01 flask源码剖析之werkzurg 了解wsgi

Posted 2020-11-22 liubing8

目录

• 01 werkzurg了解wsgi
  • 1. wsgi
  • 2. flask之werkzurg源码流程
  • 3. 总结

01 werkzurg了解wsgi

1. wsgi

django和flask内部都没有实现socket，而是wsgi实现。
wsgi是web服务网关接口，他是一个协议，实现它的协议的有：wsgiref/werkzurg/uwsgi

1. django之前

   from wsgiref.simple_server import make_server
   
   def run(environ, start_response):
       start_response('200 OK', [('Content-Type', 'text/html')])
       return [bytes('<h1>Hello, web!</h1>', encoding='utf-8'), ]
   
   if __name__ == '__main__':
       httpd = make_server('127.0.0.1', 8000, run)
       httpd.serve_forever()

2. flask之前

   from werkzeug.serving import run_simple
   from werkzeug.wrappers import BaseResponse
   
   
   def func(environ, start_response):
       print('请求来了')
       response = BaseResponse('你好')
       return response(environ, start_response)
   
   
   if __name__ == '__main__':
       run_simple('127.0.0.1', 5000, func)

2. flask之werkzurg源码流程

1. 程序启动之app.run()

   from flask import Flask
   
   app = Flask(__name__)
   
   @app.route('/index')
   def index():
       return 'hello world'
   
   if __name__ == '__main__':
       app.run()

2. 执行里边run_simple方法的第三个参数加括号

   def run(self, host=None, port=None, debug=None, load_dotenv=True, **options):
         from werkzeug.serving import run_simple
         run_simple(host, port, self, **options)

3. 触发执行__call__方法，然后去执行wsgi_app方法

   def __call__(self, environ, start_response):
    return self.wsgi_app(environ, start_response)

4. 执行wsgi_app方法里边的full_dispatch_request方法

   def wsgi_app(self, environ, start_response):
    response = self.full_dispatch_request()
    return response(environ, start_response)

   full_dispatch_request

   def full_dispatch_request(self):
       return self.finalize_request(rv)

5. 执行finalize_request方法,携带rv参数，rv为视图的返回值

   def finalize_request(self, rv, from_error_handler=False):
       response = self.make_response(rv)
       return response

6. 执行finalize_request方法里边的make_response方法

   def make_response(self, rv):
    if not isinstance(rv, self.response_class):
            if isinstance(rv, (text_type, bytes, bytearray)):
                rv = self.response_class(rv, status=status, headers=headers)
                return rv

7. response_class

   • response_class=Response
   • Response继承werkzurg的BaseResponse

3. 总结

• 请求过来，经过一系列，最后由BaseResponse返回

from werkzeug.serving import run_simple
from werkzeug.wrappers import BaseResponse

def func(environ, start_response):
    print('请求来了')
    response = BaseResponse('你好')
    return response(environ, start_response)


if __name__ == '__main__':
    run_simple('127.0.0.1', 5000, func)