I am trying to integrate Yammer API in my Vue.JS project, for Http calls I am using Vue-Resource plugin. While making GET Http call to get posts from Yammer it gives me following error -
Response to preflight request doesn't pass access control check: No
'Access-Control-Allow-Origin' header is present on the requested
resource.
I tried postman tool and that gives successful response, but when I try to run the same thing in my Vue.JS project using Vue-Resource plugin it wont work.
The Vue.JS code snippet -
function(){
this.$http.get("https://www.yammer.com/api/v1/messages/my_feed.json").then((data)=>{
console.log(data);
});
In main.vue file i have -
Vue.http.interceptors.push((request, next) => {
request.headers.set('Authorization', 'Bearer my_yammer_token')
request.headers.set('Accept', '*/*')
next()
})
Then I tried the code snippets provided by Postman tool for jquery, that too not working.
jQuery code -
var settings = {
"url": "https://www.yammer.com/api/v1/messages/my_feed.json",
"method": "GET",
"timeout": 0,
"headers": {
"Authorization": "Bearer my_yammer_token",
"Cookie": "yamtrak_id=some_token; _session=some_token"
},
};
$.ajax(settings).done(function (response) {
console.log(response);
});
Though, I found similar questions but nothing worked for me.
I am working this to resolve from last 2 days but getting failed again and again. Please guide/help me.
A browser has higher security requirements than a request in PostMan. In a browser, you are only allowed to make XHR requests to your own current host (combination of domain + port) but not to other remote hosts. To nevertheless make a request to a remote host, you can use the browser built-in CORS. By using this, your browser makes a pre-flight request to the remote host to ask if the current page is allowed to request from that host. This is done via the Access-Control response headers. In your case, this header is probably missing or not allowing your page to access, which is why the request does not go through. Please read further into that topic.
However, in your case, using CORS probably won't be a solution for two reasons: To use CORS, the remote host must present a header which allows every requesting host (*) or your specific one. If you cannot set that setting anywhere on the remote host, it won't work. Second, it is not safe to place your authorization token into client-side JavaScript code. Everybody can just read your JS code and extract the authorization token. For that reason, you usually make the actual API call from the server-side and then pass the data to the client. You can use your own authentication/authorization against your server and then use the static authorization key on the server to request the data from the remote host. In that case, you'll never expose the authorization key to your user. Also, on the server-side, you do not have to deal with CORS as it works just like PostMan or curl as opposed to a browser.
So I am trying to send a GET Request in my JavaScript via AJAX. The problem is that I can send the Request in Postman and it works fine. When I use the feature to generate the AJAX code and I insert it in the my local index.html the Request seems to be blocked.
var settings = {
"async": true,
"crossDomain": true,
"url": "http://www.bibsonomy.org/api/posts?resourcetype=bookmark&group=ukp&format=json",
"method": "GET",
"headers": {
"Authorization": "Basic key",
"Cache-Control": "no-cache"
}
}
$.ajax(settings).done(function (response) {
console.log(response);
});
Console output:
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource
at https://www.bibsonomy.org/api/posts?resourcetype=bookmark&group=ukp&format=json.
(Reason: CORS header ‘Access-Control-Allow-Origin’ missing).
I have no idea why it is not working and why Postman does not get this error.
Please add Access-Control-Allow-Origin: * in the header of the request.
You should try to add this to your settings
xhrFields: {
withCredentials: true
},
crossDomain: true
This has to be handled from the server side. Only if the server adds a header that the it permits requests from localhost:port(if you are in development),
or you can add
set Access-Control-Allow-Origin: "*" for accepting requests from all clients,
browser will be able to successfully complete the request.
The cross origin validation is a browser provided security against Cross domain attacks. The browser sends a preflight (OPTIONS) request to the server to ensure the request will be a valid one, and on successful return only a valid request will be sent.
So the reliable way to fix this, is a fix in the api provider(server) to accept requests from your domain/localhost.
However you can do a work around for just your browser, you can check this answer for such a method.
I have called third party API using Jquery AJAX. I am getting following error in console:
Cross-Origin Read Blocking (CORB) blocked cross-origin response MY URL with MIME type application/json. See https://www.chromestatus.com/feature/5629709824032768 for more details.
I have used following code for Ajax call :
$.ajax({
type: 'GET',
url: My Url,
contentType: 'application/json',
dataType:'jsonp',
responseType:'application/json',
xhrFields: {
withCredentials: false
},
headers: {
'Access-Control-Allow-Credentials' : true,
'Access-Control-Allow-Origin':'*',
'Access-Control-Allow-Methods':'GET',
'Access-Control-Allow-Headers':'application/json',
},
success: function(data) {
console.log(data);
},
error: function(error) {
console.log("FAIL....=================");
}
});
When I checked in Fiddler, I have got the data in response but not in Ajax success method.
