#31209: Logic flaw in the tutorial 4.
-------------------------------------+-------------------------------------
Reporter: Saitama996 | Owner: nobody
Type: | Status: closed
Cleanup/optimization |
Component: Documentation | Version: 3.0
Severity: Normal | Resolution: invalid
Keywords: | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Changes (by felixxm):
* status: new => closed
* resolution: => invalid
Old description:
> The flaw in the [https://docs.djangoproject.com/en/3.0/intro/tutorial04/]
> where,
>
> Writing a form
>
> polls/templates/polls/detail.html
>
> {{{
> <h1>{{ question.question_text }}</h1>
>
> {% if error_message %}<p><strong>{{ error_message }}</strong></p>{% endif
> %}
>
> <form action="{% url 'polls:vote' question.id %}" method="post">
> {% csrf_token %}
> {% for choice in question.choice_set.all %}
> <input type="radio" name="choice" id="choice{{ forloop.counter }}"
> value="{{ choice.id }}"> <!-- This should be value={{choice.pk}} -->
> <label for="choice{{ forloop.counter }}">{{ choice.choice_text
> }}</label><br>
> {% endfor %}
> <input type="submit" value="Vote">
> </form>
> }}}
>
> As you can see the value is passed as the choice id, however when it
> comes to the function,
>
> {{{
> def vote(request, question_id):
> question = get_object_or_404(Question, pk=question_id)
> try:
> selected_choice =
> question.choice_set.get(pk=request.POST['choice'])
> }}}
>
> here the selected_choice is picked upon the primary key, which is fine
> in this case, but in case there is a conflict between the id and pk, this
> wont work.
New description:
The flaw in the [https://docs.djangoproject.com/en/3.0/intro/tutorial04/]
where,
Writing a form
polls/templates/polls/detail.html
{{{
<h1>{{ question.question_text }}</h1>
{% if error_message %}<p><strong>{{ error_message }}</strong></p>{% endif
%}
<form action="{% url 'polls:vote' question.id %}" method="post">
{% csrf_token %}
{% for choice in question.choice_set.all %}
<input type="radio" name="choice" id="choice{{ forloop.counter }}"
value="{{ choice.id }}"> <!-- This should be value={{choice.pk}} -->
<label for="choice{{ forloop.counter }}">{{ choice.choice_text
}}</label><br>
{% endfor %}
<input type="submit" value="Vote">
</form>
}}}
As you can see the value is passed as the choice id, however when it comes
to the function,
{{{
def vote(request, question_id):
question = get_object_or_404(Question, pk=question_id)
try:
selected_choice =
question.choice_set.get(pk=request.POST['choice'])
}}}
here the selected_choice is picked upon the primary key, which is fine in
this case, but in case there is a conflict between the id and pk, this
wont work.
--
Comment:
In `Question` and `Choice` models we don't have custom `id` fields that
are not primary keys, so I don't see any value in changing this. We do the
same for `question.id` in `get_object_or_404(Question, pk=question_id)`.
--
Ticket URL: <https://code.djangoproject.com/ticket/31209#comment:1>
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