Django View 进阶

返回404

from django.http import HttpResponse,  HttpResponseNotFound
 
def not_found(request):
    return HttpResponse('Not found', status=)
    或
    return HttpResponseNotFound('Not found')

注意 返回的页面和status=200一样都是'Not found'

自定义错误视图

1. 修改配置文件

# settings.py
 
DEBUG = False
ALLOWED_HOSTS = ['*']

2. 创建视图函数

# views.py
from django.http import  HttpResponse
def not_found_view(request):
    return HttpResponse('404页面')
 
def server_error(request):
    return HttpResponse('500页面')

3. 配置项目路由

# urls.py
from .  import views
 
handler404 = views.not_found_view
handler500 = views.server_error
 
# handler403 = views.403_view
# handler400 = views.400_view

render()函数

render(request, template_name, context=None, content_type=None, status=None, using=None)

必填项

• request：request用户生成response

• template_name：模板名称，可以是列表会使用先找到的那个

可选项

• context：渲染模板的context字典，默认是{}

• content_type：响应的 MIME type，默认使用 settings.py中 DEFAULT_CONTENT_TYPE

• status：响应状态码 默认 status=200

• using：模板引擎，可更改默认引擎，如jinja2

redirect()函数

redirect(to, permanet=False, *args,  **kwargs)，返回一个HttpResponseRedirect

to参数可以是：

model对象、视图名称、相对或绝对URL地址

object    = MyModel.objects.get(...)
return     redirect(object)
return     redirect('some-view-name', foo='bar' )
return     redirect('/some/url/')
return     redirect('https://example.com/', permanent=True)

get_object_or_404() 函数

from django.shortcuts import get_object_or_404
def my_view(request):
    my_object = get_object_or_404(MyModel, pk=1)
 
# 代码等同于
from  django.http import Http404
def my_view(request):
    try:
        my_object = MyModel.objects.get(pk=1)
    except MyModel.DoesNotExist:
        raise Http404("No MyModel matches    the given query.")

其他 get_list_or_404()函数

reverse() 反向解析URL

reverse(viewname, urlconf=None, agrs=None, kwargs=None, current_app=None)

reverse_lazy(viewname, urlconf=None, agrs=None, kwargs=None, current_app=None)  惰性解析，Django启动加载顺序  如类中用reverse_lazy()，类视图

装饰器

• require_http_methods(request_method_list)

• require_GET()

• require_POST()

• require_safe()  安全性请求 GET、HEAD

• gzip_page()  内容压缩， 一般会在代理服务器里处理，Nginx

• cache_control(**kwargs)，告诉浏览器的缓存，和memecache不同，可用在password

• never_cache()

• login_required()  验证页面必须登录，常用

• transaction.atmoic  事务功能

from django.views.decorators.http import require_http_methods
from django.db.transaction import atomic
 
@require_http_methods(["GET", "POST"])
@atomic
def my_view(request):
    pass

HttpRequest and HttpResponse

https://docs.djangoproject.com/en/1.11/ref/request-response/

用户请求属性

• HttpReqeust.scheme

• HttpReqeust.body

• HttpReqeust.path

• HttpReqeust.method

• HttpReqeust.GET

• HttpReqeust.POST

• HttpReqeust.COOKIES

• HttpReqeust.FILES

• HttpReqeust.META

应用程序设置的属性

• HttpReqeust.current_app

• HttpReqeust.urlconf

中间件设置的属性

• HttpReqeust.session

• HttpReqeust.site

• HttpReqeust.user

• HttpReqeust.user.is_authenticated

• ......

发送邮件(Django自带)

django.core.mail.send_mail(subject, message, from_email, recipient_list,

fail_sliently=False, auth_user=None, auth_password=None, connection=None, html_message=None)

# settings.py
EMAIL_HOST = 'smtp.126.com'
EMAIL_PORT = 25
EMAIL_HOST_USER = '******'
EMAIL_HOST_PASSWORD = '******'
# EMAIL_USE_SSL = True # if port is 587, set True
# EMAIL_USE_TLS = True # if port is 465, set True
 
# views.py
from django.core.mail import send_mail
 
def send_email(request):
 
    if request.method == "POST":
        subject = request.POST.get('subject', '')
        message = request.POST.get('message', '')
        from_email = request.POST.get('from_email', '')
        if subject and message and from_email:
            try:
                send_mail(subject, message, from_email, ['nin@jianxin.com.cn'])
            except Exception as e:
                return HttpResponse(str(e))
 
            return HttpResponse('发送成功！')
        else:
            return HttpResponse("确保字段填写正确！")
 
    elif request.method == "GET":
        return render(request, 'send_email.html')

导出CSV

import csv
def download_csv(request):
    response = HttpResponse(content_type='text/csv')
    response['Content-Disposition'] = 'attachment;filename="download.csv"'
 
    writer = csv.writer(response)
    writer.writerow(['First    Row', 'Foo', 'Bar', 'Baz'])
    writer.writerow(['SecondRow', 'A', 'B', 'C', '"Testing"', "Here's a quote"])
    return response
 
def download(request):
    f = open('601318.csv', 'rb')
    response = HttpResponse(f, content_type='application/csv')
    response['Content-Disposition'] = 'attachment;filename="601318.csv"'
    f.close()
    return response

上传文件

# views.py
def upload(request):
    if request.method == "POST":
        upload_file = request.FILES.get('file', None)
        if upload_file is None:
            return HttpResponse('No file get')
        else:
            with open(upload_file.name, 'wb') as f:
                for chunk in upload_file.chunks():
                    f.write(chunk)
 
                # f.write(upload_file.read())
            return HttpResponse('OK')
    elif request.method == "GET":
        return render(request, 'upload.html')
 
# upload.html
<h1>Upload</h1>
<form method="post" enctype="multipart/form-data">
    {% csrf_token %}
    <label for="file">Upload: </label><input type="file" id="file" name="file"/><br/>
 
    <input type="submit" value="upload"/>
</form>

说明：

• request.FILES

• enctype 默认是 "application/x-www-form-urlencoded"