Django如何启动源码分析
启动
我们启动Django是通过python manage.py runsever
的命令
解决
这句话就是执行manage.py文件,并在命令行发送一个runsever字符串
解析manage.py
#!/usr/bin/env python
import os
import sys
if __name__ == "__main__":
#os.environ.setdefault 方法可以修改系统环境变量,但是只能os.environ 只能影响到当前运行程序
os.environ.setdefault("DJANGO_SETTINGS_MODULE", "zx2.settings")
try:
#导入模块,其实这里不单单只是导入execute_from_command_line这个方法,更多的是检查Django的模块,配置是否有问题
from django.core.management import execute_from_command_line
except ImportError:
# The above import may fail for some other reason. Ensure that the
# issue is really that Django is missing to avoid masking other
# exceptions on Python 2.
try:
#精准判断是不是django模块的问题
import django
except ImportError:
raise ImportError(
"Couldn't import Django. Are you sure it's installed and "
"available on your PYTHONPATH environment variable? Did you "
"forget to activate a virtual environment?"
)
raise
#sys.argv是从外部获取参数,最后执行下面这个方法
execute_from_command_line(sys.argv)
测试sys.argv
发现两种启动获取的参数不一样,但是第二个参数一样
命令行启动项目
['manage.py', 'runserver']
pycharm 启动项目
['C:/Users/Administrator/Desktop/01python/django/zx1/manage.py', 'runserver', '127.0.0.1:8000']
解析execute_from_command_line(sys.argv)
项目启动入口
def execute_from_command_line(argv=None):
"""
管理应用程序的简单方法
A simple method that runs a ManagementUtility.
"""
utility = ManagementUtility(argv)
utility.execute()
ManagementUtility初始化代码
class ManagementUtility(object):
"""
封装django-admin 和 manage.py的公共逻辑代码
Encapsulates the logic of the django-admin and manage.py utilities.
"""
def __init__(self, argv=None):
#把argv给self对象
self.argv = argv or sys.argv[:]
#返回path最后的文件名。若path以/或\结尾,那么就会返回空值,为zx1
self.prog_name = os.path.basename(self.argv[0])
self.settings_exception = None
utility.execute()分析
def execute(self):
"""
给定命令行参数,这将确定哪个子命令将要被运行,创建一个适合该命令的解析器,并运行它。
Given the command-line arguments, this figures out which subcommand is
being run, creates a parser appropriate to that command, and runs it.
"""
try:
#self.argv[1]值为runserver
subcommand = self.argv[1]
except IndexError:
subcommand = 'help' # Display help if no arguments were given.
#预处理选项以提取--settings和--pythonpath。
# Preprocess options to extract --settings and --pythonpath.
#这些选项可能会影响可用的命令,因此
# These options could affect the commands that are available, so they
#必须提前处理。
# must be processed early.
#创建一个命令分析器
parser = CommandParser(None, usage="%(prog)s subcommand [options] [args]", add_help=False)
parser.add_argument('--settings')
parser.add_argument('--pythonpath')
parser.add_argument('args', nargs='*') # catch-all
try:
#self.argv[2:]值为'127.0.0.1:8000',可以推断出这部分可能和启动服务器有关,并且有默认的ip和端口号
options, args = parser.parse_known_args(self.argv[2:])
handle_default_options(options)
except CommandError:
pass # Ignore any option errors at this point.
try:
#获取app配置信息
settings.INSTALLED_APPS
except ImproperlyConfigured as exc:
self.settings_exception = exc
if settings.configured:
# Start the auto-reloading dev server even if the code is broken.
# The hardcoded condition is a code smell but we can't rely on a
# flag on the command class because we haven't located it yet.
#判断外部输入命令,这部分就是启动的核心代码了
if subcommand == 'runserver' and '--noreload' not in self.argv:
try:
autoreload.check_errors(django.setup)()
except Exception:
# The exception will be raised later in the child process
# started by the autoreloader. Pretend it didn't happen by
# loading an empty list of applications.
apps.all_models = defaultdict(OrderedDict)
apps.app_configs = OrderedDict()
apps.apps_ready = apps.models_ready = apps.ready = True
# Remove options not compatible with the built-in runserver
# (e.g. options for the contrib.staticfiles' runserver).
# Changes here require manually testing as described in
# #27522.
_parser = self.fetch_command('runserver').create_parser('django', 'runserver')
_options, _args = _parser.parse_known_args(self.argv[2:])
for _arg in _args:
self.argv.remove(_arg)
# In all other cases, django.setup() is required to succeed.
else:
django.setup()
self.autocomplete()
if subcommand == 'help':
if '--commands' in args:
sys.stdout.write(self.main_help_text(commands_only=True) + '\n')
elif len(options.args) < 1:
sys.stdout.write(self.main_help_text() + '\n')
else:
self.fetch_command(options.args[0]).print_help(self.prog_name, options.args[0])
# Special-cases: We want 'django-admin --version' and
# 'django-admin --help' to work, for backwards compatibility.
elif subcommand == 'version' or self.argv[1:] == ['--version']:
sys.stdout.write(django.get_version() + '\n')
elif self.argv[1:] in (['--help'], ['-h']):
sys.stdout.write(self.main_help_text() + '\n')
else:
self.fetch_command(subcommand).run_from_argv(self.argv)
后续代码有点看的迷糊了,没有找到socket启动的部分,以后再来
原文地址:https://www.cnblogs.com/zx125/p/11745863.html
时间: 2024-11-08 18:29:23