I have a script that uses ajax to retrieve PHP data for video files on my server (godaddy shared hosting), and then play the video file on my php page if it is the highest ranked video, like so:
<script id="source" language="javascript" type="text/javascript">
$(function refreshscreen ()
{
$.ajax({
url: 'screen.php',
data: "",
pass to api.php
dataType: 'json',
success: function(data)
{
var id = data[0];
var name = data[1];
var votes = data[2];
var video = data[3];
var image = data[4];
$('.screen').hide(); $("#video"+id+"").show();
var whichvideo = "thevideo" + id;
var videoplay = document.getElementById(whichvideo);
var killvideo = document.getElementsByClassName('videobg');
var allvideos = document.getElementsByClassName("videobg");
for(var x=0; x < allvideos.length; x++)
{
var allvideosid = document.getElementById(allvideos[x]);
if ($(allvideos[x]).attr("id") == whichvideo) {
allvideos[x].play();
} else {
allvideos[x].pause();
}
}
},
complete: function() {
// Schedule the next request when the current one's complete
setTimeout(refreshscreen, 5000);
}
});
});
And then the screen.php referenced above:
<?php
$host = "localhost";
$user = "myuserhere";
$pass = "mypasshere";
$databaseName = "mydbnamehere";
$tableName = "mytablenamehere";
$con = mysql_connect($host,$user,$pass);
$dbs = mysql_select_db($databaseName, $con);
$result = mysql_query("SELECT * FROM $tableName ORDER BY votes DESC");
$array = mysql_fetch_row($result);
echo json_encode($array);
?>
This all works fine, and the video switches as it should when a new higher ranked video is voted in, however, periodically, the video will freeze when playing, completely at random. My guess is that we are overloading the server with the setTimeout function of the ajax script, so I am wondering if there is a way I can clean up this script to avoid the freezing, or an alternative method.
Thanks in advance.
I've cleaned up the code:
var currentID = -1;
function refreshscreen() {
$.getJSON('screen.php', data => {
var topID = data[0];
// Schedule the next request
setTimeout(refreshscreen, 5000);
if (topID === currentID) return; // top rated video hasn't changed
$('.screen').hide();
$("#video" + topID).show();
var pauseID = "thevideo" + currentID;
var playID = "thevideo" + topID;
$(".videobg").each(function() {
if (this.id === pauseID) this.pause();
if (this.id === playID) this.play();
});
currentID = topID;
});
}
$(document).ready(function () {
refreshscreen();
});
The biggest change is keeping track of the currently playing video and exiting right away if it hasn't changed. Other than that I got rid of all the unused variables and used jQuery throughout. This should be much easier to debug at the least and might fix the error to boot.
I want my page to consistently check if the user session is still active.
if using event listener. My concern is that php file execution time is limited. is there way to set php execution to infinite? or is there a better way of doing this?
JS:
$(document).ready(function() {
var loginSource = new EventSource("/structure/ajax/check_login_session.php");
loginSource.addEventListener("login-verification", function(e) {
var response = JSON.parse(e.data);
if (data.login_failed) {
login_fail_redirect();
}
});
})
php
function send_response() {
if (empty($_SESSION['user_info']) || empty($_SESSION['user_info']['active'])) {
$response = array("status" => "failed", "login_failed" => 1);
} else {
$response = array("status" => "success", "login_failed" => 0);
}
echo "event: login-verification\n";
echo 'data: '.json_encode($response);
echo "\n\n";
flush();
}
while (true) {
send_response();
sleep(2);
}
Use a javascript setInterval instead. It will send timed requests to the backend to check if the session is active or not.
$(document).ready(function() {
setInterval(function {
var loginSource = new EventSource("/structure/ajax/check_login_session.php");
loginSource.addEventListener("login-verification", function(e) {
var response = JSON.parse(e.data);
if (data.login_failed) {
login_fail_redirect();
}
});
},1000); //time in ms
})
Then replace this code from your backend:
while (true) {
send_response();
sleep(2);
}
to
send_response();
I have a big problem to make a progress bar in AJAX. The whole page is in AJAX, inside one of the webpage is AJAX which loads a function to get some big rows from the database.
