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Do a javascript redirect after an ajax call

I'm trying to use ajax to parse data to be processed on a php page and have php echo a javascript redirect to another page but it is not working. I have read that js does not work after running an ajax call so I will like to know if there s a way around it. This is my code:
html
<form>
<div class="depart_time bottom_white w-40 ml-auto">
<p>Time</p>
<input type="time" name = "return_time" id = "rt">
</div>
<div class = "search_button r_search">
<button id = "r_search" onclick = "return false" onmousedown = "rent()">SEARCH</button>
</div>
</form>
ajax call is a normal xhttp request that gets sent to php for processing after which a redirection should occur:
if(isset($_POST['return_time'])){
echo '<script type="text/javascript">window.location.href="link.html"</script>';
}
Please an help is appreciated. I'm new to using ajax.
EDIT
the ajax code:
gid("r_search").addEventListener("mousedown", rent);
function rent(){
rt = gid('rt').value;
r_search = gid('r_search').value;
form_array = '&rt=' + rt +
'&r_search=' + r_search;
send_data = form_array;
ajax_data('app/rent.php', 'error', send_data);
//gid('error').innerHTML = send_data;
}
function ajax_data(php_file, getId, send_data){
gid(getId).innerHTML = "loading";
var xhttpReq = new XMLHttpRequest();
xhttpReq.open("POST", php_file, true);
xhttpReq.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xhttpReq.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
gid(getId).innerHTML = xhttpReq.responseText;
}
};
xhttpReq.send(send_data);
}
please note that 'gid' is for getelementbyid

You have to make bit alteration to your way of redirection.
First you need to make changes in your PHP response
if(isset($_POST['return_time'])){
...
// If you get your process success return 1
if(success) {
echo 1; die();
} else {
// else set some flag that you could get on your AJAX response
echo 0; die();
}
}
Now, get this flag on your AJAX and make changes to your below functions:
function ajax_data(php_file, getId, send_data){
gid(getId).innerHTML = "loading";
var xhttpReq = new XMLHttpRequest();
xhttpReq.open("POST", php_file, true);
xhttpReq.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xhttpReq.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
if( xhttpReq.responseText == 1 ) window.location.href="URL where you wish to redirect page";
}
};
xhttpReq.send(send_data);
}
I've written this answer for others who come here for help.

Singleton class not just once instantiated in php

I need a help with a singleton class. I`m creating a wordpress plugin, and need to have live notifications from server. For that I used AJAX long polling and my code looks like this.
This is a php code used for serving AJAX request and for LOG class which is singleton and called from many different places in project
if (isset($_GET['log']) && $_GET['log'] == 'true')
{
$response = array();
$response['msg'] = SI_log::get_instance()->get_message();
$response['type'] = 'something';
echo json_encode($response);
}
class SI_log{
private $log_messages = array();
private static $instance = NULL;
private $log_file;
public static function get_instance()
{
if (static::$instance === NULL) {
static::$instance = new static();
}
return static::$instance;
}
public function add_message( $message, $type )
{
array_push($this -> log_messages, $message);
}
public function get_message()
{
return end($this->log_messages);
}}?>
This is javascript for retrieving notifications and its a part of admin section in the wordpress.
<script type="text/javascript" charset="utf-8">
function waitForMsg(){
setTimeout(waitForMsg,5000);
document.getElementById("alerts").childNodes = new Array();
var request = new XMLHttpRequest();
request.open('GET', '<?php echo get_site_url() . '/wp-content/plugins/si/admin/c-si-log.php?log=true'?>', true);
request.onload = function() {
if (request.status >= 200 && request.status < 400) {
var resp = request.responseText;
alert(resp);
var json = eval('('+resp+ ')');
document.getElementById("alerts").innerHTML= json['type'] +"<hr>";
if (json['type'] == 'WARNING'){
var html_element = '<div class="alert-message warning" id = "alert_warning"><div class="box-icon"></div><p>'+json['msg']+'</p></div>';
}
if (json['type'] == 'INFO'){
var html_element = '<div class="alert-message info" id = "alert_info"><div class="box-icon"></div><p>'+json['msg']+'</p></div>';
}
if (json['type'] == 'ERROR'){
var html_element = '<div class="alert-message errorr" id = "alert_error"><div class="box-icon"></div><p>'+json['msg']+'</p></div>';
}
document.getElementById("alerts") . innerHTML= html_element;
}else{
alert('<?php echo get_site_url() . '/wp-content/plugins/si/admin/c-si-log.php?log=true' ?>');
}
};
request.onerror = function() {
// There was a connection error of some sort
alert("request isnt good");
};
request.send();
}
window.onload = function (){
if (document.readyState != 'loading'){
waitForMsg();
} else {
document.addEventListener('DOMContentLoaded', waitForMsg);
}
}
</script>
This is how is singleton class called from another class for notification input
SI_log::get_instance()->add_message("action triggered", 'INFO');
I assume the problem is singleton pattern implementation in SI_log class, so there is not only one instance of that class but many more, and when i try to retrieve the notification ie. when I trigger some action, notification isn`t stored in the same object. I used alert(resp); in cilent page to display response and response looks like this
{
"msg":false,
"type":"something"
}
and in log.php you can see that the type value is fine, so it's not communication problem. Can anyone help me please?
NOTE: I must use Javascript because versioning problems so don't ask me why i didn't use JQuery

