I am working on a web crawler that can integrate with our partner portals and submit post requests to make bid changes.
The trouble is that the crawler runs in an environment which cannot execute jQuery, only native Javascript.
I have determined that the following AJAX code successfully sends the post request:
$.ajax({
type: "POST",
url: "http://acp.example.com/campaigns/122828",
data: "data-string"
});
Is there a way to translate the above statement into native javascript so that the crawler can execute it?
UPDATE
When executing hex494D49's native Javascript below, I am receiving a "NetworkError: 404 Not Found - http://acp.fyber.com/campaigns/122828" message.
However, when I execute the original AJAX code in firebug, it successfully sends the POST request.
Any idea why the same url would return a 404 error using native Javascript as opposed to AJAX?
Thanks
Sending AJAX request using POST method
var xhr = new XMLHttpRequest();
var url = "url";
var data = "email=hey#mail.com&password=101010";
xhr.open("POST", url, true);
xhr.setRequestHeader("Content-type","application/x-www-form-urlencoded");
xhr.onreadystatechange = function () {
if (xhr.readyState == 4 && xhr.status == 200) {
// do something with response
console.log(xhr.responseText);
}
};
xhr.send(data);
Sending AJAX request using GET method
xhr = new XMLHttpRequest();
var url = "url?email=hey#mail.com&password=101010";
xhr.open("GET", url, true);
xhr.onreadystatechange = function () {
if (xhr.readyState == 4 && xhr.status == 200) {
// do something with response
console.log(xhr.responseText);
}
}
xhr.send();
To avoid unexpected requests to the server, it's a good practice to use encodeURIComponent() method on any user-entered parameters that will be passed as part of a URI.
Related
What my purpose is below
Visting a web and the js.file in this web will load php file, and it will return data to html.
It's meaning every time when I reload web, I will get newest data.
I have try this in js.file
let XML = new XMLHttpRequest();
XML.open('post', url, true);
XML.send('mydata');
then use responseText to get data I want
Indeed, I don't need send any data.
I can do what I want to do, but I am not sure this way is right or not.
Because I think ajax should not use in this case, it must be send something and return something.
What you are saying is you only want to get data without sending anything which is called a http get request, you can do that as below.
function get(url)
{
var xm = new XMLHttpRequest();
// false for synchronous
xm.open("GET",url,false);
xm.send(null);
return xm.responseText;
}
console.log(get('your Url'));
You need to specify the url of your Http Endpoint ( Back-End ).
If your are making a asynchronous request then below code works,,
function get(theUrl, callback)
{
var xmlHttp = new XMLHttpRequest();
xmlHttp.onreadystatechange = function() {
if (xmlHttp.readyState == 4 && xmlHttp.status == 200)
callback(xmlHttp.responseText);
}
// true for asynchronous
xmlHttp.open("GET", theUrl, true);
xmlHttp.send(null);
}
get('your url',(responseText)=>{
console.log(responsetext);
});
I'm trying to make a call to the Yelp API from JavaScript, but getting an error. Below is my code. I believe I will have to use Oauth, but I don't know where should I put it in the header.
function doAjax(){
var xhr = new XMLHttpRequest();
var url = "http://api.yelp.com/v2/searchterm=cream+puffs&location=chicago";
xhr.onreadystatechange = function(){
if(xhr.readyState == 4 && xhr.status == 200){
var some = JSON.parse(xhr.responseText);
}
}
xhr.open('GET', url, true);
xhr.send();
}
The problem is that you are trying to access a resource that is on a different domain from your application. In this case your application resides on http://fiddle.jshell.net and the resource is at http://api.yelp.com.
CORS is one way to get around this, see here:
http://en.wikipedia.org/wiki/Cross-origin_resource_sharing
I am working on a small project using Node.js.
The objective is to send an HTTP Request to an array of websites and display what they return to me.
First someone helped me to figure out that I needed a specific Node.js module (XMLHttpRequest). So I "required" it after installing it with NPM. Then I instantiate it.
var XMLHttpRequest = require("xmlhttprequest").XMLHttpRequest;
var xmlHttp = new XMLHttpRequest();
xmlHttp.open( "GET", theUrl, false );
//I don't think I need this
xmlHttp.send(null);
//Log some stuff to the console, namely the "response"
console.log(xmlHttp.responseText);
console.log(xmlHttp.statusText);
console.log("Finished!");
Now I believe what this will do is send a GET message to "theUrl", and then save the response in the xmlHttp Object's responseText member.
So now I should have a response. I should be able to print that as text (console.log(xmlHttp.responseText);). What should be in this response?
I expect to get something like "200 OK" but that is nowhere in the response I get. Am I going about this in the right way?
I plan on using the Async Node.js module to send a request like this to an array of URLs, trim up their response (name of the website name, the response status code, and each of the response headers).
You can use below;
var XMLHttpRequest = require("xmlhttprequest").XMLHttpRequest;
var xhr = new XMLHttpRequest();
xhr.onreadystatechange = function() {
if (this.readyState == 4) {
// responseText => response body as string
// status => 200 is OK, 404 page not found
}
};
xhr.open("GET", "yor_url");
xhr.send();
responseText: response body as string
status: 200 is OK, 404 page not found
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.
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.