纠正Django模板的if/else语句语法 [英] Correct if/else statement syntax for django templates

问题描述

我有一个约会应用程序，我需要在用户匹配的每个个人资料下方创建一个链接.然后，该链接应将其用户ID传递到模板中，以便仅根据用户ID在当前用户和该特定用户之间显示消息.我在使用Django模板中的if/else语句的语法时遇到麻烦.我将如何去做?

I have a dating app and I need to create a link that is underneath each profile that a user matches on. Then, that link should pass their user id into the template so that messages are only displayed between the current user and that particular user based on the user id. I am having trouble here with the syntax of if/else statements within the Django template. How would I go about doing this?

** base.html/href消息链接**

**base.html/href messages link **

<li class="nav-item">
                    <a class="nav-link" href="{% url 'dating_app:messages' user.id %}">Check Messages</a>
                </li>

models.py/InstantMessage

class InstantMessage(models.Model):

    sender = models.ForeignKey(settings.AUTH_USER_MODEL, related_name= 'sender',on_delete=models.CASCADE )
    receiver = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
    message = models.TextField()
    date = models.DateTimeField(auto_now_add=True)


    def __unicode__(self):
        return self.message

messages.html

<div id="msg-list-div" class="panel-body">
        <ul id="msg-list" class="list-group">
            <br><br><br>
            {% for obj in messages %}
                {% if obj.sender == request.user and obj.receiver == profile%}

                    {% if obj.sender == request.user%}
                        <li class="text-right list-group-item">{{obj.message}}<br>{{ obj.date }}<li>
                    {% elif obj.receiver == profile %}
                        <li class="text-left list-group-item">{{obj.message}}<br>{{ obj.date }}<li>
                    {%endif%} 

                {%endif%}   
                {% empty %}
                    <li class="text-right list-group-item">No messages yet...Keep mingling!</li>
            {% endfor %}

        </ul>
</div>

matches.html/href链接为messages.html

<p><a href="{% url 'dating_app:messages' profile.id %}">chat</a></p>

views.py/messages

def messages(request, profile_id):
    messages = InstantMessage.objects.all()
    profile = get_object_or_404(Profile,id=profile_id)

    return render(request, 'dating_app/messages.html', {'messages': messages,'profile':profile,})

models.py

class Profile(AbstractBaseUser):

    class Meta:
        swappable = 'AUTH_USER_MODEL'


    email                       = models.EmailField(verbose_name="email")
    username                    = models.CharField(max_length=30, unique=True)
    date_joined                 = models.DateTimeField(verbose_name='date joined', auto_now_add=True)
    last_login                  = models.DateTimeField(verbose_name='last login', auto_now=True)
    is_admin                    = models.BooleanField(default=False)
    is_active                   = models.BooleanField(default=True)
    is_staff                    = models.BooleanField(default=False)
    is_superuser                = models.BooleanField(default=False)
    #what I added
    description                 = models.TextField()
    photo                       = models.ImageField(upload_to='profile_photo',blank=False, height_field=None, width_field=None, max_length=100)
    matches                     = models.ManyToManyField(settings.AUTH_USER_MODEL, related_name='+', blank=True)

    USERNAME_FIELD = 'username'
    REQUIRED_FIELDS = ['description','photo','email']

    objects = ProfileManager()

    def __str__(self):
        return self.username

    def has_perm(self, perm, obj=None):
        return self.is_admin

    def has_module_perms(self,app_label):
        return True


class UserVote(models.Model):

