I thought I could catch an error in send like this
try {
xhr.send();
} catch(e) {
// fix-me: With the
// bookmarklet on a https page
// you can't even send a HEAD
// request due to security
// restrictions. Check for
// this case here.
console.log("xhr.send, e=", e, method, window.location.href, url)
debugger;
}
console.log("I am here now");
However I never get to that console.log statement in the catch block after xhr.send.
In the console I instead get a message like this.
Mixed Content: The page at 'about:blank' was loaded over HTTPS,
but requested an insecure XMLHttpRequest endpoint 'http://m.org/'.
This request has been blocked; the content must be served over HTTPS.
I am here now.
Is it supposed to work this way? (I am using Google Chrome.)
Is there any way to find out that there was an error? (Except looking in the console. ;-) )
UPDATE
#giuscri added the very good question if I did consider that this is async. I actually missed that it could be, but it is not. A bit surprisingly. ;-)
Please see the this example. It contains this code:
var url = "http://nowhere.org/";
var xhr = new XMLHttpRequest();
xhr.onreadystatechange = function() {
console.log("onreadystatechance, readyState=", xhr.readyState);
};
xhr.onprogress = function(event) {
console.log("onprogress, readyState=", xhr.readyState);
console.log("onprogress, event=", event);
};
xhr.onerror = function(event) {
console.log("onerror, readyState=", xhr.readyState);
console.log("onerror, event=", event);
};
var method = "HEAD";
xhr.open(method, url, true);
try {
xhr.send();
} catch(e) {
console.log("xhr.send, e=", e, method, window.location.href, url);
}
console.log("After send");
When you run this page from https:// (as in the link above) the onerror function is not run. If you run the same example from file:// then onerror is run.
Connecting from HTTPS to HTTP URIs drops the security given by the underlying encryption. Web browsers blocks such requests until explicitly allowed by the user in order to prevent data leakage over plaintext connections. Further, there is also a change in origin (scheme, domain, port).
I allowed Mixed Content for the page you linked and I got the error about the different origin in console. Looks like the code works.
By the way, support for synchronous requests using XMLHttpRequest is deprecated, because it blocks user interaction until the request completes.
Related
I am trying to play an audio using Google Text-To-Speech. Therefore I need to post a request to their endpoint with the Referer and the User-Agent properly set. This call should return an MP3 that I can play.
However, I get Refused to set unsafe header errors. This is my code. How can I do this?
$.ajax({
url: 'http://translate.google.com/translate_tts?ie=UTF-8&q=Hello&tl=en&client=t',
beforeSend: function(xhr) {
xhr.setRequestHeader("Referer", "http://translate.google.com/");
xhr.setRequestHeader("User-Agent", "stagefright/1.2 (Linux;Android 5.0)");
}, success: function(data){
el.mp3 = new Audio(data);
el.mp3.play();
}
});
You can't. It is impossible.
The specification requires that the browser abort the setRequestHeader method if you try to set the Referer header (it used to be that User-Agent was also forbidden but that has changed)..
If you need to set Referer manually then you'll need to make the request from your server and not your visitor's browser.
(That said, if you need to be deceptive about the user agent or referer then you are probably trying to use the service in a fashion that the owner of it does not want, so you should respect that and stop trying).
Note that while jQuery wraps XHR, the same rules apply to fetch.
Empty Origin and Referer headers with GET XMLHttpRequest from <iframe>
Well actually, it is possible; at least for ordinary web pages.
The trick consists in injecting an XMLHttpRequest
function into an empty <iframe>.
The origin of an empty <iframe> happens to be about://blank, which results in empty Origin and Referer HTTP headers.
