I need a script that, when user closes the page, waits few seconds (without popups) and then closes the page.
I remember seeing somewhere here a way to do this, using ajax (if I remember correctly), by running a php file and waiting the answer before closing, but I can't find it anymore. The php file contained sleep-function.
Any help is greatly appreciated
(This is used mainly to fade out text. When user comes to site text fades in via css3 transition, and when he leaves page the text fades out. I just need time for fadeout. Yes, I know this is not user-friendly but I was specially asked to do it this way)
Your probably thinking of a synchronous ajax request (which blocks the UI):
window.addEventListener('unload',function()
{
var xhr = new XMLHttpRequest();
xhr.open('GET', 'script.php?when=unload',false);//<-- false makes request synchronous
xhr.send();
},false);
But there are other ways, check this answer
On the whole, I'd not do things like this. If a site attempted to deny me the option of closing the window when I feel like it, I'd never use/visit it again. That, and the fact that your JS code is still subject to how the browser implements it, and the browser can be controlled by the client's OS. If I close the browser application, a JS event has nothing to say in that matter, especially if I terminate the browser process (using kill -9, or ctrl+alt+del).
The very least you can do is offer the client a choice, to either force-quit, or wait, explaining why you'd rather the client waited a while:
window.addEventListener('beforeunload',function u(e)
{
var forceQuit = confirm('\tDo you wish to leave Now?\n
if you do, some changes you made won\'t be saved');
if (forceQuit)
{
return e;
}
//synchronous ajax result here, or:
e.returnValue = false;
e.cancelBubble = true;
if (e.preventDefault)
{
e.preventDefault();
e.stopPropagation();
}
setTimeout(function()
{//first, remove handler, so the beforeunload's behaviour is back to default
window.removeEventListener('beforeunload',u,false);
//dispatch new beforeunload event:
window.dispatchEvent( new Event('beforeunload'));
},5000);
},false);
Have a look at jquery unload. You can bind a delay-function to the unload-event.
I just started this book - "AJAX and PHP Second edition" and I failed on the very first example.I'm pretty sure the code is just as it is shown in the book, but still when I run index.htm in the error console(Mozzila 6.0) I get this : "xmlResponse is NULL http://localhost/ajax/quickstart/quickstart.js.I don't know what's going on but really don't want to give up at the very begining so I'll pase all the 3 files and hopefully anyone would point me where the problem is.
Here is the index.htm :
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>AJAX with PHP, 2nd Edition: Quickstart</title>
<script type="text/javascript" src="quickstart.js"></script>
</head>
<body onload="process();">
Server wants to know your name:
<input type="text" id="myName" />
<div id="divMessage" ></div>
</body>
</html>
here is the quickstart.js :
// stores the reference to the XMLHttpRequest object
var xmlHttp = createXmlHttpRequestObject();
// retrieves the XMLHttpRequest object
function createXmlHttpRequestObject()
{
// stores the reference to the XMLHttpRequest object
var xmlHttp;
// if running Internet Explorer 6 or older
if(window.ActiveXObject)
{
try {
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
}
catch (e) {
xmlHttp = false;
}
}
// if running Mozilla or other browsers
else
{
try {
xmlHttp = new XMLHttpRequest();
}
catch (e) {
xmlHttp = false;
}
}
// return the created object or display an error message
if (!xmlHttp)
alert("Error creating the XMLHttpRequest object.");
else
return xmlHttp;
}
// make asynchronous HTTP request using the XMLHttpRequest object
function process(name)
{
// proceed only if the xmlHttp object isn't busy
if (xmlHttp.readyState == 4 || xmlHttp.readyState == 0)
{
// retrieve the name typed by the user on the form
name = encodeURIComponent(
document.getElementById("myName").value);
// execute the quickstart.php page from the server
xmlHttp.open("GET", "quickstart.php?name=" + name, true);
// define the method to handle server responses
xmlHttp.onreadystatechange = handleServerResponse;
// make the server request
xmlHttp.send();
}
else
// if the connection is busy, try again after one second
setTimeout('process()', 1000);
}
// callback function executed when a message is received from the
//server
function handleServerResponse()
{
// move forward only if the transaction has completed
if (xmlHttp.readyState == 4)
{
