Cross domain requests and jQuery/AJAX - javascript

I had read earlier that cross domain requests are not possible through AJAX (since XHR is bound to same origin policy)... Hence we use JSONP, which uses dynamic script injection (since script tag is not bound by same origin policy).
However, I was going through the jQuery AJAX documentation and saw one setting saying "crossDomain".
So, is Cross domain requests now supported through jQuery/AJAX? Is it the same as what we get through JSONP?

I made a project that use cross domain requests. You have few examples.
It is here, on Github.
Use this function in your client-side code (javascript):
function getHTML(url, callback){
url = url.trim();
$.ajax({
url: url,
type: 'GET',
success: function(res) {
var headline = res.responseText;
if(headline === ""){
callback("There was a problem with the page. Be sure that your url is correct.");
return;
}
callback(null, headline);
}
});
}

Related

Failed posting data with axios [duplicate]

I'm trying to load a cross-domain HTML page using AJAX but unless the dataType is "jsonp" I can't get a response. However using jsonp the browser is expecting a script mime type but is receiving "text/html".
My code for the request is:
$.ajax({
type: "GET",
url: "http://saskatchewan.univ-ubs.fr:8080/SASStoredProcess/do?_username=DARTIES3-2012&_password=P#ssw0rd&_program=%2FUtilisateurs%2FDARTIES3-2012%2FMon+dossier%2Fanalyse_dc&annee=2012&ind=V&_action=execute",
dataType: "jsonp",
}).success( function( data ) {
$( 'div.ajax-field' ).html( data );
});
Is there any way of avoiding using jsonp for the request? I've already tried using the crossDomain parameter but it didn't work.
If not is there any way of receiving the html content in jsonp? Currently the console is saying "unexpected <" in the jsonp reply.
jQuery Ajax Notes
Due to browser security restrictions, most Ajax requests are subject to the same origin policy; the request can not successfully retrieve data from a different domain, subdomain, port, or protocol.
Script and JSONP requests are not subject to the same origin policy restrictions.
There are some ways to overcome the cross-domain barrier:
CORS Proxy Alternatives
Ways to circumvent the same-origin policy
Breaking The Cross Domain Barrier
There are some plugins that help with cross-domain requests:
Cross Domain AJAX Request with YQL and jQuery
Cross-domain requests with jQuery.ajax
Heads up!
The best way to overcome this problem, is by creating your own proxy in the back-end, so that your proxy will point to the services in other domains, because in the back-end not exists the same origin policy restriction. But if you can't do that in back-end, then pay attention to the following tips.
**Warning!**
Using third-party proxies is not a secure practice, because they can keep track of your data, so it can be used with public information, but never with private data.
The code examples shown below use jQuery.get() and jQuery.getJSON(), both are shorthand methods of jQuery.ajax()
CORS Anywhere
2021 Update
Public demo server (cors-anywhere.herokuapp.com) will be very limited by January 2021, 31st
The demo server of CORS Anywhere (cors-anywhere.herokuapp.com) is meant to be a demo of this project. But abuse has become so common that the platform where the demo is hosted (Heroku) has asked me to shut down the server, despite efforts to counter the abuse. Downtime becomes increasingly frequent due to abuse and its popularity.
To counter this, I will make the following changes:
The rate limit will decrease from 200 per hour to 50 per hour.
By January 31st, 2021, cors-anywhere.herokuapp.com will stop serving as an open proxy.
From February 1st. 2021, cors-anywhere.herokuapp.com will only serve requests after the visitor has completed a challenge: The user (developer) must visit a page at cors-anywhere.herokuapp.com to temporarily unlock the demo for their browser. This allows developers to try out the functionality, to help with deciding on self-hosting or looking for alternatives.
CORS Anywhere is a node.js proxy which adds CORS headers to the proxied request.
To use the API, just prefix the URL with the API URL. (Supports https: see github repository)
If you want to automatically enable cross-domain requests when needed, use the following snippet:
$.ajaxPrefilter( function (options) {
if (options.crossDomain && jQuery.support.cors) {
var http = (window.location.protocol === 'http:' ? 'http:' : 'https:');
options.url = http + '//cors-anywhere.herokuapp.com/' + options.url;
