實現點贊功能

一、點贊功能設計

1、博客、評論、回復可點贊

2、可取消點贊

3、可看到點贊數

前端設計

                <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>喜歡</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'){
                        //更新點贊狀態
                        var element = $(obj.getElementsByClassName('glyphicon'));
                        if(is_like){
                            element.addClass('active');
                        }else {
                            element.removeClass('active');
                        }
                        //更新點贊數量
                        var liked_num = $(obj.getElementsByClassName('liked-num'));
                        liked_num.text(data['liked_num']);
                    }else {
                        alert(data['message']);
                    }
                },
                error: function(xhr){
                    console.log(xhr)
                }
            });
        }

模型設計

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


#點贊數量
class LikeCount(models.Model):
    # 將您的模型ForeignKey 設為ContentType 通過ContentType找到具體的模型
    content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE)
    object_id = models.PositiveIntegerField()  # 記錄對應模型的主鍵值 該字段可以存儲您將要關聯的模型中的主鍵值
    # 給您的模型一個 GenericForeignKey，並為其傳遞上述兩個字段的名稱。如果將這些字段分別命名
    # 為“ content_type”和“ object_id”，則可以忽略這些-這些是默認字段名稱 GenericForeignKey。
    content_object = GenericForeignKey('content_type', 'object_id')

    liked_num = models.IntegerField(default=0)

#具體誰對哪個對象點贊,點贊記錄
class LikeRecord(models.Model):
    #保存被點贊對象這個信息
    # 將您的模型ForeignKey 設為ContentType 通過ContentType找到具體的模型
    content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE)
    object_id = models.PositiveIntegerField()  # 記錄對應模型的主鍵值 該字段可以存儲您將要關聯的模型中的主鍵值
    # 給您的模型一個 GenericForeignKey，並為其傳遞上述兩個字段的名稱。如果將這些字段分別命名
    # 為“ content_type”和“ object_id”，則可以忽略這些-這些是默認字段名稱 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'),
]

后端實現

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):
    # 獲取數據
    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')

    # 處理數據
    if request.GET.get('is_like') == 'true':
        # 要點贊
        like_record, created = LikeRecord.objects.get_or_create(content_type=content_type, object_id=object_id, user=user)
        if created:
            # 未點贊過，進行點贊
            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:
            # 已點贊過，不能重復點贊
            return ErrorResponse(402, 'you were liked')
    else:
        # 要取消點贊
        if LikeRecord.objects.filter(content_type=content_type, object_id=object_id, user=user).exists():
            # 有點贊過，取消點贊
            like_record = LikeRecord.objects.get(content_type=content_type, object_id=object_id, user=user)
            like_record.delete()
            # 點贊總數減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:
            # 沒有點贊過，不能取消
            return ErrorResponse(403, 'you were not liked')

自定義模版標簽，獲取點贊數量，獲取點贊狀態用來實時顯示狀態，獲取對象的content_type模型

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

#用於注冊，我們一會做的那些方法變成一個模版標簽，可以給這個磨板試用，所以導入的是模版這個庫
register = template.Library()

#寫一個方法
#發這個方法注冊一下
@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可以獲取所在模版頁面的模版變量
@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、前后端開發建議

功能需求分析——模型設計——前端初步開發——后端實現——完善前端代碼