实现点赞功能

一、点赞功能设计

1、博客、评论、回复可点赞

2、可取消点赞

3、可看到点赞数

前端设计

                <div class="like" onclick="likeChange(this,'{% get_content_type blog %}',{{ blog.pk }})">
                    <span class="glyphicon glyphicon-thumbs-up {% get_likes_status blog %}"></span>
                    <span class="liked-num">{% get_like_count blog %}</span>
                    <span>喜欢</span>
                </div>

        function likeChange(obj, content_type, object_id){
            var is_like = obj.getElementsByClassName('active').length == 0
            $.ajax({
                url: "{% url 'like_change' %}",
                type: 'GET',
                data: {
                    content_type: content_type,
                    object_id: object_id,
                    is_like: is_like
                },
                cache: false,
                success: function(data){
                    console.log(data)
                    if(data['status']=='SUCCESS'){
                        //更新点赞状态
                        var element = $(obj.getElementsByClassName('glyphicon'));
                        if(is_like){
                            element.addClass('active');
                        }else {
                            element.removeClass('active');
                        }
                        //更新点赞数量
                        var liked_num = $(obj.getElementsByClassName('liked-num'));
                        liked_num.text(data['liked_num']);
                    }else {
                        alert(data['message']);
                    }
                },
                error: function(xhr){
                    console.log(xhr)
                }
            });
        }

模型设计

from django.db import models
from django.contrib.contenttypes.fields import GenericForeignKey
from django.contrib.contenttypes.models import ContentType
from django.contrib.auth.models import User


#点赞数量
class LikeCount(models.Model):
    # 将您的模型ForeignKey 设为ContentType 通过ContentType找到具体的模型
    content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE)
    object_id = models.PositiveIntegerField()  # 记录对应模型的主键值 该字段可以存储您将要关联的模型中的主键值
    # 给您的模型一个 GenericForeignKey，并为其传递上述两个字段的名称。如果将这些字段分别命名
    # 为“ content_type”和“ object_id”，则可以忽略这些-这些是默认字段名称 GenericForeignKey。
    content_object = GenericForeignKey('content_type', 'object_id')

    liked_num = models.IntegerField(default=0)

#具体谁对哪个对象点赞,点赞记录
class LikeRecord(models.Model):
    #保存被点赞对象这个信息
    # 将您的模型ForeignKey 设为ContentType 通过ContentType找到具体的模型
    content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE)
    object_id = models.PositiveIntegerField()  # 记录对应模型的主键值 该字段可以存储您将要关联的模型中的主键值
    # 给您的模型一个 GenericForeignKey，并为其传递上述两个字段的名称。如果将这些字段分别命名
    # 为“ content_type”和“ object_id”，则可以忽略这些-这些是默认字段名称 GenericForeignKey。
    content_object = GenericForeignKey('content_type', 'object_id')

    user = models.ForeignKey(User, on_delete=models.CASCADE)
    liked_time = models.DateTimeField(auto_now_add=True)

路由

from django.urls import path
from . import views

urlpatterns = [
    path('like_change',views.like_change,name='like_change'),
]

后端实现

from django.shortcuts import render
from django.contrib.contenttypes.models import ContentType
from django.http import JsonResponse
from django.db.models import ObjectDoesNotExist
from .models import LikeCount, LikeRecord


def ErrorResponse(code, message):
    data = {}
    data['status'] = 'ERROR'
    data['code'] = code
    data['message'] = message
    return JsonResponse(data)

def SuccessResponse(liked_num):
    data = {}
    data['status'] = 'SUCCESS'
    data['liked_num'] = liked_num
    return JsonResponse(data)

def like_change(request):
    # 获取数据
    user = request.user
    if not user.is_authenticated:
        return ErrorResponse(400, 'you were not login')

    content_type = request.GET.get('content_type')
    object_id = int(request.GET.get('object_id'))

    try:
        content_type = ContentType.objects.get(model=content_type)
        model_class = content_type.model_class()
        model_obj = model_class.objects.get(pk=object_id)
    except ObjectDoesNotExist:
        return ErrorResponse(401, 'object not exist')

    # 处理数据
    if request.GET.get('is_like') == 'true':
        # 要点赞
        like_record, created = LikeRecord.objects.get_or_create(content_type=content_type, object_id=object_id, user=user)
        if created:
            # 未点赞过，进行点赞
            like_count, created = LikeCount.objects.get_or_create(content_type=content_type, object_id=object_id)
            like_count.liked_num += 1
            like_count.save()
            return SuccessResponse(like_count.liked_num)
        else:
            # 已点赞过，不能重复点赞
            return ErrorResponse(402, 'you were liked')
    else:
        # 要取消点赞
        if LikeRecord.objects.filter(content_type=content_type, object_id=object_id, user=user).exists():
            # 有点赞过，取消点赞
            like_record = LikeRecord.objects.get(content_type=content_type, object_id=object_id, user=user)
            like_record.delete()
            # 点赞总数减1
            like_count, created = LikeCount.objects.get_or_create(content_type=content_type, object_id=object_id)
            if not created:
                like_count.liked_num -= 1
                like_count.save()
                return SuccessResponse(like_count.liked_num)
            else:
                return ErrorResponse(404, 'data error')
        else:
            # 没有点赞过，不能取消
            return ErrorResponse(403, 'you were not liked')

自定义模版标签，获取点赞数量，获取点赞状态用来实时显示状态，获取对象的content_type模型

from django import template
from django.contrib.contenttypes.models import ContentType
from ..models import LikeCount,LikeRecord

#用于注册，我们一会做的那些方法变成一个模版标签，可以给这个磨板试用，所以导入的是模版这个库
register = template.Library()

#写一个方法
#发这个方法注册一下
@register.simple_tag
def get_like_count(obj):
    content_type = ContentType.objects.get_for_model(obj)
    like_count, created = LikeCount.objects.get_or_create(content_type=content_type, object_id=obj.pk)
    return like_count.liked_num

#takes_context=True可以获取所在模版页面的模版变量
@register.simple_tag(takes_context=True)
def get_likes_status(context, obj):
    content_type = ContentType.objects.get_for_model(obj)
    user = context['user']
    if not user.is_authenticated:
        return ''
    if LikeRecord.objects.filter(content_type=content_type,object_id=obj.pk,user=context['user']).exists():
        return 'active'
    else:
        return ''

@register.simple_tag
def get_content_type(obj):
    content_type = ContentType.objects.get_for_model(obj)
    return content_type.model

 二、前后端开发建议

功能需求分析——模型设计——前端初步开发——后端实现——完善前端代码