Please help me out.
dataType:'jsonp',
You are making a JSONP request, but the server is responding with JSON.
The browser is refusing to try to treat the JSON as JSONP because it would be a security risk. (If the browser did try to treat the JSON as JSONP then it would, at best, fail).
See this question for more details on what JSONP is. Note that is a nasty hack to work around the Same Origin Policy that was used before CORS was available. CORS is a much cleaner, safer, and more powerful solution to the problem.
It looks like you are trying to make a cross-origin request and are throwing everything you can think of at it in one massive pile of conflicting instructions.
You need to understand how the Same Origin policy works.
See this question for an in-depth guide.
Now a few notes about your code:
contentType: 'application/json',
This is ignored when you use JSONP
You are making a GET request. There is no request body to describe the type of.
This will make a cross-origin request non-simple, meaning that as well as basic CORS permissions, you also need to deal with a pre-flight.
Remove that.
dataType:'jsonp',
The server is not responding with JSONP.
Remove this. (You could make the server respond with JSONP instead, but CORS is better).
responseType:'application/json',
This is not an option supported by jQuery.ajax. Remove this.
xhrFields: {
withCredentials: false },
This is the default. Unless you are setting it to true with ajaxSetup, remove this.
headers: {
'Access-Control-Allow-Credentials' : true,
'Access-Control-Allow-Origin':'*',
'Access-Control-Allow-Methods':'GET',
'Access-Control-Allow-Headers':'application/json',
},
These are response headers. They belong on the response, not the request.
This will make a cross-origin request non-simple, meaning that as well as basic CORS permissions, you also need to deal with a pre-flight.
In most cases, the blocked response should not affect the web page's behavior and the CORB error message can be safely ignored. For example, the warning may occur in cases when the body of the blocked response was empty already, or when the response was going to be delivered to a context that can't handle it (e.g., a HTML document such as a 404 error page being delivered to an tag).
https://www.chromium.org/Home/chromium-security/corb-for-developers
I had to clean my browser's cache, I was reading in this link, that, if the request get a empty response, we get this warning error. I was getting some CORS on my request, and so the response of this request got empty, All I had to do was clear the browser's cache, and the CORS got away. I was receiving CORS because the chrome had saved the PORT number on the cache, The server would just accept localhost:3010 and I was doing localhost:3002, because of the cache.
Return response with header 'Access-Control-Allow-Origin:*'
Check below code for the Php server response.
<?php header('Access-Control-Allow-Origin: *');
header('Content-Type: application/json');
echo json_encode($phparray);
You have to add CORS on the server side:
If you are using nodeJS then:
First you need to install cors by using below command :
npm install cors --save
Now add the following code to your app starting file like ( app.js or server.js)
var express = require('express');
var app = express();
var cors = require('cors');
var bodyParser = require('body-parser');
//enables cors
app.use(cors({
'allowedHeaders': ['sessionId', 'Content-Type'],
'exposedHeaders': ['sessionId'],
'origin': '*',
'methods': 'GET,HEAD,PUT,PATCH,POST,DELETE',
'preflightContinue': false
}));
require('./router/index')(app);
It's not clear from the question, but assuming this is something happening on a development or test client, and given that you are already using Fiddler you can have Fiddler respond with an allow response:
Select the problem request in Fiddler
Open the AutoResponder tab
Click Add Rule and edit the rule to:
Method:OPTIONS server url here, e.g. Method:OPTIONS http://localhost
*CORSPreflightAllow
Check Unmatched requests passthrough
Check Enable Rules
A couple notes:
Obviously this is only a solution for development/testing where it isn't possible/practical to modify the API service
Check that any agreements you have with the third-party API provider allow you to do this
As others have noted, this is part of how CORS works, and eventually the header will need to be set on the API server. If you control that server, you can set the headers yourself. In this case since it is a third party service, I can only assume they have some mechanism via which you are able to provide them with the URL of the originating site and they will update their service accordingly to respond with the correct headers.
If you are working on localhost, try this, this one the only extension and method that worked for me (Angular, only javascript, no php)
https://chrome.google.com/webstore/detail/moesif-orign-cors-changer/digfbfaphojjndkpccljibejjbppifbc/related?hl=en
In a Chrome extension, you can use
chrome.webRequest.onHeadersReceived.addListener
to rewrite the server response headers. You can either replace an existing header or add an additional header. This is the header you want:
Access-Control-Allow-Origin: *
https://developers.chrome.com/extensions/webRequest#event-onHeadersReceived
I was stuck on CORB issues, and this fixed it for me.
have you tried changing the dataType in your ajax request from jsonp to json? that fixed it in my case.