I tried to make progress bar in this script in a foreach loop a flush() method and by writing/reading to $_SESSION, but still nothing. I really tried everything I don`t know how to do this. Need only this to complete my project. Could someone help me with this?
It is anyway which script I want to load, how is the template for this progress bar to use it in GET or POST ajax, for any AJAX.
<script>
jQuery(document).ready(function($) {
$(document).on('click','#save',function () {
setTimeout(getProgress,1000);
$(this).text('Pobieram analizę...');
$.urlParam = function(name){
var results = new RegExp('[\?&]' + name + '=([^&#]*)').exec(window.location.href);
if (results==null){
return null;
}
else{
return decodeURI(results[1]) || 0;
}
}
var id = $.urlParam('id');
var idt = $.urlParam('idt');
$.ajax({
url: "views/getresults.php?id="+id+"&idt="+idt,
success: function(data) {
$("#loadresults").append(data);
}
});
setTimeout(getProgress,3000);
return false;
});
function getProgress(){
$.ajax({
url: 'views/listen.php',
success: function(data) {
if(data<=100 && data>=0){
console.log(data);
$('#loadresults').html('<div id="progress"><div class="progress-bar" role="progressbar" style="width:'+ (data / 100)*100 +'%">'+ data + '/' +100+'</div></div>');
setTimeout(getProgress,1000);
console.log('Repeat');
} else {
$('#loadresults').text('Pobieram dane');
console.log('End');
}
}
});
}
});
</script>
and here is a getresults.php
foreach($result as $resul) {
$count++;
session_start();
$_SESSION['progress'] = $count;
$_SESSION['total'] = 100;
session_write_close();
sleep(1);
}
unset($_SESSION['progress']);
and a get progress function listen.php
<?php
session_start();
echo (!empty($_SESSION['progress']) ? $_SESSION['progress'] : '');
if (!empty($_SESSION['progress']) && $_SESSION['progress'] >= $_SESSION['total']) {
unset($_SESSION['progress']);
}
?>
Writing and reading session doesn't work because the standard behavior of PHP is to lock the session file while your main code is being executed.
Try to create a file and update the its content with the percentage done during the execution of your function. Something like:
<?php
function slowFunction() {
$file = uniqid();
file_put_contents($file, 0);
// Long while that makes your stuff
// you have to know how many loops you will make to calculate the progress
$total = 100;
$done = 0;
while($done < $total) {
$done++;
// You may want not to write to the file every time to minimize changes of being writing the file
// at the same time your ajax page is fetching it, i'll let it to you...
$progress = $done / $total;
file_put_contents($file, $progress);
}
unlink($file); // Remove your progress file
}
?>
You can't get the progress of the data download from ajax. Once you request you to the server, the next response will be only after fetching the data or when the error occurs.
The solution to you is, get the data as fractions. Such as first download the 1/10th of the data, and in the success callback, recursively call the ajax again requesting the 2/10th data. On each success callback, you could change the progress bar.
Take a look at Server Side Events or Long polling as options
i have a simple form: when i submit it without javascript/jquery, it works fine, i have only one insertion in my data base, everything works fine.
I wrote some jquery to have result in ajax above the input button, red message if there was an error, green if the insertion was done successfully. I also display a small gif loader.
I don't understand why when i use this jquery, two loaders appear at the same time and two insertions are done in my database.
I reapeat that when i comment the javascript, it works fine, i'm totally sure that my php is ok.
