


What are the differences between CGI, FastCGI, APACHE2HANDLER and CLI? This article mainly introduces the four common running methods of PHP, and explains CGI, FastCGI, APACHE2HANDLER, and CLI in detail. I hope to be helpful.
SAPI: Server Application Programming Interface server application programming port. It is the interface for PHP to interact with other applications. PHP scripts can be executed in many ways, through the web server, directly on the command line, or embedded in other programs. SAPI provides an interface for external communication. Common SAPIs include: cgi, fast-cgi, cli, Apache module dll, etc.
1. CGI
CGI is the common gateway interface. It is a program. In layman’s terms, CGI is like a bridge that connects web pages and The execution program in the WEB server is connected, it passes the instructions received by the HTML to the server's execution program, and then returns the results of the server's execution program to the HTML page. CGI is extremely cross-platform and can be implemented on almost any operating system.
When the CGI method encounters a connection request (user request), it must first create a cgi sub-process, activate a CGI process, then process the request, and end the sub-process after processing. This is the fork-and-execute pattern. Therefore, a server using CGI will have as many CGI sub-processes as there are connection requests. Repeated loading of sub-processes is the main reason for low CGI performance. When the number of user requests is very large, a large amount of system resources such as memory, CPU time, etc. will be occupied, resulting in low performance.
2. FastCGI
fast-cgi is an upgraded version of cgi. FastCGI is like a long-live CGI that can be executed all the time. , as long as it is activated, it will not take time to fork every time. PHP uses PHP-FPM (FastCGI Process Manager), the full name of PHP FastCGI Process Manager, for management.
Load the FastCGI process manager (IIS ISAPI or Apache Module) when the Web Server starts. The FastCGI process manager initializes itself, starts multiple CGI interpreter processes (visible multiple php-cgi) and waits for connections from the Web Server.
When a client request reaches the Web Server, the FastCGI process manager selects and connects to a CGI interpreter. The web server sends CGI environment variables and standard input to the FastCGI subprocess php-cgi.
After the FastCGI sub-process completes processing, it returns standard output and error information to the Web Server from the same connection. When the FastCGI child process closes the connection, the request is processed. The FastCGI child process then waits for and handles the next connection from the FastCGI process manager (running in the Web Server). In CGI mode, php-cgi exits at this point.
In the above case, you can imagine how slow CGI usually is. Every web request to PHP must reparse php.ini, reload all extensions, and reinitialize all data structures. With FastCGI, all of this happens only once, when the process starts. An added benefit is that persistent database connections work.
3. APACHE2HANDLER
PHP is an Apache module. After the system starts, the Apache server pre-generates multiple process copies to reside in the memory. Once a request appears, it will be used immediately. These idle sub-processes are processed so that there is no delay caused by spawning sub-processes. These server copies do not exit immediately after processing an HTTP request, but stay in the computer waiting for the next request. The response to client browser requests is faster and the performance is higher.
4. CLI
cli is the command line running mode of PHP. You often use it, but you may not notice it (for example: we often use it under Linux) Use "php -m" to find out which extensions PHP has installed, which is the PHP command line running mode;
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The above is the detailed content of Detailed explanation of PHP's CGI, FastCGI, APACHE2HANDLER, and CLI operating modes. For more information, please follow other related articles on the PHP Chinese website!

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。

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。

在php中,可以使用substr()函数来读取字符串后几个字符,只需要将该函数的第二个参数设置为负值,第三个参数省略即可;语法为“substr(字符串,-n)”,表示读取从字符串结尾处向前数第n个字符开始,直到字符串结尾的全部字符。

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。


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