Libevent Learning in PHP

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Application Learning of libevent in PHP

1, libevent introduction

2, Why to learn libevent

3, Php libevent expansion module installation

4. Libevent constants and PHP functions

5. select/poll model

6. epoll/kqueue model

1, libevent introduction

Libevent is an event-triggered network library for many platforms such as Windows, Linux, andFreeBSD, with internal use of Select,poll,Epoll, Kqueue such as system invoke management event mechanism. The libevent is cross-platform and has extraordinary performance. as event-driven as Nodejs; Official website:http://libevent.org/

The latest stable version

Https://github.com/downloads/libevent/libevent/libevent-2.0.16-stable.tar.gz

Main modules:

Event Processing Framework

Event Engine Module

Buffer Management Module

Signal Processing Module

PHP does not natively support multi-threading,PHP The concurrency mechanism cannot be implemented well. Pecl provided by Pcntl (Process Control),libevent extensions,sockets package,stream system functions, you can use PHP easy to develop high-performance, high-concurrency network applications.

Simple Application case: pcntl fork n worker . master process   after the request, processing information sent to worker Program , worker back to client when finished processing . master process &NBSP can be followed by the amount of concurrency, to set worker the number is n size, and monitor (monitoring) worker The data for the , which starts more processes when it is insufficient. Same as nginx principle.

attached:Php Network Programming Framework

Http://code.google.com/p/swoole/downloads/list

2, why to learn libevent

HTTP server can be said to be a classic app for Libevent. The standard notation of HTTP can be found from libevent, which is the non-blocking HTTP server, which is the socket processing and the HTTP protocol processing.

Learning Libevent can help to improve the programming skills, in addition to network program design,libevent code has a lot of useful design techniques and basic data structure, such as information hiding, function pointers,C language Polymorphism support, linked list and heap, etc. [1] all contribute to improving their own procedural prowess.

There are three types of processing for requests:

1. connection Input Fork a new process

2. Connection Input Pthread_create

3, connection input throw a event-based array; main process do nonblocking things;

3, Php libevent expansion module installation

Curl–o https://github.com/downloads/libevent/libevent/libevent-2.0.16-stable.tar.gz

TAR–ZXVF libevent-2.0.16-stable.tar.gz

Cd libevent-2.0.16-stable

/usr/local/php/bin/phpize

./configure

Make

Make install

Vi/usr/local/php/etc/php.ini

Extension_dir= "";

Extension=libevent.so

Php–m | grep Lib

Installation Successful

4. libevent Constants and PHP functions

#define Ev_timeout 0x01

#define Ev_read 0x02

#define Ev_write 0x04

#define Ev_signal 0x08

#define Ev_persist 0x10

#define EV_ET 0x20

#define Evloop_once 0x01

#define Evloop_nonblock 0x02

Value	Constant name	Meaning
1	Ev_timeout	Event becomes active after time has passed
2	Ev_read	FD ready, can read when the event becomes active state
4	Ev_write	When FD is ready, the event becomes active when it can be written
8	Ev_signal	For signal detection
16	Ev_persist	Indicates that the event is persistent
32	Ev_et	Indicates whether the underlying edge trigger event is supported
1	Evloop_once	If Evloop_once is set , the loop waits for certain events to become active, and executes the active event until no more events can be executed and will be returned.
2	Evloop_nonblock	If Evloop_nonblock is set , the loop does not wait for the event to be triggered: the loop will only detect if an event is ready to be triggered immediately, and if so, the callback that executes the event.

Event_base_freee ()

Frees the resource, which cannot destroy the binding event

Event_base_loop ()

Handling events, handling event loops based on the specified base

Event_base_loopbreak ()

Immediately cancels the event loop, with the same behavior for each break statement

Event_base_loopexit ()

Exits a loop after a specified time

Event_base_new ()

Create and initial events

Event_base_priority_init ()

Prioritize events

Event_base_set ()

Associating events to event base

Event_buffer_base_set ()

Associating cached events to event_base

Event_buffer_disable ()

To disable a cached event

Event_buffer_enable ()

To enable a specified cached event

Event_buffer_fd_set ()

Change the file system description of a cache

Event_buffer_free ()

Releasing Cache events

Event_buffer_new ()

To create a new cache event

Event_buffer_priority_set ()

Priority setting for cache events

Event_buffer_read ()

Reading data from a cache event

Event_buffer_set_callback ()

Sets or resets the callback Hansh function to the cached event

Event_buffer_timeout_set ()

Sets the read and write time to timeout for a cached event

Event_buffer_watermark_set

To set a watermark token for read-write events

Event_buffer_write ()

Write data to the cache event

Event_add ()

Adds an execution event to the specified settings

Event_del ()

To remove an event from a set event

Event_free ()

Emptying the event handle

Event_new ()

To create a new event

Event_set ()

Prepare to add an event in Event_add

5. select/Poll model

If you use sockets extension, here are socket_select (),Stream_select (). For a large number of applications, thesocket_select (),stream _select () is already a good enough system call interface.

6. epoll/kqueue model

<?php

function Print_line ($FD, $events, $arg)

{

static $max _requests = 0;

$max _requests++;

if ($max _requests = = 10) {

Exit Loop after Ten writes

Event_base_loopexit ($arg [1]);

}

Echo fgets ($FD);

}

Create Base and Event

$base = Event_base_new ();

$event = Event_new ();

$FD = STDIN;

Set Event Flags

Event_set ($event, $FD, Ev_read | Ev_persist, "Print_line", Array ($event, $base));

Set Event Base

Event_base_set ($event, $base);

Enable Event

Event_add ($event);

Start Event Loop

Event_base_loop ($base);

Reference:

[1] http://blog.csdn.net/sparkliang/article/details/4957667

[2] http://blog.csdn.net/laoyi19861011/article/details/6539244

[3] http://blog.csdn.net/laoyi19861011/article/details/6537859

[4] http://www.wangafu.net/~nickm/libevent-book/Ref3_eventloop.html

[5] http://www.ooso.net/archives/607

[6] http://blog.csdn.net/vaal_water/article/details/6968695

[7] http://blog.csdn.net/shagoo/article/details/6396089

[8] http://blog.si.kz/index.php/2010/02/03/libevent-for-php

[9] http://www.ibm.com/developerworks/cn/aix/library/au-libev/index.html

[Ten] Https://github.com/kakserpom/phpdaemon

[One] http://www.cnblogs.com/imvkmark/archive/2011/12/21.html

[ http://www.oschina.net/question/12_15837 ]

Libevent Learning in PHP