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Python

Posted by Rodrigo Muñoz
Rodrigo Muñoz
Courses Plus Student 20,171 Points

Django: How can I retrieve a value from the middleware

I'm trying to retrieve loading times per view and displaying it in the page. To do so I'm using a middleware and a context_processor setup but I can't find the way to retrieve this values to the context of the view.

Here is the example:

I've added the middleware and context_processor to the settings.

middlewares.py:

from __future__ import unicode_literals, absolute_import
from django.db import connection
from time import time
from operator import add
import re

from functools import reduce


class StatsMiddleware(object):

    def process_view(self, request, view_func, view_args, view_kwargs):
        # get number of db queries before we do anything
        n = len(connection.queries)

        # time the view
        start = time()
        response = view_func(request, *view_args, **view_kwargs)
        total_time = time() - start

        # compute the db time for the queries just run
        db_queries = len(connection.queries) - n
        if db_queries:
           db_time = reduce(add, [float(q['time']) for q in connection.queries[n:]])
        else:
           db_time = 0.0

        # and backout python time
        python_time = total_time - db_time

        stats = {
            'total_time': total_time,
            'python_time': python_time,
            'db_time': db_time,
            'db_queries': db_queries,
        }

        # this works fine
        print(stats)

        # replace the comment if found
        if response:
            try:
                # detects TemplateResponse which are not yet rendered
                if response.is_rendered:
                    rendered_content = response.content
                else:
                    rendered_content = response.rendered_content
            except AttributeError:  # django < 1.5
                rendered_content = response.content
            if rendered_content:
                s = rendered_content
                # The following code is commented 
                # because it can't compile bytes and 
                # as long as I understand the values comes 
                # from the rendered template which are the ones I'm interested in getting
                # regexp = re.compile(
                #     r'(?P<cmt><!--\s*STATS:(?P<fmt>.*?)ENDSTATS\s*-->)'
                # )
                # match = regexp.search(s)
                # if match:
                #     s = (s[:match.start('cmt')] +
                #          match.group('fmt') % stats +
                #          s[match.end('cmt'):])
                #     response.content = s

        return response

context_processors.py

#from django.template import RequestContext

def foo(request):
    context_data = dict()
    context_data["stats"] = "stats"
    return context_data

views.py:

from django.shortcuts import render
from accounts.models import User    


def myFunc(request):
    users = User.objects.all()
    return render(request, 'index.html, {'users_list': users})

index.html:

{{stats}}
<br>
{% for user in users_list  %}
     {{user}} <br>
{% endfor %}

What is the proper way to retrieve these values?