//options.url = "http://cors.corsproxy.io/url=" + options.url;
}
});
$.get(
'http://en.wikipedia.org/wiki/Cross-origin_resource_sharing',
function (response) {
console.log("> ", response);
$("#viewer").html(response);
});
Whatever Origin
Whatever Origin is a cross domain jsonp access. This is an open source alternative to anyorigin.com.
To fetch the data from google.com, you can use this snippet:
// It is good specify the charset you expect.
// You can use the charset you want instead of utf-8.
// See details for scriptCharset and contentType options:
// http://api.jquery.com/jQuery.ajax/#jQuery-ajax-settings
$.ajaxSetup({
scriptCharset: "utf-8", //or "ISO-8859-1"
contentType: "application/json; charset=utf-8"
});
$.getJSON('http://whateverorigin.org/get?url=' +
encodeURIComponent('http://google.com') + '&callback=?',
function (data) {
console.log("> ", data);
//If the expected response is text/plain
$("#viewer").html(data.contents);
//If the expected response is JSON
//var response = $.parseJSON(data.contents);
});
CORS Proxy
CORS Proxy is a simple node.js proxy to enable CORS request for any website.
It allows javascript code on your site to access resources on other domains that would normally be blocked due to the same-origin policy.
CORS-Proxy gr2m (archived)
CORS-Proxy rmadhuram
How does it work?
CORS Proxy takes advantage of Cross-Origin Resource Sharing, which is a feature that was added along with HTML 5. Servers can specify that they want browsers to allow other websites to request resources they host. CORS Proxy is simply an HTTP Proxy that adds a header to responses saying "anyone can request this".
This is another way to achieve the goal (see www.corsproxy.com). All you have to do is strip http:// and www. from the URL being proxied, and prepend the URL with www.corsproxy.com/
$.get(
'http://www.corsproxy.com/' +
'en.wikipedia.org/wiki/Cross-origin_resource_sharing',
function (response) {
console.log("> ", response);
$("#viewer").html(response);
});
The http://www.corsproxy.com/ domain now appears to be an unsafe/suspicious site. NOT RECOMMENDED TO USE.
CORS proxy browser
Recently I found this one, it involves various security oriented Cross Origin Remote Sharing utilities. But it is a black-box with Flash as backend.
You can see it in action here: CORS proxy browser
Get the source code on GitHub: koto/cors-proxy-browser
You can use Ajax-cross-origin a jQuery plugin.
With this plugin you use jQuery.ajax() cross domain. It uses Google services to achieve this:
The AJAX Cross Origin plugin use Google Apps Script as a proxy jSON
getter where jSONP is not implemented. When you set the crossOrigin
option to true, the plugin replace the original url with the Google
Apps Script address and send it as encoded url parameter. The Google
Apps Script use Google Servers resources to get the remote data, and
return it back to the client as JSONP.
It is very simple to use:
$.ajax({
crossOrigin: true,
url: url,
success: function(data) {
console.log(data);
}
});
You can read more here:
http://www.ajax-cross-origin.com/
If the external site doesn't support JSONP or CORS, your only option is to use a proxy.
Build a script on your server that requests that content, then use jQuery ajax to hit the script on your server.
Just put this in the header of your PHP Page and it ill work without API:
header('Access-Control-Allow-Origin: *'); //allow everybody
or
header('Access-Control-Allow-Origin: http://codesheet.org'); //allow just one domain
or
$http_origin = $_SERVER['HTTP_ORIGIN']; //allow multiple domains
$allowed_domains = array(
'http://codesheet.org',
'http://stackoverflow.com'
);
if (in_array($http_origin, $allowed_domains))
{
header("Access-Control-Allow-Origin: $http_origin");
}
I'm posting this in case someone faces the same problem I am facing right now. I've got a Zebra thermal printer, equipped with the ZebraNet print server, which offers a HTML-based user interface for editing multiple settings, seeing the printer's current status, etc. I need to get the status of the printer, which is displayed in one of those html pages, offered by the ZebraNet server and, for example, alert() a message to the user in the browser. This means that I have to get that html page in Javascript first. Although the printer is within the LAN of the user's PC, that Same Origin Policy is still staying firmly in my way. I tried JSONP, but the server returns html and I haven't found a way to modify its functionality (if I could, I would have already set the magic header Access-control-allow-origin: *). So I decided to write a small console app in C#. It has to be run as Admin to work properly, otherwise it trolls :D an exception. Here is some code:
