I'm creating a form and using it to get data input to send to a MySQL database via php. If someone hits refresh on the page Firefox ressends the last set of information to the php page which in turn sends it to the database. Is there anyway to prevent this?
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- Not a "way" but strict rule, from HTTP standard.Your Common Sense– Your Common Sense2010-12-12 13:25:22 +00:00Commented Dec 12, 2010 at 13:25
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6 Answers
To fix that problem, there exists Post/Redirect/Get pattern you need to follow :)
Post/Redirect/Get (PRG) is a common design pattern for web developers to help avoid certain duplicate form submissions and allow user agents to behave more intuitively with bookmarks and the refresh button.
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You need to do a redirect to the same page:
$current_url = (empty($_SERVER['HTTPS']) ? "http://" : "https://") . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI']; header ('Location: ' . $current_url); exit (); answered Dec 12, 2010 at 13:26
István Ujj-Mészáros
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Your Common Sense
The only answer with actual code, and it turns to be ugly as a nightmare. May you please choose a bit less ugly construction? Not to repeat whole string twice to alter just one letter, for example?
Your Common Sense
@Agent I'd leave whole https inside of condition in sake of readability. Though ternary operator is a huge hole in readability itself. And also HTTP_HOST should be used instead of SERVER_NAME
István Ujj-Mészáros
@Col Shrapnel: Edited according to your suggestions. Thanks.
The usual way to do this is to use a redirect.
You get the request, use the data it contains to load your database or whatever, and then perform a redirect (I think you're supposed to use a 303 redirect for this, but I've heard of a lot of people using 302s to avoid certain browser glitches).
The net effect of this is that there was no POST data sent when the redirect occurred, so refreshing can't cause it to be resent and screw up your application/database.
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If you don't like any of the above and are using JQUERY. You could do a simple load or ajax function to send the information to your script.
This will erase any chance of duplicate sending and you no page reload. I like this method best, it's fast and easy.
Another solution you can do is have your form send to another page, a bit like this:
<form action="chat_server.php" method="post"> Message: <input type="text" name="message" /> <input type="submit" /> </form> On the chat_server.php file, you do what you need to do with the data and at the end, you do
echo '<meta http-equiv="REFRESH" content="0; url=chat.php" />'; Give it a try, should get rid of your problem.
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Yes. After inserting data you do a redirect.
answered Dec 12, 2010 at 13:25
Klaus Byskov Pedersen
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use a code in a hidden input and this code getting by a table codes for exmaple and if the code sending remove it from database and if the code not set in the table dont accept the query