// status of 200 indicates the transaction completed
//successfully
if (xmlHttp.status == 200)
{
// extract the XML retrieved from the server
xmlResponse = xmlHttp.responseXML;
// obtain the document element (the root element) of the XML
//structure
xmlDocumentElement = xmlResponse.documentElement;
// get the text message, which is in the first child of
// the the document element
helloMessage = xmlDocumentElement.firstChild.data;
// display the data received from the server
document.getElementById("divMessage").innerHTML =
'<i>' + helloMessage
+ '</i>';
// restart sequence
setTimeout('process()', 1000);
}
// a HTTP status different than 200 signals an error
else
{
alert("There was a problem accessing the server: " +
xmlHttp.statusText);
}
}
}
and finally the quickstart.php :
<?php
// we'll generate XML output
header('Content-Type: text/xml');
// generate XML header
echo '<?xml version="1.0" encoding="UTF-8" standalone="yes"?>';
// create the <response> element
echo '<response>';
// retrieve the user name
$name = $_GET['name'];
// generate output depending on the user name received from client
$userNames = array('YODA', 'AUDRA', 'BOGDAN', 'CRISTIAN');
if (in_array(strtoupper($name), $userNames))
echo 'Hello, master ' . htmlentities($name) . '!';
else if (trim($name) == '')
echo 'Stranger, please tell me your name!';
else
echo htmlentities($name) . ', I don\'t know you!';
// close the <response> element
echo '</response>';
?>
Thanks in advanced!
Leron
There are a couple of problems I found with your code. Mentioning some of them
You are calling the process() on body-onload. This means, when the DOM is ready, the browser calls the process() function. This, IMO, is not something you would want. Instead, have a button, which calls this process function with the onclick event. Something like:
<button onclick="process('YODA');return false;">Click Me!</button>
Process is defined as taking one parameter called name, you are passing none. So, make a fix something like this:
<button onclick="myProcess();return false;">Click Me!</button>
And is your JS section/file
function myProcess(){
process(encodeURIComponent(document.getElementById('myName').value));
}
Do not have that document.getElementById(..) inside the process function. It defeats the entire purpose of passing that parameter 'name'
I would ask you to use a really good browser like Mozilla Firefox, or Google Chrome (since you seem to give IE6 a prefence in your code, atleast seems like it!). Chrome has a fantastic inspector window. Once you get the hang of it, you will almost fall in love with it. I did! ;-)
I would suggest, you use libraries like jQuery(www.jquery.com) or something, for ajax. Makes your life easier! :-)
EDIT
I would suggest the following steps, since you want to get this piece of code working.
First open the url [BASE-URL]/quickstate.php?name=YODA. If everything is just fine, you should see the XML that should be the response to your AJAX call. If not, there's some problem with the PHP file(or a few settings of your server), and not anything else. I feel this step wouldn't be a problem.
Next, once the page is loaded, type 'YODA' in the textbox, type this in the browser's URL box: javascript:process(''). This should call the function that has the ajax call. You could keep a tab on the data transferred section of the firebug(I dont know the name exactly, but its the 'Network' section in Google Chrome). You could analyse the headers sent to the PHP scripts, and the response (including the HTTP error codes) sent back to you from the server. I also feel this wont be a problem.
What causes the problem is: The DOM of the page is loaded. The AJAX call is made once the DOM is ready. This means the AJAX request is made even before you type anything in that textbox. And thus, the request that goes to the server has a empty value for name parameter. This is exactly, (IMO) the reason why things are not working for you. But even then, this is not the reason why you see a null for XML out there. Could you do a console.log(xmlHttp) and tell us the results?
That all looks correct. Where are hosting the PHP script? On a local installation of Apache, or a server you have access to? In Firefox, you can install the incredible Firebug add-on, go to the scripts tab, and see exactly what the request is returning. Whatever it is, Fx isn't recognising it as XML (hence the xmlResponse member being NULL).
I'm trying to do my own bookmarklet and I already tried to read some response in SO but nothing to answer the weird reaction I got from my script.
