Get objects from a many to many field

Question

I have an m2m field called "admins" inside a model and I need to obtain from a view all the selected entries in that field, which are user IDs. Then with the user IDs obtain the emails for every user. Is it possible?

The exact thing I want to do is to send a mass email to all the admins of a space inside this platform.

Spaces model:

class Space(models.Model):

    """     
    Spaces model. This model stores a "space" or "place" also known as a
    participative process in reality. Every place has a minimum set of
    settings for customization.

    There are three main permission roles in every space: administrator
    (admins), moderators (mods) and regular users (users).
    """
    name = models.CharField(_('Name'), max_length=250, unique=True,
        help_text=_('Max: 250 characters'))
    url = models.CharField(_('URL'), max_length=100, unique=True,
        validators=[RegexValidator(regex='^[a-z0-9_]+$',
        message='Invalid characters in the space URL.')],
        help_text=_('Valid characters are lowercase, digits and \
    admins = models.ManyToManyField(User, related_name="space_admins", verbose_name=_('Administrators'), help_text=_('Please select the \
        users that will be administrators of this space'), blank=True,
        null=True)
    mods = models.ManyToManyField(User, related_name="space_mods",
        verbose_name=_('Moderators'), help_text=_('Please select the users \
        that will be moderators of this space.'), blank=True, null=True)
    users = models.ManyToManyField(User, related_name="space_users", verbose_name=_('Users'), help_text=_('Please select the users that \
        can participate on this space'), blank=True, null=True)

View for sending just one email:

@login_required
def add_intent(request, space_url):

    """
    Returns a page where the logged in user can click on a "I want to
    participate" button, which after sends an email to the administrator of
    the space with a link to approve the user to use the space.
    
    :attributes:  space, intent, token
    :rtype: Multiple entity objects.
    :context: space_url, heading
    """
    space = get_object_or_404(Space, url=space_url)
    #admins = space.admins??

    try:
        intent = Intent.objects.get(user=request.user, space=space)
        heading = _("Access has been already authorized")
        
    except Intent.DoesNotExist:
        token = hashlib.md5("%s%s%s" % (request.user, space,
                            datetime.datetime.now())).hexdigest()
        intent = Intent(user=request.user, space=space, token=token)
        intent.save()
        subject = _("New participation request")
        body = _("User {0} wants to participate in space {1}.\n \
                 Please click on the link below to approve.\n {2}"\
                 .format(request.user.username, space.name,
                 intent.get_approve_url()))
        heading = _("Your request is being processed.")
        send_mail(subject=subject, message=body,
                  from_email="[email protected]",
                  recipient_list=[space.author.email])

        # Send a notification to all the admins in that space
        #send_mass_mail()

    return render_to_response('space_intent.html', \
            {'space_name': space.name, 'heading': heading}, \
            context_instance=RequestContext(request))

Solution 1

You can use:

space.related.all()

to return a QuerySet of User

Solution 2

For Django >= 1.9

space.admins.all()

As mentioned by Salvatore Iovene

Solution 3

To get all many_to_many objects (not for specific space), for me works

Space.admins.through.objects.all()

(Django 2.14)

Comments

[CastleDweller]

It returns an AttributeError Space object doesn't have "related_admins" imgur.com/nEMQi

[Salvatore Iovene]

You don't need to use the related name there. Simply space.admins.all() will do.

[alvas]

What happens when you want to space.admins.all() returns RecursionError?

[Love Putin]

Getting AttributeError: 'ManyToManyDescriptor' object has no attribute 'all'