There is an edge case worth mentioning in this context: Chrome (some versions, at least) checks CORS preflights using the algorithm set up for CORB. IMO, this is a bit silly because preflights don't seem to affect the CORB threat model, and CORB seems designed to be orthogonal to CORS. Also, the body of a CORS preflight is not accessible, so there is no negative consequence just an irritating warning.
Anyway, check that your CORS preflight responses (OPTIONS method responses) don't have a body (204). An empty 200 with content type application/octet-stream and length zero worked well here too.
You can confirm if this is the case you are hitting by counting CORB warnings vs. OPTIONS responses with a message body.
It seems that this warning occured when sending an empty response with a 200.
This configuration in my .htaccess display the warning on Chrome:
Header always set Access-Control-Allow-Origin "*"
Header always set Access-Control-Allow-Methods "POST,GET,HEAD,OPTIONS,PUT,DELETE"
Header always set Access-Control-Allow-Headers "Access-Control-Allow-Headers, Origin,Accept, X-Requested-With, Content-Type, Access-Control-Request-Method, Access-Control-Request-Headers, Authorization"
RewriteEngine On
RewriteCond %{REQUEST_METHOD} OPTIONS
RewriteRule .* / [R=200,L]
But changing the last line to
RewriteRule .* / [R=204,L]
resolve the issue!
I have a similar problem. My case is because the contentType of server response is application/json, rather than text/javascript.
So, I solve it from my server (spring mvc):
// http://127.0.0.1:8080/jsonp/test?callback=json_123456
#GetMapping(value = "/test")
public void testJsonp(HttpServletRequest httpServletRequest,
HttpServletResponse httpServletResponse,
#RequestParam(value = "callback", required = false) String callback) throws IOException {
JSONObject json = new JSONObject();
json.put("a", 1);
json.put("b", "test");
String dataString = json.toJSONString();
if (StringUtils.isBlank(callback)) {
httpServletResponse.setContentType("application/json; charset=UTF-8");
httpServletResponse.getWriter().print(dataString);
} else {
// important: contentType must be text/javascript
httpServletResponse.setContentType("text/javascript; charset=UTF-8");
dataString = callback + "(" + dataString + ")";
httpServletResponse.getWriter().print(dataString);
}
}
Response headers are generally set on the server. Set 'Access-Control-Allow-Headers' to 'Content-Type' on server side
I had the same problem with my Chrome extension. When I tried to add to my manifest "content_scripts" option this part:
//{
// "matches": [ "<all_urls>" ],
// "css": [ "myStyles.css" ],
// "js": [ "test.js" ]
//}
And I remove the other part from my manifest "permissons":
"https://*/"
Only when I delete it CORB on one of my XHR reqest disappare.
Worst of all that there are few XHR reqest in my code and only one of them start to get CORB error (why CORB do not appare on other XHR I do not know; why manifest changes coused this error I do not know). That's why I inspected the entire code again and again by few hours and lost a lot of time.
I encountered this problem because the format of the jsonp response from the server is wrong. The incorrect response is as follows.
callback(["apple", "peach"])
The problem is, the object inside callback should be a correct json object, instead of a json array. So I modified some server code and changed its format:
callback({"fruit": ["apple", "peach"]})
The browser happily accepted the response after the modification.
Try to install "Moesif CORS" extension if you are facing issue in google chrome. As it is cross origin request, so chrome is not accepting a response even when the response status code is 200
I have a REST api made in Laravel 5.1 hosted in a remote server. Now, I', trying to consume that API from another website (that I have in local).
In Laravel I set the required lines to send the CORS headers. I also tested the API using Postman and everything seems to be ok!
In the Frontend
Then, in the website I sent the POST request using ajax, with this code:
var url="http://xxx.xxx.xxx.xxx/apiLocation";
var data=$("#my-form").serialize();
$.ajax({
type: "POST",
url: url,
data: data,
headers: { 'token': 'someAPItoken that I need to send'},
success: function(data) {
console.log(data);
},
dataType: "json",
});
Buy then I get this error in the console:
XMLHttpRequest cannot load http://xxx.xxx.xxx.xxx/apiLocation.
Response to preflight request doesn't pass access control check: No
'Access-Control-Allow-Origin' header is present on the requested
resource. Origin 'http://localhost' is therefore not allowed access.