I'm doing an AJAX call from my bookmarklet, so I do the little trick :
var newScript = document.createElement("script");
newScript.type = "text/javascript";
newScript.src = "http://example.com/urlToMyJS.js";
document.body.appendChild(newScript);
void(0);
And the urlToMyJS.js is like this :
var u = 'http://example.com/scriptToCall.php';
var request = new XMLHttpRequest();
request.open("GET", u, true);
request.onreadystatechange = function() {
var done = 4, ok = 200;
if (request.readyState == done && request.status == ok) {
if (request.responseText) {
alert(request.responseText);
}
}
};
request.send(null);
The weird part is :
The javascript is always launched and scriptToCall.php is always called too (it logs every hit)
The alert shows the responseText when I click on the bookmarklet on example.com
Sometimes, on other sites, the alert shows nothing (but still appears)
Some other times, the alert doesn't even show... (but I still have the log hit...)
Do you have any idea why it does that? And if yes, do you have any idea how I could make it always show the responseText?
status won't be ok unless you are testing the bookmarklet on your own site (example.com).
When you run the bookmarklet on a different site to example.com (which is after all the whole point of having a bookmarklet), it will be doing a cross-origin XMLHttpRequest to example.com. Depending on what browser you're using, that might do the request, but you won't be able to read the response due to the Same Origin Policy. It's an essential security feature that you can't make user-impersonating XMLHttpRequests to other servers.
If you want to make an XMLHttpRequest back to your server, you must do it from a document on your server, typically by having the bookmarklet create an <iframe> pointing to example.com.
Alternatively, use JSONP (<script> inclusion) to call scriptToCall.php.
Well, finally, I used another trick :
var newScript = document.createElement("script");
newScript.type = "text/javascript";
newScript.src = "http://example.com/scriptToCall.php";
document.body.appendChild(newScript);
void(0);
This way (the PHP is sending a javascript header), no more AJAX. It was nonsense in my case since both file were in the same server/folder, 1 movement instead of 2!
Anyway, thanks bobince for all the details I might use in the future !
I can find lots of information on how Long Polling works (For example, this, and this), but no simple examples of how to implement this in code.
All I can find is cometd, which relies on the Dojo JS framework, and a fairly complex server system..
Basically, how would I use Apache to serve the requests, and how would I write a simple script (say, in PHP) which would "long-poll" the server for new messages?
The example doesn't have to be scaleable, secure or complete, it just needs to work!
It's simpler than I initially thought.. Basically you have a page that does nothing, until the data you want to send is available (say, a new message arrives).
Here is a really basic example, which sends a simple string after 2-10 seconds. 1 in 3 chance of returning an error 404 (to show error handling in the coming Javascript example)
msgsrv.php
<?php
if(rand(1,3) == 1){
/* Fake an error */
header("HTTP/1.0 404 Not Found");
die();
}
/* Send a string after a random number of seconds (2-10) */
sleep(rand(2,10));
echo("Hi! Have a random number: " . rand(1,10));
?>
Note: With a real site, running this on a regular web-server like Apache will quickly tie up all the "worker threads" and leave it unable to respond to other requests.. There are ways around this, but it is recommended to write a "long-poll server" in something like Python's twisted, which does not rely on one thread per request. cometD is an popular one (which is available in several languages), and Tornado is a new framework made specifically for such tasks (it was built for FriendFeed's long-polling code)... but as a simple example, Apache is more than adequate! This script could easily be written in any language (I chose Apache/PHP as they are very common, and I happened to be running them locally)
Then, in Javascript, you request the above file (msg_srv.php), and wait for a response. When you get one, you act upon the data. Then you request the file and wait again, act upon the data (and repeat)
What follows is an example of such a page.. When the page is loaded, it sends the initial request for the msgsrv.php file.. If it succeeds, we append the message to the #messages div, then after 1 second we call the waitForMsg function again, which triggers the wait.
The 1 second setTimeout() is a really basic rate-limiter, it works fine without this, but if msgsrv.php always returns instantly (with a syntax error, for example) - you flood the browser and it can quickly freeze up. This would better be done checking if the file contains a valid JSON response, and/or keeping a running total of requests-per-minute/second, and pausing appropriately.
