How to get a json response from yaler - javascript

I create an account with yaler, to comunicate with my arduino yun. It works fine, and i'm able to switch on and off my leds.
Then i created a web page, with a button that calls an ajax function with GET method to yaler (yaler web server accept REST style on the URL)
$.ajax({
url: "http://RELAY_DOMAIN.try.yaler.net/arduino/digital/13/1",
dataType: "json",
success: function(msg){
var jsonStr = msg;
},
error: function(err){
alert(err.responseText);
}
});
This code seem to work fine, infact the led switches off and on, but i expect a json response in success function (msg) like this:
{
"command":"digital",
"pin":13,
"value":1,
"action":"write"
}
But i get an error (error function). I also tried to alert the err.responseText, but it is undefined....
How could i solve the issue? Any suggestions???
Thanks in advance....

If the Web page containing the above Ajax request is served from a different origin, you'll have to work around the same origin policy of your Web browser.
There are two ways to do this (based on http://forum.arduino.cc/index.php?topic=304804):
CORS, i.e. adding the header Access-Control-Allow-Origin: * to the Yun Web service
JSONP, i.e. getting the Yun to serve an additional JS function if requested by the Ajax call with a query parameter ?callback=?
CORS can probably be configured in the OpenWRT part of the Yun, while JSONP could be added to the Brige.ino code (which you seem to be using).

I had the same problem. I used JSONP to solve it. JSONP is JSON with padding. Basically means you send the JSON data with a sort of wrapper.
Instead of just the data you have to send a Java Script function and this is allowed by the internet.
So instead of your response being :
{"command":"digital","pin":13,"value":0,"action":"write"}
It should be:
showResult({command:"analog",pin:13,value:0,action:"write"});
I changed the yunYaler.ino to do this.
So for the html :
var url = 'http://try.yaler.net/realy-domain/analog/13/210';
$.ajax({
type: 'GET',
url: url,
async: false,
jsonpCallback: 'showResult',
contentType: "application/json",
dataType: 'jsonp',
success: function(json) {
console.dir(json.action);
},
error: function(e) {
console.log(e.message);
}
});
};
function showResult(show)
{
var str = "command = "+show.command;// you can do the others the same way.
alert (str);
}
My JSON is wrapped with a showResult() so its made JSONP and its the function I called in the callback.
Hope this helps. If CORS worked for you. Could you please put up how it worked here.

Related

How to Get Response From rest URL using jquery

I have a URL https://aua.maharashtra.gov.in/aua/rest/checkauastatus
When I visit the URL in a browser, I get an XML response. I want to collect that response in a String using Javascript or jQuery. I tried many things but nothing worked.
Please help me to get that response in a String.
Try this:
$.ajax({
type:'POST',
url:'https://aua.maharashtra.gov.in/aua/rest/checkauastatus',
success: function(response)
{
alert(response);
}
Just see if your expected reponse is coming or not.
Hope this helps.
If you are trying to make a request to other domains, use the below code for reference.
$.ajax({
url: 'https://aua.maharashtra.gov.in/aua/rest/checkauastatus',
dataType: 'jsonp',
jsonpCallback: 'dataResult',
jsonp: 'callback',
});
function dataResult(data) {
//Access your data here.
};
If you are calling ajax with different domain , then ajax will not work, You have to call your server and collect data. For e.g using curl, then return as response. You can also use jsonp if it supports.

Ajax response with JSONP, can see result cannot use it

I have the following javascript:
jQuery(document).ready( function($) {
var id = "123";
var api = "example.com:8999/".concat(id)
$.ajax({
url : api,
type: 'GET',
dataType: 'jsonp',
// jsonpCallback: "localcallback",
success: function (data) { alert('success'); }
})
});
I can see the response in chrome dev tools, but the alert isn't getting called. Ultimately I need to work with this response to set the value of a div.
Image of chrome tools:
Thanks
EDIT: Put 'POST', was using 'GET', still not working. Also, I think I'd prefer "mom and pop" json, but due to CORS and the fact I'm not good with the web and am just trying to hack this together.
Your server is not returning JSONP. It's returning plain JSON. If you specify JSONP, then the server must explicitly create a JSONP formatted response or the ajax response will not be received and processed properly.
FYI, a JSONP request is sent via a script tag (that's how it gets around the same-origin limitation for cross domain requests) and the response has to be formatted as a script that calls a function and passed the requested data to that function. You can read about how JSONP works here.
Just make your ajax call without specifying the 'dataType' attribute, then control should come back to your success callback if your ajax call completes successfully.
FYI: jQuery will try to find the response data type based on the MIME type of that response.
Example:
$( function() {
$.ajax({
url :"http://example.com:8999/123",
type: 'GET',
success: function (data) {
console.log(data); // Prints the response on console
alert('success');
}
})
});
If you want to make this call only with JSONP then it would be better to share the reason with us, so that we can suggest a better solution if possible.

