Question

假设我正在创建一个表单，并且我通过绑定传递一些隐藏的值，不能更改。我的问题是如何测试恶意用户是否更改了此隐藏值？我不确定表单中绑定数据到底是什么以及初始值之间的区别。

在Django中，forms.py是一个名为changed_data的属性，但我不知道是否可以提供帮助。

示范代码：

forms.py

class ConfirmForm(forms.Form):
    client_id = forms.CharField(widget=forms.HiddenInput())
    identifier = forms.CharField(widget=forms.HiddenInput())

    def clean(self):
        # Maybe here the validation process of cliend_id and identifier like:
        clean_client_id = self.cleaned_data.get('client_id')
        clean_identifier = self.cleaned_data.get('identifier')
        if last_client_id == clean_client_id and 
           last_identifier == clean_identifier:
            return self.cleaned_data
        else:
            raise forms.ValidationError("False data.")

views.py

def form_confirm_handler(request):
    if request.method == 'POST':
        form = ConfirmForm(request.POST)
        if form.is_valid():
            #Do something...
            return redirect('home:index')

    #The following values are not fixed. Are generated variables!
    bound_data = {'client_id':'123456','identifier':'wuiy5895'}
    form = ConfirmForm(bound_data)
    return render(request, 'client/theform.html', {'form':form})

html模板

<form action="{% url 'client:confirm' %}" method="post">
    <p>Do you really want to proceed?</p>
    {% csrf_token %}
    {{ form.client_id }}
    {{ form.identifier }}
    <button id="submit" type="submit" name="submit" class="btn" value="accept">Accept</button>
    <button id="cancel" type="submit" name="cancel" class="btn btn-primary" value="cancel">Cancel</button>
</form>

提前致谢！

Answer 1

我找到了4个（简单）解决这个问题的方法。

Django最有效的解决方案是：

class TheFormName():
    client_id = forms.CharField(show_hidden_initial=True, widget=forms.HiddenInput())
    identifier = forms.CharField(show_hidden_initial=True, widget=forms.HiddenInput())

def clean(self):
    if self.has_changed():
        raise forms.ValidationError('Fields are not valid.')

    return self.cleaned_data

第二种解决方案是使用changed_data来查看更改内容：

def clean(self):
    for field_name in self.changed_data:
        # loop through the fields which have changed
        print "field {} has changed. New value {}".format(field_name, cleaned_data['field_name']

我的案例已翻译成这个，但与has_changed()方法完全相同：

def clean(self):
    if len(self.changed_data) > 0:
        raise forms.ValidationError('Fields are not valid.')

    return self.cleaned_data

另一种看起来更像黑客的解决方案是：

self.cleaned_data['cliend_id'] == self.instance.cliend_id
self.cleaned_data['identifier'] == self.instance.identifier

最终的解决方案更复杂一点是使用clean()方法内部的会话（以及视图之外）。 Django Docs的示例：

from django.contrib.sessions.backends.db import SessionStore
import datetime
s = SessionStore()
s['last_login'] = datetime.datetime(2005, 8, 20, 13, 35, 10)
s.save()
s.session_key
>>> '2b1189a188b44ad18c35e113ac6ceead'

s = SessionStore(session_key='2b1189a188b44ad18c35e113ac6ceead')
s['last_login']

@LarsVegas

提供的这篇文章In Django 1.4, do Form.has_changed() and Form.changed_data, which are undocumented, work as expected?也很有用

Answer 2

创建一个名为temper_seal

的新隐藏字段

temper_seal = forms.CharField(widget=forms.HiddenInput())

将temper_seal的初始值设置为client_id和identifier的哈希值以及仅为您的服务器所知的随机常量字符串。

当表单返回用户数据时，请散列client_id和identifier的值以及之前使用的常量字符串。将此值与隐藏temper_seal字段中提交的值进行比较。如果它们相同，则用户不会更改client_id和identifier中的数据。

Answer 3

我一直在想你是否可以使用会话变量。

def form_confirm_handler(request):
    if request.method == 'POST':
        form = ConfirmForm(request.POST)
        if form.is_valid():

            if form.cleaned_data.get['client_id'] == request.session.get('client_id'):
                //.....
            else:
                //.....

            //delete the session after comparing
            del request.session['client_id']
            del request.session['identifier']

            return redirect('home:index')

    #The following values are not fixed. Are generated variables!

    request.session['client_id'] = '123456'
    request.session['identifier'] = 'wuiy5895'

    bound_data = {
        'client_id': request.session.get('client_id'), 
        'identifier': request.session.get('identifier')
    }

    form = ConfirmForm(bound_data)
    return render(request, 'client/theform.html', {'form':form})

Django / Forms：如何根据收到的数据验证初始数据（如果匹配）？

3 个答案: