django高级之点赞文章评论及上传文件

Posted shuyang

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目录:

  • 点赞
  • 文章评论
  • 上传文件
  • 保留页面条件

一、点赞

1、所用技术:

  • django model F查询
  • js应用:$(function () {}); 为文件加载完成执行ready() 方法。等同于on时间,多实例,使用。

    定时器方法:setInterval(方法,间隔多长时间(毫秒)执行一次)

      var obj = setInterval(function () {

          if(xxx <= 0){
            clearInterval(obj);  //结束执行
      },100);

    ps.setTimeout(表达式,延时时间)在执行时,是在载入后延迟指定时间后,去执行一次表达式,记住,次数是一次 

  • css应用:

    position属性

    

描述
absolute

生成绝对定位的元素,相对于 static 定位以外的第一个父元素进行定位。

元素的位置通过 "left", "top", "right" 以及 "bottom" 属性进行规定。

fixed

生成绝对定位的元素,相对于浏览器窗口进行定位。

元素的位置通过 "left", "top", "right" 以及 "bottom" 属性进行规定。

relative

生成相对定位的元素,相对于其正常位置进行定位。

因此,"left:20" 会向元素的 LEFT 位置添加 20 像素。

static 默认值。没有定位,元素出现在正常的流中(忽略 top, bottom, left, right 或者 z-index 声明)。
inherit 规定应该从父元素继承 position 属性的值。
  • 在Ajax操作时候,回调函数中的 $(this)已经不是原来的$(this)。需在外层函数声明。

2、应用代码:

前端:

技术分享
 1 <div>
 2                 <div>{{ row.title }}</div>
 3                 <div>{{ row.user.username }}  评论:{{ row.comment_count }}
 4     <!--使用相对定位-->
 5                     <div style="display: inline-block;position: relative;">
 6                         赞:<a class="new-like" new-id="{{ row.id }}">{{ row.like_count }}</a>
 7                     </div>
 8                 </div>
 9             </div>
10 <script src="/static/jquery-3.2.1.js"></script>
11     <script>
12         $(function () {
13             bindLikeEvent();
14         });
15 
16         function bindLikeEvent() {
17             $(.new-like).click(function () {
18                 // 获取当前新闻ID
19                 var newId = $(this).attr(new-id);
20                 var $this = $(this);
21                 $.ajax({
22                     url: /do_like.html,
23                     type: "POST",
24                     data: {newId: newId},
25                     dataType: JSON,
26                     success:function (arg) {
27                         if(arg.status){
28                             var origin = $this.text();
29                             var count = parseInt(origin);
30                             if(arg.code == 666){
31                                 $this.text(count - 1 );
32                                 showLikeCount($this,-1);
33 
34                             }else if(arg.code == 999){
35                                 $this.text(count + 1 );
36                                 showLikeCount($this,+1);
37 
38                             }
39                         }else{
40                             alert(arg.msg);
41                         }
42                     }
43 
44                 })
45             })
46         }
47         
48         function showLikeCount($this,text) {
49             var fontSize = 5;
50             var top = 0;
51             var right = 0;
52             var opacity = 1;
53 
54             var tag = document.createElement(span);
55             // var tag = document.getElementById()
56             tag.innerText = text;
57             tag.style.position = "absolute";
58             // 默认大小
59             tag.style.fontSize = fontSize + "px";
60             tag.style.top = top + px;
61             tag.style.right = right + px;
62             tag.style.opacity = opacity;
63             $this.after(tag);
64 
65             // 定时器,没0.5s执行一次
66             var obj = setInterval(function () {
67                 fontSize += 5;
68                 top -= 5;
69                 right -= 5;
70                 opacity -= 0.1;
71 
72                 tag.style.fontSize = fontSize + "px";
73                 tag.style.top = top + px;
74                 tag.style.right = right + px;
75                 tag.style.opacity = opacity;
76                 if(opacity <= 0){
77                     clearInterval(obj);
78                     tag.remove();
79                 }
80             },100);
81 
82         }
83     </script>
View Code

后端:

技术分享
 1 import json
 2 from django.db.models import F
 3 from django.db import transaction
 4 from utils.response import LikeResponse
 5 
 6 def do_like(request):
 7     """
 8     点赞
 9     :param request:
10     :return:
11     """
12     response = LikeResponse()
13     try:
14         new_id = request.POST.get(‘newId‘)
15         # 当前登录用户ID
16         # uid = request.session.get(‘uid‘)
17         uid = 1
18 
19         exist_like = models.Like.objects.filter(nnew_id=new_id,uuser_id=uid).count()
20         with transaction.atomic():
21             if exist_like:
22                 models.Like.objects.filter(nnew_id=new_id, uuser_id=uid).delete()
23                 models.News.objects.filter(id=new_id).update(like_count=F(‘like_count‘) - 1)
24                 response.code = 666
25             else:
26                 models.Like.objects.create(nnew_id=new_id,uuser_id=uid)
27                 models.News.objects.filter(id=new_id).update(like_count=F(‘like_count‘) + 1)
28                 response.code = 999
29     except Exception as e:
30         response.msg = str(e)
31     else:
32         response.status = True
33     return HttpResponse(json.dumps(response.get_dict()))
View Code

ps.response实例化

技术分享
 1 class BaseResponse(object):
 2     def __init__(self):
 3         self.status = False
 4         self.data = None
 5         self.msg = None
 6 
 7     def get_dict(self):
 8         return self.__dict__
 9 
10 
11 class LikeResponse(BaseResponse):
12     def __init__(self):
13         self.code = 0
14         super(LikeResponse,self).__init__()
15 
16 # obj = LikeResponse()
17 # print(obj.__dict__)
View Code

