


GZIP (GNU-ZIP) is a compression technology. After GZIP compression, the page size can be reduced to 30% or even smaller than the original size. In this way, users will feel refreshed and happy when browsing!
To implement GZIP compressed pages, the browser and the server need to support it. In fact, it is server compression. After being transmitted to the browser, the browser decompresses and parses it. We don’t need to worry about the browser, because most browsers now support parsing GZIP pages. We just need to compress the page on the server side and then output it to the browser.
This is a bit wordy, let’s get down to business:
Just like to make compressed cookies, you must first get the raw materials, and to compress a page, you must first obtain the content to be output. The ob_start() (ob => output buffer) function in PHP can achieve this function. It can first put the content to be output in the program into a place called "buffer". Of course, you can understand it as making compressed cookies. A workbench for temporarily placing raw materials.
This function must be used before the page is output, so it is generally placed at the top of the code. Because it is like a workbench, you have to prepare it before the raw materials arrive, otherwise there will be no place to put the raw materials when they arrive, and problems will occur. After using ob_start() to get the page to be compressed, we can make compressed cookies. No, the page should be compressed! But it seems that there is still a lack of a compressor, EZ, we use the zlib extension of PHP to make one:
{
If( !headers_sent() && // If the page header information has not been output yet
extension_loaded("zlib") && // And the zlib extension has been loaded into PHP
strstr($_SERVER["HTTP_ACCEPT_ENCODING"],"gzip")) //And the browser says it can accept GZIP pages
{
$content = gzencode($content." n//This page has been compressed",9); Attach a comment label "//This page has been compressed" to the content to be compressed, and then execute it with the gzencode() function provided by zlib For compression level 9, the value range of this parameter is 0-9, 0 means no compression, and 9 means maximum compression. Of course, the higher the degree of compression, the more CPU is consumed.
//Then use the header() function to send some header information to the browser, telling the browser that this page has been compressed with GZIP!
header("Content-Encoding: gzip");
header("Vary: Accept-Encoding");
header("Content-Length: ".strlen($content));
}
Return $content; //Return the compressed content, or send the compressed cookies back to the workbench.
}
After the compressor is ready, we put the compressor on the workbench, so the original ob_start() becomes
ob_start('ob_gzip'); //Yes, just add a parameter to ob_start(), and the parameter name is the function name of the "compressor" we just made. In this way, when the content enters the buffer, PHP will call the ob_gzip function to compress it.
Well, all the work is done, final delivery:
ob_end_flush(); //End the buffer and output the content. Of course, you don't need this function, because the buffer content will be automatically output at the end of the program execution.
The complete example is as follows:
//Enable a workbench with ob_gzip compressor
ob_start('ob_gzip');
//Prepare some content to be compressed
for($i=0; $i
{
echo('Here are the raw materials for compressed biscuits, here are the raw materials for compressed biscuits, raw materials');
}
//Output the compression result
ob_end_flush();
//This is ob_gzip compressor
function ob_gzip($content)
{
If( !headers_sent() &&
extension_loaded("zlib") &&
strstr($_SERVER["HTTP_ACCEPT_ENCODING"],"gzip"))
{
$content = gzencode($content." n//This page has been compressed",9);
header("Content-Encoding: gzip");
header("Vary: Accept-Encoding");
header("Content-Length: ".strlen($content));
}
Return $content;
}
?>
After actual testing, if GZIP is not used in the above code, it is 4.69KB = 4802.56B. After enabling GZIP, it is reduced to 104B
. Uh... I may not be good at math. I will calculate the percentage of the original compression. .
In addition, the following is the log information obtained using FlashGet. You can see the header information added to our program:
QUOTE:
Fri Jan 25 17:53:10 2008 HTTP/1.1 200 OK
Fri Jan 25 17:53:10 2008 Date: Fri, 25 Jan 2008 09:53:10 GMT
Fri Jan 25 17:53:10 2008 Connection: close
Fri Jan 25 17:53:10 2008 X-Powered-By: PHP/5.2.5
Fri Jan 25 17:53:10 2008 Content-Encoding: gzip
Fri Jan 25 17:53:10 2008 Vary: Accept-Encoding
Fri Jan 25 17:53:10 2008 Content-Length: 104
Fri Jan 25 17:53:10 2008 Content-type: text/html

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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