PHP-Push technology realizes the refresh function
Server push The "push" technology was very popular some time ago, but most of the information on the Internet is cgi. I occasionally saw such an introduction on a French website, but it is a pity that it is in French. I can’t understand it, so I can only understand something from his program. Now I’ll put together an example for everyone to learn from. It can be used for data transmission in chat rooms, news updates on websites, and other frequently updated pages.
In the past, refreshing was done mainly by adding tags to the page.
Or use javascript's timeout+reload, but this refreshing method depends on the time setting, and cannot continuously transmit data and the time is difficult to determine. A server that uses Server push establishes a permanent connection with the client after the client makes a request, and then the server continuously pushes data packets to the server according to the client's request. Those delays that you are not aware of will make you feel that the server's response and your request have reached the level of synchronization.
Let’s look at an example first and then explain.
http://www.BkJia.com/DownloadFilesa2004-11-14img.php
set_time_limit(0);
$file = "./1.jpg";
$sep = "gIrLsKiCkAsSiTsAySsOoNaTsHiRt";
if(ereg(".*MSIE.*",$HTTP_SERVER_VARS["HTTP_USER_AGENT"])){
//If it is an IE browser, output directly and exit, IE It's not supported, I haven't tried it yet
header("Cache-Control: no-cache");
header("Pragma: no-cache");
header("Content-type: image/jpeg");
header("Content-size: " . filesize($file));
readfile($file);
}else{
header("Content -Type: multipart/x-mixed-replace; boundary=$sep");
//Here is the key, take a look at the MIME type description
//You will understand
print "--$sep
";
do{
print "Content-Type: image/jpeg
";
readfile($file);
print "
--$sep
";
Flush();
$mt = filemtime($file);
do{
sleep (1);
clearstatcache();
}while($mt == filemtime($file));
}while(1);
}
? >
This is a permanently executed page (when the network is constant), constantly outputting the content of the image , the following is the page called.
You will find a problem when using it: why the picture does not update automatically. This is because the client has not made a request to the server for a period of time, that is, there is no new content input to the browser for a certain period of time, and a connection timeout may occur. What's the solution? You can add an empty signal to the browser in the execution page, similar to the ftp connection method. In the above page, add a print("") between do...while(1);
After reading this example, you should Now you know how to handle the constantly updated content. The key lies in the processing in the http://www.BkJia.com/DownloadFilesa2004-11-14img.php page (which can be to check the new content and output it). When calling, you can have img, script, frame, etc.

php把负数转为正整数的方法:1、使用abs()函数将负数转为正数,使用intval()函数对正数取整,转为正整数,语法“intval(abs($number))”;2、利用“~”位运算符将负数取反加一,语法“~$number + 1”。

实现方法:1、使用“sleep(延迟秒数)”语句,可延迟执行函数若干秒;2、使用“time_nanosleep(延迟秒数,延迟纳秒数)”语句,可延迟执行函数若干秒和纳秒;3、使用“time_sleep_until(time()+7)”语句。

php除以100保留两位小数的方法:1、利用“/”运算符进行除法运算,语法“数值 / 100”;2、使用“number_format(除法结果, 2)”或“sprintf("%.2f",除法结果)”语句进行四舍五入的处理值,并保留两位小数。

判断方法:1、使用“strtotime("年-月-日")”语句将给定的年月日转换为时间戳格式;2、用“date("z",时间戳)+1”语句计算指定时间戳是一年的第几天。date()返回的天数是从0开始计算的,因此真实天数需要在此基础上加1。

方法:1、用“str_replace(" ","其他字符",$str)”语句,可将nbsp符替换为其他字符;2、用“preg_replace("/(\s|\ \;||\xc2\xa0)/","其他字符",$str)”语句。

php判断有没有小数点的方法:1、使用“strpos(数字字符串,'.')”语法,如果返回小数点在字符串中第一次出现的位置,则有小数点;2、使用“strrpos(数字字符串,'.')”语句,如果返回小数点在字符串中最后一次出现的位置,则有。

在PHP中,可以利用implode()函数的第一个参数来设置没有分隔符,该函数的第一个参数用于规定数组元素之间放置的内容,默认是空字符串,也可将第一个参数设置为空,语法为“implode(数组)”或者“implode("",数组)”。

php字符串有下标。在PHP中,下标不仅可以应用于数组和对象,还可应用于字符串,利用字符串的下标和中括号“[]”可以访问指定索引位置的字符,并对该字符进行读写,语法“字符串名[下标值]”;字符串的下标值(索引值)只能是整数类型,起始值为0。


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