CSRF With Ajax Polling - python

I have some AJAX that polls the server every 5 seconds:
var date = $('article').first().find('time').text();
console.log(date);
setInterval(function() {
$.post('pollNewEntries', {'date':date}, newEntrySuccess)
}, 5000);
Unfortunately, I'm getting a 403 error every time the AJAX tries to poll the server, stating that I have made an invalid CSRF request. I've used AJAX with forms before and included the CSRF token within the forms, but I"m not sure how I would do it with a formless AJAX request like above.

The solution to this problem is described in the Django documentation: https://docs.djangoproject.com/en/dev/ref/contrib/csrf/#ajax
Add this code to the top of your js:
$.ajaxSetup({
beforeSend: function(xhr, settings) {
function getCookie(name) {
var cookieValue = null;
if (document.cookie && document.cookie != '') {
var cookies = document.cookie.split(';');
for (var i = 0; i < cookies.length; i++) {
var cookie = jQuery.trim(cookies[i]);
// Does this cookie string begin with the name we want?
if (cookie.substring(0, name.length + 1) == (name + '=')) {
cookieValue = decodeURIComponent(cookie.substring(name.length + 1));
break;
}
}
}
return cookieValue;
}
if (!(/^http:.*/.test(settings.url) || /^https:.*/.test(settings.url))) {
// Only send the token to relative URLs i.e. locally.
xhr.setRequestHeader("X-CSRFToken", getCookie('csrftoken'));
}
}
});

You need to pass csrf token along with your post data:
var date = $('article').first().find('time').text();
console.log(date);
setInterval(function() {
$.post('pollNewEntries', {'date':date, 'csrfmiddlewaretoken': '{{csrf_token}}'}, newEntrySuccess)
}, 5000);

Simply add these lines in your script. Here is an example in coffeescript :
### CSRF methods ###
csrfSafeMethod = (method) ->
# these HTTP methods do not require CSRF protection
return (/^(GET|HEAD|OPTIONS|TRACE)$/.test(method))
$.ajaxSetup(
crossDomain: false
beforeSend: (xhr, settings) ->
if !csrfSafeMethod(settings.type)
xhr.setRequestHeader("X-CSRFToken", $.cookie('csrftoken'))
)
Read the documentation : CSRF
In other hand, as user1427661 suggests to you, it will be better to use HTTP GET method instead of POST, because you only need to read data and don't write anything. See the W3 docs.

Related

Returning two arrays from a python script in Django and utilizing in Ajax simultaneously

I have a python script running in views.py within Django which returns two very large string arrays, x and y. It currently is able to run off a button press within my index.html.
def python_file(request):
final()
return HttpResponse("ran")
The ajax code I have running to do the button press.
<script src="http://code.jquery.com/jquery-3.3.1.min.js" integrity="sha256-FgpCb/KJQlLNfOu91ta32o/NMZxltwRo8QtmkMRdAu8=" crossorigin="anonymous"></script>
<script>
function gotoPython(){
$.ajax({
url: "/python_file",
context: document.body
}).done(function() {
alert('finished python script');
});
}
</script>
It's also attached to the URLS.py. I know there's no array being returned right now, because I am unsure how to run the script, get the data simultaneously, then add it to the page without refreshing the page. So, I am asking what would be the best practice to do what I described. Any help would be appreciated.
This is generally what I do, not sure if it's best practice, but I return it with Json
I included two examples, and POST and a GET.
I also included some other stuff I usually return status and msg. When I catch an error or have an invalid POST I send back status = False and msg = '{error message}, then I can show that error message in the front end with Javascript. I keep this standardized in my project, but you do you.
def python_file(request):
xArray, yArray = final()
import json
data = {
'status': True, # True=All Good. False=Caught Error but didn't crash.
'x': xArray,
'y': yArray,
'msg': 'returning x and y arrays',
}
return HttpResponse(
json.dumps(data),
content_type="application/json"
)
function gotoPython(){
$.ajax({
method: 'GET',
url: '/python_file',
success: function(data){
console.log(data)
if (data['status']){
// do things with arrays
data['x']
data['y']
}else{
console.log('Server Replied with Error, but did not Crash');
console.log(data['msg']);
};
},
error: function(event,xhr,settings,errorText){
// general `xhr.status` Key for common errors
// 0 = Server didn't Reply (Server Down)
// 400 = Bad Request (Syntax Error)
// 403 = Forbidden (Login Token Expired or not in Group)
// 403 = Not Found (Invalid Url)
// 500 = Server Error (Django Crash)
},
});
};
function gotoPythonWithData(){
// if you wanted to POST data to this function you'd just do
// Note: Requires csrfmiddlewaretoken in template
// Throw this anywhere (it's hidden): {% csrf_token %}
submitData = {
'return_item_count': 25,
'csrfmiddlewaretoken': $('[name=\'csrfmiddlewaretoken\']').val(),
};
$.ajax({
method: 'POST',
url: '/python_file',
data: submitData,
success: function(data){
if (data['status']{
// do stuff
}else{
console.log(data['msg']);
};
},
error: function(event,xhr,settings,errorText){
},
});
};
Note: Some things like, Django Decimal objects, can not be be put into a Json Dump. In the Decimal example you've got to turn them into a Float or an Int
You can add parameters to the ajax.done(function) in order to get what your server returned.
$.ajax({
url: "/python_file",
context: document.body
}).done(function (response, textStatus, jqXHR) {
// What happens when the call is successful (200 <= status code < 300
console.log(response); // Logs what you returned from your django
// x + "separator" + y
})
.fail(function (jqXHR, textStatus, errorThrown) {
// Status code over 400
})
.always(function (jqXHR, textStatus, errorThrown) {
// Always happens
...
});
You can check ajax documentation here : https://api.jquery.com/jquery.ajax/#jQuery-ajax-settings-settings
And your django view should return some text content :
def view(response):
// code
return HttpResponse(status=200, content=x + "separator" + y)

