django-附件上传、media、extra、事务
2024-10-11 05:43:53
1 普通上传
1.1 html
<form action="/index/" method="post" enctype="multipart/form-data">
{% csrf_token %}
<p><input type="text" name="user" id="user"></p>
<p><input type="file" name="myFile" id="file"></p>
<input type="submit">
</form>
1.2 views
def index(request):
if request.method == "POST":
print(request.POST)
print(request.FILES)
file_obj = request.FILES.get("myFile")
print(file_obj.name) with open(file_obj.name,"wb") as f:
for line in file_obj:
f.write(line) return HttpResponse("上传成功。")
return render(request, "index.html")
2 基于ajax实现
2.1 Html
<p><input type="file" name="myFile" id="file"></p>
{% csrf_token %}
<button>ajaxSend</button>
<script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.js "></script>
<script>
$("button").click(function () {
var formdata = new FormData();
formdata.append("imgFile", $("#file")[0].files[0]);
formdata.append("csrfmiddlewaretoken", $("[name='csrfmiddlewaretoken']").val());
$.ajax({
url: "/upload_img/",
type: "POST",
data: formdata,
processData: false,
contentType: false,
success: function (msg) {
console.log(msg)
}
})
})
</script>
2.2 views
import os,json
def upload_img(request):
if request.is_ajax():
obj = request.FILES.get("imgFile")
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
}
return HttpResponse(json.dumps(data))
3 伪ajax上传
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
3.1 html
<input type="text" placeholder="默认值看看刷新之后在不在" />
<form method="POST" target="uploadIframe" action="/upload_img2/" enctype="multipart/form-data">
{% csrf_token %}
<input type="text" name="user" />
<a class="add-pub-btn pub-icons">
上传
<input type="file" name="avatar" id="imgUrl" />
</a>
<input type="submit" value="提交" />
</form>
<iframe id="ifm" name="uploadIframe" onload="successCallback(this);" style="display: none;" ></iframe>
<div id="imgList"></div>
<script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.js "></script>
<script>
function successCallback(ths){
var response = ths.contentWindow.document.body.innerHTML;
response = JSON.parse(response);
console.log(response);
var img = document.createElement('img');
img.src = "/" + response.data; $('#imgList').append(img);
}
</script>
3.2 views
def upload2(request):
return render(request,"iframe_upload.html") def upload_img2(request):
response = BaseResponse()
try:
obj = request.FILES.get("avatar")
img_path = os.path.join("static","img",obj.name)
with open(img_path,mode="wb") as f:
for chunk in obj.chunks():
for chunk in obj.chunks():
f.write(chunk)
except Exception as e:
response.msg = str(e)
else:
request.status = True
response.data = img_path
return HttpResponse(json.dumps(response.get_dict()))
4 上传按钮美化
4.1 css
<style>
.add-pub-btn {
width: 62px;
height: 31px;
line-height: 31px;
display: block;
text-align: center;
color: #fff;
font-size: 14px;
font-weight: 700;
margin-top: 5px;
cursor: pointer;
}
.pub-icons {
background: url(/static/img/bottom.png?v=2.8) no-repeat 0 0;
}
#imgUrl {
border: 0;
filter: alpha(opacity=0);
background: 0 0;
opacity: 0;
-moz-opacity: 0;
width: 62px;
height: 31px;
left: 5px;
top: 5px\9;
position: absolute;
cursor: pointer;
}
</style>
4.2 按钮设置
<a class="add-pub-btn pub-icons">
上传
<input type="file" name="avatar" id="imgUrl" />
</a>
5 图片预览
本图片的预览功能,主要利用html.js的FileReader进行实现的
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>注册</title>
<!-- 最新版本的 Bootstrap 核心 CSS 文件 -->
<link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css"
integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">
<style>
#avatar {
margin-top: 5px;
margin-bottom: 5px;
position: relative;
width: 100px;
height: 100px;
} #avatar_img, #file {
width: 100px;
height: 100px;
position: absolute;
left: 15px;
top: 0;
} #file {
opacity: 0;
}
</style>
</head>
<body>
<div class="container">
<div class="row">
<div class="col-md-8" id="avatar">
<img src="default.png" class="img-thumbnail" id="avatar_img">
<input type="file" id="file">
</div>
</div>
</div> <script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.js "></script>
<script type="text/javascript">
// 预览功能
$("#file").change(function () {
var choose_file = $("#file")[0].files[0];
var reader = new FileReader();
reader.readAsDataURL(choose_file);
reader.onload = function () {
$("#avatar_img").attr("src", this.result)
}
});
</script> </body>
</html>
6 文件上传路径
6.1 配置
在settings中配置
MEDIA_ROOT=os.path.join(BASE_DIR,"blog","media")
MEDIA_URL="/media/"
在urls.py中配置
from django.views.static import serve url(r'^media/(?P<path>.*)$', serve, {'document_root': settings.MEDIA_ROOT}),
6.2 使用
<img src='/media/avatarDir/a.png'>
7 extra
有些情况下,Django的查询语法难以简单的表达复杂的 WHERE 子句,对于这种情况, Django 提供了 extra() QuerySet修改机制 — 它能在 QuerySet生成的SQL从句中注入新子句
extra可以指定一个或多个 参数,例如 select, where or tables. 这些参数都不是必须的,但是你至少要使用一个!要注意这些额外的方式对不同的数据库引擎可能存在移植性问题.(因为你在显式的书写SQL语句),除非万不得已,尽量避免这样做
# in sqlite:
article_obj=models.Article.objects
.filter(nid=1)
.extra(select={"standard_time":"strftime('%%Y-%%m-%%d',create_time)"})
.values("standard_time","nid","title")
print(article_obj)
# <QuerySet [{'title': 'MongoDb 入门教程', 'standard_time': '2017-09-03', 'nid': 1}]>
current_user = models.UserInfo.objects.filter(username=username).first() #当前用户
【每一步的分析过程】
1、models.Article.objects.all() #查出每一篇文章
2、models.Article.objects.all().filter(user=current_user) #查出当前用户的所有文章
3、models.Article.objects.all().filter(user=current_user).extra(select={"filter_create_date":"strftime('%%Y/%%m',create_time)"}).values_list("filter_create_date")
#查出当前用户的所有文章的create_time,并且只取出年份和月份
解决方案:使用extra方法
extra使用来进行过滤的,参数select必须等于一个字典(转成sql的where语句去执行,查出create_time,然后转换成自己格式化的时间)
4、models.Article.objects.all().filter(user=current_user).extra(select={"filter_create_date":"strftime('%%Y/%%m',create_time)"}).values_list("filter_create_date").annotate(Count("title"))
#按照查询出来的年份和月份进行分组,并且显示文章个数
8 事务使用
from django.contrib.auth import authenticate
with transaction.atomic():
models.ArticleUpDown.objects.create(user_id=user_id, article_id=article_id)
models.Article.objects.filter(nid=article_id).update(up_count=F("up_count") + 1)
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