Django view functions and resources

Article directory

- 1.View
- - 1.1 File or folder
  - 1.2 Relative and absolute import urls
  - 1.3 View parameters
  - 1.4 Return value
  - 1.5 Response header
  - 1.6 FBV and CBV
- 2. Static resources
- - 2.1 Static files
  - 2.2 Media files

1. View

1.1 File or folder

1.2 Relative and absolute import urls

Note on implementation: Do not make relative imports in the project root directory.

in principle:

absolute import
Relative import (deep level)

1.3 View parameters

urlpatterns = [
    path('login/', account.login, name="login"),
    path('auth/', order.auth, name='auth'),
]

from django.shortcuts import HttpResponse


def login(request):
    return HttpResponse("login")

What are requests?

Objects, packages, can hold many things.

requests is an object that stores all the content sent to us by the browser, so it contains:
- All data related to the request: currently accessed URL, request method,...
- Additional data added by django

from django.shortcuts import HttpResponse


def login(request):
    # 1. Current URL /api/login/
    print(request.path_info)

    # 2. Parameters passed by URL
    print(request.GET)
    print(request.GET.get("age"))

    # 3. Request method GET/POST
    print(request.method)

    # 4. If post request is made, pass the request body (original data)
    print(
        request.body) # b'{"code":"083Sjmll2yla694F3bll2DguCM2SjmlG","unionId":"oP6QCsyT_9bk1dfSaVf0GEV5Y-yE"}' b'v1=123 & amp;v2=456\ '

    # 4.1 Request body + request header b'v1=123 & amp;v2=456' + content-type:application/x-www-form-urlencoded
    print(request.POST)
    print(request.POST.get("v1"))
    print(request.POST.get("v2"))

    # 4.2 Request body + request header file
    print(request.FILES) #File format + multipart/form-data
    print(request.FILES.get("n1"))
    print(request.FILES.get("n2"))

    # 5. Request header
    # {'Content-Length': '', 'Content-Type': 'text/plain', 'Host': '127.0.0.1:8000', 'Connection ': 'keep-alive', 'Cache-Control': 'max-age=0', 'Sec-Ch-Ua': '" Not A;Brand"; v="99", "Chromium";v="102", "Google Chrome";v="102"', 'Sec-Ch-Ua-Mobile' : '?0', 'Sec-Ch-Ua-Platform': '"macOS"', 'Upgrade-Insecure-Requests': '1', 'User- Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS application/xhtml + xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9', 'Sec-Fetch-Site': 'none', 'Sec-Fetch-Mode': 'navigate', 'Sec-Fetch-User': '?1', \ 'Sec-Fetch-Dest': 'document', 'Accept-Encoding': 'gzip, deflate, br', 'Accept-Language': 'zh-CN,zh;q =0.9,en;q=0.8,zh-TW;q=0.7', 'Cookie': 'csrftoken=CdidpKSGbLxzmOXnbmlkvrZep1eJmKLAA81T73UjcjxEnMOa4YOZqtc849AkYfUy'}
    print(request.headers)

    # 5.1 The request header has a special cookie
    # request.headers['cookie'] # 'csrftoken=CdidpKSGbLxzmOXnbmlkvrZep1eJmKLAA81T73UjcjxEnMOa4YOZqtc849AkYfUy;session=xxxx'
    # {'csrftoken': 'CdidpKSGbLxzmOXnbmlkvrZep1eJmKLAA81T73UjcjxEnMOa4YOZqtc849AkYfUy'}
    print(request.COOKIES)

    # 6.Other values in requests
    print(request.resolver_match)

    return HttpResponse("login")

1.4 Return value

HttpResponse
JsonResponse
render
redirect

from django.shortcuts import HttpResponse, redirect, render
from django.http import JsonResponse


def auth(request):
    pass


def login(request):
    # 1. Get request data
    print(request)

    # 2. Judge the conditions based on the request data GET/POST GET.get("xx") POST.get("xx")

    # 3. Return data

    # 3.1 String/byte/text data (picture verification code)
    # return HttpResponse("login")

    # 3.2 JSON format (separation of front-end and back-end, app applet back-end, ajax request)
    # data_dict = {"status": True, 'data': [11, 22, 33]}
    # return JsonResponse(data_dict)

    # 3.3 Redirect
    # return redirect("https://www.baidu.com")
    # return redirect("http://127.0.0.1:8000/api/auth/")
    # return redirect("http://127.0.0.1:8000/api/auth/")
    # return redirect("/api/auth/")
    # return redirect("/api/auth/") # name
    #
    # from django.urls import reverse
    # url = reverse("auth")
    # return redirect(url) # name
    # return redirect("auth")

    # 3.4 Rendering
    # - a. Find 'login.html' and read the content. Question: Where to find it?
    # - By default, search in the path specified by settings.TEMPLATES.DIRS first. (public)
    # - Find the templates directory of each registered app in the registration order, and go to this directory to find 'login.html'
    # - Generally speaking, the principle is to find the template in that app.
    # - b. Render (replace) to get the replaced string
    # - c. Return to browser
    return render(request, 'api/login.html')

1.5 response header

from django.shortcuts import HttpResponse, redirect, render
from django.http import JsonResponse


def login(request):
    res = HttpResponse("login")
    res['xx1'] = "hahaha"
    res['xx2'] = "hahaha"
    res['xx3'] = "hahaha"

    res.set_cookie('k1',"aaaaaaaa")
    res.set_cookie('k2',"bbbbbb")

    return res

1.6 FBV and CBV

FBV, views are written in the form of functions. (currently mainstream)
CBV, views are written in the form of classes.

Please note that these are just appearances and the essence is exactly the same.

2. Static resources

Static resources:

Development needs: css, js, pictures.

- /static/ of the root directory
- Already downloaded in the app directory /static/ folder

Media files: data uploaded by users (excel/pdf/video)
```
- /media/ of the root directory
```

2.1 Static files

INSTALLED_APPS = [
    # 'django.contrib.admin',
    # 'django.contrib.auth',
    # 'django.contrib.contenttypes',
    # 'django.contrib.sessions',
    # 'django.contrib.messages',
    'django.contrib.staticfiles',
    "apps.api.apps.ApiConfig",
    "apps.web.apps.WebConfig",
]
...

STATIC_URL = '/static/'
STATICFILES_DIRS = (
    os.path.join(BASE_DIR, 'static'),
)

Sequence: static folder in the project root directory and static folder in the registered app directory
Multi-app development: The pictures of each app are placed in their respective /static/appname/. . .

in development process

prohibit
```
<img src="/static/api/1.png">
```

suggestion

{% load static %}

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<h1>Login page</h1>
<a href="/xxx/xxxxx/">Replace dao xx</a>
<a href="{% url 'login' %}">Jump</a>

<img src="{% static 'api/1.png' %}">

</body>
</html>

2.2 Media files

urls.py

from django.contrib import admin
from django.urls import path, re_path, include
from django.conf.urls.static import static
from django.conf import settings

from apps.api import views


# Many functions, many URLs
urlpatterns = [
    path('api/', include('apps.api.urls')),
] + static(settings.MEDIA_URL, document_root=settings.MEDIA_ROOT)