[Django middleware for AJAX messages] Middleware for JSON responses. It adds to each JSON response array with messages from django.contrib.messages framework. It allows handle messages on a page with javascript. Django 1.10. #tags: django, python, ajax

messages.html

<div id="messages">
    {% for message in messages %}

        <div {% if message.tags %}class="alert alert-dismissable alert-{{ message.tags }}"{% endif %}>
            <a class="close" data-dismiss="alert" href="#">&times;</a>
            {{ message }}
        </div>

    {% endfor %}
</div>

middleware.py

import json
from django.contrib import messages


class AjaxMessaging(object):
    """
    Middlware for JSON responses. It adds to each JSON response array with messages from django.contrib.messages framework
    It allows handle messages on a page with javascript
    """
    def __init__(self, get_response):
        self.get_response = get_response
        # One-time configuration and initialization.

    def __call__(self, request):

        # Code to be executed for each request before
        # the view (and later middleware) are called.

        response = self.get_response(request)

        # Code to be executed for each request/response after
        # the view is called.

        if request.is_ajax():
            if response['Content-Type'] in ["application/javascript", "application/json"]:
                try:
                    if isinstance(response.content, bytes):
                        content = json.loads(response.content.decode(response.charset))
                    else:
                        content = json.load(response.content)
                except ValueError:
                    return response

                django_messages = []

                for message in messages.get_messages(request):
                    django_messages.append({
                        "level": message.level,
                        "message": message.message,
                        "extra_tags": message.tags,
                    })

                content['django_messages'] = django_messages

                response.content = json.dumps(content)
        return response

script.js

$(document).ready(function() {
    function addMessage(text, extra_tags) {
        var message = $(`
            <div class="alert alert-dismissable alert-${extra_tags}">\n
                <a class="close" data-dismiss="alert" href="#">&times;</a>\n
                    ${text}\n
            </div>`).hide();
        $("#messages").append(message);
        message.fadeIn(500);

        setTimeout(function() {
            message.fadeOut(500, function() {
                message.remove();
            });
        }, 3000);
    }

    $(document).ajaxComplete(function (e, xhr, settings) {
        var contentType = xhr.getResponseHeader("Content-Type");
        if (contentType == "application/javascript" || contentType == "application/json") {
            var json = $.evalJSON(xhr.responseText);
            $.each(json.django_messages, function (i, item) {
                addMessage(item.text, item.tags);
            });

        }
    }).ajaxError(function (e, xhr, settings, exception) {
        addMessage("There was an error processing your request, please try again.", "error");
    })

});