我相信很多人的lamp环境都是直接复制一堆参数安装进去的，这里有可能成功，也有可能失败，如果是新手，估计要碰到各种错误，就算安装成功，也未必知道那些参数是干嘛的，反正装进去能用就行。
我当初开始的时候也是这样， 完全一脸懵逼，直到我后来进修了( C语言，Linux，Linux系统编程，计算机原理等 )才能玩转服务器配置，理解原理。
本文通过一个经典的验证码功能，告诉你如何按需安装扩展!!!
要封装一个php的验证码类库，那么需要gd扩展的支持，由于我之前的php是精简编译安装的，没有gd库的支持，所以要先安装php的gd库
要想成功安装gd库，需要安装很多的依赖: zlib, png, jpeg, libiconv, freetype
1，zlib我之前在安装 php memcache的扩展时候，已经安装过了
2，安装png
wget http://prdownloads.sourceforge.net/libpng/libpng-1.5.4.tar.gz?download
mv libpng-1.5.4.tar.gz\?download libpng-1.5.4.tar.gz
tar xf libpng-1.5.4.tar.gz
cd libpng-1.5.4/
./configure
make && sudo make install
3，安装jpeg
wget http://www.ijg.org/files/jpegsrc.v9b.tar.gz
tar xf jpegsrc.v9b.tar.gz
cd jpeg-9b/
./configure
make && sudo make install
4，安装libiconv
wget https://ftp.gnu.org/pub/gnu/libiconv/libiconv-1.15.tar.gz
tar xf libiconv-1.15.tar.gz
cd libiconv-1.15/
./configure
make && sudo make install
5，安装freeType
wget https://download.savannah.gnu.org/releases/freetype/freetype-2.9.tar.gz
tar xf freetype-2.9.tar.gz
cd freetype-2.9/
./configure
make && sudo make install
6，到了最关键的地方了，安装php gd扩展
切换到php原码包下 ext/gd 这个目录
>先执行phpize外挂模块( /usr/local/php54/bin/phpize )
>./configure --with-php-config=/usr/local/php54/bin/php-config -with-png-dir --with-freetype-dir --with-jpeg-dir -with-zlib-dir --with-gd
>make && sudo make install
开始封装php验证码库，最后效果
<?php
class Captcha {
//验证码字符个数
protected $num;
//宽度
protected $width;
//高度
protected $height;
//资源
protected $im;
//类型: 1:纯数字, 2:纯字母 3:数字与字母混合
protected $codeType;
//生成的验证码字符串
protected $codeString;
public function __construct( $_num = 4, $_width = 150, $_height = 50, $_codeType = 3 ){
$this->num = $_num;
$this->width = $_width;
$this->height = $_height;
$this->codeType = $_codeType;
$this->codeString = $this->createCodeString();
}
public function __get( $name ) {
if( $name == 'codeString' ) {
return $this->codeString;
}
return false;
}
protected function createCodeString(){
switch( $this->codeType ){
case 1:
$code = $this->createNumCode();
break;
case 2:
$code = $this->createCharCode();
break;
case 3:
$code = $this->createNumCharCode();
break;
default:
die( "暂时没有其他的验证码类型,你可以继承这个类来添加额" );
}
return $code;
}
protected function createNumCode(){
$numString = join( "", range( 0, 9 ) );
return substr( str_shuffle( $numString ), 0, $this->num );
}
protected function createCharCode(){
$charString = join( "", range( 'a', 'z' ) );
$charString .= strtoupper( $charString );
return substr( str_shuffle( $numString ), 0, $this->num );
}
protected function createNumCharCode(){
$numCharString = join( "", range( 0, 9 ) );
$charString = join( "", range( 'a', 'z' ) );
$charString .= strtoupper( $charString );
$mixedString = $numCharString . $charString;
return substr( str_shuffle( $mixedString ), 0, $this->num );
}
protected function createCanvas(){
$this->im = imagecreatetruecolor( $this->width, $this->height );
}
protected function fillCanvas( $type ){
switch( $type ) {
case 1:
$color = imagecolorallocate( $this->im, mt_rand( 0, 150 ), mt_rand( 0, 150 ), mt_rand( 0, 150 ) );
break;
case 2:
$color = imagecolorallocate( $this->im, mt_rand( 150, 255 ), mt_rand( 150, 255 ), mt_rand( 150, 255 ) );
break;
default:
die( "不支持的填充类型" );
break;
}
imagefill( $this->im, 0, 0, $color );
}
protected function drawCodeString(){
for( $i = 0; $i < $this->num; $i++ ){
$fontColor = imagecolorallocate( $this->im, mt_rand( 0, 255 ), mt_rand( 0, 255 ), mt_rand( 0, 255 ) );
$char = $this->codeString[$i];
$x = ( $i * ( ($this->width) / $this->num ) ) + mt_rand( 5, 10 );
$y = mt_rand( 0, $this->height / 2 ) + mt_rand( 5, 10 );
imagestring( $this->im, 5, $x, $y, $char, $fontColor );
}
}
protected function renderImage(){
header( "Content-type:image/png" );
imagepng( $this->im );
}
protected function fillDisturb(){
for( $i = 0; $i < 100; $i++ ){
$color = imagecolorallocate( $this->im, mt_rand( 0, 255 ), mt_rand( 0, 255 ), mt_rand( 0, 255 ) );
imagesetpixel( $this->im, mt_rand( 0, $this->width ), mt_rand( 0, $this->height ), $color );
}
}
public function render(){
//创建画布/背景
$this->createCanvas();
//填充画布颜色
$this->fillCanvas( 1 );
//填充干扰元素
$this->fillDisturb();
//填充验证码
$this->drawCodeString();
//显示验证码
$this->renderImage();
}
}
$capt = new Captcha();
//echo $capt->codeString . PHP_EOL;
$capt->render();
?>
小结：
1，复习类库的封装
2，理解扩展安装原理