Cannot retrieve data from endpoint

I have installed Chatterbot for Django integration. I followed the easy tutorial with every step and made it so that the endpoint was: http://127.0.0.1:8000/chatterbot/ What I did next was try to communicate with that endpoint to see if I would get back any results. So I made an Ajax request as follows:
var query = {"text": "My input statement"};
$.ajax({
type: 'POST',
url: "http://127.0.0.1:8000/chatterbot/",
data: JSON.stringify(query),
contentType: 'application/json',
success: function (data) {
console.log(data);
}
});
However, what returns in console is: POST http://127.0.0.1:8000/chatterbot/ 403 (Forbidden) and what returns in the cmd prompt when I run my server is:
csrf: WARNING - Forbidden (CSRF token missing or incorrect.):
/chatterbot/ [29/Mar/2018 02:16:43] "POST /chatterbot/ HTTP/1.1" 403
2502
Why am I getting this error? How can I fix it so I receive the call back from the endpoint?
View for this page:
def IndexView(request):
latest_questions = Questions.objects.all().order_by("-date_published")[:5]
popular_questions = Questions.objects.all().order_by("-num_replies")[:5]
return render(request, 'core/index.html',
{'latest_questions': latest_questions, 'popular_questions': popular_questions
})
Try this code
// using jQuery
function getCookie(name) {
var cookieValue = null;
if (document.cookie && document.cookie !== '') {
var cookies = document.cookie.split(';');
for (var i = 0; i < cookies.length; i++) {
var cookie = jQuery.trim(cookies[i]);
// Does this cookie string begin with the name we want?
if (cookie.substring(0, name.length + 1) === (name + '=')) {
cookieValue = decodeURIComponent(cookie.substring(name.length + 1));
break;
}
}
}
return cookieValue;
}
var csrftoken = getCookie('csrftoken');
var query = {
"text": "My input statement",
"csrfmiddlewaretoken": csrftoken
};
$.ajax({
type: 'POST',
url: "http://127.0.0.1:8000/chatterbot/",
data: query,
contentType: 'application/json',
success: function (data) {
console.log(data);
}
});
one way is to send the csrfmiddlewaretoken like below
var query = {
"text": "My input statement",
'csrfmiddlewaretoken': "{{csrf_token }}"
};
other way is to use #csrf_exempt decorator
from django.views.decorators.csrf import csrf_exempt
#csrf_exempt
def IndexView(request):
# .... code.....
other is to add a script
function csrfSafeMethod(method) {
// these HTTP methods do not require CSRF protection
return (/^(GET|HEAD|OPTIONS|TRACE)$/.test(method));
}
$.ajaxSetup({
beforeSend: function(xhr, settings) {
if (!csrfSafeMethod(settings.type) && !this.crossDomain) {
xhr.setRequestHeader("X-CSRFToken", csrftoken);
}
}
});
Reference: https://docs.djangoproject.com/en/2.0/ref/csrf/
If you dont want to use CSRF tokens just add this above your code.
from django.views.decorators.csrf import csrf_exempt
#csrf_exempt
def IndexView(request):
# your code

