Django check if checkbox is selected

Question

I'm currently working on a fairly simple django project and could use some help. Its just a simple database query front end.

Currently I am stuck on refining the search using checkboxes, radio buttons etc

The issue I'm having is figuring out how to know when a checkbox (or multiple) is selected. My code so far is as such:

views.py

def search(request):
    if 'q' in request.GET:
        q = request.GET['q']
        if not q:
            error = True;
        elif len(q) > 22:
            error = True;
        else:           
            sequence = Targets.objects.filter(gene__icontains=q)
            request.session[key] = pickle.dumps(sequence.query)
            return render(request, 'result.html', {'sequence' : sequence, 'query' : q, 'error' : False})    
    return render(request, 'search.html', {'error': True})

search.html

<p>This is a test site</p></center>

        <hr>
        <center>
            {% if error == true %}
                <p><font color="red">Please enter a valid search term</p>
            {% endif %}
         <form action="" method="get">
            <input type="text" name="q">
            <input type="submit" value="Search"><br>            
         </form>
         <form action="" method="post">
            <input type='radio' name='locationbox' id='l_box1'> Display Location
            <input type='radio' name='displaybox' id='d_box2'> Display Direction
         </form>
        </center>

My current idea is that I check which checkboxes/radio buttons are selected and depending which are, the right data will be queried and displayed in a table.

So specifically: How do I check if specific check-boxes are checked? and how do I pass this information onto views.py

Answer 1

Radio Buttons:

In the HTML for your radio buttons, you need all related radio inputs to share the same name, have a predefined "value" attribute, and optimally, have a surrounding label tag, like this:

<form action="" method="post">
    <label for="l_box1"><input type="radio" name="display_type" value="locationbox" id="l_box1">Display Location</label>
    <label for="d_box2"><input type="radio" name="display_type" value="displaybox" id="d_box2"> Display Direction</label>
</form>

Then in your view, you can look up which was selected by checking for the shared "name" attribute in the POST data. It's value will be the associated "value" attribute of the HTML input tag:

# views.py
def my_view(request):
    ...
    if request.method == "POST":
        display_type = request.POST.get("display_type", None)
        if display_type in ["locationbox", "displaybox"]:
            # Handle whichever was selected here
            # But, this is not the best way to do it.  See below...

That works, but it requires manual checks. It's better to create a Django form first. Then Django will do those checks for you:

forms.py:

from django import forms

DISPLAY_CHOICES = (
    ("locationbox", "Display Location"),
    ("displaybox", "Display Direction")
)

class MyForm(forms.Form):
    display_type = forms.ChoiceField(widget=forms.RadioSelect, choices=DISPLAY_CHOICES)

your_template.html:

<form action="" method="post">
    {# This will display the radio button HTML for you #}
    {{ form.as_p }}
    {# You'll need a submit button or similar here to actually send the form #}
</form>

views.py:

from .forms import MyForm
from django.shortcuts import render

def my_view(request):
    ...
    form = MyForm(request.POST or None)
    if request.method == "POST":
        # Have Django validate the form for you
        if form.is_valid():
            # The "display_type" key is now guaranteed to exist and
            # guaranteed to be "displaybox" or "locationbox"
            display_type = request.POST["display_type"]
            ...
    # This will display the blank form for a GET request
    # or show the errors on a POSTed form that was invalid
    return render(request, 'your_template.html', {'form': form})

Checkboxes:

Checkboxes work like this:

forms.py:

class MyForm(forms.Form):
    # For BooleanFields, required=False means that Django's validation
    # will accept a checked or unchecked value, while required=True
    # will validate that the user MUST check the box.
    something_truthy = forms.BooleanField(required=False)

views.py:

def my_view(request):
    ...
    form = MyForm(request.POST or None)
    if request.method == "POST":
        if form.is_valid():
            ...
            if request.POST["something_truthy"]:
                # Checkbox was checked
                ...

Further reading:

https://docs.djangoproject.com/en/1.8/ref/forms/fields/#choicefield

https://docs.djangoproject.com/en/1.8/ref/forms/widgets/#radioselect

https://docs.djangoproject.com/en/1.8/ref/forms/fields/#booleanfield