PHP issue with sleep() and redirect
Question
I have the following dumb code:
<?
echo "<html><br><br><br><div id='loading'><p><img src='loader.gif'> Please wait 6 seconds...</p></div></html>";
sleep(6);
header('Location: http://google.com/');
?>
Why doesn't the HTML piece of code show up in the browser before sleeping 6 seconds and then redirecting? The codes doesn't output the HTML code at all, waits 6 seconds then sends me to the location. What do I do wrong?
4 answers
solution1
6 2012-09-06 11:22:28
This will not work. Because the first echo will start output. After that header call will just fail. However you can do it with refresh header on PHP side.
<?php
header('Refresh: 5;URL=http://www.google.com/'); // refresh header
echo "<html><head>";
// meta refresh
echo "<meta http-equiv=\"refresh\" content=\"5;URL=http://www.google.com/\" />";
echo "</head><body><br><br><br><div id='loading'><p><img src='loader.gif'> Please wait 6 seconds...</p></div></body></html>";
?>
<script type="text/javascript">
// javascript refresh
window.setTimeout(function(){
location.href="http://www.google.com";
},5000);
</script>
On the above script 3 things were handled.
- HTTP Refresh header
- Meta refresh
- Javascript Refresh
Note: Meta refresh is deprecated (though I have shown in example). HTTP Refresh header is recommended.
solution2
3 ACCPTED 2012-09-06 11:22:04
You would need to do something like (this won't work):
<?php
echo "<html><br><br><br><div id='loading'><p><img src='loader.gif'> Please wait 6 seconds...</p></div></html>";
@ob_flush(); //flush the output buffer
flush(); //flush anything else
sleep(6); //wait
header('Location: http://google.com/'); //redirect
?>
However : This won't work as expected, you cannot redirect the browser after sending content (PHP will throw and error and tell you this)
Instead you should:
<?php
echo "<html><meta http-equiv=\"refresh\" content=\"6;URL='http://YOURURL.com/'\"><br><br><br><div id='loading'><p><img src='loader.gif'> Please wait 6 seconds...</p></div></html>";
?>
Where the <meta http-equiv="refresh" content="6;URL='http://YOURURL.com/'"> tag is an HTML tag to tell the browser to change to the provided url after 6 seconds
To avoid adding the meta tag, you could also do this:
<?php
header('Refresh: 6;URL=http://www.YOURURL.com/');
echo "<html><br><br><br><div id='loading'><p><img src='loader.gif'> Please wait 6 seconds...</p></div></html>"
?>
But to be safe you should add both the header and the meta tag!
solution3
1 2012-09-06 11:30:58
From PHP documentation :
Remember that header() must be called before any actual output is sent, either by normal HTML tags, blank lines in a file, or from PHP. It is a very common error to read code with include, or require, functions, or another file access function, and have spaces or empty lines that are output before header() is called. The same problem exists when using a single PHP/HTML file.
So you can't use the header() function after echo .
I suggest you to use javascript or the meta tag instead.
solution4
-1 2012-09-06 11:26:04
I think you are looking for header('Refresh: 6; url=http://google.com/') ; to do redirect
buffering and script sleep is not needed.
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