    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
    voter = models.ForeignKey(settings.AUTH_USER_MODEL, related_name='given_vote', on_delete=models.CASCADE)
    vote = models.BooleanField(default=False)

    class Meta:
        unique_together = (('user', 'voter'))


class InstantMessage(models.Model):

    sender = models.ForeignKey(settings.AUTH_USER_MODEL, related_name= 'sender',on_delete=models.CASCADE )
    receiver = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
    message = models.TextField()
    date = models.DateTimeField(auto_now_add=True)


    def __unicode__(self):
        return self.message

整个模型.py

from django.db import models
from django.contrib.auth.models import AbstractBaseUser,BaseUserManager, User
from dating_project import settings
from django.contrib.auth import get_user_model


class ProfileManager(BaseUserManager):



    def create_user(self, username, email,description,photo, password=None):
        if not email:
            raise ValueError("You must creat an email")
        if not username:
            raise ValueError("You must create a username!")
        if not description:
            raise ValueError("You must write a description")
        if not photo:
            raise ValueError("You must upload a photo")

        user = self.model(
                email=self.normalize_email(email),
                username = username, 
                description= description,
                photo= photo,

            )

        user.set_password(password)
        user.save(using=self._db)
        return user 


    def create_superuser(self, username, email,description,photo, password):
        user = self.create_user(
                email=self.normalize_email(email),
                password=password,
                username=username,
                description=description,
                photo=photo,

            )

        user.is_admin=True
        user.is_staff=True
        user.is_superuser=True
        user.save(using=self._db)
        return user




class Profile(AbstractBaseUser):

    class Meta:
        swappable = 'AUTH_USER_MODEL'


    email                       = models.EmailField(verbose_name="email")
    username                    = models.CharField(max_length=30, unique=True)
    date_joined                 = models.DateTimeField(verbose_name='date joined', auto_now_add=True)
    last_login                  = models.DateTimeField(verbose_name='last login', auto_now=True)
    is_admin                    = models.BooleanField(default=False)
    is_active                   = models.BooleanField(default=True)
    is_staff                    = models.BooleanField(default=False)
    is_superuser                = models.BooleanField(default=False)
    #what I added
    description                 = models.TextField()
    photo                       = models.ImageField(upload_to='profile_photo',blank=False, height_field=None, width_field=None, max_length=100)
    matches                     = models.ManyToManyField(settings.AUTH_USER_MODEL, related_name='+', blank=True)



    USERNAME_FIELD = 'username'
    REQUIRED_FIELDS = ['description','photo','email']


    objects = ProfileManager()


    def __str__(self):
        return self.username


    def has_perm(self, perm, obj=None):
        return self.is_admin


    def has_module_perms(self,app_label):
        return True



class UserVote(models.Model):

    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
    voter = models.ForeignKey(settings.AUTH_USER_MODEL, related_name='given_vote', on_delete=models.CASCADE)
    vote = models.BooleanField(default=False)

    class Meta:
        unique_together = (('user', 'voter'))



class InstantMessage(models.Model):

    sender = models.ForeignKey(settings.AUTH_USER_MODEL, related_name= 'senderr',on_delete=models.CASCADE )
    receiver = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
    message = models.TextField()
    date = models.DateTimeField(auto_now_add=True)


    def __unicode__(self):
        return self.message

推荐答案

正如已经建议的那样，最好在视图中而不是在模板中完成所有繁重的工作:

As already suggested it is better to do all heavy work in a view, not in a template:

def messages(request, profile_id):
    messages = InstantMessage.objects.filter(sender=request.user, receiver_id=profile_id, )
    profile = get_object_or_404(Profile,id=profile_id)
    ...

想象一下，如果 InstantMessage 包含数十亿条记录- InstantMessage.objects.all()的工作速度有多快?以及出于什么原因.

Imagine if InstantMessage contains billions of records - how fast would InstantMessage.objects.all() work? And for what reason.

由于您要呈现聊天"，我想您需要这样的东西:

And since you want to render "a chat", I guess you need something like this:

from django.db.models import Q
...
    messages = InstantMessage.objects.filter(Q(sender_id=request.user.id, receiver_id=profile_id,) 
            | Q(sender_id=profile_id, receiver_id=request.user.id,) ).\
        values('sender_id', 'message', 'date', ).\
        order_by('date',)

另请参见文档.

和模板:

{% for msg in messages %}
    <li class="{% if msg.sender_id == request.user.id %}text-right{% else %}text-left{% endif %} list-group-item">
        {{ msg.message }}<br/>{{ msg.date }}
    </li>
{% empty %}
    ...
{% endfor %}

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