The singleton pattern is useful when we need to make sure we only have a single instance of a class for the entire request lifecycle in a web application.
So, you can't do the thing you want to achieve in this way.
Instead, use it as a base/parent class and extend it on other classes when you need it.

Call output of a PHP randomizer via AJAX

Current setting:
In the same PHP document I have a PHP randomizer function and the HTML that calls that function -- a separate txt document with strings that are called by the php function:
Function
<?php
function rand_line($fileName, $maxLineLength = 4096) {
$handle = #fopen($fileName, "strings.txt");
if ($handle) {
$random_line = null;
$line = null;
$count = 0;
while (($line = fgets($handle, $maxLineLength)) !== false) {
$count++;
if(rand() % $count == 0) {
$random_line = $line;
}
}
if (!feof($handle)) {
echo "Error: unexpected fgets() fail\n";
fclose($handle);
return null;
} else {
fclose($handle);
}
return $random_line;
}
}
?>
I call the function in the HTML using:
<?php echo rand_line("strings.txt");?>
<input type="button" value="Another String" onClick="window.location.reload()">
This tends to be slow when multiple users access the page and press the button to obtain a new status.
What I would like to achieve:
Improve the performance and make the whole thing not so heavy: maybe the randomizer is unnecessarily complicated and I could work with AJAX calls for example, but if possible keeping the string list inside the strings.txt file and separated from the PHP script and HTML.
Sorry if I don't know what I'm talking about... I'm not a proficient programmer. Just a guy that hacks stuff together once in a while :)

You really don't want to use window.location.reload();
That is terrible... You do not want to refresh a page...
location.reload() sends http request for a whole new page (whole HTML), and then not only that your browser needs to render whole HTML again, you have to transfer more duplicated data through a network, from point A to point B.
You should send HTTP request only for a data that you need (you don't need whole HTML again, you loaded it the 1st time you visited page).
Instead, use XMLHttpRequest javascript library (AJAX) to request only for a portion of data (in your case => random line string)
HTML:
<!DOCTYPE html>
<html>
<head lang="en">
<script type="text/javascript">
function loadDoc(url, cfunc) {
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function () {
if (xhttp.readyState == 4 && xhttp.status == 200) {
cfunc(xhttp);
}
};
xhttp.open("GET", url, true)
xhttp.send();
}
function randomLine(xhttp) {
alert(xhttp.responseText);
}
</script>
</head>
<body>
<input type="button" value="Get random line" onClick="loadDoc('http://localhost:8080/myScript.php', randomLine)">
</body>
</html>
PHP:
myScript.php
<?php
function rand_line($fileName, $maxLineLength = 4096)
{
...
}
echo rand_line("strings.txt");
?>

