I need a request to be sent to an external website with the html back. I then need to extract the text within <td></td>. I am completely new to JSON, and am unsure if it's possible to do this using ajax.
Please could someone point me in the right direction and/or give example code.
You can't directly make a request to an external site via JS and read HTML from it. It's forbidden by the same origin policy. Either the external site has to support you by offering something like JSONP or CORS (not supported by all browsers yet), or you'll have to proxy the request via your own server.
Related
I am trying to hit USPS address validation API by AJAX call and I am getting 'Cross-Origin Request Blocked' error.
However when I am trying to access the same address though URL, I am getting the results.
Has this error something to do with approval thing?
The id I am using for this has been approved and I am able to get the result by the API through URL.
I want to access it though scripting. Please help.
Any help would be appreciated.
Thanks in advance.
I think the way you might want to do this is to have the Ajax requests go to your web server -- the same HTTP server where the page came from. And then your server-side program (in PHP, or Python or whatever you're using) relays the request to the USPS server.
Making the request browser-side, from Ajax directly to the USPS server, is just the kind of suspicious activity (called Cross-Site Scripting) that browsers are learning to block.
CORS could theoretically be one way to unblock a Cross-Origin Request, but in that scheme it would be the USPS API server that ultimately grants that permission for pages from your domain. Tech detail: by inserting an Access-Control-Allow-Origin header in response to a request with an Origin header in the Ajax back-and-forth.
I am trying to implement OAUTH for accessing Flickr APIs. My AJAX call to flickr.com keeps failing.
Sample Error Message:
XMLHttpRequest cannot load http://www.flickr.com/services/oauth /request_token?oauth_callback=oob&oauth…signature_method=HMAC-SHA1&oauth_timestamp=1368375405647&oauth_version=1.0. Origin http://localhost:8080 is not allowed by Access-Control-Allow-Origin.
Initially I used chrome and read the html file as file://path. I used to get the error 'null not allowed by access-control-allow-origin'. I solved this problem by copying the html file to 'local IIS server', 'local python webserver' and then a 'remote webserver'. I created python web server using > python -m http.server 8080'
I realize my cross browser call to flickr.com using XMLHttpRequest is failing. I tried by various solutions suggested in this forum:
Using newer Chrome 26.0.1410.64 m, which I guess supports CORS
I launched chrome with --disable-web-security
I created a web server using python -m http.server 8080 on local machine and then on a remote machine and copied the html file to the site
I copied file to a local MSFT IIS server
I defined URL in etc/hosts file to avoid numeric IP
I still get the same error (with relevant URL in the error message)
code clipping:
urlString="http://www.flickr.com/services/oauth/request_token?"+
"oauth_callback="+"oob"+'&'+
"oauth_consumer_key="+consumerKey+'&'+
"oauth_nonce="+nonce+'&'+
"oauth_signature="+esignature+'&'+
"oauth_signature_method="+macAlgorithm+'&'+
"oauth_timestamp="+timeStamp+'&'+
"oauth_version=1.0";
$.ajax({
url: urlString,
success:function(data){
alert(data);
}
});
In order to CORS work, both ends must enable it.
The first end is the browser, and, as you are using Chrome 26.*, yours is ok.
The second end is the server:
Before making a GET request to a domain different than the one the page is on, the browser sends an OPTIONS request to that domain. In response to this request, the server should include some headers that tell if a cross-domain request (GET, POST or other) is allowed.
One of those headers is Access-Control-Allow-Origin.
So when you run your page from your file system (file:// "protocol"), the OPTIONS means something like "Flickr, can I make a cross-domain call to you? I'm calling from null". Flickr does not recognize that domain as allowed and returns the error you are getting.
Same way, when you run your page from your local server, the OPTIONS says "(...) I'm calling from localhost:8080". Flickr does not recognize that domain as allowed as well.
The solution:
I don't know the Flickr oauth service, but I know that, as any other service, to make a CORS call to it, the page must be in a domain allowed by it. From your tests, I'm guessing Flickr does't allow many other domains.
But... an alternative to CORS is JSONP. I did a little research, Flickr oauth seems to support it.
Check this page for details: http://www.flickr.com/services/api/explore/flickr.auth.oauth.getAccessToken
There's another question talking about that specific subject:
Is JSONP supported in the new Flickr OAuth API?
About JSONP, this can get you started: How to make a JSONP request from Javascript without JQuery?
It is not possible to implement Oauth 1.0 through just javascript without any server side script. Since the flickr's new authentication process is based on Oauth 1.0a. You got to use a server-side script.