Get prayer time JSON data using JQUERY and Ajax

I want to READ JSON data using Jquery ana Ajax from this link
http://praytime.info/getprayertimes.php?lat=31.950001&lon=35.9333&gmt=180&m=3&y=2013&school=0&format=json&callback=?
and this is my code:
$(document).ready(function() {
var strUser ="http://praytime.info/getprayertimes.php?lat=31.950001&lon=35.9333&gmt=180&m=3&y=2013&school=0&format=json&callback=?";
$.ajax({
url: strUser ,
dataType: 'jsonp',
success: function(data){
jQuery.each(data, function(){
alert("yes");
});
}
});
});
I tried this code with other links , and it's correct, but from the specified link I don't get any out put, can you help me??
The url you are trying to access with JSONP doesnot support it. The server will need to return the response as JSON, but also wrap the response in the requested call back. So a way to solve this problem is using a server side proxy, which fetches the response from the specified url and passes it on to your client side js, like:
$.ajax({
type: "GET",
url: url_to_yourserverside_proxy,
dataType: "json",
success: function( data ) {
console.log(data);
}
});
where
url_to_yourserverside_proxy is a server side file that fetches response from the url specified
URL is outputting json but for cross domain need jsonp.
Not all API's provide jsonp. If cross domain API doesn't provide jsonp and isn't CORS enabled you will need to use a proxy to retrieve data due to same origin policy

jQuery $.getJSON not working

I am try to get a URL from a one server and using that URL to get contents of another server.
$.ajax({url : 'http://localhost:8080/geturl.jsp?A=1&B=2,C=3',
success : function (data)
{
alert(data);
$.getJSON(data, function (mydata)
{
alert(mydata);
});
},
error : function (data, status, xhr)
{
}
});
I know that we cannot make cross-domain requests in through ajax call, thats why i am using getJSON, i have the following problems
When i simply pass the data to the url part of getJSON (as shown in the code), the alert-box show the correct URL but no get request is being performed ( get requests were monitored from FireBug).
When a hard-code the data to be "http://www.google.com" then the get request is being performed but the no response comes, although the response headers comes and response code is 200 (but it was marked as RED in the Firebug (Dont know why :( )
When I tries to fetch a webpage host in localhost domain, then it is fetched correctly although the response was not JSON.
I have the following doubts
If the getJSON function accecpts only JSON objects as reponse then why no error came when perform above 3.
Whats the correct code to perform my the required functionality.
Suggestions to what happened in each case
Thanks in advance for the answers :)
The getJSON function can only be used across domains to fetch JSONP.
It does not magically evade any security restrictions.
http://api.jquery.com/jQuery.ajax/
This should be a working example for jsonp:
var request = jQuery.ajax(
{
url: "http://Your url",
success: function (data) { console.log('success!'); console.log(data); },
error: function (data) { console.log('error!'); console.log(data); },
dataType: "jsonp",
type: "GET",
data: { key: 'value' }
});

Calling a webservice using JQuery

I am using this code from http://www.joe-stevens.com/2010/01/04/using-jquery-to-make-ajax-calls-to-an-asmx-web-service-using-asp-net/
function callWebService(address) {
var result;
$("#result").addClass("loading");
$.ajax({
type: "POST",
url: address,
data: "{}",contentType: "application/json; charset=utf-8",
dataType: "json",
success: Success,
error: Error
});
}
function Success(data, status) {
$("#result").removeClass("loading");
$("#result").html(data.d);
alert("Success");
}
function Error(request, status, error) {
$("#result").removeClass("loading");
$("#result").html(request.statusText);
alert("Error");
}
I don't understand what is wrong with this code. It keeps returning "Error"
Also make sure that the service URL that you're trying to access is in the same domain as your site. AJAX calls won't succeed if you cross domains, since browsers subject AJAX calls to the same domain policy. Can you also include the URL you're trying to access?
If you're trying to access a resource at a different domain, you may want to consider a JSONP request instead. See the jQuery AJAX documentation for a discussion of how to use JSONP.
I think if you combine knowing the URL you're trying to access along with Justin and mohlsen's suggestions, I think we can help.
Your code looks fine at first glance.
I recommend you use FireBug to attempt to isolate the problem further, as it will allow you to see the actual HTTP requests, POSTed data, etc...
A few suggestions based on some code I have doing this. But as others have said, make sure to manually look at the data going out and coming back. Your link references asp.net webservice, is that what you are calling since you didn't mention it.
Make sure the "address" url is of the form /location/page.asmx/methodname
You might need to pass the data to the success method in the call
success: function(msg) {
//msg is a json object, .d is the data field returned by asp.net
if (msg.d.length > 0)
ProcessData(msg.d);
else
HandleError('No data was returned.');
},
error: function() {
HandleError('There was a problem calling the webservice.');
}

Categories

Resources