Django项目中基于CSRF令牌AJAX的帖子

Question

So I found out the error and it was in my HTML. I just added {% csrf_token %} and it worked :) thanks for the assist guys!

(I used the JS snippet given to me in the first answer but I am still getting a 403 Forbidden error!) what could I be doing wrong?

I recently learnt JS and tried the following JS code for AJAX POST but I am getting a 403 error. Did some further research and found that I needed to pass a CSRF token. I have gone through a lot of tutorials online but the only solutions I was able to find were of JQuery and I have no idea how that syntax works. I need to know how to pass a CSRF token via Javascript AJAX based post for a django project. My code is;

var upvoteBtn = document.querySelector('#upvote');
var downvoteBtn = document.querySelector('#downvote');

upvoteBtn.addEventListener('click', jL);
downvoteBtn.addEventListener('click', cL);

function jL(event) {
    document.getElementById("upvote").style.display='none';
    document.getElementById("downvote").style.display='none';
    var http = new XMLHttpRequest ();
    var url = 'entered my url here';
    var data = 'title=Post%20Title&body=Body';
    var method = 'POST';

    http.open(method, url, true);
    http.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded')
    http.setRequestHeader("X-CSRFToken", csrftoken);
    http.onreadystatechange = function() {

    if (http.readyState === XMLHttpRequest.DONE && http.status === 200){
        document.getElementById("first").innerHTML = "this post has been voted";
        console.log("upvote given");
    }
    else if (http.readyState === XMLHttpRequest.DONE && http.status !== 200){
        console.log("error!", http.responseText);
    }
};

http.send(data);
}

function cL(event){
    document.getElementById("upvote").style.display='none';
    document.getElementById("downvote").style.display='none';
    var http = new XMLHttpRequest ();
    var url = 'entered my url here';
    var data = 'title=Post%20Title&body=Body';
    var method = 'POST';

    http.open(method, url, true);
    http.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded')
    http.setRequestHeader("X-CSRFToken", csrftoken);
    http.onreadystatechange = function() {

    if (http.readyState === XMLHttpRequest.DONE && http.status === 200){
        document.getElementById("first").innerHTML = "got downvoted";
        console.log("downvoted!");
    }
    else if (http.readyState === XMLHttpRequest.DONE && http.status !== 200){
        console.log("error!", http.responseText);
    }
}; 
http.send(data);
}

//function for CSRF token
function getCookie(cname) {
    var name = cname + "=";
    var decodedCookie = decodeURIComponent(document.cookie);
    var ca = decodedCookie.split(';');
    for(var i = 0; i <ca.length; i++) {
        var c = ca[i];
        while (c.charAt(0) == ' ') {
            c = c.substring(1);
        }
        if (c.indexOf(name) == 0) {
            return c.substring(name.length, c.length);
        }
    }
    return "";
}    
var csrftoken = getCookie('csrftoken'); 

Answer 1

You need to call:

xhr.setRequestHeader("X-CSRFToken", csrftoken);

when you prepare your xhr request. (in your example xhr is named http )

you can get the csrftoken from the cookie, but in order to do that you need to implement a getCookie function.

Something like this should do the trick:

function getCookie(cname) {
    var name = cname + "=";
    var decodedCookie = decodeURIComponent(document.cookie);
    var ca = decodedCookie.split(';');
    for(var i = 0; i <ca.length; i++) {
        var c = ca[i];
        while (c.charAt(0) == ' ') {
            c = c.substring(1);
        }
        if (c.indexOf(name) == 0) {
            return c.substring(name.length, c.length);
        }
    }
    return "";
}

var csrftoken = getCookie('csrftoken');

Update

In your code this should look something like this:

upvoteBtn.addEventListener('click', jL);
downvoteBtn.addEventListener('click', cL);

//first define your getCookie function
function getCookie(cname) {
    var name = cname + "=";
    var decodedCookie = decodeURIComponent(document.cookie);
    var ca = decodedCookie.split(';');
    for(var i = 0; i <ca.length; i++) {
        var c = ca[i];
        while (c.charAt(0) == ' ') {
            c = c.substring(1);
        }
        if (c.indexOf(name) == 0) {
            return c.substring(name.length, c.length);
        }
    }
    return "";
}

function jL(event) {
    //...
    //Then when you prepare you data fetch the token
    var csrftoken = getCookie('csrftoken');

    http.open(method, url, true);
    http.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded')
    //Now set it
    http.setRequestHeader("X-CSRFToken", csrftoken);
    //... the rest of your code
}

function cL(event){
    //do the same here
}

Answer 2

Add this piece of code into your JS:

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 = $.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;
}

function csrfSafeMethod(method) {
    // these HTTP methods do not require CSRF protection
    return (/^(GET|HEAD|OPTIONS|TRACE)$/.test(method));
}

function sameOrigin(url) {
    // test that a given url is a same-origin URL
    // url could be relative or scheme relative or absolute
    var host = document.location.host; // host + port
    var protocol = document.location.protocol;
    var sr_origin = '//' + host;
    var origin = protocol + sr_origin;
    // Allow absolute or scheme relative URLs to same origin
    return (url == origin || url.slice(0, origin.length + 1) == origin + '/') ||
        (url == sr_origin || url.slice(0, sr_origin.length + 1) == sr_origin + '/') ||
        // or any other URL that isn't scheme relative or absolute i.e relative.
        !(/^(\/\/|http:|https:).*/.test(url));
}

if (!csrfSafeMethod(http.responseType) && sameOrigin(http.responseUrl)) {
    http.setRequestHeader("X-CSRFToken", getCookie('csrftoken'));
}

Basically you need to add the CSRF token to the headers. I cannot find the link where I found this piece of code, if anyone knows would be great.