$('#addCtg').submit(function () {
var action = $(this).attr('action');
var name = $('#name').val() ;
$('.messages').slideUp('800', function() {
$('#addCtg input[type="submit"]').hide().after('<img src="spin.gif" class="loader">');
$.post(action, {
name: name
}, function (data) {
$('.messages').html(data);
$('.messages').slideDown('slow');
$('.loader').fadeOut();
$('#addCtg input[type="submit"]').fadeIn();
});
});
return false;
});
I really don't understand why it doesn't work, because i use the 'return false' to change the basic behaviour of the submit button
Basic php just in case:
<?php
require_once('Category.class.php');
if (isset($_POST['name'])) {
$name = $_POST['name'] ;
if ($name == "") {
echo '<div class="error">You have to find a name for your category !</div>' ;
exit();
} else {
Category::addCategory($name) ;
echo '<div class="succes">Succes :) !</div>' ;
exit();
}
} else {
echo '<div class="error">An error has occur: name not set !</div>';
exit();
}
And finnaly my function in php to add in the database, basic stuff
public static function addCategory($name) {
$request = myPDO::getInstance()->prepare(<<<SQL
INSERT INTO category (idCtg, name)
VALUES (NULL, :name)
SQL
);
$r = $request->execute(array(':name' => $name));
if ($r) {
return true ;
} else {
return false ;
}
}
I rarely ask for help, but this time i'm really stuck, Thank you in advance
You're calling: $('.messages') - I bet you have 2 elements with the class messages. Then they will both post to your server.
One possible reason could be because you are using button or submit to post ajax request.
Try this,
$('#addCtg').submit(function (e) {
e.preventDefault();
var action = $(this).attr('action');
var name = $('#name').val() ;
$('.messages').slideUp('800', function() {
$('#addCtg input[type="submit"]').hide().after('<img src="spin.gif" class="loader">');
$.post(action, {
name: name
}, function (data) {
$('.messages').html(data);
$('.messages').slideDown('slow');
$('.loader').fadeOut();
$('#addCtg input[type="submit"]').fadeIn();
});
});
return false;
});
I'm making a web app that requires that I check to see if remote servers are online or not. When I run it from the command line, my page load goes up to a full 60s (for 8 entries, it will scale linearly with more).
I decided to go the route of pinging on the user's end. This way, I can load the page and just have them wait for the "server is online" data while browsing my content.
If anyone has the answer to the above question, or if they know a solution to keep my page loads fast, I'd definitely appreciate it.
I have found someone that accomplishes this with a very clever usage of the native Image object.
From their source, this is the main function (it has dependences on other parts of the source but you get the idea).
function Pinger_ping(ip, callback) {
if(!this.inUse) {
this.inUse = true;
this.callback = callback
this.ip = ip;
var _that = this;
this.img = new Image();
this.img.onload = function() {_that.good();};
this.img.onerror = function() {_that.good();};
this.start = new Date().getTime();
this.img.src = "http://" + ip;
this.timer = setTimeout(function() { _that.bad();}, 1500);
}
}
This works on all types of servers that I've tested (web servers, ftp servers, and game servers). It also works with ports. If anyone encounters a use case that fails, please post in the comments and I will update my answer.
Update: Previous link has been removed. If anyone finds or implements the above, please comment and I'll add it into the answer.
Update 2: #trante was nice enough to provide a jsFiddle.
http://jsfiddle.net/GSSCD/203/
Update 3: #Jonathon created a GitHub repo with the implementation.
https://github.com/jdfreder/pingjs
Update 4: It looks as if this implementation is no longer reliable. People are also reporting that Chrome no longer supports it all, throwing a net::ERR_NAME_NOT_RESOLVED error. If someone can verify an alternate solution I will put that as the accepted answer.