If the page errors, it appends the error to the #messages div, waits 15 seconds and then tries again (identical to how we wait 1 second after each message)
The nice thing about this approach is it is very resilient. If the clients internet connection dies, it will timeout, then try and reconnect - this is inherent in how long polling works, no complicated error-handling is required
Anyway, the long_poller.htm code, using the jQuery framework:
<html>
<head>
<title>BargePoller</title>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.2.6/jquery.min.js" type="text/javascript" charset="utf-8"></script>
<style type="text/css" media="screen">
body{ background:#000;color:#fff;font-size:.9em; }
.msg{ background:#aaa;padding:.2em; border-bottom:1px #000 solid}
.old{ background-color:#246499;}
.new{ background-color:#3B9957;}
.error{ background-color:#992E36;}
</style>
<script type="text/javascript" charset="utf-8">
function addmsg(type, msg){
/* Simple helper to add a div.
type is the name of a CSS class (old/new/error).
msg is the contents of the div */
$("#messages").append(
"<div class='msg "+ type +"'>"+ msg +"</div>"
);
}
function waitForMsg(){
/* This requests the url "msgsrv.php"
When it complete (or errors)*/
$.ajax({
type: "GET",
url: "msgsrv.php",
async: true, /* If set to non-async, browser shows page as "Loading.."*/
cache: false,
timeout:50000, /* Timeout in ms */
success: function(data){ /* called when request to barge.php completes */
addmsg("new", data); /* Add response to a .msg div (with the "new" class)*/
setTimeout(
waitForMsg, /* Request next message */
1000 /* ..after 1 seconds */
);
},
error: function(XMLHttpRequest, textStatus, errorThrown){
addmsg("error", textStatus + " (" + errorThrown + ")");
setTimeout(
waitForMsg, /* Try again after.. */
15000); /* milliseconds (15seconds) */
}
});
};
$(document).ready(function(){
waitForMsg(); /* Start the inital request */
});
</script>
</head>
<body>
<div id="messages">
<div class="msg old">
BargePoll message requester!
</div>
</div>
</body>
</html>
I've got a really simple chat example as part of slosh.
Edit: (since everyone's pasting their code in here)
This is the complete JSON-based multi-user chat using long-polling and slosh. This is a demo of how to do the calls, so please ignore the XSS problems. Nobody should deploy this without sanitizing it first.
Notice that the client always has a connection to the server, and as soon as anyone sends a message, everyone should see it roughly instantly.
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<!-- Copyright (c) 2008 Dustin Sallings <dustin+html#spy.net> -->
<html lang="en">
<head>
<title>slosh chat</title>
<script type="text/javascript"
src="http://code.jquery.com/jquery-latest.js"></script>
<link title="Default" rel="stylesheet" media="screen" href="style.css" />
</head>
<body>
<h1>Welcome to Slosh Chat</h1>
<div id="messages">
<div>
<span class="from">First!:</span>
<span class="msg">Welcome to chat. Please don't hurt each other.</span>
</div>
</div>
<form method="post" action="#">
<div>Nick: <input id='from' type="text" name="from"/></div>
<div>Message:</div>
<div><textarea id='msg' name="msg"></textarea></div>
<div><input type="submit" value="Say it" id="submit"/></div>
</form>
<script type="text/javascript">
function gotData(json, st) {
var msgs=$('#messages');
$.each(json.res, function(idx, p) {
var from = p.from[0]
var msg = p.msg[0]
msgs.append("<div><span class='from'>" + from + ":</span>" +
" <span class='msg'>" + msg + "</span></div>");
});
// The jQuery wrapped msgs above does not work here.
var msgs=document.getElementById("messages");
msgs.scrollTop = msgs.scrollHeight;
}
function getNewComments() {
$.getJSON('/topics/chat.json', gotData);
}
$(document).ready(function() {
$(document).ajaxStop(getNewComments);
$("form").submit(function() {
$.post('/topics/chat', $('form').serialize());
return false;
});
getNewComments();
});
</script>
</body>
</html>
Tornado is designed for long-polling, and includes a very minimal (few hundred lines of Python) chat app in /examples/chatdemo , including server code and JS client code. It works like this:
Clients use JS to ask for an updates since (number of last message), server URLHandler receives these and adds a callback to respond to the client to a queue.
When the server gets a new message, the onmessage event fires, loops through the callbacks, and sends the messages.
