CODEWITHSUNDEEP
phpmysql
Rangana Sampath
Rangana Sampath

Reputation: 1457

How to periodically push data to the user interface in php

i need to implement a simple project using PHP and MySql in which i need to push data to the user's UI when some one else is updating the database, and i need to periodically do this too, so when some one else accessing the same table and modify it, another person who uses the UI can see the updates, sorry if i'm being silly but up to now i'm only aware of saving data to a database and retrieving and showing it to the user(simplest form of data base connection). how can i achieve this in php, please some one help me on this matter, if the answer explains the things in detail it is good, because i'm very novice to this.thanks in advance.

rangana.

Upvotes: 2

Views: 1362

Answers (2)

Seb
Seb

Reputation: 11

If the web page has no data to return, then get the page to wait for a period while polling the database. You must use the sleep statement to avoid maxing out your server.

Warning: Some servers wont let the user open another page while one is in progress, which may cause you problems in some situations. So either dont hold the page open for too long, or maybe try to get the ajax page to use a different session.

// do this when you have put new data in to database
setappdata("lastupdate",microtime(true));

// use this loop to poll for new data
$loop = 0;
$lastupdate=$_SESSION["lastupdate"];
while ($lastupdate==$last=getappdata("lastupdate") and $loop<10) {
   $loop++;
   usleep(500000);  //0.5sec
}     

// use a table called appdata to store application data
function getappdata($var) {
   $query = "SELECT data FROM appdata WHERE var='$var'";
   $res1=mysql_query($query);
   if (mysql_numrows($res1)<1) return false;
   return mysql_result($res1,0,"data");
}

function setappdata($var,$data) {
   $query = "SELECT data FROM appdata WHERE var='$var'";
   $res1=mysql_query($query);
   if (mysql_numrows($res1)>0) $query = "UPDATE appdata SET data='$data' WHERE var='$var'";
   else $query = "INSERT INTO appdata SET var='$var',data='$data'";
   return mysql_query($query);
}

Upvotes: 1

Amber
Amber

Reputation: 526603

These topics may get you started:

http://en.wikipedia.org/wiki/Push_technology

http://en.wikipedia.org/wiki/Reverse_Ajax

Upvotes: 0

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