JsonResponse对象，form表单上传文件，request对象方法

三板斧 HttpResponse , render , redirect

• HttpResponse >>> 返回字符串类型
• render >>> 返回HTML页面，并且在返回给浏览器之前还可以给HTML传值
• redirect >>> 重定向

# 视图函数必须要返回一个HttpResponse对象  正确   研究三者的源码即可得处结论
The view app01.views.index didn't return an HttpResponse object. It returned None instead.

# render简单内部原理
		from django.template import Template,Context
    res = Template('<h1>{{ user }}</h1>')
    con = Context({'user':{'username':'jason','password':123}})
    ret = res.render(con)
    print(ret)
    return HttpResponse(ret)

JsonResponse对象

json格式的数据有什么用？

前后端数据交互需要使用到json作为过度。实现跨语言传输数据。

前端序列化

import json
from django.http import JsonResponse


def ab_json(request):
    user_dict = {'username': 'junjie', 'age': 18, 'hobby': 'silk','describe':'黑丝白丝我都爱'}
    json_str = json.dumps(user_dict, ensure_ascii=False)
    return HttpResponse(json_str)
  
  # 浏览器输出：
  {"username": "junjie", "age": 18, "hobby": "silk", "describe": "黑丝白丝我都爱"}

使用JasonResponse对象方法

以下JasonResponse源代码：

class JsonResponse(HttpResponse):

    def __init__(self, data, encoder=DjangoJSONEncoder, safe=True,
                 json_dumps_params=None, **kwargs):
        if safe and not isinstance(data, dict):
            raise TypeError(
                'In order to allow non-dict objects to be serialized set the '
                'safe parameter to False.'
            )
        if json_dumps_params is None:
            json_dumps_params = {}
        kwargs.setdefault('content_type', 'application/json')
        data = json.dumps(data, cls=encoder, **json_dumps_params)
        super(JsonResponse, self).__init__(content=data, **kwargs)

 data = json.dumps(data, cls=encoder, **json_dumps_params)
 # 注意：**json_dumps_params，** 即打散字典键值对，以'username'='junjie'的形式，所以{'ensure_ascii':False}，能够成立

def ab_json(request):
    user_dict = {'username': 'junjie', 'age': 18, 'hobby': 'silk','describe':'黑丝白丝我都爱'}
    return JsonResponse(user_dict,json_dumps_params={'ensure_ascii':False})
# 浏览器输出：
{"username": "junjie", "age": 18, "hobby": "silk", "describe": "黑丝白丝我都爱"}

form表单上传文件及后端如何操作

form表单上传文件类型的数据

• method必须指定成post
• enctype必须换成formdata

<form action="" method="post" enctype="multipart/form-data">
    <p>username:<input type="text" name="username"></p>
    <p>file: <input type="file" name="file"></p>
    <input type="submit">
</form>

def upload_img(request):
    if request.method == 'POST':
        print(request.POST) 
        """
        输出：
        <QueryDict: {'username': ['junjie']}> <class 'django.http.request.QueryDict'>
        """
    return render(request,'uploadimg.html')

获取文件对象以及浏览器上传图片。

def upload_img(request):
    if request.method == 'POST':
        print(request.FILES)  # 获取文件数据
        """
        <MultiValueDict: {'file': [<InMemoryUploadedFile: 认真了.png (image/png)>]}>
        """
        img_obj = request.FILES.get('file')  # 文件对象
        print(img_obj)  # 输出：认真了.png
        print(img_obj.name) # 输出：认真了.png
        with open(img_obj.name,'wb') as f:
            for line in img_obj.chunks(): #
                f.write(line)
    return render(request, 'uploadimg.html')

request对象方法

标签：username,form,img,JsonResponse,request,dumps,json,params
来源： https://www.cnblogs.com/xiejunjie8888/p/15960687.html