// Create a listener.
HttpListener listener = new HttpListener();
// Add the prefixes.
//foreach (string s in prefixes)
//{
// listener.Prefixes.Add(s);
//}
listener.Prefixes.Add("http://*:1234/"); // accept connections from everywhere,
//because the printer is accessible only within the LAN (no portforwarding)
listener.Start();
Console.WriteLine("Listening...");
// Note: The GetContext method blocks while waiting for a request.
HttpListenerContext context;
string urlForRequest = "";
HttpWebRequest requestForPage = null;
HttpWebResponse responseForPage = null;
string responseForPageAsString = "";
while (true)
{
context = listener.GetContext();
HttpListenerRequest request = context.Request;
urlForRequest = request.RawUrl.Substring(1, request.RawUrl.Length - 1); // remove the slash, which separates the portNumber from the arg sent
Console.WriteLine(urlForRequest);
//Request for the html page:
requestForPage = (HttpWebRequest)WebRequest.Create(urlForRequest);
responseForPage = (HttpWebResponse)requestForPage.GetResponse();
responseForPageAsString = new StreamReader(responseForPage.GetResponseStream()).ReadToEnd();
// Obtain a response object.
HttpListenerResponse response = context.Response;
// Send back the response.
byte[] buffer = System.Text.Encoding.UTF8.GetBytes(responseForPageAsString);
// Get a response stream and write the response to it.
response.ContentLength64 = buffer.Length;
response.AddHeader("Access-Control-Allow-Origin", "*"); // the magic header in action ;-D
System.IO.Stream output = response.OutputStream;
output.Write(buffer, 0, buffer.Length);
// You must close the output stream.
output.Close();
//listener.Stop();
All the user needs to do is run that console app as Admin. I know it is way too ... frustrating and complicated, but it is sort of a workaround to the Domain Policy problem in case you cannot modify the server in any way.
edit: from js I make a simple ajax call:
$.ajax({
type: 'POST',
url: 'http://LAN_IP:1234/http://google.com',
success: function (data) {
console.log("Success: " + data);
},
error: function (e) {
alert("Error: " + e);
console.log("Error: " + e);
}
});
The html of the requested page is returned and stored in the data variable.
To get the data form external site by passing using a local proxy as suggested by jherax you can create a php page that fetches the content for you from respective external url and than send a get request to that php page.
var req = new XMLHttpRequest();
req.open('GET', 'http://localhost/get_url_content.php',false);
if(req.status == 200) {
alert(req.responseText);
}
as a php proxy you can use https://github.com/cowboy/php-simple-proxy
Your URL doesn't work these days, but your code can be updated with this working solution:
var url = "http://saskatchewan.univ-ubs.fr:8080/SASStoredProcess/do?_username=DARTIES3-2012&_password=P#ssw0rd&_program=%2FUtilisateurs%2FDARTIES3-2012%2FMon+dossier%2Fanalyse_dc&annee=2012&ind=V&_action=execute";
url = 'https://google.com'; // TEST URL
$.get("https://images"+~~(Math.random()*33)+"-focus-opensocial.googleusercontent.com/gadgets/proxy?container=none&url=" + encodeURI(url), function(data) {
$('div.ajax-field').html(data);
});
<div class="ajax-field"></div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
You need CORS proxy which proxies your request from your browser to requested service with appropriate CORS headers. List of such services are in code snippet below. You can also run provided code snippet to see ping to such services from your location.
$('li').each(function() {
var self = this;
ping($(this).text()).then(function(delta) {
console.log($(self).text(), delta, ' ms');
});
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdn.rawgit.com/jdfreder/pingjs/c2190a3649759f2bd8569a72ae2b597b2546c871/ping.js"></script>
<ul>
<li>https://crossorigin.me/</li>
<li>https://cors-anywhere.herokuapp.com/</li>
<li>http://cors.io/</li>
<li>https://cors.5apps.com/?uri=</li>
<li>http://whateverorigin.org/get?url=</li>
<li>https://anyorigin.com/get?url=</li>
<li>http://corsproxy.nodester.com/?src=</li>
<li>https://jsonp.afeld.me/?url=</li>
<li>http://benalman.com/code/projects/php-simple-proxy/ba-simple-proxy.php?url=</li>
</ul>
Figured it out.
Used this instead.
$('.div_class').load('http://en.wikipedia.org/wiki/Cross-origin_resource_sharing #toctitle');

