I've got an app, frontend is React, and backend is Flask with a single app.py file. After I try to submit the form using a post request, I get an internal server error 500 in my JS console and in the terminal it says: 'NoneType' object has no attribute 'upper'.
This error arises after I click the submit button of the form. So it looks like the backend is not handling the request correctly.
I've tried restarting my flask server and I've added CORS to the app. I will post frontend code as well in case that helps to show context.
I guess I'm just wondering if my backend code is correctly handling the request to extract the value inputText from the textarea part of the form, or if something else is amiss? Is it reaching the server at all?
The app.py code:
from flask import Flask, request
from flask_cors import CORS
app = Flask(__name__)
app.debug = True
CORS(app)
#app.route('/process', methods=['POST'])
def result():
text = request.form.get('inputText')
upper_text = text.upper()
print(upper_text)
return upper_text
I set proxy: "http://localhost:5000" in package.json.
React Form Component code:
import React, { useState } from "react";
import axios from "axios";
import Button from '#material-ui/core/Button';
import { TextField } from '#material-ui/core';
import DisplayUpper from './DisplayUpper';
function Form() {
const [inputText, setInputText] = useState("");
const [fetchedData, setFetchedData] = useState("");
const [isSubmitted, setSubmitted] = useState(false);
const handleSubmit = (e) => {
setSubmitted(true)
console.log("button clicked");
const config = {
headers: {'Access-Control-Allow-Origin': '*'}
};
axios
.post("http://localhost:5000/process", {
inputText: inputText,
}, config)
.then((res) => {
console.log("res", res);
setFetchedData(res.data);
})
.catch((er) => {
console.log(er);
});
}
return (
<div>
<form onSubmit={handleSubmit} method="post">
<label>
Enter Text :
<TextField multiline={true} variant="outlined"
name="inputText"
value={inputText}
onChange={(e) => setInputText(e.target.value)}
/>
</label>
<Button variant="contained" color="primary" type="submit" name="Submit">
SUBMIT
</Button>
</form>
{isSubmitted && <DisplayUpper/>}
</div>
);
}
export default Form;
In this case axois is sending json data, so to access that data you can use request.json (instead of request.form). Once you replace request.form with request.json the code should work.
(sorry for my bad English)
Hello. I know partly how ajax is used with Django. but I have some problems. Some of them are: how to render a template with ajax? How to send Django to template with ajax? I searched the internet but I couldn't find exactly what I wanted.
I would be glad if you could also recommend a detailed resource on the use of ajax and Django. (free:( ).please help me guy.thanks now.
First you have to create instances in your Django's views.py file which returns the data you wanna display in template.
Then you need to create an ajax function inside the template. Here is a basic ajax function that can be modified to your needs:
<script>
function loadDoc() {
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
document.getElementById("demo").innerHTML = this.responseText;
}
};
xhttp.open("GET", "demo_get.asp", true);
xhttp.send();
}
</script>
What it does is reach out to the source of data in your case it will probably be the instances in views.py. "readyState == 4" tells you the data load is complete, while "this.status == 200" tells you if the request is successful.
The question on how to display the data depends on you and the type of data.
I have a Django project that requires page refreshes any time I want to update the content. Currently it uses the built in Django Class Based Views, which in turn use Templates.
I want to start implementing some javascript calls to refresh tables/forms/modal windows with new data, mostly in response to button clicks. I'm trying to use Vue to accomplish this, and I have created a Django REST Framework backend to facilitate this.
I got a simple 'Hello world' vue class working where the data is hard coded into the data field of the Vue class. I can't seem to make the jump to getting data from the API though. I am getting an Unauthorized response. I am using vue-resource for the HTTP API call.
I have unit tests where I call the API from the DRF APITestCase using the self.client.get('api/path') and they work as expected (unauthorized when there is no authenticated user attached to request, authorized when there is).
I have debugged into the DRF Permission class to see why the request is being refused and it is because there is no authenticated User attached to the request.
I have added SessionAuthentication to the DEFAULT_AUTHENTICATION_CLASSES in settings.
My question is, how do I add an authenticated user to the request so that when the Vue method is called from within my webapp the API request will be authorized?
I'm not sure if this is complicating matters but I am using a custom user model within Django for authentication.
I am hoping to start off by implementing a few Vue controls throughout my website, for instance the tables and forms mentioned. I don't want to turn this into a single page app. I would like to continue using the Django views for user authentication.
My Vue code looks like so;
new Vue({
delimiters: ['${', '}$'],
el: '.events-table',
data: {
message: 'Hello Vue!',
demo: [
{ id: 5 },
{ id: 2 },
{ id: 3 },
],
events: [],
},
http: {
root: 'http://localhost:8000',
},
methods: {
getEvents: function () {
this.$http.get('api/eventlog/events/?format=json').then(
function (data, status, request) {
if (status == 200) {
this.events = data.body.results;
}
}
)
}
},
mounted: function () {
this.getEvents();
}
})
I changed the http property like so
http: {
root: window.location.origin,
},
and now it seems to recognise that the request is coming from an authenticated session.
I have this route config:
$routeProvider
.when('/store', {
templateUrl: '/static/js/partials/store.html',
controller: 'StoreController'
})
.when('/groups', {
templateUrl: '/static/js/partials/groups.html',
controller: 'GroupsController'
})
.when('/groups/:id', {
templateUrl: '/static/js/partials/group_page.html',
controller: 'GroupPageController'
})
.when('/purchases', {
templateUrl: '/static/js/partials/purchases.html',
controller: 'PurchaseController'
})
.when('/settings', {
templateUrl: '/static/js/partials/settings.html',
controller: 'SettingsController'
})
.otherwise({redirectTo: '/static/js/partials//store'});
There are lots of django variables and other django stuff used in those HTML files.
