相关解释：
1,ini_get : Returns the value of the configuration option as a string on success,or an empty string on failure(读取 PHP.ini 配置文件中的值)
2,; Whether to allow the treatment of URLs (like http:// or ftp://) as files.
allow_url_fopen = On(配置文件中的内容)
3,fopen( "rb"): 在操作二进制文件时如果没有指定 'b' 标记，可能会碰到一些奇怪的问题，包括坏掉的图片文件以及关于 \r\n 字符的奇怪问题。
注意: 为移植性考虑，强烈建议在用 fopen() 打开文件时总是使用 'b' 标记。
注意: 再一次，为移植性考虑，强烈建议你重写那些依赖于 't' 模式的代码使其使用正确的行结束符并改成 'b' 模式。
4,strtolower -- Make a string lowercase
5,curl_init() :curl_init -- Initialize a cURL session(初始化一个cUrl会话)
resource curl_init ( [string url] )
Initializes a new session and return a cURL handle for use with the curl_setopt(),curl_exec(),and curl_close() functions.
url--If provided,the CURLOPT_URL option will be set to its value. You can manually set this using the curl_setopt() function.
Returns a cURL handle on success,FALSE on errors.
6,curl_setopt -- Set an option for a cURL transfer(提供设置)
bool curl_setopt ( resource ch,int option,mixed value )
Sets an option on the given cURL session handle. (具体请看 PHP 手册) There:
CURLOPT_URL ：The URL to fetch. You can also set this when initializing a session with curl_init().
CURLOPT_CONNECTTIMEOUT ：The number of seconds to wait whilst trying to connect. Use 0 to wait indefinitely.(无限期等待 设置为 0)
CURLOPT_RETURNTRANSFER ：TRUE to return the transfer as a string of the return value of curl_exec() instead of outputting it out directly.
CURLOPT_FAILONERROR ：TRUE to fail silently if the HTTP code returned is greater than or equal to 400. The default behavior is to return the page normally,ignoring the code.
CURLOPT_USERAGENT ：The contents of the "User-Agent: " header to be used in a HTTP request.
7,curl_exec : Perform a cURL session,This function should be called after you initialize a cURL session and all the options for the session are set.
如果成功则返回 TRUE，失败则返回 FALSE。 However,if the CURLOPT_RETURNTRANSFER option is set,it will return the result on success,FALSE on failure
8,curl_close -- Close a cURL session下面是一些参考代码:
PHP 采集程序 常用函数
PHP 采集获取指定网址的内容