Python flask : I have a flask middleware in which I want to calculate the time taken by the requests and add it to the header of the response

Question

我有以下中间件:

from werkzeug.wrappers import Request
from datetime import datetime 

class TimingMiddleware(object):
    def __init__(self, app):
        self.app = app

    def __call__(self, environ, start_response):
        request = Request(environ)

        startTime = datetime.now()

        response = self.app(environ, start_response)

        endTime = datetime.now()
        timeTaken = (endTime-startTime).total_seconds()

        return response

我想将此 timeTaken 值添加到响应的 header 中。我尝试过从 Flask 导入并使用 make_response 和 Response 但没有成功。

Answer 1

这很有趣。这是我快速拼凑而成的。似乎有效:

class TimingMiddleware:
    def __init__(self, app):
        self.app = app

    def __call__(self, env, start_response):
        start_time = datetime.now()

        def injecting_start_response(status, headers, exc_info=None):
            end_time = datetime.now()
            time_taken = (end_time - start_time).total_seconds()
            headers.append(('X-Time-Taken', str(time_taken)))
            return start_response(status, headers, exc_info)

        return self.app(env, injecting_start_response)