The client-side JS receives the message, adds it to the page, then asks for updates since this new message ID.
I think the client looks like a normal asynchronous AJAX request, but you expect it to take a "long time" to come back.
The server then looks like this.
while (!hasNewData())
usleep(50);
outputNewData();
So, the AJAX request goes to the server, probably including a timestamp of when it was last update so that your hasNewData() knows what data you have already got.
The server then sits in a loop sleeping until new data is available. All the while, your AJAX request is still connected, just hanging there waiting for data.
Finally, when new data is available, the server gives it to your AJAX request and closes the connection.
Here are some classes I use for long-polling in C#. There are basically 6 classes (see below).
Controller: Processes actions required to create a valid response (db operations etc.)
Processor: Manages asynch communication with the web page (itself)
IAsynchProcessor: The service processes instances that implement this interface
Sevice: Processes request objects that implement IAsynchProcessor
Request: The IAsynchProcessor wrapper containing your response (object)
Response: Contains custom objects or fields
This is a nice 5-minute screencast on how to do long polling using PHP & jQuery:
http://screenr.com/SNH
Code is quite similar to dbr's example above.
Here is a simple long-polling example in PHP by Erik Dubbelboer using the Content-type: multipart/x-mixed-replace header:
<?
header('Content-type: multipart/x-mixed-replace; boundary=endofsection');
// Keep in mind that the empty line is important to separate the headers
// from the content.
echo 'Content-type: text/plain
After 5 seconds this will go away and a cat will appear...
--endofsection
';
flush(); // Don't forget to flush the content to the browser.
sleep(5);
echo 'Content-type: image/jpg
';
$stream = fopen('cat.jpg', 'rb');
fpassthru($stream);
fclose($stream);
echo '
--endofsection
';
And here is a demo:
http://dubbelboer.com/multipart.php
I used this to get to grips with Comet, I have also set up Comet using the Java Glassfish server and found lots of other examples by subscribing to cometdaily.com
Take a look at this blog post which has code for a simple chat app in Python/Django/gevent.
Below is a long polling solution I have developed for Inform8 Web. Basically you override the class and implement the loadData method. When the loadData returns a value or the operation times out it will print the result and return.
If the processing of your script may take longer than 30 seconds you may need to alter the set_time_limit() call to something longer.
Apache 2.0 license. Latest version on github
https://github.com/ryanhend/Inform8/blob/master/Inform8-web/src/config/lib/Inform8/longpoll/LongPoller.php
Ryan
abstract class LongPoller {
protected $sleepTime = 5;
protected $timeoutTime = 30;
function __construct() {
}
function setTimeout($timeout) {
$this->timeoutTime = $timeout;
}
function setSleep($sleep) {
$this->sleepTime = $sleepTime;
}
public function run() {
$data = NULL;
$timeout = 0;
set_time_limit($this->timeoutTime + $this->sleepTime + 15);
//Query database for data
while($data == NULL && $timeout < $this->timeoutTime) {
$data = $this->loadData();
if($data == NULL){
//No new orders, flush to notify php still alive
flush();
//Wait for new Messages
sleep($this->sleepTime);
$timeout += $this->sleepTime;
}else{
echo $data;
flush();
}
}
}
protected abstract function loadData();
}
This is one of the scenarios that PHP is a very bad choice for. As previously mentioned, you can tie up all of your Apache workers very quickly doing something like this. PHP is built for start, execute, stop. It's not built for start, wait...execute, stop. You'll bog down your server very quickly and find that you have incredible scaling problems.
That said, you can still do this with PHP and have it not kill your server using the nginx HttpPushStreamModule: http://wiki.nginx.org/HttpPushStreamModule
You setup nginx in front of Apache (or whatever else) and it will take care of holding open the concurrent connections. You just respond with payload by sending data to an internal address which you could do with a background job or just have the messages fired off to people that were waiting whenever the new requests come in. This keeps PHP processes from sitting open during long polling.
This is not exclusive to PHP and can be done using nginx with any backend language. The concurrent open connections load is equal to Node.js so the biggest perk is that it gets you out of NEEDING Node for something like this.
You see a lot of other people mentioning other language libraries for accomplishing long polling and that's with good reason. PHP is just not well built for this type of behavior naturally.