HTML:
<iframe id="iframe"></iframe>
JavaScript:
const iframe = document.getElementById('iframe');
const iframeWin = iframe.contentWindow || iframe;
const iframeDoc = iframe.contentDocument || iframeWin.document;
let script = iframeDoc.createElement('SCRIPT');
script.append(`function sendWithoutOrigin(url) {
var request = new XMLHttpRequest();
request.open('GET', url);
request.onreadystatechange = function() {
if(request.readyState === XMLHttpRequest.DONE) {
if(request.status === 200) {
console.log('GET succeeded.');
}
else {
console.warn('GET failed.');
}
}
}
request.send();
}`);
iframeDoc.documentElement.appendChild(script);
JavaScript evocation:
var url = 'https://api.serivce.net/';
url += '?api_key=' + api_write_key;
url += '&field1=' + value;
iframeWin.sendWithoutOrigin(url);
Having the possibility of sending empty Origin and Referer HTTP headers is important to safeguard privacy when using third-party API services. There are instances where the originating domain name may reveal sensitive personal information; like being suggestive of a certain medical condition for example. Think in terms of https://hypochondriasis-support.org :-D
The code was tested by inspecting the requests in a .har file, saved from the Network tab in the F12 Developer View in Vivaldi.
No attempt in setting the User-Agent header was made. Please, comment if this also works.
There are some header, which browser doesn't allow programmer to set its value in any of the javascript framework (like jQuery, Angular, etc.) or XMLHttpRequest ; while making AJAX request. These are called the forbidden headers: Forbidden Header
I have the following code:
var req = new XMLHttpRequest();
req.onload = function(){
if (req.status === "200"){
doSomethingWithTheReceivedData();
}
else {
alert("Error msg");
}
};
However when running index.html directly from my computer (when it isn't being served from my server) I get "NS_ERROR_DOM_BAD_URI: Access to restricted URI denied" in the Firefox web console of course because the relative path that the script is trying to access isn't available on my computer (it is on my server).
Now I want to handle this error correctly, because currently when a user clicks the button that triggers this code nothing happens. I already added the status code check, but that doesn't seem to work for handling this error, I assume a request is never returned? So how do I handle such an error?
Use a try-catch when you send the request:
try{
req.send(null);
}catch(e){
alert(e.message);
}
I have a JSON script loaded from an external website. In its simplest form, the code has been like this (and working):
jQuery.getJSON("http://adressesok.posten.no/api/v1/postal_codes.json?postal_code=" + document.querySelector("input").value + "&callback=?",
function(data){
document.querySelector("output").textContent = data.postal_codes[0].city;
});
However, the website owner don't want jQuery if it's not crucial, so I recoded .getJSON to the request = new XMLHttpRequest(); model:
request = new XMLHttpRequest();
request.open("GET", "http://adressesok.posten.no/api/v1/postal_codes.json?postal_code=" + document.querySelector("input").value + "&callback=?", true);
request.onload = function() {
var data = JSON.parse(request.responseText);
document.querySelector("output").textContent = data.postal_codes[0].city;
};
request.onerror = function() { /* this gets called every time */ };
I've modified my code many times, read documentations over and over again, yet the .onerror function is the only one always displaying. This is the console:
Which in Norwegian says that this script requested CORS, that it can't find the origin in the head of Access-Control-Allow-Origin, and that the XMLHttpRequest had a network error, and says "no access".
There could be several reasons as to why this occurs:
1: There's something wrong with the new code
2: There's something in the .getJSON jQuery function (a hack?) that prevents the error from happening
3: There's something crucial in the new code that I have forgot adding
4: There's something with my browser (IE 11 at the moment)
5: Something else?
It would be lovely with some help on this.
DEMO: http://jsbin.com/muxigulegi/1/
That isn't a network error. It's a cross origin error. The request is successful but the browser is denying access to the response to your JavaScript.
Since you have callback=? in the URL, jQuery will generate a JSONP request instead of an XMLHttpRequest request. This executes the response as a script instead of reading the raw data.
You are manually creating an XMLHttpRequest, so it fails due to the Same Origin Policy.
Create a JSONP request instead.
From http://api.jquery.com/jquery.getjson/:
JSONP
If the URL includes the string "callback=?" (or similar, as defined by the server-side API), the request is treated as JSONP instead. See the discussion of the jsonp data type in $.ajax() for more details.
You do have a callback. Which means that the JQuery function can request data from another domain, unlike your XHR call.
i try to make a Firefox Addon which runs a XMLHttp Request in Javascript. I want to get the data from this request and send it to *.body.innerhtml.
That's my code so far...
var xhr = new XMLHttpRequest();
xhr.open("GET", "http://xx.xxxxx.com", true);
xhr.send();
setTimeout(function() { set_body(xhr.responseHtml); }, 6000);
Instead of receiving the data, I get "undefined". If I change xhr.responseHtml to responseText I get nothing. I don't know why I'm getting nothing. I'm working on Ubuntu 12.04 LTS with Firefox 12.0.
