[feature] Made HTML template configurable in send_email

Author: pandafy

docs/developer/admin-theme.rst

@@ -232,19 +232,21 @@ In case the HTML version if not needed it may be disabled by setting
 
     send_email(subject, body_text, body_html, recipients, **kwargs)
 
-================= ==========================================================================================
-**Parameter**     **Description**
-``subject``       (``str``) The subject of the email template.
-``body_text``     (``str``) The body of the text message to be emailed.
-``body_html``     (``str``) The body of the html template to be emailed.
-``recipients``    (``list``) The list of recipients to send the mail to.
-``extra_context`` **optional** (``dict``) Extra context which is passed to the template. The dictionary keys
-                  ``call_to_action_text`` and ``call_to_action_url`` can be passed to show a call to action
-                  button. Similarly, ``footer`` can be passed to add a footer.
-``**kwargs``      Any additional keyword arguments (e.g. ``attachments``, ``headers``, etc.) are passed
-                  directly to the `django.core.mail.EmailMultiAlternatives
-                  <https://docs.djangoproject.com/en/4.1/topics/email/#sending-alternative-content-types>`_.
-================= ==========================================================================================
+====================== ==========================================================================================
+**Parameter**          **Description**
+``subject``            (``str``) The subject of the email template.
+``body_text``          (``str``) The body of the text message to be emailed.
+``body_html``          (``str``) The body of the html template to be emailed.
+``recipients``         (``list``) The list of recipients to send the mail to.
+``extra_context``      **optional** (``dict``) Extra context which is passed to the template. The dictionary keys
+                       ``call_to_action_text`` and ``call_to_action_url`` can be passed to show a call to action
+                       button. Similarly, ``footer`` can be passed to add a footer.
+``html_body_template`` **(optional, str)** The path to the template used for generating the HTML version. By
+                       default, it uses the template specified in :ref:`openwisp_email_template`.
+``**kwargs``           Any additional keyword arguments (e.g. ``attachments``, ``headers``, etc.) are passed
+                       directly to the `django.core.mail.EmailMultiAlternatives
+                       <https://docs.djangoproject.com/en/4.1/topics/email/#sending-alternative-content-types>`_.
+====================== ==========================================================================================
 
 .. important::
 

openwisp_utils/admin_theme/email.py

@@ -11,15 +11,23 @@
 logger = logging.getLogger(__name__)
 
 
-def send_email(subject, body_text, body_html, recipients, extra_context={}, **kwargs):
+def send_email(
+    subject,
+    body_text,
+    body_html,
+    recipients,
+    extra_context=None,
+    html_email_template=app_settings.OPENWISP_EMAIL_TEMPLATE,
+    **kwargs,
+):
+    extra_context = extra_context or {}
     mail = EmailMultiAlternatives(
         subject=subject,
         body=strip_tags(body_text),
         from_email=settings.DEFAULT_FROM_EMAIL,
         to=recipients,
         **kwargs,
     )
-
     if app_settings.OPENWISP_HTML_EMAIL and body_html:
         context = dict(
             subject=subject,
@@ -29,7 +37,7 @@ def send_email(subject, body_text, body_html, recipients, extra_context={}, **kw
         context.update(extra_context)
 
         html_message = render_to_string(
-            app_settings.OPENWISP_EMAIL_TEMPLATE,
+            html_email_template,
             context=context,
         )
         mail.attach_alternative(html_message, 'text/html')

openwisp_utils/admin_theme/templates/openwisp_utils/email_template.html

@@ -96,7 +96,7 @@
       {% endblock call_to_action %}
       {% block mail_footer %}
         {% if footer %}
-          {{ footer }}
+          {{ footer | safe }}
         {% endif %}
       {% endblock mail_footer %}
     </div>