In the Backend
In the API I set this (using a Laravel Middleware to set the headers):
return $next($request)
->header('Access-Control-Allow-Origin', '*')
->header('Access-Control-Allow-Methods', 'GET, POST, PUT, DELETE, OPTIONS');
So, I'm confused about where is exactly the problem.
In the server? but then why with Postman work fine?
Is in the Ajax call? so, then what should I add?
Your backend code must include some explicit handling for OPTIONS requests that sends a 200 response with just the configured headers; for example:
if ($request->getMethod() == "OPTIONS") {
return Response::make('OK', 200, $headers);
}
The server-side code also must send an Access-Control-Allow-Headers response header that includes the name of the token request header your frontend code is sending:
-> header('Access-Control-Allow-Headers', 'token')
but then why with Postman work fine?
Postman isn’t a web app and isn’t bound by same-origin restrictions placed on web apps by browsers to block them from making cross-origin requests. Postman is a browser bolt-on for convenience of testing requests in the same way they could be made outside the browser using curl or whatever from the command line. Postman can freely make cross-origin requests.
https://developer.mozilla.org/docs/Web/HTTP/Access_control_CORS in contrast explains how browsers block web apps from making cross-origin requests but also how you can un-block browsers from doing that by configuring your backend to send the right CORS headers.
https://developer.mozilla.org/docs/Web/HTTP/Access_control_CORS#Preflighted_requests explains why the browser is sending that OPTIONS request your backend needs to handle.
This question has been asked a few times and answered as well, however I am trying to implement the suggested approach but going nowhere. Its a typical CORS issue. Except in my case I want to be able to use localhost or my pc IP on the browser. If my config has been set to use IP, using localhost gives me the CORS error and vice versa. Any guidance is appreciated.
Note: Please ignore different ip addresses in my screenshot and text.
Failed to load resource: the server responded with a status of 405 (Method Not Allowed)
localhost/:1 XMLHttpRequest cannot load http://192.168.1.2/ARES/store/1.0/core/rest/authenticate/-99/-99. Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost' is therefore not allowed access. The response had HTTP status code 405.
My code is as below: I cant find a way to set the header correctly to us Allow-Origin.
Ext.Ajax.request({
url: url,
timeout: 2000,
cors: true,
method: 'GET',
headers: {
'Access-Control-Allow-Origin': 'http://localhost/'
},
success: function(response, options) {
Ext.getBody().unmask();
Manager.app.fireEvent('showLoginView');
},
failure: function(response, options) {
Ext.getBody().unmask();
}
});
When I run it in the browser I see Request Headers as below:
or simply create shortcut for chrome with
"C:\Program Files (x86)\Google\Chrome\Application\chrome.exe" --disable-web-security
this will open chrome with disable-web-security flag and your request will reach server without problem or additional "OPTIONS" methods
From Mozilla Developer Network:
The Cross-Origin Resource Sharing standard works by adding new HTTP headers that allow servers to describe the set of origins that are permitted to read that information using a web browser.
Emphasis by me.
You won't be able to set CORS headers client side, because they are a means against client-side exploitation. Any user will be able to mess with your client side code, so every security measure has to be server-side.
The header you use, Access-Control-Allow-Origin, is to be used as a HTTP response header, not a request header. The answer how to implement it correctly heavily depends on the backend language/framework used, which you should make a different question.
But if I understand your question correctly, you are only working on localhost AKA 192.168.x.y and you only have issues with "cross-site requests" between hostname and IP. Using a relative URL should be the solution. Instead of url:"http://localhost/ARES/store/1.0/core/rest/authenticate/-99/-99" or url:"http://192.168.1.2/ARES/store/1.0/core/rest/authenticate/-99/-99", you should use url:"../ARES/store/1.0/core/rest/authenticate/-99/-99".
It is done on the webservice end: This is how I achieved it: Following code goes in the Global.asax file. Hope it helps someone.
protected void Application_BeginRequest(object sender, EventArgs e)
{
HttpContext.Current.Response.AddHeader("Access-Control-Allow-Origin", "*");
if (HttpContext.Current.Request.HttpMethod == "OPTIONS")
{
//These headers are handling the "pre-flight" OPTIONS call sent by the browser
HttpContext.Current.Response.AddHeader("Access-Control-Allow-Methods", "GET, POST, OPTIONS,PUT, DELETE");
HttpContext.Current.Response.AddHeader("Access-Control-Allow-Headers", "Content-Type, Accept");
HttpContext.Current.Response.AddHeader("Access-Control-Max-Age", "1728000");
HttpContext.Current.Response.End();
}
}