Ping is ICMP, but if there is any open TCP port on the remote server it could be achieved like this:
function ping(host, port, pong) {
var started = new Date().getTime();
var http = new XMLHttpRequest();
http.open("GET", "http://" + host + ":" + port, /*async*/true);
http.onreadystatechange = function() {
if (http.readyState == 4) {
var ended = new Date().getTime();
var milliseconds = ended - started;
if (pong != null) {
pong(milliseconds);
}
}
};
try {
http.send(null);
} catch(exception) {
// this is expected
}
}
you can try this:
put ping.html on the server with or without any content, on the javascript do same as below:
<script>
function ping(){
$.ajax({
url: 'ping.html',
success: function(result){
alert('reply');
},
error: function(result){
alert('timeout/error');
}
});
}
</script>
You can't directly "ping" in javascript.
There may be a few other ways:
Ajax
Using a java applet with isReachable
Writing a serverside script which pings and using AJAX to communicate to your serversidescript
You might also be able to ping in flash (actionscript)
You can't do regular ping in browser Javascript, but you can find out if remote server is alive by for example loading an image from the remote server. If loading fails -> server down.
You can even calculate the loading time by using onload-event. Here's an example how to use onload event.
Pitching in with a websocket solution...
function ping(ip, isUp, isDown) {
var ws = new WebSocket("ws://" + ip);
ws.onerror = function(e){
isUp();
ws = null;
};
setTimeout(function() {
if(ws != null) {
ws.close();
ws = null;
isDown();
}
},2000);
}
Update: this solution does not work anymore on major browsers, since the onerror callback is executed even if the host is a non-existent IP address.
To keep your requests fast, cache the server side results of the ping and update the ping file or database every couple of minutes(or however accurate you want it to be). You can use cron to run a shell command with your 8 pings and write the output into a file, the webserver will include this file into your view.
The problem with standard pings is they're ICMP, which a lot of places don't let through for security and traffic reasons. That might explain the failure.
Ruby prior to 1.9 had a TCP-based ping.rb, which will run with Ruby 1.9+. All you have to do is copy it from the 1.8.7 installation to somewhere else. I just confirmed that it would run by pinging my home router.
There are many crazy answers here and especially about CORS -
You could do an http HEAD request (like GET but without payload).
See https://ochronus.com/http-head-request-good-uses/
It does NOT need a preflight check, the confusion is because of an old version of the specification, see
Why does a cross-origin HEAD request need a preflight check?
So you could use the answer above which is using the jQuery library (didn't say it) but with
type: 'HEAD'
--->
<script>
function ping(){
$.ajax({
url: 'ping.html',
type: 'HEAD',
success: function(result){
alert('reply');
},
error: function(result){
alert('timeout/error');
}
});
}
</script>
Off course you can also use vanilla js or dojo or whatever ...
If what you are trying to see is whether the server "exists", you can use the following:
function isValidURL(url) {
var encodedURL = encodeURIComponent(url);
var isValid = false;
$.ajax({
url: "http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20html%20where%20url%3D%22" + encodedURL + "%22&format=json",
type: "get",
async: false,
dataType: "json",
success: function(data) {
isValid = data.query.results != null;
},
error: function(){
isValid = false;
}
});
return isValid;
}
This will return a true/false indication whether the server exists.
If you want response time, a slight modification will do:
function ping(url) {
var encodedURL = encodeURIComponent(url);
var startDate = new Date();
var endDate = null;
$.ajax({
url: "http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20html%20where%20url%3D%22" + encodedURL + "%22&format=json",
type: "get",
async: false,
dataType: "json",
success: function(data) {
if (data.query.results != null) {
endDate = new Date();
} else {
endDate = null;
}
},
error: function(){
endDate = null;
}
});
if (endDate == null) {
throw "Not responsive...";
}
return endDate.getTime() - startDate.getTime();
}
The usage is then trivial:
var isValid = isValidURL("http://example.com");
alert(isValid ? "Valid URL!!!" : "Damn...");
Or:
var responseInMillis = ping("example.com");
alert(responseInMillis);
const ping = (url, timeout = 6000) => {
return new Promise((resolve, reject) => {
const urlRule = new RegExp('(https?|ftp|file)://[-A-Za-z0-9+&##/%?=~_|!:,.;]+[-A-Za-z0-9+&##/%=~_|]');
if (!urlRule.test(url)) reject('invalid url');
try {
fetch(url)
.then(() => resolve(true))
.catch(() => resolve(false));
setTimeout(() => {
resolve(false);
}, timeout);
} catch (e) {
reject(e);
}
});
};
use like this:
ping('https://stackoverflow.com/')
.then(res=>console.log(res))
.catch(e=>console.log(e))
I don't know what version of Ruby you're running, but have you tried implementing ping for ruby instead of javascript? http://raa.ruby-lang.org/project/net-ping/
let webSite = 'https://google.com/'
https.get(webSite, function (res) {
// If you get here, you have a response.
