探讨file_get_contents与curl效率及稳定性的分析

做过好多抓取别家网站内容的产品，习惯了使用方便快捷的file_get_contents函数，但是总是会遇到获取失败的问题，尽管按照手册中的例子设置了超时，可多数时候不会奏效：

$config['context'] = stream_context_create(array(‘http' => array(‘method' => “get”,
   'timeout' => 5//这个超时时间不稳定，经常不奏效
   )
  ));

这时候，看一下服务器的连接池，会发现一堆类似的错误，让你头疼万分：
file_get_contents(http://***): failed to open stream…
不得已，安装了curl库，写了一个函数替换：

<span style="color:#000000; font-weight:bold">function</span> curl_file_get_contents<span style="color:#009900">(</span><span style="color:#000088">$durl</span><span style="color:#009900">)</span><span style="color:#009900">{</span>
   <span style="color:#000088">$ch</span> <span style="color:#339933">=</span> <span style="color:#990000">curl_init</span><span style="color:#009900">(</span><span style="color:#009900">)</span><span style="color:#339933">;</span>
   <span style="color:#990000">curl_setopt</span><span style="color:#009900">(</span><span style="color:#000088">$ch</span><span style="color:#339933">,</span> curlopt_url<span style="color:#339933">,</span> <span style="color:#000088">$durl</span><span style="color:#009900">)</span><span style="color:#339933">;</span>
   <span style="color:#990000">curl_setopt</span><span style="color:#009900">(</span><span style="color:#000088">$ch</span><span style="color:#339933">,</span> curlopt_timeout<span style="color:#339933">,</span> <span style="color:#cc66cc">5</span><span style="color:#009900">)</span><span style="color:#339933">;</span>
   <span style="color:#990000">curl_setopt</span><span style="color:#009900">(</span><span style="color:#000088">$ch</span><span style="color:#339933">,</span> curlopt_useragent<span style="color:#339933">,</span> _useragent_<span style="color:#009900">)</span><span style="color:#339933">;</span>
   <span style="color:#990000">curl_setopt</span><span style="color:#009900">(</span><span style="color:#000088">$ch</span><span style="color:#339933">,</span> curlopt_referer<span style="color:#339933">,</span>_referer_<span style="color:#009900">)</span><span style="color:#339933">;</span>
   <span style="color:#990000">curl_setopt</span><span style="color:#009900">(</span><span style="color:#000088">$ch</span><span style="color:#339933">,</span> curlopt_returntransfer<span style="color:#339933">,</span> <span style="color:#cc66cc">1</span><span style="color:#009900">)</span><span style="color:#339933">;</span>
   <span style="color:#000088">$r</span> <span style="color:#339933">=</span> <span style="color:#990000">curl_exec</span><span style="color:#009900">(</span><span style="color:#000088">$ch</span><span style="color:#009900">)</span><span style="color:#339933">;</span>
   <span style="color:#990000">curl_close</span><span style="color:#009900">(</span><span style="color:#000088">$ch</span><span style="color:#009900">)</span><span style="color:#339933">;</span>
   <span style="color:#b1b100">return</span> <span style="color:#000088">$r</span><span style="color:#339933">;</span>
 <span style="color:#009900">}</span>

如此，除了真正的网络问题外，没再出现任何问题。
这是别人做过的关于curl和file_get_contents的测试：
file_get_contents抓取google.com需用秒数：
2.31319094
2.30374217
2.21512604
3.30553889
2.30124092
curl使用的时间：
0.68719101
0.64675593
0.64326
0.81983113
0.63956594
差距很大吧？呵呵，从我使用的经验来说，这两个工具不只是速度有差异，稳定性也相差很大。建议对网络数据抓取稳定性要求比较高的朋友使用上面的curl_file_get_contents函数，不但稳定速度快，还能假冒浏览器欺骗目标地址哦！