通过GET获得一个指定url的页面内容 有3种方式来获取一个url的内容： PHP提供的文件函数file_get_contents() cURL扩展 PEAR中的HTTP_Request类 //方式1$page = file_get_contents('http://www.example.com/robots.txt');//方式2$c = curl_init('http://www.ex
通过GET获得一个指定url的页面内容
有3种方式来获取一个url的内容：
- PHP提供的文件函数file_get_contents()
- cURL扩展
- PEAR中的HTTP_Request类
//方式1
$page = file_get_contents('http://www.example.com/robots.txt');
//方式2
$c = curl_init('http://www.example.com/robots.txt');
curl_setopt($c, CURLOPT_RETURNTRANSFER, true);
$page = curl_exec($c);
curl_close($c);
//方式3
require_once 'HTTP/Request.php';
$r = new HTTP_Request('http://www.example.com/robots.txt');
$r->sendRequest();
$page = $r->getResponseBody();
可以通过这些方式来获取XML文档，通过结合http_build_query()来建立一个查询字符串，可以通过url中加入username@password的形式来访问受保护的页面，通过cURL和PEAR的HTTP_Client类来跟踪重定向。
通过POST获得一个URL
让PHP模拟发送一个POST请求并获得服务器的反馈内容
//1
$url = 'http://www.example.com/submit.php';
$body = 'monkey=uncle&rhino=aunt';
$options = array('method' => 'POST', 'content' => $body);
$context = stream_context_create(array('http' => $options));
print file_get_contents($url, false, $context);
//2
$url = 'http://www.example.com/submit.php';
$body = 'monkey=uncle&rhino=aunt';
$c = curl_init($url);
curl_setopt($c, CURLOPT_POST, true);
curl_setopt($c, CURLOPT_POSTFIELDS, $body);
curl_setopt($c, CURLOPT_RETURNTRANSFER, true);
$page = curl_exec($c);
curl_close($c);
//3
require 'HTTP/Request.php';
$url = 'http://www.example.com/submit.php';
$r = new HTTP_Request($url);
$r->setMethod(HTTP_REQUEST_METHOD_POST);
$r->addPostData('monkey','uncle');
$r->addPostData('rhino','aunt');
$r->sendRequest();
$page = $r->getResponseBody();
通过Cookie获得一个URL
//2
$c = curl_init('http://www.example.com/needs-cookies.php');
curl_setopt($c, CURLOPT_COOKIE, 'user=ellen; activity=swimming');
curl_setopt($c, CURLOPT_RETURNTRANSFER, true);
$page = curl_exec($c);
curl_close($c);
//3
require 'HTTP/Request.php';
$r = new HTTP_Request('http://www.example.com/needs-cookies.php');
$r->addHeader('Cookie','user=ellen; activity=swimming');
$r->sendRequest();
$page = $r->getResponseBody();
通过Header获得一个URL
通过修改header中的信息可以来伪造 Referer 或 User-Agent 后请求目标URL，不少防盗链网站经常会采用判断Referer中的信息来源决定是否允许下载或访问资源。需要具备一些HTTP的HEADER背景知识。
标记网页
其实这个代码经过简单修改还可以应用到替换网页中的敏感关键字，这在天朝是很有用的一个功能
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$body = '
I like pickles and herring.
@@##@@A pickle picture
I have a herringbone-patterned toaster cozy.
Herring is not a real HTML element!
';
$words = array('pickle','herring');
$patterns = array();
$replacements = array();
foreach ($words as $i => $word) {
$patterns[] = '/' . preg_quote($word) .'/i';
$replacements[] = "\\0";
}
// Split up the page into chunks delimited by a
// reasonable approximation of what an HTML element
// looks like.
$parts = preg_split("{(<(?:\"[^\"]*\"|'[^']*'|[^'\">])*>)}",
$body,
-1, // Unlimited number of chunks
PREG_SPLIT_DELIM_CAPTURE);
foreach ($parts as $i => $part) {
// Skip if this part is an HTML element
if (isset($part[0]) && ($part[0] == '<')) { continue; }
// Wrap the words with s
$parts[$i] = preg_replace($patterns, $replacements, $part);
}
// Reconstruct the body
$body = implode('',$parts);
print $body;
提取页面所有链接
也是一个很不错的功能，在做采集之类的程序时可以用的上
采用了tidy扩展的实现方式：
$doc = new DOMDocument();
$opts = array('output-xml' => true,
// Prevent DOMDocument from being confused about entities
'numeric-entities' => true);
$doc->loadXML(tidy_repair_file('linklist.html',$opts));
$xpath = new DOMXPath($doc);
// Tell $xpath about the XHTML namespace
$xpath->registerNamespace('xhtml','http://www.w3.org/1999/xhtml');
foreach ($xpath->query('//xhtml:a/@href') as $node) {
$link = $node->nodeValue;
print $link . "\n";
通过正则提取链接：
$html = file_get_contents('linklist.html');
$links = pc_link_extractor($html);
foreach ($links as $link) {
print $link[0] . "\n";
}
function pc_link_extractor($html) {
$links = array();
preg_match_all('/]*)[\"\']?[^>]*>(.*?)<\/a>/i', $html,$matches,PREG_SET_ORDER); foreach($matches as $match) { $links[] = array($match[1],$match[2]); } return $links;
将文本转换为HTML
bbcode的概念和这个很像，所以将这个贴出来
function pc_text2html($s) {
$s = htmlentities($s);
$grafs = split("\n\n",$s);
for ($i = 0, $j = count($grafs); $i < $j; $i++) {
// 转换html超链接
$grafs[$i] = preg_replace('/((ht|f)tp:\/\/[^\s&]+)/',
'$1',$grafs[$i]); // 转换email链接
$grafs[$i] = preg_replace('/[^@\s]+@([-a-z0-9]+\.)+[a-z]{2,}/i', '$1',$grafs[$i]); // 开始一个新段落
$grafs[$i] = '
'.$grafs[$i].'
'; } return implode("\n\n",$grafs);}
将HTML转换为文本
已经有现成的代码来实现这个功能http://www.chuggnutt.com/html2text.php
用这个函数strip_tags( ) 可以
