I'm making a widget on iphone but I can't get data from the url.
On IE, I can get data. However, on chrome and on iphone I can't get the data but it only shows undefined instead of data.
function a() {
var url="www.xxx.xxx";
var request = new XMLHttpRequest();
request.open('GET', url, false);
request.send();
xmlDoc = request.responseXML;
}
please help me!! I'm really appreciated for any answers.
Create a function something like below,to receive the data from server.
request.onreadystatechange = function(){
if(request.readyState == 4){
console.log(request.responseText);
}
}
Please make sure that you are making request from the same Origin. That means if you are in site www.abc.com then you can make request for www.abc.com/download/ or www.abc.com/site and so on. But if you request for www.gdb.com then it will probably fail with this error in your console "No 'Access-Control-Allow-Origin' header is present on the requested resource." The browser prevents this activity for security reasons. It needs to be on the same domain.
Try using JQuery sometimes. It's API is very easy to use and is very helpful for doing tasks. You will need to add the script to the page first like this:
<script src="//code.jquery.com/jquery-1.11.2.min.js"></script>
You can download the script or use the live version and link to it like above.
Next you can make a call like this to make a GET request. Observer that it returns data when successful. This makes your job easy but remember you need to make call from same domain.
$.ajax({
type: "GET",
url: "http://wwww.something.com"
})
.done(function( data ) {
alert(data);
})
.fail( function(xhr, textStatus, errorThrown) {
alert(xhr.responseText);
});
To know more about Cross Site HTTP Requests: CORS
Here is a thread that may help you to understand better: “No 'Access-Control-Allow-Origin'
would setting the responseType work?
call the request.responseType = 'document'; before send.
Related
I have a webpage in which I need to just get the raw data of a specified pastebin file, let's just say http://pastebin.com/qnNPx6G9, and store it as a variable. I've tried many, many, many variations on xml and ajax requests, but nothing works. Here's what I've tried. What am I doing wrong?
I've tried with Ajax:
$.ajax({
url: "http://pastebin.com/api/api_post.php",
type: "GET",
dataType: "x-www-form-urlencoded",
data: {
"api_dev_key": "mydevkey",
"api_option": "paste",
"api_paste_code": "blah blah"
},
success: function(res) {
alert(JSON.stringify(res));
},
error: function(res) {
alert(JSON.stringify(res));
}
});
//this is in the form of create paste, because I was seeing if it would work where get did not- it didn't.
And with regular XMLHttpRequest:
var xhr = new XMLHttpRequest();
xhr.open('POST'/*also tried GET*/, 'http://pastebin.com/raw/qnNPx6G9', true); //I've also tried /raw.php?i=qnNPx6G9
xhr.onreadystatechange = function() {
if (xhr.readyState == 4) {
alert(this.responseText);
}
};
xhr.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
xhr.send("api_option=trends&api_dev_key=DEVKEY");
//I tried trends because creating a paste and getting a paste didn't work.
Please help! I'm sorry if this is a stupid question or anything is unclear, I'm not that good at understanding APIs. Thanks!
And no, I can't use PHP.
You are trying to make a CORS request that pastebin obviously doesn't allow as console shows up this error:
No 'Access-Control-Allow-Origin' header is present on the requested
resource.
I think your only option is to use a server-side programming language in order to access pastebin remotely, CORS requests are only allowed just in the case the where remote server authorised it, else you have no way to bypass it.
Read more about CORS here
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 need to call OpenMRS REST API from Java script to get data from OpenMRS. Below is my java script code:
function myfunction(){
var xhr = new XMLHttpRequest();
xhr.open("GET", "http://localhost:8081/openmrs-standalone/ws/rest/v1/person?q=John", false);
xhr.setRequestHeader("Authorization: Basic YWRtaW46QWRtaW4xMjM");
xhr.send("");
alert(xhr.status);
}
Where YWRtaW46QWRtaW4xMjM is my base64 coded username:password as explained here. If I do not put the authorization line in the code and check the web app using Firebug, it returns 401 unauthorized status that is expected. But if I put the authorization, nothing is returned and in firebug I do not see any response as well. If I check the URL directly on browser, the page asks for username and password and after giving correct credential, it returns the data normaly. So I am getting some problem of providing the http authentication right from the java script of the app. I have also considered the methods explained here but no luck. Can anyone please help me to authorize the http request right from the javascript?