*EDIT #2*
Fully-functioning script. Grabs initial strings via PHP, and stores in array for later JavaScript usage. Minimizes # of calls.
PHP to grab strings from file; generates a default (random) string, as well as an array of strings for later use with button.
/**
* #input array $file
* #return array (mixed) [0] => string, [1] => array
*/
$randomStringFromFile = function($file) {
if (!$file) return false;
/**
* #return Removes carriage returns from the file
* and wraps $val with single-quotes so as
* to not break JavaScript
*/
$add_quotes = function(&$val) {
return str_replace("\n", "", "'$val'");
};
return [$file[rand(0, count($file)-1)], array_map($add_quotes, $file)];
};
$randomString = $randomStringFromFile( #file('strings.txt') ) ?: false;
JavaScript
<div id="string_container"><?php echo $randomString[0]; // defaults random string to page ?></div><br>
<button onclick="getString();">Another String</button>
<script>
var getString = function() {
var arr = [<?php echo implode(',', $randomString[1]); ?>],
setString = document.getElementById('string_container').innerHTML = arr[Math.floor(Math.random() * arr.length)];
};
</script>
Place the above in your page and you should be good to go.
EDIT (ORIGINAL)
We can remove PHP from the equation entirely using the following (fastest method):
<div id="string_container"></div><br>
<button onclick="getString();">Another String</button>
<script>
var getString = function() {
var request = new XMLHttpRequest(),
file = 'strings.txt';
request.open('GET', file);
request.onload = function() {
if (request.status === 200) {
var arr = request.responseText.split("\n"), /** assuming line breaks in file are standard carriage returns (Unix); "\r" if Windows */
setString = document.getElementById('string_container').innerHTML = arr[Math.floor(Math.random() * arr.length-1)];
}
};
request.send();
};
</script>
ORIGINAL w/PHP
We can simplify the PHP even further, removing loops from the equation altogether.
$randomStringFromFile = function($file) {
if (!$file) return false;
return $file[rand(0, count($file)-1)];
};
echo $randomStringFromFile( #file('strings.txt') ) ?: 'No worky!';
Using file() will return the contents in an array, thus allowing you to simply select a key at random and return the value.
NOTE On average, $file[rand(0, count($file)-1)] outperformed array_rand() (E.g. $file[array_rand($file)];) when selecting a key at random. By negligible amounts, have you.. ~0.0002s vs ~0.0005s, respectively.

You can simplify your code
function rand_line($fileName, $maxLineLength = 4096) {
$f = file($fileName);
$length = $maxLineLength + 1;
do {
$line = $f[array_rand($f)];
$length = strlen($line);
} while ($length > $maxLineLength);
return $line;
}

How to retrieve a php form with AJAX at specific time spans

I want to display a form with a script I adapted from this question. The script is in a file I wrote called queries.js, and its purpose is to print the content of a php form called "dbMinAlert.php" in a div like this <div id="recentExits" name="recentExits"></div> located in my project's index, I tried invoking getNewData(); in my index.php file using this tag <body onLoad="getNewData()"> but it doesn't seem to do anything at all.
var data_array = ''; // this is a global variable
function getNewData() {
$.ajax({
url: "dbMinAlert.php",
})
.done(function(res) {
data_array = res; // the global variable is updated here and accessible elsewhere
getNewDataSuccess();
})
.fail(function() {
// handle errors here
})
.always(function() {
// we've completed the call and updated the global variable, so set a timeout to make the call again
setTimeout(getNewData, 2000);
});
}
function getNewDataSuccess() {
//console.log(data_array);
document.getElementById("recentExits").innerHTML=data_array;
}
getNewData();`
---This php code works and it actually does what I expect it to do. The real problem is the javascript, for all I care the next php form could print a "Hello world" message, but I want it displayed inside the div I placed in my index, without having to post a thing to dbMinAlert.php.
define("HOST", "localhost");
define("DBUSER", "root");
define("PASS", "password");
define("DB", "mydb");
// Database Error - User Message
define("DB_MSG_ERROR", 'Could not connect!<br />Please contact the site\'s administrator.');
$conn = mysql_connect(HOST, DBUSER, PASS) or die(DB_MSG_ERROR);
$db = mysql_select_db(DB) or die(DB_MSG_ERROR);
$query = mysql_query("
SELECT *
FROM outputs, products
WHERE products.idProduct=outputs.idProduct
ORDER BY Date DESC, Time DESC limit 5
");
echo '<ul class="news">';
while ($data = mysql_fetch_array($query)) {
$date = date_create($data['Date']);
$time = date_create($data['Time']);
echo '<li><figure><strong>'.date_format($date,'d').'</strong>'.date_format($date,'M').date_format($date,'Y').'</figure>'.$data["idProduct"]." ".$data['prodName'].'</li>';
}
echo '</ul>';

