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PONginx + uWsgi + Django strange json response behavior
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copied!<p>Some tech specifications:</p> <ul> <li>CentOS 6.0</li> <li>uWSGI 0.9.9.2</li> <li>Nginx 1.0.5</li> <li>Django 1.3.1</li> </ul> <p>uWSGI:</p> <pre><code> [uwsgi] socket = 127.0.0.1:3031 master = true processes = 5 uid = xx gid = xx env = DJANGO_SETTINGS_MODULE=xx.settings module = django.core.handlers.wsgi:WSGIHandler() post-buffering = 8192 harakiri = 30 harakiri-verbose = true disable-logging = true logto = /var/log/xx.log vacuum = true optimize = 2 </code></pre> <p>JSON serializer:</p> <pre><code>class LazyEncoder(simplejson.JSONEncoder, json.Serializer): def default(self, obj): if isinstance(obj, Promise): return force_unicode(obj) if isinstance(obj, Decimal): u_value = force_unicode(obj) if u'.' in u_value: return float(u_value) return int(u_value) return super(lazy_encoder, self).default(obj) </code></pre> <p>JSON HttpResponse:</p> <pre><code>class JsonResponse(HttpResponse): status_code = 200 json_status_code = 200 message = _('OK') def __init__(self, json={}, *args, **kwargs): mimetype = kwargs.pop('mimetype', 'application/json') if not 'status' in json: json['status'] = {'code': self.json_status_code, 'message': self.message} super(JsonResponse, self).__init__(LazyEncoder(indent=settings.DEBUG and 4 or None, separators=settings.DEBUG and (', ', ': ') or (',', ':')).encode(json), mimetype=mimetype, *args, **kwargs) </code></pre> <p>I have a few subclasses of JsonResponse with other json_status_code and message.</p> <p>View:</p> <pre><code>.... if application.status == Application.STATUS_REMOVED: return JsonApplicationSuspendedResponse() .... return JsonResponse() </code></pre> <p><em><strong>PROBLEM:</em></strong></p> <p>Even when the application status is changing it happens that I receives old json lest say for 3 - 4 seconds and then it returning JsonApplicationSuspendedResponse() correctly.</p> <p>I checked the database application status update takes place immediately, also noticed that if I reboot uWSGI and send request response is correct and the opposite situation happens. Second request after status change can have old json.</p> <p>It looks as if they write the response for few sencods and had a problem with her refresh (Cache is disabled).</p> <p>Any ideas where it might be the problem ?</p> <p>The same code works fine on Apache2 and mod_wsgi</p> <p><strong>fixed</strong></p> <p>This was a really stupid bug, in JsonResponse I had:</p> <pre><code>def __init__(self, json={}, *args, **kwargs): </code></pre> <p>part <strong>json={}</strong> is quite important here, JsonResponse and each subclass of JsonResponse after init shared initial dict and its contents, so the answer looked like a did not change.</p> <pre><code>def __init__(self, json=None, *args, **kwargs): mimetype = kwargs.pop('mimetype', 'application/json') if not json: json = {} if not 'status' in json: json['status'] = {'code': self.json_status_code, 'message': self.message} </code></pre> <p><strong>Thanks for your time</strong></p>

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