二、文章评论

1、所用技术

  • python:

  字典,列表,通过引用赋值,一个修改全部都改的特性

  递归取值

2、应用

前端:

技术分享
1 <h1>评论</h1>
2  {{ comment_html|safe }}
View Code

后端:

技术分享
 1 def build_comment_data(li):
 2     dic = {}
 3     for item in li:
 4         item[children] = []
 5         dic[item[id]] = item
 6 
 7     result = []
 8     for item in li:
 9         pid = item[parent_id]
10         if pid:
11             dic[pid][children].append(item)
12         else:
13             result.append(item)
14 
15     return result
16 
17 def build_comment_tree(com_list):
18     """
19     {‘user‘: ‘银秋良1‘, ‘children‘: [],content:‘xxx‘],
20     {‘user‘: ‘银秋良2‘, ‘children‘: [{‘user‘: ‘型谱‘, ‘children‘: [{‘user‘: ‘银秋良‘, ‘children‘: [], ‘parent_id‘: 3, ‘content‘: ‘你是流氓‘, ‘id‘: 5}], ‘parent_id‘: 1, ‘content‘: ‘你个文盲‘, ‘id‘: 3}], ‘parent_id‘: None, ‘content‘: ‘灌我鸟事‘, ‘id‘: 1}
21     {‘user‘: ‘银秋良3‘, ‘children‘: [{‘user‘: ‘详解‘, ‘children‘: [], ‘parent_id‘: 2, ‘content‘: ‘好羡慕你们这些没脸的人呀‘, ‘id‘: 4}], ‘parent_id‘: None, ‘content‘: ‘管我鸟事‘, ‘id‘: 2}
22 
23     [
24         {‘user‘: ‘银秋良‘, ‘children‘: [], ‘parent_id‘: 3, ‘content‘: ‘你是流氓‘, ‘id‘: 5}
25     ]
26 
27     """
28     tpl = """
29     <div class="item">
30         <div class="title">{0}:{1}</div>
31         <div class="body">{2}</div>
32     </div>
33     """
34     html = ""
35     for item in com_list:
36         if not item[children]:
37             html +=tpl.format(item[user],item[content],"")
38         else:
39             html +=tpl.format(item[user], item[content], build_comment_tree(item[children]))
40     return html
41 
42 def comment_list(request):
43     """
44     获取多级评论列表
45     :param request:
46     :return:
47     """
48     li = [
49         {id: 1, user: 银秋良, content: 灌我鸟事, parent_id: None},
50         {id: 2, user: 银秋良, content: 管我鸟事, parent_id: None},
51         {id: 3, user: 型谱, content: 你个文盲, parent_id: 1},
52         {id: 4, user: 详解, content: 好羡慕你们这些没脸的人呀, parent_id: 2},
53         {id: 5, user: 银秋良, content: 你是流氓, parent_id: 3},
54         {id: 6, user: 银秋良, content: 你冷库无情, parent_id: 5},
55         {id: 7, user: 银秋良, content: 你才冷酷无情, parent_id: 4},
56         {id: 8, user: 银秋良, content: 你无理取闹, parent_id: 4},
57     ]
58     com_list = build_comment_data(li)
59     """
60     {‘user‘: ‘银秋良‘, ‘children‘: [{‘user‘: ‘型谱‘, ‘children‘: [{‘user‘: ‘银秋良‘, ‘children‘: [], ‘parent_id‘: 3, ‘content‘: ‘你是流氓‘, ‘id‘: 5}], ‘parent_id‘: 1, ‘content‘: ‘你个文盲‘, ‘id‘: 3}], ‘parent_id‘: None, ‘content‘: ‘灌我鸟事‘, ‘id‘: 1}
61     {‘user‘: ‘银秋良‘, ‘children‘: [{‘user‘: ‘详解‘, ‘children‘: [], ‘parent_id‘: 2, ‘content‘: ‘好羡慕你们这些没脸的人呀‘, ‘id‘: 4}], ‘parent_id‘: None, ‘content‘: ‘管我鸟事‘, ‘id‘: 2}
62     """
63 
64     html = build_comment_tree(com_list)
65 
66     return render(request,comment_list.html,{comment_html:html})
67 
68 def fetch_comment(request):
69     li = [
70         {id: 1, user: 银秋良, content: 灌我鸟事, parent_id: None},
71         {id: 2, user: 银秋良, content: 管我鸟事, parent_id: None},
72         {id: 3, user: 型谱, content: 你个文盲, parent_id: 1},
73         {id: 4, user: 详解, content: 好羡慕你们这些没脸的人呀, parent_id: 2},
74         {id: 5, user: 银秋良, content: 你是流氓, parent_id: 3},
75         {id: 6, user: 银秋良, content: 你冷库无情, parent_id: 5},
76         {id: 7, user: 银秋良, content: 你才冷酷无情, parent_id: 4},
77         {id: 8, user: 银秋良, content: 你无理取闹, parent_id: 4},
78     ]
79     com_list = build_comment_data(li)
80     # 第一种选择
81     html = build_comment_tree(com_list)
82     return HttpResponse(html)
83     # 第二种选择,前端递归去生成
84     # return HttpResponse(json.dumps(com_list))
View Code

