
for line in results['stale']:
print(line.name if include_versions else line) # 只打印名字
def main():
args = docopt(__doc__, version='pip-diff')
kwargs = {
'r1': args['<reqfile1>'],
'r2': args['<reqfile2>'],
'include_fresh': args['--fresh'],
'include_stale': args['--stale'],
'excludes': args['<package>']
}
diff(**kwargs)
if __name__ == '__main__':
main()
bin/pip-grep
辅助源码
#!/usr/bin/env python # 最标准的py文件头
# -*- coding: utf-8 -*-
"""Usage: # docopt命令行
pip-grep [-s] <reqfile> <package>...
Options:
-h --help Show this screen.
"""
import os
from docopt import docopt
from pip.req import parse_requirements # 解析reqirements文件
from pip.index import PackageFinder # 查找库
from pip._vendor.requests import session # 不懂
requests = session() # 参考：生成会话，管理上下文
class Requirements(object):
def __init__(self, reqfile=None):
super(Requirements, self).__init__() # 标准的父类init方式，一般我对object类的子类不加这个，可能加上更好
self.path = reqfile # reqirement文件路径
self.requirements = []
if reqfile: # 如果有reqfile，则加载reqfile文件
self.load(reqfile)
def __repr__(self): # 打印
return '<Requirements \'{}\'>'.format(self.path) # 更pythonic的方法是用单引号嵌套双引号
def load(self, reqfile):
if not os.path.exists(reqfile): # 文件存在性检查
raise ValueError('The given requirements file does not exist.')
finder = PackageFinder([], [], session=requests) # 包查找器，requests管理上下文
for requirement in parse_requirements(reqfile, finder=finder, session=requests): # pip解析的依赖包对象
if requirement.req:
if not getattr(requirement.req, 'name', None): # 处理pip版本低的问题，标准化
# Prior to pip 8.1.2 the attribute `name` did not exist.
requirement.req.name = requirement.req.project_name
self.requirements.append(requirement.req) # 将req属性写入requirements
def grep(reqfile, packages, silent=False): # 查找函数 反馈是否满足依赖
try:
r = Requirements(reqfile) # 实例化
except ValueError: # 处理初始化错误
if not silent:
print('There was a problem loading the given requirement file.')
exit(os.EX_NOINPUT)
for req in r.requirements: # 处理每个依赖包
if req.name in packages:
if not silent: # 命令行打印
print('Package {} found!'.format(req.name))
exit(0) # 满足依赖则返回0 疑问：为什么结束循环？是不是没判断版本？
if not silent: #
print('Not found.')
exit(1) # 不满足以来则返回1
def main():
args = docopt(__doc__, version='pip-grep')
kwargs = {'reqfile': args['<reqfile>'], 'packages': args['<package>'], 'silent': args['-s']}
grep(**kwargs) # 安全的参数使用方法，先定义有哪些参数，然后用**传递
if __name__ == '__main__':
main() # 命令行使用