Only show object once and count it - django

Question

after searching for a long time without getting an answer i'm gonna try here.
I'm working on django. My project is a mailling system, each time a recipient open a mail i know what mail get opened who opened it and when it get opened.
Here is the table where i display the stats. It shows me every recipient and the datetime, but my problem is that i want to see every recipient once, and then to show how many times it get opened.
<tbody>
{% for stat_mail in stat_mail %}
{% ifchanged stat_mail.recipient %}
<tr>
<td>{{ stat_mail.recipient }}</td>
<td>{{ stat_mail.datetime }}</td>
<td>{{ stat_mail.recipient_set.all|length }}</td>
</tr>
{% endifchanged %}
{% endfor %}
</tbody>
For example :
Test 1 opened the mail at 5PM and at 8PM, so the table should display
Test 1 / 5PM, 8PM / 2
The name of the recipient, the date of the oppening, and the number of oppening.
Sorry for the bad english but i'm french :)
Hope someone can help me, if u have other question or need more code just ask.
Thanks a lot !
EDIT : My models.py
class Recipient(models.Model):
name = models.CharField(max_length=255, verbose_name= ('Nom'), null=True, blank=True)
first_name = models.CharField(max_length=255, verbose_name= ('Prénom'), null=True, blank=True)
mail = models.EmailField(verbose_name= ('Adresse du destinataire'))
def __unicode__(self):
return u'%s %s' % (self.name, self.first_name)
class Tag(models.Model):
name = models.CharField(max_length=255, blank=False)
recipients = models.ManyToManyField(Recipient, verbose_name='Destinataires', null=False, blank=False, related_name="tags")
def __unicode__(self):
return self.name
class Mail(models.Model):
subject = models.CharField(max_length=255, verbose_name= ('Sujet'), blank=False, null=False)
content = HTMLField(verbose_name= ('Contenu'), blank=False, null=False, default=' ')
tags = models.ManyToManyField(Tag, verbose_name= ('Destinataires'), null=True, blank=True, related_name='mails')
recipients = models.ManyToManyField(Recipient, verbose_name='Destinataires', null=True, blank=True, related_name='mails')
date_create = models.DateTimeField(verbose_name= ('Date de création'), default=datetime.now, blank=False, editable = False)
writer = models.ForeignKey(Intervenant, verbose_name= ('Personne écrivant la compagne'), null=True, blank=True)
holding = models.ForeignKey(Holding, verbose_name= ('Organisation'),related_name= ('Questionnaire_mail'), null=False, blank=False, default=1, editable = False)
sended = models.BooleanField(verbose_name = ('Compagne envoyée ?'), default=False, editable=False)
opened = models.IntegerField(verbose_name=("Nombre totale d'ouverture"), default=0, editable=False)
email = models.EmailField(verbose_name='Destinataire de Test', blank=True, null=True)
date_create = models.DateTimeField(verbose_name= ('Date de création'), default=datetime.now, blank=False, editable = False)
date_sent = models.DateTimeField(verbose_name= ('Date de création'), blank=True, null=True, editable = False)
def __unicode__(self):
return self.subject
class Mail_Stats(models.Model):
mail = models.ForeignKey(Mail, verbose_name= ('Compagne'), related_name='mails_stats')
recipient = models.ForeignKey(Recipient, verbose_name= ('Destinataires'), null=True, blank=True, related_name='mails_stats')
datetime = models.DateTimeField(verbose_name= ('Date et Heure'), auto_now_add=True)

Answer 1

You should prepare your data in the view and then pass it to the template. Something like this (untested):
from django.shortcuts import render
from .models import Mail_Stats
def stats_view(request):
recipient_list = [] # this will be put in the template context
current_recipient = None
cnt_read = 0
read_datetime_list = []
for stat in Mail_Stats.objects.all().order_by('mail', 'recipient'):
if stat.recipient != current_recipient:
if cnt_read > 0:
recipient_list.append({
'recipient': current_recipient,
'read_datetime_list': read_datetime_list,
'cnt_read': cnt_read
})
current_recipient = stat.recipient
cnt_read = 0
read_datetime_list = []
cnt_read += 1
read_datetime_list.append(stat.datetime)
# add last recipient to the list, if not None
if current_recipient is not None:
recipient_list.append({
'recipient': current_recipient,
'read_datetime_list': read_datetime_list,
'cnt_read': cnt_read
})
render(request, 'mail_stats.html', { 'recipient_list': recipient_list })
Then in your template you could simply do something like this:
<tbody>
{% for r in recipient_list %}
<tr>
<td>{{ r.recipient }}</td>
<td>
<ul>
{% for dt in r.read_datetime_list %}
<li>{{ dt }}</li>
{% endfor %}
</ul>
</td>
<td>{{ r.cnt_read }}</td>
</tr>
{% endfor %}
</tbody>
The important thing is: do not struggle doing complex stuff in templates, keep them only for presentation purposes. Move all logic in the view (or models, or utility modules), there you can leverage all the power of Python.