ps.使用方式:

返回给前端JavaScrip,由前端递归渲染。本例为服务器直接渲染返回

三、上传文件

1、所使用技术:

  • js:

  - 基于FormData
    - 缺点,兼容性不好
    - 优点,Ajax直接发送

  - 伪Ajax,兼容性更好
    - iframe,天生局部刷新
    - form,天生整个页面刷新

2、应用:

前端:

技术分享
 1 <!DOCTYPE html>
 2 <html lang="en">
 3 <head>
 4     <meta charset="UTF-8">
 5     <title>Title</title>
 6 </head>
 7 <body>
 8     <input type="text" placeholder="默认值看看刷新之后在不在" />
 9     <form method="POST" target="xxxxxx" action="/upload_img2/" enctype="multipart/form-data">
10         {% csrf_token %}
11         <input type="text" name="user" />
12         <a style="width: 60px;height: 30px;background-color: darkslateblue;color: white;display: inline-block;position: relative;">
13             上传
14             <input type="file" name="avatar" style="opacity: 0;position: absolute;left: 0;top:0;right: 0;bottom: 0;" />
15         </a>
16         <input type="submit" value="提交" />
17     </form>
18     <iframe id="ifm" name="xxxxxx" onload="successCallback(this);" style="display: none;" ></iframe>
19     <div id="imgList"></div>
20     <script src="/static/jquery-3.2.1.js"></script>
21     <script>
22         function successCallback(ths){
23             var response = ths.contentWindow.document.body.innerHTML;
24             response = JSON.parse(response);
25             console.log(response);
26             var img = document.createElement(img);
27             img.src = "/" + response.data;
28 
29             $(#imgList).append(img);
30 
31         }
32     </script>
33 
34 </body>
35 </html>
View Code

后端:

技术分享
 1 def upload_img2(request):
 2     response = BaseResponse()
 3     try:
 4         user = request.POST.get(user)
 5         obj = request.FILES.get(avatar)
 6         img_path = os.path.join(static, img, obj.name)
 7         with open(img_path,mode=wb) as f:
 8             for chunk in obj.chunks():
 9                 f.write(chunk)
10     except Exception as e:
11         response.msg = str(e)
12     else:
13         response.status = True
14         response.data = img_path
15     return HttpResponse(json.dumps(response.get_dict()))
View Code

四、保留页面条件

1、所用技术:

  django request.GET.urlencode() 获取url.get方法

  django from django.http.request import QueryDict 导入QueryDict方法

  ps.POST,不要写action

2、应用:

前端:

list

技术分享
 1 <!DOCTYPE html>
 2 <html lang="en">
 3 <head>
 4     <meta charset="UTF-8">
 5     <title>Title</title>
 6 </head>
 7 <body>
 8     <a href="/add_host.html?{{ url_param }}">添加</a>
 9     <ul>
10         {% for item in hosts %}
11             <li>{{ item }}</li>
12         {% endfor %}
13     </ul>
14 </body>
15 </html>
View Code

add

技术分享
 1 <!DOCTYPE html>
 2 <html lang="en">
 3 <head>
 4     <meta charset="UTF-8">
 5     <title>Title</title>
 6 </head>
 7 <body>
 8     <form method="POST">
 9         {% csrf_token %}
10         <input type="text" name="hostname" />
11         <input type="submit" value="提交" />
12     </form>
13 </body>
14 </html>
View Code

后端:

技术分享
 1 from django.http.request import QueryDict
 2 def host_list(request):
 3     print(request.GET,type(request.GET))
 4     # request.GET._mutable = True
 5     
 6     obj = QueryDict(mutable=True)
 7     obj[_zhaofengfeng] = request.GET.urlencode() # page=10&id=1
 8     url_param = obj.urlencode()
 9 
10     hosts = [c1.com,c2.com,c3.com]
11     return render(request,host_list.html,{hosts:hosts,url_param:url_param})
12 
13 def add_host(request):
14     if request.method == "GET":
15         return render(request,add.html)
16     else:
17         url_params = request.GET.get(_zhaofengfeng)
18         host = request.POST.get(hostname)
19         url ="/host_list.html?"+url_params
20         return redirect(url)
View Code

 









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