I tried to send the token request using JSONP in FireFox with CORS on(using a third-party add-on) and it worked fine. But without using any add-ons, it's not possible as the response from flickr is in text format(not in a JSON format) and the request fails.
You can either use server-side code for token request. OR Use the deprecated flickr API for authentication.
I am trying to post to a server listening on a different port, but FireFox insists on sending an OPTIONS request because apparently I am not using the proper URL. How can I POST to localhost:8161 without FireFox thinking the request might be cross domain and sending OPTIONS?
Here you have an answer:
How do I send a cross-domain POST request via JavaScript?
It is not easy to detail it in a better way.
You can add iframe whose src contains url with different port
Given all the coverage FireSheep has been getting, I have been trying to work out the best practices for balancing HTTP / HTTPS usage for some sites I manage (e.g. blogging sites, magazine sites with user contributed comments).
To me, its over kill to deliver all pages over HTTPS if the user is logged in. If a page is public (e.g. a blog) there is little point encrypting the public page. All I want to do is prevent session hijacking by sniffing cookies over HTTP channels.
So, one plan is:
Login form is over HTTPS
Issue two cookies: One cookie is 'public' and identifies there user for read only aspects (e.g. 'welcome bob!'). The second cookie is private and 'HTTPS only'. This is the cookie that is verified whenever the user makes a change (e.g. adds a comment, deletes a post).
This means that all 'changing' requests must be issued over HTTPS.
We use a lot of AJAX. Indeed, many comment forms use AJAX to post the content.
Obviously, I cant use AJAX directly to post content to a HTTPS backend from a HTTP frontend.
My question is: Can I use script injection (I think this is commonly called 'JSONP'?) to access the API? So in this case there would be a HTTP public page that sends data to the private backend by injecting a script accessed via HTTPS (so that the private cookie is visible in the request).
Can you have HTTPS content inside a HTTP page? I know you get warnings the other way around, but I figure that HTTPS inside HTTP is not a security breach.
Would that work? It seems to work in chrome and FF, but its IE that would be the party pooper!
Another way is to have an iframe which points to a https page that can make all kinds (GET, POST, PUT etc) of Ajax calls to the server over https (same domain as iframe is on https too). Once the response is back inside the iframe, you can post a message back to the main window using HTML5 postMessage API.
Pseudo code:
<iframe src="https://<hostname>/sslProxy">
sslProxy:
MakeAjaxyCall('GET', 'https://<hostname>/endpoint', function (response) {
top.postMessage(response, domain);
});
This works in all modern browsers except IE <= 7 for which you'll have to either resort to JSONP or cross domain communication using Flash.
The problem with JSONP is that you can only use it for GETs.
Can you have HTTPS content inside a
HTTP page? I know you get warnings the
other way around, but I figure that
HTTPS inside HTTP is not a security
breach.breach.
Including HTTPS content inside a regular HTTP page won't raise any alerts in any browser.
However, I don't think JSONP will help you out of this one. Using GETs to post content and modify data is a very bad idea, and prone to other attacks like CSFR
I want to use mootools and SqueezBox class to handle a request to a RESTful service. I don't want to use any server-side script. I am using AJAX. I send a request to the following url using GET method.
http://www.idevcenter.com/api/v1/links/links-upcoming.json
but I receive a 404 error. Is it because cross-site scripting? here is my code:
SqueezeBox.initialize({handler:'url',ajaxOptions:{method:'GET'}});
$('a.modal').addEvent('click',function(e){
new Event(e).stop();
SqueezeBox.fromElement($('a.modal'));
});
In Firebug console, sometimes 'aborted' is shown and sometimes '404'.what is wrong with that?
XMLHttpRequest is subject to the Same Origin Policy; if the document your JavaScript is running within is not from the same origin as the service you're trying to call, the call will be disallowed for security reasons.
There is now a proposed standard for cross-origin resource sharing to address this. It may be that the service you're trying to use supports it; if so, using a browser that implements CORS (recent versions of Firefox and Chrome do, as do some others) may work. IE8 supports it but requires that you do extra work.
You cannot use XMLHttpRequest (that is, ordinary "ajax") to call a service on a server that is not in your domain.
You can, however, use the JSONP trick, which takes advantage of the fact that the browser will load Javascript from other domains. However, the service has to know that you're going to do that, and it has to understand the protocol. That particular service seems perfectly willing to give me a JSON response, but it doesn't pay attention when I give it a "callback" parameter. (I've tried both "callback" and "jsonp" and the JSON blob that comes back is the same, without a function call wrapper.)