PHP的線上使用者計數器

現在我將告訴你如何看到有多少使用者在瀏覽您的網站。有許多方法來顯示它，但我試圖保持它簡單，乾淨。

首先，我們必須建立兩個表，您的資料庫教程。

CREATE TABLE `uonline` (
  `session` varchar(100) NOT NULL,
  `time` int(5) NOT NULL default '0'
) ENGINE=MyISAM DEFAULT CHARSET=latin1;

這將建立兩個表。一個是會議和其他的是時間。他們將我們的資訊儲存。

現在是PHP的時間。讓我們一起創造我們的主要變數

<?php教程
session_start();
$ses = session_id();
$time = time();
$timech=$time-300;
session_start(); - This wills start a session
$ses = session_id(); - This will get our session's ID
$time = time(); - This will get the time
$timech=$time-300; - This will set our time to 5min

Now we have to connect to the database:

// Declare SQL login info
$host = "localhost";
$username = "";
$password = "";
$dbname = "";
 
// Now we are going to connect to our database
mysql教程_connect("$host", "$username", "$password")or die("<font style='color:red'><b>Can not connect:</b> ".mysql_error()."</font>");
mysql_select_db("$db_name")or die("<font style='color:red'><b>Can not select the database:</b> ".mysql_error()."</font>");

$host = "localhost"; - Your SQL's host name, usually it's "localhost"
$username = ""; - Your MySQL username
$password = ""; - Your MySQL password
$dbname = ""; - Your database's name

Now we have to look for existing sessions and get the number of sessions.

$result = mysql_query("SELECT * FROM uonline WHERE session='$ses'");
$num = mysql_num_rows($result); 

$result = mysql_query("SELECT * FROM uonline WHERE session='$ses'"); - This will select all info from session column where it's value is "$ses"
$num = mysql_num_rows($result); - It will tell us how many active records are in session column

if($num == "0"){
$result1 = mysql_query("INSERT INTO uonline (session, time)VALUES('$ses', '$time')");
}else{
$result2 = mysql_query("UPDATE uonline SET time='$time' WHERE session = '$ses'");
}

if($num=="0"){ - If there's no records in session column then we must insert some records
$result1 = mysql_query("INSERT INTO uonline (session, time)VALUES('$ses', '$time')"); - Inserts session's ID and time to database
}else{ - But if there was more records than 0, let's update their records
$result2 = mysql_query("UPDATE uonline SET time='$time' WHERE session = '$ses'"); - Updates existing records
} - Ends If statement

Now let's find our info again from the columns:

$result3 = mysql_query("SELECT * FROM uonline");

$result3 = mysql_query("SELECT * FROM uonline"); - This will get all info from uonline table

It's time for showing how many users are looking your site:

$usersonline = mysql_num_rows($result3);
echo "There are: <b>".$usersonline."</b> users online";

$usersonline = mysql_num_rows($result3); - It will get the number of records in columns
echo "There are: <b>".$usersonline."</b> users online"; - This will show how many users are on your site

When the users have left, you must delete their records from database.

mysql_query("DELETE FROM uonline WHERE time<$timech");
?>

mysql_query("DELETE FROM uonline WHERE time<$timech"); - Deletes records from database when 5min has been thru.

And here's the full code:

<?php
session_start();
$ses = session_id();
$time = time();
$timech=$time-300; 
 
$host = "localhost";
$username = "";
$password = "";
$dbname = "";
 
mysql_connect("$host", "$username", "$password")or die("<font style='color:red'><b>Can not connect:</b> ".mysql_error()."</font>");
mysql_select_db("$db_name")or die("<font style='color:red'><b>Can not select the database:</b> ".mysql_error()."</font>");  
 
$result = mysql_query("SELECT * FROM uonline WHERE session='$ses'");
$num = mysql_num_rows($result); 
 
if($num == "0"){
$result1 = mysql_query("INSERT INTO uonline (session, time)VALUES('$ses', '$time')");
}else{
$result2 = mysql_query("UPDATE uonline SET time='$time' WHERE session = '$ses'");
} 
 
$result3 = mysql_query("SELECT * FROM uonline"); 
 
$usersonline = mysql_num_rows($result3);
echo "There are: <b>".$usersonline."</b> users online";  
 
mysql_query("DELETE FROM uonline WHERE time<$timech");
?>