Passing POST data from form into GET method to generate graph - django

Question

I'm trying get user input from a HTML form and use that value to populate a ChartJS graph in my Django app called DisplayData which has a template called Display.html. I have an API set up to pass data into ChartJS called display/api/chart/data/ which I use to get two lists to populate the Chart with. In order make the Chart, I am getting data from my models and graphing the data value (integer) against the timestamp of when the value of recorded. This is one of the queries that gets the data:
all_entries = models.Entries.objects.all().filter(parent=2)
Right now, I have it hardcoded to one time of data value (as seen above, to the integer 2), but I would like the user to have a form where they can input a number and submit it, generating the chart by using that integer as a filter. The user input integer would be placed inside the parent= portion of the code above.
I have the following urls set up.
urls.py
urlpatterns=[
url(r'^$',views.DisplayView, name='DisplayView'),
url(r'^api/data/$', views.get_data, name='api-data'),
url(r'^display/api/chart/data/$', views.ChartData.as_view()),
url(r'^logs/', views.LogDisplay, name='Display-Logs'),
]
In order to achieve this, I have added a form in my Display.html file above the code for ChartJs as follows.
Display.html
{% block content %}
<div class="row">
<h4>Enter measurable number:</h4>
<form method="POST">
{% csrf_token %}
<input type="number" name="textfield">
<button type="submit">Submit</button>
</form>
</div>
<div class='padded'>
<div class='col-sm-12' url-endpoint='{% url "api-data" %}'>
<h1>Graph Data</h1>
<canvas id="myChart" width="400" height="400"></canvas>
</div>
</div>
<script>
{% block jquery %}
var endpoint = 'display/api/chart/data/'
var defaultData = []
var defaultLabels = [];
$.ajax({
method: "GET",
url: endpoint,
success: function(data){
defaultLabels = data.labels
defaultData = data.default
console.log(data)
var ctx = document.getElementById("myChart");
var myChart = new Chart(ctx, {
type: 'line',
data: {
labels: defaultLabels,
datasets: [{
label: '# Measurable',
data: defaultData,
borderWidth: 1
}]
},
options: {
scales: {
yAxes: [{
ticks: {
beginAtZero:true
}
}]
}
}
});
},
error: function(error_data){
console.log("error")
console.log(error_data)
}
})
{% endblock %}
</script>
{% endblock %}
The first part of the code is the form to get data from the user, the second part is the code to generate the graph which we can ignore right now since the graph works (when I hardcode the value).
In my views file, I have the following code to get the input from the user and then place it in the required place for the query.
views.py
class ChartData(APIView):
authentication_classes = []
permission_classes = []
def post(self, request, format=None):
display_id = self.request.POST.get("textfield")
print(request.data)
try:
display_id = int(display_id)
except ValueError:
display_id = 2
return display_id
def get(self, request, format=None):
display_id = self.request.POST.get("textfield")
print('value of display_id ')
print(display_id)
#insert value from form into parent= below
all_entries = models.Entries.objects.all().filter(parent=display_id)
all_measurables = models.Measurables.objects.all().filter(user_id=request.user.id) #change to current user
all_times = [m.timestamp for m in all_entries]
all_data = []
for m in all_entries:
data = m.data
json_data = json.loads(data)
value = json_data['value']
all_data.append(value)
data = {
"labels": all_times,
"default": all_data,
}
return Response(data)
However, when I run this program, upon entering a number into the textfield and hitting submit the value of display_id seems to be None. Where am I going wrong and how can I achieve what I am trying to do?