You have to execute the function for the first time.
getNewData();

It could be the way you are returning the result from php. Instead of doing multiple echo, could you first assign your result in single php variable and finally do single echo.
$result = '<ul class="news">';
while ($data = mysql_fetch_array($query)) {
$date = date_create($data['Date']);
$time = date_create($data['Time']);
$result = $result + '<li><figure><strong>'.date_format($date,'d').'</strong>'.date_format($date,'M').date_format($date,'Y').'</figure>'.$data["idProduct"]." ".$data['prodName'].'</li>';}
$result = $result + '</ul>';
echo $result;

I found a solution in this question and my code ended up Like this.
I just had to invoke the function in my index by typing <body onload="return getOutput();">
JavaScript
//Min-Max Alerts
// handles the click event for link 1, sends the query
function getOutput() {
getRequest(
'dbMinAlert.php', // URL for the PHP file
drawOutput, // handle successful request
drawError // handle error
);
return false;
}
// handles drawing an error message
function drawError() {
var container = document.getElementById('recentExits');
container.innerHTML = 'Bummer: there was an error!';
}
// handles the response, adds the html
function drawOutput(responseText) {
var container = document.getElementById('recentExits');
container.innerHTML = responseText;
}
// helper function for cross-browser request object
function getRequest(url, success, error) {
var req = false;
try{
// most browsers
req = new XMLHttpRequest();
} catch (e){
// IE
try{
req = new ActiveXObject("Msxml2.XMLHTTP");
} catch(e) {
// try an older version
try{
req = new ActiveXObject("Microsoft.XMLHTTP");
} catch(e) {
return false;
}
}
}
if (!req) return false;
if (typeof success != 'function') success = function () {};
if (typeof error!= 'function') error = function () {};
req.onreadystatechange = function(){
if(req.readyState == 4) {
return req.status === 200 ?
success(req.responseText) : error(req.status);
}
}
req.open("GET", url, true);
req.send(null);
return req;
}

Trouble receiving Javascript variable when sent to PHP

Problem: Trouble receiving what is being sent to my PHP document.
Javascript:
$('#form_id').submit(function(event){
event.preventDefault();
event.stopPropagation();
var message;
var myRegExp = validation stuff
var urlToValidate = document.getElementById("url").value;
if (!myRegExp.test(urlToValidate)){
}else{
var code = (urlToValidate).slice(-22)
var request = new XMLHttpRequest();
request.addEventListener('readystatechange', function(event){
if (this.readyState == 4){
if (this.status ==200){
console.log (this.status);
}else{
console.log('Server replied with HTTP status ' + this.status);
}
}
});
request.open('POST', 'php/submit.php', true);
request.setRequestHeader('Content-Type', 'text/plain');
request.send("code=" + code);
}
});
Then I'm using this code on my php/submit.php:
if (!empty($_POST['code'])) {
$code = $_POST['code'];
echo $code;
};
I feel like I'm not using the right tag names for PHP because I'm new to all of this. I'll note that I'm using form id but getting the value from an input.
Ramblings
I'm trying to send a user input that has been validated and sliced to mySQL database.
I achieved the string I wanted with javascript and passed it to a variable.
I'm trying to send it to a separate php file in another folder with a request.send(the_javaS_variable).
Now in the console I can see the variable holds the correct text value and I see it sending with state 4 and 200.
But it never shows up on the submit.php page.

try this and remove the console.log()
$('#form_id').submit(function(event){
var myRegExp = validation stuff
var urlToValidate = document.getElementById("url").value;
if (!myRegExp.test(urlToValidate)){
// failed
}else{
var code = 'code='+(urlToValidate).slice(-22);
$.post('php/submit.php', code, function() {
// success stuff
});
}
return false;
});