CODEWITHSUNDEEP
phpjavascripthtmlajax
tyler
tyler

Reputation: 1293

Load page while PHP is executing

What Im trying to do: Display a loading gif or text... at the very least show a black screen before and during the time the php is being executed.

What I have tried.

I have tested using flush () and I get nothing until the entire php process is finished. I dont particularly like this concept either but I'll take anything.

I am considering using two pages to accomplish this though the current project is nearly complete and would take some time to consolidate the scattered html/php code.

Currently I'm doing 3-simpleXML_load_file(), 1-include(), 1-file_get_contents() I have javascript function plotting data from one of the simpleXML_Load_file()...

Im up for moving parts of the code to a different file but it's a big task. So id like some advise or suggestions on how to proceed.

If I need to elaborate more just ask!

Thanks, JT 

 <html>
 <head>
 <?php
$lat = $_POST['Lat'];
$long = $_POST['Lon'];
 $weather_hourly = simplexml_load_file('http:....lat='.$lat.'&lon='.$long.'');
 ?>
 <script type="text/javascript">

 <!--Plot function-->
 $(function() 
 {
 var d = 
 [
<?php
//Pulling in hourly data to plot temp vs time
$i=0;
$array=array();
while ($i<=100)
{
    echo '['. (strtotime($weather_hourly->data->{'time-layout'}->{'start-valid-time'}[$i])*1000) .','.$weather_hourly->data->parameters->temperature->value[$i] .'],';
    $value = $weather_hourly->data->parameters->temperature->value[$i];
    array_push($array,$value);
    $i++;
}
    foreach ($array as $key => $value) 
    { 
                    $value = (string) $value;
                    $min_sec_array[] = $value;
    }
?>

</script>
 </head>
 <body>
 <div id=graph>
 </div>
 </body

Upvotes: 3

Views: 34078

Answers (6)

Sofia
Sofia

Reputation: 456

I know this is an old question, but the answer provided in this page by rpnew is extremely clear and easy to adjust to your project's requirements. It is a combination of AJAX and PHP.

The HTML page PHPAjax.html which calls the PHP script:

<html>
<head>    
    <script type="text/javascript">
        document.write('<div id="loading">Loading...</div>');

        //Ajax Function
        function getHTTPObject()
        {
            var xmlhttp;
            if (window.ActiveXObject)
            {
                try
                {
                    xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
                }
                catch (e)
                {
                    try
                    {
                        xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
                    }
                    catch (E)
                    {
                        xmlhttp = false;
                    }
                }
            }
            else
            {
                xmlhttp = false;
            }
            if (window.XMLHttpRequest)
            {
                try
                {
                    xmlhttp = new XMLHttpRequest();
                }
                catch (e)
                {
                    xmlhttp = false;
                }
            }
            return xmlhttp;
        }
        //HTTP Objects..
        var http = getHTTPObject();

        //Function which we are calling...
        function AjaxFunction()
        {
            url='PHPScript.php';
            http.open("GET",url, true);
            http.onreadystatechange = function()
            {
                if (http.readyState == 4)
                {
                    //Change the text when result comes.....
                    document.getElementById("content").innerHTML="http. responseText";
                }
            }
            http.send(null);
        }
    </script>
</head>
<body onload="AjaxFunction()">
</body>
</html>

The Background PHP Script PHPScript.php:

<?php
    sleep(10);
    echo "I'm from PHP Script";
?>

Save both files in the same directory. From your browser open the HTML file. It will show 'Loading...' for 10 seconds and then you will see the message changing to "I'm from PHP Script".

Upvotes: 0

user2127434
user2127434

Reputation:

I think you don't have a problem with flushing your PHP output to the browser, but more likely with getting the browser to start rendering the partial html output. Unfortunately, browser behavior on partial html is browser-specific, so if you want something to work the same in any browser, the AJAX solution suggested in other answers is the better way to go.

But if you don't like that added complexity of a full AJAX solution, you can try to make your html output "nice" in the sense of providing some body output that can be formatted without needing the rest of the html output. This is were your sample code fails: It spends most of its time outputting data into a script tag inside the html header. The browser never even sees the start of the body until your PHP code has practically finished executing. If you first write your complete body, then add the script tag for the data there, you give the browser something to at least try to render whilst waiting for the final script to be completed.

I've found the same issue (albeit not in PHP) discussed here: Stack Overflow question "When do browsers start to render partially transmitted HTML?" In particular, the accepted answer there provides a fairly minimal non-AJAX example to display and hide a placeholder whilst the html file hasn't completely loaded yet.

Upvotes: 0

sailingthoms
sailingthoms

Reputation: 948

I would recommend not to do this with plain html and php if u expect it modify the page after it is loaded. Because php is server side processing, so it is executed before the page is send to the user. U need Javascript. Using Javascript will enable u to dynamically add or remove html elements to or from the DOM tree after the page was send to the user. It is executed by the users browser.