Here is another similar but different example of how to set the header for authorization purposes, but instead using JQuery and AJAX.
var token = "xyz"
var url = "http://localhost:8081/openmrs-standalone/ws/rest/v1/person?q=John"
$.ajax({
url: url,
beforeSend: function(xhr) {
xhr.setRequestHeader("Authorization", "Bearer " + token)
},
})
.done(function (data) {
$.each(data, function (key, value) {
// Do Something
})
})
.fail(function (jqXHR, textStatus) {
alert("Error: " + textStatus);
})
Below is also an example of how you might get an access token using xhr instead of AJAX.
var data = "grant_type=password&username=myusername#website.com&password=MyPassword";
var xhr = new XMLHttpRequest();
xhr.withCredentials = true;
xhr.addEventListener("readystatechange", function () {
if (this.readyState === 4) {
console.log(this.responseText);
}
});
xhr.open("POST", "https://somewebsite.net/token");
xhr.setRequestHeader("cache-control", "no-cache");
xhr.setRequestHeader("client_id", "4444-4444-44de-4444");
xhr.send(data);
Beware of cross-site domain requests(if you're requesting a token that's not on localhost or within the domain that you are currently working in), as you'll need CORS for that. If you do run into a cross-domain issue, see this tutorial for help, and be sure you have enabled CORS requests from the API as well.
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.
Summary: Keep getting null response despite public data and setting callback to enable cross domain JSON. Please help!
A similar question has been answered here
Using the new facebook graph api, ajax calls returns null (empty)
but I'm not using jquery and have tried to adapt my code to reflect that answer.
I'm trying to use a simple example to test a simple xmlhttprequest handler. I have this link in my page:
<a href='javascript:loadXMLDoc(\"https://graph.facebook.com/btaylor?callback=methodname\",\"\")'>AJAX LINK</a>
The callback=methodname parameter is to enable cross domain JSON
I'm using a generic XMLhttprequest builder:
var req; // Request object
function loadXMLDoc(url,params){
// branch for native XMLHttpRequest object
if (window.XMLHttpRequest) {
req = new XMLHttpRequest();
req.onreadystatechange = processReqChange;
req.open("GET", url, true);
req.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
req.setRequestHeader("Content-length", params.length);
req.setRequestHeader("Connection", "close");
req.send(params);
// branch for IE/Windows ActiveX version
} else if (window.ActiveXObject) {
req = new ActiveXObject("Microsoft.XMLHTTP");
if (req) {
req.onreadystatechange = processReqChange;
req.open("GET", url, true);
req.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
req.setRequestHeader("Content-length", params.length);
req.setRequestHeader("Connection", "close");
req.send(params);
}
}
}
I then have a handler :
function processReqChange(){
if (req.readyState == 4) {
if (req.status == 200) {
alert("Done");
} else {
//alert("There was a problem retrieving the data:\n" + req.statusText);
alert("Status Code = "+req.status);
alert("There was a problem retrieving the data:\n");
alert("Failed : object = "+req);
alert(req.responseXML);
alert("Failed : response = "+req.responseText);
alert("Failed : status = "+req.statusText);
}
}else{
}
}
But I keep getting a null response (statusText OK, status code 0). Any ideas?
Thanks in advance
You can't make a cross-domain ajax request. Look into whether or not they support JSONP, or use the FB.api method from their javascript SDK
http://developers.facebook.com/docs/reference/javascript/FB.api
EDIT: I didn't read your post very thoroughly when I replied.
I see that you're adding the callback name to your ajax request, which isn't going to do any good because you're still making an XHR request, so it will still fail cross-domain. You seem to be misunderstanding how JSONP works.
Normally I'd just suggest using a framework like jQuery to abstract out the work that you shouldn't have to reinvent. If you're absolutely dedicated to doing this without jQuery, start by reading the wikipedia article on how JSONP works:
http://en.wikipedia.org/wiki/JSON#JSONP
The basic idea is:
Create a script node where the src attribute looks just like the URL you're trying to request now.
The server will respond with something like : methodname({"foo": "bar"}); instead of just JSON. Since this is being requested via a script node, your browser will execute the "methodname" function and pass in the results.
implement methodname(response) function to handle the response (i.e. do the work you intended to do in processReqChange)
Remove this line and try again:
req.setRequestHeader("Connection", "close");
It sets up the connection to close automatically, often before the send is complete.