Thanks for the code, dbr. Just a small typo in long_poller.htm around the line
1000 /* ..after 1 seconds */
I think it should be
"1000"); /* ..after 1 seconds */
for it to work.
For those interested, I tried a Django equivalent. Start a new Django project, say lp for long polling:
django-admin.py startproject lp
Call the app msgsrv for message server:
python manage.py startapp msgsrv
Add the following lines to settings.py to have a templates directory:
import os.path
PROJECT_DIR = os.path.dirname(__file__)
TEMPLATE_DIRS = (
os.path.join(PROJECT_DIR, 'templates'),
)
Define your URL patterns in urls.py as such:
from django.views.generic.simple import direct_to_template
from lp.msgsrv.views import retmsg
urlpatterns = patterns('',
(r'^msgsrv\.php$', retmsg),
(r'^long_poller\.htm$', direct_to_template, {'template': 'long_poller.htm'}),
)
And msgsrv/views.py should look like:
from random import randint
from time import sleep
from django.http import HttpResponse, HttpResponseNotFound
def retmsg(request):
if randint(1,3) == 1:
return HttpResponseNotFound('<h1>Page not found</h1>')
else:
sleep(randint(2,10))
return HttpResponse('Hi! Have a random number: %s' % str(randint(1,10)))
Lastly, templates/long_poller.htm should be the same as above with typo corrected. Hope this helps.
Why not consider the web sockets instead of long polling? They are much efficient and easy to setup. However they are supported only in modern browsers. Here is a quick reference.
The WS-I group published something called "Reliable Secure Profile" that has a Glass Fish and .NET implementation that apparently inter-operate well.
With any luck there is a Javascript implementation out there as well.
There is also a Silverlight implementation that uses HTTP Duplex. You can connect javascript to the Silverlight object to get callbacks when a push occurs.
There are also commercial paid versions as well.
For a ASP.NET MVC implementation, look at SignalR which is available on NuGet.. note that the NuGet is often out of date from the Git source which gets very frequent commits.
Read more about SignalR on a blog on by Scott Hanselman
You can try icomet(https://github.com/ideawu/icomet), a C1000K C++ comet server built with libevent. icomet also provides a JavaScript library, it is easy to use as simple as
var comet = new iComet({
sign_url: 'http://' + app_host + '/sign?obj=' + obj,
sub_url: 'http://' + icomet_host + '/sub',
callback: function(msg){
// on server push
alert(msg.content);
}
});
icomet supports a wide range of Browsers and OSes, including Safari(iOS, Mac), IEs(Windows), Firefox, Chrome, etc.
Simplest NodeJS
const http = require('http');
const server = http.createServer((req, res) => {
SomeVeryLongAction(res);
});
server.on('clientError', (err, socket) => {
socket.end('HTTP/1.1 400 Bad Request\r\n\r\n');
});
server.listen(8000);
// the long running task - simplified to setTimeout here
// but can be async, wait from websocket service - whatever really
function SomeVeryLongAction(response) {
setTimeout(response.end, 10000);
}
Production wise scenario in Express for exmaple you would get response in the middleware. Do you what you need to do, can scope out all of the long polled methods to Map or something (that is visible to other flows), and invoke <Response> response.end() whenever you are ready. There is nothing special about long polled connections. Rest is just how you normally structure your application.
If you dont know what i mean by scoping out, this should give you idea
const http = require('http');
var responsesArray = [];
const server = http.createServer((req, res) => {
// not dealing with connection
// put it on stack (array in this case)
responsesArray.push(res);
// end this is where normal api flow ends
});
server.on('clientError', (err, socket) => {
socket.end('HTTP/1.1 400 Bad Request\r\n\r\n');
});
// and eventually when we are ready to resolve
// that if is there just to ensure you actually
// called endpoint before the timeout kicks in
function SomeVeryLongAction() {
if ( responsesArray.length ) {
let localResponse = responsesArray.shift();
localResponse.end();
}
}
// simulate some action out of endpoint flow
setTimeout(SomeVeryLongAction, 10000);
server.listen(8000);
As you see, you could really respond to all connections, one, do whatever you want. There is id for every request so you should be able to use map and access specific out of api call.