Django DRF - How to do CSRF validation with token authentication

I am working on REST API using Django and Django Rest Framework.
In the front-end I have AngularJs app.
I have used Token authentication for APIs. This disables the CSRF checks.
I want keep CSRF validation with REST API. How to achieve this ?
How should I get CSRF Token value so that it can be set into the header of every POST request, using interceptor of my angular application.
I have this configuration in my app.js. Should do the trick!
app.config(function($httpProvider) {
$httpProvider.defaults.headers.common['X-Requested-With'] = 'XMLHttpRequest';
$httpProvider.defaults.xsrfCookieName = 'csrftoken';
$httpProvider.defaults.xsrfHeaderName = 'X-CSRFToken';
});
I've got the same problem when i started to use Angular 1.x with Django and DRF, and then i found this code snippet in a book i think, and it works fine for me. Include this file in your base.html file or your main html file before any javascript import, and everything will work smoothly and you can start talking to your backend.
// Place at /static/js/csrf.js
// CSRF helper functions taken directly from Django docs
function getCookie(name) {
var cookieValue = null;
if (document.cookie && document.cookie != '') {
var cookies = document.cookie.split(';');
for (var i = 0; i < cookies.length; i++) {
var cookie = jQuery.trim(cookies[i]);
// Does this cookie string begin with the name we want?
if (cookie.substring(0, name.length + 1) == (name + '=')) {
cookieValue = decodeURIComponent(cookie.substring(name.length + 1));
break;
}
}
}
return cookieValue;
}
var csrftoken = getCookie('csrftoken');
function csrfSafeMethod(method) {
// these HTTP methods do not require CSRF protection
return (/ ˆ (GET|HEAD|OPTIONS|TRACE) $ /.test(method));
}
$.ajaxSetup({
beforeSend: function (xhr, settings) {
if (!csrfSafeMethod(settings.type) && !this.crossDomain) {
xhr.setRequestHeader("X-CSRFToken", csrftoken);
}
}
});

RESTful authentication in a hybrid web app

I'm writing an hybrid web app using flask. By hybrid I mean that there is the conventional web server application built with template engine and there is RESTful API for client side application as well. So here is my confusion:
In my current application, user logs in through the web server so that an HTTP session is created, the user then can do stuff. However, in one of the pages, there is a action that is done via AJAX call to the RESTful part of the same application. Normally in this API, the user will have to authenticate itself again. But here the client side code has no way of knowing the user name and password. What's the correct pattern here?
You can authenticate the user client side in ajax call:
For example:
$.ajax({
url: 'http://example.com/api.ashx/v2/users.xml',
beforeSend: addHeaders,
dataType: "text",
processData: false,
success: function(data, status) {
// do stuff here
},
error: function(xhr, status, error) {
// do stuff here
}
});
var addHeaders = function(xhr) {
var restAuthHeader = readCookie("AuthorizationCookie");
if (restAuthHeader != null) {
xhr.setRequestHeader("Rest-Authorization-Code", restAuthHeader);
}
};
var readCookie = function(input) {
var nameEQ = input + "=";
var ca = document.cookie.split(';');
for (var i = 0; i < ca.length; i++) {
var c = ca[ i ];
while (c.charAt(0) == ' ') c = c.substring(1, c.length);
if (c.indexOf(nameEQ) == 0)
return c.substring(nameEQ.length, c.length);
}
return null;
};
Let's say you have a form with username and password to authenticate.
<form id="login-form">
<input data-key="username" type="text" placeholder="username" />
<input data-key="password" type="password" placeholder="password" />
<button type="submit">Login</button>
</form>
Your endpoint should return a token and a userid.
var $form = $('#login-form');
// post to your login endpoint with username and password
$.post('/login', {
username: $form.find('input[data-key="username"]').val(),
password: $form.find('input[data-key="password"]').val();
}).done(function (response) {
// put the token and userid in the sessionStorage or localStorage
window.sessionStorage.setItem('token', response.data.token);
window.sessionStorage.setItem('userId', response.data.userId);
}).fail(function (e) {
// handle incorrect credentials here.
alert('authentication failed');
});
You should append these to your headers to request data.
function requestEndpoint(endpoint) {
$.ajax({
// other stuff here you probably know
headers: {
'X-Auth-Token': window.sessionStorage.getItem('token'),
'X-User-Id': window.sessionStorage.getItem('userId'),
'Content-Type': 'application/json'
}
});
}
Just scan for these headers at the endpoints in flask

AJAX Python Call Definition [closed]

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I want to call a definition that is located in Python with a parameter, using AJAX. The web framework I'm using is Flask.
In my test.py file:
def example(param):
In my JS file
$.ajax({
type: 'POST',
url: "test.py"
//pass param here?
});
$.ajax({
type: 'POST',
url: "test.py"
data: {
param: param
}
});
make sure to include your CSRF token. You can learn more about it here http://flask.pocoo.org/snippets/3/
you can add this to your js code.
function getCookie(name) {
var cookieValue = null;
if (document.cookie && document.cookie != '') {
var cookies = document.cookie.split(';');
for (var i = 0; i < cookies.length; i++) {
var cookie = jQuery.trim(cookies[i]);
// Does this cookie string begin with the name we want?
if (cookie.substring(0, name.length + 1) == (name + '=')) {
cookieValue = decodeURIComponent(cookie.substring(name.length + 1));
break;
}
}
}
return cookieValue;
}
var csrftoken = getCookie('csrftoken');
function csrfSafeMethod(method) {
// these HTTP methods do not require CSRF protection
return (/^(GET|HEAD|OPTIONS|TRACE)$/.test(method));
}
$.ajaxSetup({
beforeSend: function(xhr, settings) {
if (!csrfSafeMethod(settings.type) && !this.crossDomain) {
xhr.setRequestHeader("X-CSRFToken", csrftoken);
}
}
});

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