Get cross domain data using ajax

I am using ajax to get cross domain data.
Due to browser security restrictions, most Ajax requests are subject to the same origin policy; the request can not successfully retrieve data from a different domain, subdomain, port, or protocol (Details) .
So i am using YQL https://code.tutsplus.com/tutorials/quick-tip-cross-domain-ajax-request-with-yql-and-jquery--net-10225 to get html data.
My question is how to make call using external proxy server. For example https://www.pinterest.com/ , so i am using external proxy server with direct url access like https://www.filterbypass.me/s.php?k=https://www.pinterest.com/ .
But the problem is yql query return to null, no response data.
$.ajax({
url: 'http://query.yahooapis.com/v1/public/yql?q=' + encodeURIComponent('select * from html where url="https://www.filterbypass.me/s.php?k=https://www.pinterest.com/"') + '&format=json&diagnostics=true&callback=',
dataType: 'json' ,
success: function(data) {
console.log(data);
}
});
If you are planning to use JSONP you can use getJSON which made for that. jQuery has helper methods for JSONP
$.getJSON( 'http://someotherdomain.com/service.php', function( result ) {
console.log(result);
});
Read the below links
http://api.jquery.com/jQuery.getJSON/
Basic example of using .ajax() with JSONP?

What is the difference between $.ajax with type: post and $.post

Consider this code:
$.ajax({
url: "http://x.com/api/AnnouncementCategory/Save",
type: "Post",
success: function (data) {
//Grab our data from Ground Control
alert(data);
},
error: function (event) {
//If any errors occurred - detail them here
alert("Transmission failed. (An error has occurred)");
}
});
With above code we can post data cross domain an everything is ok. But when i use this code:
$.post(' http://x.com/AnnouncementCategory/Save')
I get this error:
OPTIONS http://x.com/AnnouncementCategory/Save Request
header field X-Requested-With is not allowed by
Access-Control-Allow-Headers. jquery-1.9.1.js:8526 XMLHttpRequest
cannot load http://x.com/AnnouncementCategory/Save. Request
header field X-Requested-With is not allowed by
Access-Control-Allow-Headers.
I see the jquery source code:
function ( url, data, callback, type ) {
// shift arguments if data argument was omitted
if ( jQuery.isFunction( data ) ) {
type = type || callback;
callback = data;
data = undefined;
}
return jQuery.ajax({
url: url,
type: method,
dataType: type,
data: data,
success: callback
});
}
Jquery also use ajax in post.
**I know what is my error and just want to know:**What is the difference between $.ajax with type: post and jquery post?
jQuery's $.ajax method always sends the "x-requested-with" header for any cross domain requests, unlike the $.post. The error you are getting is because of the way external server is handling the external request. Please look here to get more info how the CORS (Cross Origin Resource Sharing – i.e. cross domain Ajax) is being handled. Also here you will find the similar problem and the solution.
The simple answer to the question you have asked is, a shorthand version of $.ajax, as described in the documentation:
http://api.jquery.com/jQuery.post/
The docs do state that:
Due to browser security restrictions, most "Ajax" requests are subject
to the same origin policy; the request can not successfully retrieve
data from a different domain, subdomain, or protocol.
The question that you didn't ask, but perhaps is what you would really like to ask, is "why does cross-domain request work for me using $.ajax with a simple POST type, but not with $.post?". For that you would probably need to provide a bit more information.

How I get respone text in application and bind to the label in cross ajax call

I am calling the web service from other domain using Ajax call and I want to get returned response from server in my application by using following code I get response text in firebug but not in my JavaScript code. Control are not showing success and error response it goes out directly.
I want response in my success or error section but both not handling in this.
I am trying lot but not finding any solution please any one help me.
I am in a trouble. I hope somebody can help me for calling cross domain web service by using Ajax call. I am trying from 1 week but didn't find any solution till. I am getting response on browser but not getting it on my actual code.
My JavaScript code.
crossdomain.async_load_javascript(jquery_path, function () {
$(function () {
crossdomain.ajax({
type: "GET",
url: "http://192.168.15.188/Service/Service.svc/GetMachineInfo?serialNumber="+123,
success: function (txt) {
$('#responseget').html(txt);
alert("hii get");
}
});
crossdomain.ajax({
type: "POST",
url: "http://192.168.15.188/Server/Service.svc/GetEvents/",
// data: "origin=" + escape(origin),
success: function (txt) {
$('#responsepost').html(txt);
alert("hii post");
}
});
});
});
</script>
You can't simply ignore the Same Origin Policy.
There are only three solutions to fetch an answer from a web-service coming from another domain :
do it server-side (on your server)
let the browser think it comes from the same domain by using a proxy on your server
change the web service server, by making it JSONP or (much cleaner today) by adding CORS headers

Why does this $.getJSON request error?

I have the following script that call a http handler. It calls the http handler, and in fiddler, I can see the JSON returned correctly, however this script always ends up in the error block. How can I determine what is wrong?
<script type="text/javascript">
function GetConfig() {
$.getJSON("http://localhost:27249/Handlers/GetServiceMenuConfiguration.ashx", function(d) {
alert("success");
}).success(function(d) {
alert("success");
}).error(function(d) {
alert("error");
}).complete(function(d) {
alert("complete");
});
}
</script>
I see that you're including the server name (localhost) and port (27249). Ajax requests are controlled by the Same Origin Policy, which forbids cross-origin requests in the normal case. (If you're not doing a cross-origin call, you don't need to include the http://localhost:27249 portion of your URL, which is what makes me think you might be doing one.)
You can do cross-origin calls if the browser supports them and if your server code handles the CORS requests properly. Alternately, you might look at using JSON-P.
JQuery's built-in JSON parser is rather picky, even well formatted JSON can sometimes fail if the headers are not set perfectly. First try to do a $.ajax request with type:text property and log the response. This will differentiate between a connection problem and parse problem.
$.ajax({
dataType:'text',
url: '/Handlers/GetServiceMenuConfiguration.ashx',
success: function(data) {
console.log(data.responseText);
}
});
If the problem is the connection, and you do need to request JSON across domains, then you could also use a library loader like LAB, yep/nope or Frame.js.

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