If you need any more details on the script please ask!
Update:
set_body Function
document.body.innerHTML = '';
document.body.innerHTML = body;
document.close();
Update SOLVED:
I had to determine the RequestHeaders (right after xhr.open):
xhr.setRequestHeader("Host", "xxx");
For following Items: Host, Origin and Referer. So it seems there was really a problem with the same origin policy.
But now it works! Thanks to all!
when you set the last param of open to true you are asking for an async event. So you need to add a callback to xhr like so:
xhr.onReadyStateChange = function(){
// define what you want to happen when server returns
}
that is invoked when the server responds. To test this without async set the third param to false. Then send() will block and wait there until the response comes back. Setting an arbitrary timeout of 6 seconds is not the right way to handle this.
This code should work:
var xhr = new XMLHttpRequest();
xhr.onreadystatechange = function () {
if (xhr.readyState == 4) {
set_body(xhr.responseText);
}
};
xhr.open("GET", "http://xx.xxxxx.com", true);
xhr.send();
Make sure that you are getting a correct response from URL http://xx.xxxxx.com. You may have a problem with cross-domain calls. If you have a page at domain http://first.com and you try to do XMLHttpRequest from domain http://second.com, Firefox will fail silently (there will be no error message, no response, nothing). This is a security measure to prevent XSS (Cross-site scripting).
Anyway, if you do XMLHttpRequest from a chrome:// protocol, it is considered secure and it will work. So make sure you use this code and make the requests from your addon, not from your localhost or something like that.
On page SomePage.aspx, by JavaScript code (XMLHttpRequest) I call SecuredPage.aspx used next code:
var httpRequest = GetXmlHttp();
var url = "https://myhost.com/SecuredPage.aspx";
var params = "param1=" + document.getElementById('param1').value +
"¶m2=" + document.getElementById('param2').value;
httpRequest.open("POST", url, true);
httpRequest.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
httpRequest.onreadystatechange = function() {
//Call a function when the state changes.
if (httpRequest.readyState == 4 && httpRequest.status == 200) {
alert(httpRequest.responseText);
}
}
httpRequest.send(params); // HERE ACCESS IS DENIED.
//---------------------------------------------
function GetXmlHttp() {
var xmlhttp = false;
if (window.XMLHttpRequest) {
xmlhttp = new XMLHttpRequest();
}
else if (window.ActiveXObject)
// Code for Internet Explorer.
{
try {
xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
}
catch (e) {
try {
xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
} catch (E) {
xmlhttp = false;
}
}
}
return xmlhttp;
}
It throws an Access is denied error. If send to http (http://myhost.com/SecuredPage.aspx), it works fine.
How is it possible to resolve this problem?
If you wish to fetch an HTTPS page via Ajax you need to do it from an HTTPS page on the same domain, there is no other way, as long as you use Ajax. This is because of the same origin policy.
That said, there are plenty of ways to do this not using Ajax, for instance you can use frames.
Another way is to use JSONP, but this requires that you are fetching, well, JSON :)
A third way, that tends not to be very useful for production websites, but still can be fun to tinker around with, is to use YQL as a proxy.
Lastly you can always set up a serverside proxy of your own, so that you call an HTTP address that fetches the HTTPS page and sends it on, but this is rarely a good solution if it can be avoided.
This is because the browser considers http and https as 2 different sites/domains, and therefore you have to adhere to the same origin policy.
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.
One way to solve it is using jsonp.
As it's been said, your problem is that your browser sees this as a cross domain request. Another way to accommodate this is to set up a crossdomain.xml file like this:
<?xml version="1.0"?>
<!DOCTYPE cross-domain-policy SYSTEM "http://www.macromedia.com/xml/dtds/cross-domain-policy.dtd">
<cross-domain-policy>
<allow-access-from domain="myhost.com" />
<allow-access-from domain="ourhost.com" />
<site-control permitted-cross-domain-policies="master-only" />
</cross-domain-policy>
I'm not an expert on this method, but I have used it successfully. Other domains can be added by adding more allow-access-from tags. You may need to do some fiddling. YMMV.