php中使用gd库实现下载网页中所有图片

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<?php

header("Content-type:text/html ; charset=utf-8");

if (!empty($_POST['submit'])){

$url = $_POST['url'];

//为了获取相对路径的图片所做的操作

$url_fields = parse_url($url);

$main_url = $url_fields['host'];

$base_url = substr($url,0,strrpos($url, '/')+1);

//获取网页内容

//设置代理服务器

$opts = array('http'=>array('request_fulluri'=>true));

$context = stream_context_create($opts);

$content = file_get_contents($url,false,$context);

//匹配img标签,将所有匹配字符串保存到数组$matches

$reg = "/<img.*?src=\"(.*?)\".*?>/i";

preg_match_all($reg, $content, $matches);

$count = count($matches[0]);

for ($i=0; $i<$count; $i++){

/*将所有图片的url转换为小写

*$matches[1][$i] = strtolower($matches[1][$i]);

*/

//如果图片为相对路径就转化为全路径

if (!strpos('a'.$matches[1][$i], 'http')){

//因为'/'是第0个位置

if (strpos('a'.$matches[1][$i], '/')){

$matches[1][$i] = 'http://'.$main_url.$matches[1][$i];

}else{

$matches[1][$i] = $base_url.$matches[1][$i];

}

}

}

//过滤重复的图片

$img_arr = array_unique($matches[1]);

//实例化图片下载类

$getImg = new DownImage();

$url_count = count($img_arr);

for ($i=0; $i<$url_count; $i++){

$getImg->source = $img_arr[$i];

$getImg->save_address = './pic/';

$file = $getImg->download();

}

echo "下载完成！哈哈，简单吧！";

}

class DownImage{

public $source;//远程图片URL

public $save_address;//保存本地地址

public $set_extension; //设置图片扩展名

public $quality; //图片的质量（0~100,100最佳，默认75左右）

//下载方法（选用GD库图片下载）

public function download(){

//获取远程图片信息

$info = @getimagesize($this->source);

//获取图片扩展名

$mime = $info['mime'];

$type = substr(strrchr($mime, '/'), 1);

//不同的图片类型选择不同的图片生成和保存函数

switch($type){

case 'jpeg':

$img_create_func = 'imagecreatefromjpeg';

$img_save_func = 'imagejpeg';

$new_img_ext = 'jpg';

$image_quality = isset($this->quality) ? $this->quality : 100;

break;

case 'png':

$img_create_func = 'imagecreatefrompng';

$img_save_func = 'imagepng';

$new_img_ext = 'png';

break;

case 'bmp':

$img_create_func = 'imagecreatefrombmp';

$img_save_func = 'imagebmp';

$new_img_ext = 'bmp';

break;

case 'gif':

$img_create_func = 'imagecreatefromgif';

$img_save_func = 'imagegif';

$new_img_ext = 'gif';

break;

case 'vnd.wap.wbmp':

$img_create_func = 'imagecreatefromwbmp';

$img_save_func = 'imagewbmp';

$new_img_ext = 'bmp';

break;

case 'xbm':

$img_create_func = 'imagecreatefromxbm';

$img_save_func = 'imagexbm';

$new_img_ext = 'xbm';

break;

default:

$img_create_func = 'imagecreatefromjpeg';

$img_save_func = 'imagejpeg';

$new_img_ext = 'jpg';

}

//根据是否设置扩展名来合成本地文件名

if (isset($this->set_extension)){

$ext = strrchr($this->source,".");

$strlen = strlen($ext);

$newname = basename(substr($this->source,0,-$strlen)).'.'.$new_img_ext;

}else{

$newname = basename($this->source);

}

//生成本地文件路径

$save_address = $this->save_address.$newname;

$img = @$img_create_func($this->source);

if (isset($image_quality)){

$save_img = @$img_save_func($img,$save_address,$image_quality);

}else{

$save_img = @$img_save_func($img,$save_address);

}

return $save_img;

}

}

?>

<form method="POST" action="">

远程url地址：<input type="text" name="url" size=30 />

<input type="submit" name="submit" value="下载该页面所有图片" />

</form>