For easier start I would recommend jQuery, because there are lots of tutorials on such topics.

JQuery

JQuery learning center

A small example:

HTML

<head>
    <meta charset="utf-8" />
    <title> </title>
    <script type="text/javascript" src="js/lib/jquery-1.9.1.js"></script>
</head>
<body>
    <h1>Addition</h1>
    <div id="error_msg"> </div>
    <div id="content">
        <!-- show loading image when opening the page -->
        <img src="images/loading.gif"/>
    </div>
    <script type="text/javascript">
       // your script to load content from php goes here
    </script>
</body>

this will be nothing more then the following until now:

enter image description here

adding the following php file

<?php

$num1 = $_GET['num1'];
$num2 = $_GET['num2'];

$result = $num1 + $num2;

echo '<p>Calculating '.$num1.' + '.$num2.' took a lot of time, but finally we were able to evaluate it to '.$result.'.</p>'
     .'<p> '.$num1.' + '.$num2.' = '.$result.'</p>';

 ?>

wont change anything of the html, but adding javascript/ Jquery inside the HTML will be kind of connection between static html and server side php. 

$(document).ready(function(){
    $.ajax({        // call php script
        url: 'php/script.php?num1=258&num2=121',
        type:'GET',
        timeout: 500,
        contentType: 'html'
    }).success(function(data){
            // remove loading image and add content received from php 
        $('div#content').html(data);

    }).error(function(jqXHR, textStatus, errorThrown){
            // in case something went wrong, show error
        $('div#error_msg').append('Sorry, something went wrong: ' + textStatus + ' (' + errorThrown + ')');
    });
});

This will change your page to show the loading animation until the php script returns its data, like:

enter image description here

So you can setup the whole page in plain html, add some loading gifs, call several php scripts and change the content without reloading the page itself.

Upvotes: 4

Seth
Seth

Reputation: 1373

The main way you can accomplish this is by using AJAX and multiple pages. To accomplish this, the first page should not do any of the processing, just put the loading image here. Next, make an AJAX request, and once the request is finished, you can show the results on the page or redirect to a different page.

Example:

File 1 (jQuery must be included also), put this in the body along with the loader animation:

<script language="javascript" type="text/javascript">
$(function(){
    var mydata = {};
    $.post('/myajaxfile.php', mydata, function(resp){
        // process response here or redirect page
    }, 'json');
});
</script>

Update: Here is a more complete example based on your code. This has not been tested and needs to have the jQuery library included, but this should give you a good idea:

File 1: file1.html 

</head>
 <body>
 <?php
$lat = $_POST['Lat'];
$long = $_POST['Lon'];
 ?>
 <!-- Include jQuery here! Also have the loading animation here. -->
 <script type="text/javascript">
$(function(){

    $.get('/file2.php?Lat=<?php echo $lat; ?>&Lon=<?php echo $long; ?>', null, function(resp){
        // resp will have the data from file2.php
        console.log(resp);
        console.log(resp['min_sec_array']);
        console.log(resp['main']);

        // here is where you will setup the graph 
        // with the data loaded
        <!--Plot function-->
    }, 'json');

});

</script>


 <div id=graph>
 </div>
 </body
 </html>

File 2: file2.php I'm not sure if you needed the $min_sec_array, but I had this example return that as well as the main data you were using before. 

$lat = $_POST['Lat'];
$long = $_POST['Lon'];
$weather_hourly = simplexml_load_file('http:....lat='.$lat.'&lon='.$long.'');

//Pulling in hourly data to plot temp vs time
$i=0;
$main = array();
$array=array();
while ($i<=100)
{
    $main[] = array((strtotime($weather_hourly->data->{'time-layout'}->{'start-valid-time'}[$i])*1000), $weather_hourly->data->parameters->temperature->value[$i]);
    $value = $weather_hourly->data->parameters->temperature->value[$i];
    array_push($array,$value);
    $i++;
}
foreach ($array as $key => $value) 
{
    $min_sec_array[] = (string) $value;
}


echo json_encode(array(
    'min_sec_array' =>$min_sec_array,
    'main' => $main
));

exit();

?>

Upvotes: 9

Adam
Adam

Reputation: 115

In response to your conversation with David Constantine below, did you try using ob_flush()?

ob_start(); 
echo '<img src="pics/loading.gif">'; 
ob_flush();

// Do your processing here

ob_end_flush();

Upvotes: 0

David Constantine
David Constantine

Reputation: 587

It is kind of nasty solution to your problem... But this can work: You work with those - 

ob_start();
//printing done here...
ob_end_flush();

at the beginning you will create your rotating ajax gif... Then you do all the processing and calculating you want... At the end of the processing, just echo a small script that does a hide to your gif...

Depends on the exact need, maybe ajax can be more elegant solution.

Upvotes: 0

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