[Solved]-Using Django Admin Actions to send bulk emails

You are on the right track. Here is my implementation of a django admin action that allows you to write a message to the selected users. (I know this is super late but might help someone else).

send_email function:

def send_email(self, request, queryset):
    form = SendEmailForm(initial={'users': queryset})
    return render(request, 'users/send_email.html', {'form': form})

send_email.html template (I borrowed the markup from the django confirm delete view for this you may want to do something different here):

{% extends "admin/base_site.html" %}
{% load i18n admin_urls static %}


{% block bodyclass %}{{ block.super }} app-{{ opts.app_label }} model-{{ opts.model_name }} delete-confirmation{% endblock %}

{% block breadcrumbs %}
<div class="breadcrumbs">
<a href="{% url 'admin:index' %}">{% trans 'Home' %}</a>
&rsaquo; <a href="{% url 'admin:app_list' app_label='users' %}">{% trans "Users" %}</a>
&rsaquo; <a href="{% url 'admin:users_user_changelist' %}">{% trans "Users" %}</a>
&rsaquo; <span>Send email</span>
</div>
{% endblock %}

{% block content %}
<p>{% blocktrans %}Write your message here{% endblocktrans %}</p>
<form method="POST" action="{% url 'users:email' %}">{% csrf_token %}
    <div>
        <div>
            <p>{{ form.users.errors }}</p>
            <p>{{ form.users.label_tag }}</p>
            <p>
                {% for user in form.users.initial %}
                    {{ user.email }}{% if not forloop.last %},&nbsp;{% endif %}
                {% endfor %}
            </p>
            <select name="users" multiple style="display: none">
                {% for user in form.users.initial %}
                    <option value="{{ user.id }}" selected>{{ user }}</option>
                {% endfor %}
            </select>
        </div>
        <div>
            <p>{{ form.subject.errors }}</p>
            <p>{{ form.subject.label_tag }}</p>
            <p>{{ form.subject }}</p>
        </div>
        <div>
            <p>{{ form.message.errors }}</p>
            <p>{{ form.message.label_tag }}</p>
            <p>{{ form.message }}</p>
        </div>
        <input type="submit" value="{% trans 'Send message' %}" />
        <a href="{% url 'admin:users_user_changelist' %}" class="button cancel-link">{% trans "No, take me back" %}</a>
    </div>
</form>
{% endblock %}

send email form class:

class SendEmailForm(forms.Form):
    subject = forms.CharField(
        widget=forms.TextInput(attrs={'placeholder': _('Subject')}))
    message = forms.CharField(widget=forms.Textarea)
    users = forms.ModelMultipleChoiceField(label="To",
                                           queryset=User.objects.all(),
                                           widget=forms.SelectMultiple())

And finally the send email view + url conf:

# url pattern
url(
    regex=r'^email-users/$',
    view=views.SendUserEmails.as_view(),
    name='email'
),


# SendUserEmails view class
class SendUserEmails(IsStaff, FormView):
    template_name = 'users/send_email.html'
    form_class = SendEmailForm
    success_url = reverse_lazy('admin:users_user_changelist')

    def form_valid(self, form):
        users = form.cleaned_data['users']
        subject = form.cleaned_data['subject']
        message = form.cleaned_data['message']
        email_users.delay(users, subject, message)
        user_message = '{0} users emailed successfully!'.format(form.cleaned_data['users'].count())
        messages.success(self.request, user_message)
        return super(SendUserEmails, self).form_valid(form)

This implementation worked fine for me. Here is what the intermediate view looks like:

You might have to change a couple of things in the template where I build out the breadcrumbs or the reverse url for the view in case you don’t have an app called users or a model called User.