// If you want, you can check the status code here to verify that it's `200` or some other `2xx`.
console.log(webSite + ' ' + res.statusCode)
}).on('error', function(e) {
// Here, an error occurred. Check `e` for the error.
console.log(e.code)
});;
if you run this with node it would console log 200 as long as google is not down.
You can run the DOS ping.exe command from javaScript using the folowing:
function ping(ip)
{
var input = "";
var WshShell = new ActiveXObject("WScript.Shell");
var oExec = WshShell.Exec("c:/windows/system32/ping.exe " + ip);
while (!oExec.StdOut.AtEndOfStream)
{
input += oExec.StdOut.ReadLine() + "<br />";
}
return input;
}
Is this what was asked for, or am i missing something?
just replace
file_get_contents
with
$ip = $_SERVER['xxx.xxx.xxx.xxx'];
exec("ping -n 4 $ip 2>&1", $output, $retval);
if ($retval != 0) {
echo "no!";
}
else{
echo "yes!";
}
It might be a lot easier than all that. If you want your page to load then check on the availability or content of some foreign page to trigger other web page activity, you could do it using only javascript and php like this.
yourpage.php
<?php
if (isset($_GET['urlget'])){
if ($_GET['urlget']!=''){
$foreignpage= file_get_contents('http://www.foreignpage.html');
// you could also use curl for more fancy internet queries or if http wrappers aren't active in your php.ini
// parse $foreignpage for data that indicates your page should proceed
echo $foreignpage; // or a portion of it as you parsed
exit(); // this is very important otherwise you'll get the contents of your own page returned back to you on each call
}
}
?>
<html>
mypage html content
...
<script>
var stopmelater= setInterval("getforeignurl('?urlget=doesntmatter')", 2000);
function getforeignurl(url){
var handle= browserspec();
handle.open('GET', url, false);
handle.send();
var returnedPageContents= handle.responseText;
// parse page contents for what your looking and trigger javascript events accordingly.
// use handle.open('GET', url, true) to allow javascript to continue executing. must provide a callback function to accept the page contents with handle.onreadystatechange()
}
function browserspec(){
if (window.XMLHttpRequest){
return new XMLHttpRequest();
}else{
return new ActiveXObject("Microsoft.XMLHTTP");
}
}
</script>
That should do it.
The triggered javascript should include clearInterval(stopmelater)
Let me know if that works for you
Jerry
You could try using PHP in your web page...something like this:
<html><body>
<form method="post" name="pingform" action="<?php echo $_SERVER['PHP_SELF']; ?>">
<h1>Host to ping:</h1>
<input type="text" name="tgt_host" value='<?php echo $_POST['tgt_host']; ?>'><br>
<input type="submit" name="submit" value="Submit" >
</form></body>
</html>
<?php
$tgt_host = $_POST['tgt_host'];
$output = shell_exec('ping -c 10 '. $tgt_host.');
echo "<html><body style=\"background-color:#0080c0\">
<script type=\"text/javascript\" language=\"javascript\">alert(\"Ping Results: " . $output . ".\");</script>
</body></html>";
?>
This is not tested so it may have typos etc...but I am confident it would work. Could be improved too...