Session Management After Login

Upon successful authentication, the system generates a unique token string which is stored in the browser's cookies and also saved in the server-side session storage along with user identification.

Authentication Middleware Implementation

To enforce login protection for specific routes:

from django.utils.deprecation import MiddlewareMixin
from django.shortcuts import redirect

class AuthMiddleware(MiddlewareMixin):
    def process_request(self, request):
        # Skip authentication check for public pages
        if request.path_info in ["/login/", "/image/code/"]:
            return
        
        # Check if user is logged in via session
        user_info = request.session.get("info")
        if user_info:
            return
        
        # Redirect unauthenticated users
        return redirect('/login/')

Register the middleware in settings.py:

MIDDLEWARE = [
    # ... other middleware
    'myapp.middleware.auth.AuthMiddleware',
]

Form Handling with Validation

The form component handles HTML generation and data validation:

from django import forms

class LoginForm(forms.Form):
    username = forms.CharField(
        label="Username",
        widget=forms.TextInput,
        required=True
    )
    password = forms.CharField(
        label="Password",
        widget=forms.PasswordInput(render_value=True),
        required=True
    )
    code = forms.CharField(
        label="Verification Code",
        widget=forms.TextInput,
        required=True
    )
    
    def clean_password(self):
        pwd = self.cleaned_data.get("password")
        return md5(pwd)

Login view implementation:

from django.shortcuts import render, redirect
from django.contrib import messages


def login(request):
    if request.method == "GET":
        form = LoginForm()
        return render(request, 'login.html', {'form': form})

    form = LoginForm(data=request.POST)
    if form.is_valid():
        user_input_code = form.cleaned_data.pop('code')
        stored_code = request.session.get('image_code', '')
        if stored_code.upper() != user_input_code.upper():
            form.add_error("code", "Invalid verification code")
            return render(request, 'login.html', {'form': form})
        
        user_obj = models.Admin.objects.filter(**form.cleaned_data).first()
        if not user_obj:
            form.add_error("password", "Invalid credentials")
            return render(request, 'login.html', {'form': form})
        
        # Store user session
        request.session["info"] = {
            'id': user_obj.id,
            'name': user_obj.username
        }
        request.session.set_expiry(60 * 60 * 24 * 7)
        
        return redirect("/admin/list/")
    
    return render(request, 'login.html', {'form': form})

Template for Login Page

<div class="account">
    <h2>Login</h2>
    <form method="post" novalidate>
        {% csrf_token %}
        <div class="form-group">
            <label>Username</label>
            {{ form.username }}
            <span style="color: red;">{{ form.username.errors.0 }}</span>
        </div>
        <div class="form-group">
            <label>Password</label>
            {{ form.password }}
            <span style="color: red;">{{ form.password.errors.0 }}</span>
        </div>
        <div class="form-group">
            <label>Verification Code</label>
            <div class="row">
                <div class="col-xs-7">
                    {{ form.code }}
                    <span style="color: red;">{{ form.code.errors.0 }}</span>
                </div>
                <div class="col-xs-5">
                    <img id="image_code" src="/image/code/" style="width: 125px;">
                </div>
            </div>
        </div>
        <input type="submit" value="Login" class="btn btn-primary">
    </form>
</div>

ModelForm Usage

ModelForms simplify database operations:

class UserModelForm(forms.ModelForm):
    name = forms.CharField(
        min_length=3,
        label="Name",
        widget=forms.TextInput(attrs={"class": "form-control"})
    )
    
    class Meta:
        model = models.UserInfo
        fields = ["name", "password", "age", 'account', 'create_time', "gender", "depart"]


def user_model_form_add(request):
    if request.method == "GET":
        form = UserModelForm()
        return render(request, 'user_model_form_add.html', {"form": form})
    
    form = UserModelForm(data=request.POST)
    if form.is_valid():
        form.save()
        return redirect('/user/list/')
    
    return render(request, 'user_model_form_add.html', {"form": form})

Verification Code Hendling

Store verification codes in sessinos with timeout:

request.session['image_code'] = code_string
request.session.set_expiry(60)

Password Security

Password encryption using MD5 with secret key:

import hashlib
from django.conf import settings

def md5(data_string):
    obj = hashlib.md5(settings.SECRET_KEY.encode('utf-8'))
    obj.update(data_string.encode('utf-8'))
    return obj.hexdigest()

User Logout

Clear session data to terminate user session:

def logout(request):
    request.session.clear()
    return redirect('/login/')

Choice Field Display

For model fields with choices, use display methods:

# In model
gender_choices = ((1, "Male"),(2, "Female"),)
gender = models.SmallIntegerField(choices=gender_choices)

# In view or template
user = models.UserInfo.objects.first()
print(user.get_gender_display())  # Outputs: Male/Female

Caching Configuration

Configure caching backend:

CACHES = {
    'default':{
        'BACKEND':'django.core.cache.backends.locmem.LocMemCache',
        'LOCATION':'unique-snowflake',
        'TIMEOUT':300,
        'OPTIONS':{
            'MAX_ENTRIES':300,
            'CULL_FREQUENCY':2,
        }
    }
}

Use cache decorator:

from django.views.decorators.cache import cache_page

@cache_page(15)
def test_cache(request):
    import time
    t = time.time()
    return HttpResponse('time is %s'%(t))

Debugging with Traceback

Capture exception stack traces:

import traceback
try:
    a
except:
    print(traceback.format_exc())