But they are not being parsed. For example:
{% trans 'vouchers' %}
is shown in the view insted of 'vouchers'
Why is this happening? How to fix this?
Django templating engine is done on the server side
Angularjs routeProvide is implemented for client side routing.
Hence, your django variables will not be parsed. (since all changes are done on client-side by angularjs and dont actually and is not interpreted by the django templating engine)
There are LOTS of post and pages discussing the use of Django and AJAX, and I've read hundreds over the past day or so looking for the answer to this question. A quick overview:
May of the examples show a hard-coded URL like this:
$.post("/projects/create/", {"name" : name}, function(data) {...
or some use the URL template tag, but with no parameters:
$.post("{% url create_project %}", {"name" : name}, function(data) {...
However, I'd like to include a Django-style parameter in a URL. Here's my url definition:
url(r'ajax/entity_name/(?P<pk>\w+)/$',EntityAjaxView.as_view(),name='entity_name'),
Yes, I'm using a class based view, and it is based on DetailView. This view looks by default for a pk value to be provided in the URL, and in a normal template I would use:
{% url entity_name id_number %}
to provide a link. In my code, I want to grab the value entered in an input box for the pk value. Here is a snippet of my JavaScript (which doesn't work):
var id_number = $('#id_endowmententity_set-' + rownum + '-id_number').val()
$.ajax({
type: "GET",
url: '{% url entity_name id_number %}',
So, my question is, can I use the URL template tag with a value from an input box?
(I know that I could use POST instead of GET and pass the id_number in the POST data, but that won't work well with the DetailView.)
Django is a server-side application. Javascript is client-side. Django templates get rendered on the server, so {% url entity_name id_number %} is evaluated on the server side, and then it's value is returned to the client. Just because of this, it's impossible for you to combine Django templates with javascript. However there are couple of things you can do to solve your problem.
Since you are making an ajax call, and the ajax call depends on some user input, usually the best route for the client to send any type of user input to the server is by either using querystring (thing after ? in the URL) or by sending a POST data. So the simplest thing is to change your your url not to include the pk in the url, but for the view to get that as part of GET or POST data.
url(r'ajax/entity_name/$', EntityAjaxView.as_view(), name='entity_name'),
and the view (sorry I'm not familiar with class based views):
def entity_name(request):
pk = request.GET.get('pk')
...
That seems to me to be the most elegant solution. If however you absolutely need to construct the url on the client side, you can generate a template url on the server side and then replace whatever parts you need on the client side to get the full url. This however requires more maintenance and therefore is more error prone. Simple js example of this approach:
var id_number = $('#id_endowmententity_set-' + rownum + '-id_number').val(),
url = '{% url entity_name 0 %}'.replace('0', id_number);
$.ajax({
type: "GET",
url: url,
...
});
It is possible to set an Ajax url on the element you are selecting using an attribute and it will behave like Django urls. Importantly, you can even access the url in Javascript file. I use it a lot
HTML
<div class="card-body" id="js-products" data-url="{% url 'chart-data' %}">
<div class="chart-area">
<canvas id="testChart"></canvas>
</div>
</div>
Note: the data-url attribute set on parent div
JAVASCRIPT
$(document).ready(function () {
var endpoint = $("#js-products").attr("data-url");
var defaultData = [];
var labels = []
$.ajax({
method: 'GET',
url: endpoint,
success: function (data) {
labels = data.labels
defaultData = data.data_default
setChart()
},
error: function (error_data) {
console.log(error_data)
}
})
function setChart() {
var ctx = document.getElementById('testChart').getContext('2d');
var myChart = new Chart(ctx, {
type: 'line',
responsive: true,
data: {
labels: labels,
datasets: [{
label: 'Monthly Performance',
data: defaultData,
}]
},
options: {
scales: {
yAxes: [{
ticks: {
beginAtZero: true
}
}]
}
}
});
}
});
DJANGO VIEWS
Am using django rest framework class view but you can use either of function or class based view
class ChartData(APIView):
authentication_classes = []
permission_classes = []
def get(self, request, format=None):
labels = ['Products', 'User', 'May']
data_default = [SeedProduct.objects.all().count(),
User.objects.all().count(), 4]
data = {
'labels': labels,
'data_default': data_default,
}
return Response(data)
DJANGO URLS:
import the view class from views
path('api/chart/data', views.ChartData.as_view(), name="chart-data"),
It's pretty time consuming to go round trip to a server just to fetch a URL. The best strategy to keep URLs dry and avoid this is to generate javascript that emulates Django's native url reverse function and then serve that code statically with the rest of your client side JS.
django-render-static does just that.
This worked for me.
my URL was:
path('myurl/<str:type>', views.myfunction, name='myfunction')
my views.py file:
def myfunction(request,type):
return render(request, "payment.html", context)
In my template, I solved the issue by:
<button type="button" class="btn"
onclick="myfunction('forward');">My Button Name
</button>
<script>
function myfunction(type){
let url = "{% url 'appName:myfunction' 'ok' %}".replace('ok', type);
$.ajax({
method: 'POST',
url: url,
data: {
csrfmiddlewaretoken: '{{ csrf_token }}'
}
});
}
</script>