django 文件上传和菜单分级，mysql支持事务，F模块自增字段, python发送get,post请求

一、文件上传
方法一

上传文件视图函数
def upload_img(request):
obj = request.FILES.get('file')    #前端js设置的key

img_path = os.path.join('static','img',obj.name)

with open(img_path,mode='wb') as f:
for chunk in obj.chunks():
f.write(chunk)
data = {
'status': True,
'path': img_path
}
import json
return HttpResponse(json.dumps(data))

前端页面
form表单
<form>
<div class="form-group">
<label for="exampleInputFile">上传图片</label>
<input type="file" id="exampleInputFile">
<button type="button" class="btn btn-default" id="uploadfile">上传</button>
{#                    <p class="help-block">Example block-level help text here.</p>#}
</div>

<div class="form-group">
<label for="select_news">选择新闻类型</label>
<select class="form-control" id="select_news">
<option>42区</option>
<option>段子</option>
<option>图片</option>
<option>挨踢1024</option>
<option>你问我答</option>
</select>
</div>
<div class="form-group">
<label for="news_url">新闻链接</label>
<input type="text" class="form-control" id="news_url" placeholder="Url">
</div>

<div class="form-group">
<label for="news_title">新闻标题</label>
<textarea class="form-control" rows="3" id="news_title"></textarea>
</div>

<div class="form-group">
<label for="news_summary">新闻简介</label>
<textarea class="form-control" rows="3" id="news_summary"></textarea>
</div>

<div class="modal-footer">
<button type="button" class="btn btn-default" data-dismiss="modal">关闭</button>
<button type="button" class="btn btn-primary" id="news_publish">提交</button>
</div>
</form>

js 通过FormData方法处理
$(document).ready(function () {
$('#uploadfile').click(function () {
var formData = new FormData();
formData.append('file',$('#exampleInputFile')[0].files[0]);
$.ajax({
url: '/upload',
type: 'POST',
data: formData,
processData: false, //添加这两个参数，表示将原生文件发到后台
contentType: false,
success: function (res) {
console.log(res);
}
})
})
});

方法二

前端页面用form和iframe组合伪造ajax提交
<form method="POST" target="xxxxxx" action="/upload_img2/" enctype="multipart/form-data">
{% csrf_token %}
<input type="text" name="user" />
<a style="width: 60px;height: 30px;background-color: darkslateblue;color: white;display: inline-block;position: relative;">
上传
<input type="file" name="avatar" style="opacity: 0;position: absolute;left: 0;top:0;right: 0;bottom: 0;" />
</a>
<input type="submit" value="提交" />
</form>
<iframe id="ifm" name="xxxxxx" onload="successCallback(this);" style="display: none;" ></iframe>

注: form属性target的值必须和iframe的name属性值一样

view视图函数处理上传请求
def upload_img2(request):
response = BaseResponse()
try:
user = request.POST.get('user')    #处理post请求
obj = request.FILES.get('avatar')    #处理上传文件
img_path = os.path.join('static', 'img', obj.name)
with open(img_path,mode='wb') as f:
for chunk in obj.chunks():
f.write(chunk)
except Exception as e:
response.msg = str(e)
else:
response.status = True
response.data = img_path
return HttpResponse(json.dumps(response.get_dict()))

二、django对mysql事务的支持
view视图

import json
from django.db.models import F    # F模块实现数据库字段自增
from django.db import transaction    #支持事务原子性，对数据库的连续操作，操作成功必须每个sql都成功，否则都失败
from utils.response import LikeResponse

def do_like(request):
"""
点赞
:param request:
:return:
"""
response = LikeResponse()
try:
new_id = request.POST.get('newId')
# 当前登录用户ID
# uid = request.session.get('uid')
uid = 1

exist_like = models.Like.objects.filter(nnew_id=new_id,uuser_id=uid).count()
with transaction.atomic():    #事务
if exist_like:
models.Like.objects.filter(nnew_id=new_id, uuser_id=uid).delete()
models.News.objects.filter(id=new_id).update(like_count=F('like_count') - 1)
response.code = 666
else:
models.Like.objects.create(nnew_id=new_id,uuser_id=uid)
models.News.objects.filter(id=new_id).update(like_count=F('like_count') + 1)
response.code = 999
except Exception as e:
response.msg = str(e)
else:
response.status = True
return HttpResponse(json.dumps(response.get_dict()))

三、多级菜单，多级评论

view视图
from django.shortcuts import render, HttpResponse, redirect

# Create your views here.
import json
from django.db.models import F
from app01 import models
from django.db import transaction
from utils.response import LikeResponse

def comment_list(request):
li = [
{'id': 1, 'user': '银秋良', 'content': '灌我鸟事', 'parent_id': None},
{'id': 2, 'user': '银秋良', 'content': '管我鸟事', 'parent_id': None},
{'id': 3, 'user': '型谱', 'content': '你个文盲', 'parent_id': 1},
{'id': 4, 'user': '详解', 'content': '好羡慕你们这些没脸的人呀', 'parent_id': 2},
{'id': 5, 'user': '银秋良', 'content': '你是流氓', 'parent_id': 3},
{'id': 6, 'user': '银秋良', 'content': '你冷库无情', 'parent_id': 5},
{'id': 7, 'user': '银秋良', 'content': '你才冷酷无情', 'parent_id': 4},
{'id': 8, 'user': '银秋良', 'content': '你无理取闹', 'parent_id': 4},
]

com_list = build_comment_data(li)
html = build_comment_tree(com_list)

return render(request, 'comment_list.html', {'comment_html': html})

#将列表子元素放入父级元素中
def build_comment_data(li):
dic = {}
for item in li:
item['children'] = []
dic[item['id']] = item

result = []
for item in li:
pid = item['parent_id']
if pid:
dic[pid]['children'].append(item)
else:
result.append(item)
return result

#生成 html页面
def build_comment_tree(com_list):
tpl = """
<div class='item'>
<div class='title'>{0}:{1}</div>
<div class='body'>{2}</div>
</div>
"""

html = ""
for item in com_list:
if not item['children']:
html += tpl.format(item['user'],item['content'],"")
else:
html += tpl.format(item['user'], item['content'], build_comment_tree(item['children']))
return html

comment_list.html页面
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
.body{
margin-left: 30px;
}
.hide{
display: none;
}

</style>
</head>
<body>
<h1>评论</h1>
{{ comment_html|safe }}

<h1>菜单</h1>
<hr/>
<script src="/static/jquery-3.1.1.js"></script>
<script>
$(function () {
$('.title').click(function () {
if ($(this).next().hasClass('hide')){
$(this).next().removeClass('hide');
}else{
$(this).next().addClass('hide');
}
})
})
</script>

</body>
</html>

四、python实现get和post请求
客户端：
import requests
response = requests.get('

传递字典类型参数
data_dict = {
'k1':'v1',
'k2':'v2'
}
content-type: application/x-www-form-urlencoded
response = requests.post('
print(response.text)

传递json类型参数
content-type: appcation/json
response = requests.post('
print(response.text)

服务端Django：
from django.views.decorators.csrf import csrf_exempt,csrf_protect
@csrf_exempt
def asset(request):
if request.method == "GET":
return HttpResponse('收到:GET')
else:
print(request.POST)
print(request.body)
return HttpResponse('收到:POST')