PHP 验证URL
示例
过滤URL时，filter_var()将返回过滤的数据（在这种情况下为URL）；如果找不到有效的URL，则返回false：
网址：example.com
var_dump(filter_var('example.com', FILTER_VALIDATE_URL));
var_dump(filter_var('example.com', FILTER_VALIDATE_URL, FILTER_FLAG_SCHEME_REQUIRED));
var_dump(filter_var('example.com', FILTER_VALIDATE_URL, FILTER_FLAG_HOST_REQUIRED));
var_dump(filter_var('example.com', FILTER_VALIDATE_URL, FILTER_FLAG_PATH_REQUIRED));
var_dump(filter_var('example.com', FILTER_VALIDATE_URL, FILTER_FLAG_QUERY_REQUIRED));结果：
bool(false) bool(false) bool(false) bool(false) bool(false)
网址：http://example.com
var_dump(filter_var('http://example.com', FILTER_VALIDATE_URL));
var_dump(filter_var('http://example.com', FILTER_VALIDATE_URL, FILTER_FLAG_SCHEME_REQUIRED));
var_dump(filter_var('http://example.com', FILTER_VALIDATE_URL, FILTER_FLAG_HOST_REQUIRED));
var_dump(filter_var('http://example.com', FILTER_VALIDATE_URL, FILTER_FLAG_PATH_REQUIRED));
var_dump(filter_var('http://example.com', FILTER_VALIDATE_URL, FILTER_FLAG_QUERY_REQUIRED));结果：
string(18) "http://example.com" string(18) "http://example.com" string(18) "http://example.com" bool(false) bool(false)
网址：http://www.example.com
var_dump(filter_var('http://www.example.com', FILTER_VALIDATE_URL));
var_dump(filter_var('http://www.example.com', FILTER_VALIDATE_URL, FILTER_FLAG_SCHEME_REQUIRED));
var_dump(filter_var('http://www.example.com', FILTER_VALIDATE_URL, FILTER_FLAG_HOST_REQUIRED));
var_dump(filter_var('http://www.example.com', FILTER_VALIDATE_URL, FILTER_FLAG_PATH_REQUIRED));
var_dump(filter_var('http://www.example.com', FILTER_VALIDATE_URL, FILTER_FLAG_QUERY_REQUIRED));结果：
string(22) "http://www.example.com" string(22) "http://www.example.com" string(22) "http://www.example.com" bool(false) bool(false)
网址：http://www.example.com/path/to/dir/
var_dump(filter_var('http://www.example.com/path/to/dir/', FILTER_VALIDATE_URL));
var_dump(filter_var('http://www.example.com/path/to/dir/', FILTER_VALIDATE_URL, FILTER_FLAG_SCHEME_REQUIRED));
var_dump(filter_var('http://www.example.com/path/to/dir/', FILTER_VALIDATE_URL, FILTER_FLAG_HOST_REQUIRED));
var_dump(filter_var('http://www.example.com/path/to/dir/', FILTER_VALIDATE_URL, FILTER_FLAG_PATH_REQUIRED));
var_dump(filter_var('http://www.example.com/path/to/dir/', FILTER_VALIDATE_URL, FILTER_FLAG_QUERY_REQUIRED));结果：
string(35) "http://www.example.com/path/to/dir/" string(35) "http://www.example.com/path/to/dir/" string(35) "http://www.example.com/path/to/dir/" string(35) "http://www.example.com/path/to/dir/" bool(false)
网址：http://www.example.com/path/to/dir/index.php
var_dump(filter_var('http://www.example.com/path/to/dir/index.php', FILTER_VALIDATE_URL));
var_dump(filter_var('http://www.example.com/path/to/dir/index.php', FILTER_VALIDATE_URL, FILTER_FLAG_SCHEME_REQUIRED));
var_dump(filter_var('http://www.example.com/path/to/dir/index.php', FILTER_VALIDATE_URL, FILTER_FLAG_HOST_REQUIRED));
var_dump(filter_var('http://www.example.com/path/to/dir/index.php', FILTER_VALIDATE_URL, FILTER_FLAG_PATH_REQUIRED));
var_dump(filter_var('http://www.example.com/path/to/dir/index.php', FILTER_VALIDATE_URL, FILTER_FLAG_QUERY_REQUIRED));结果：
string(44) "http://www.example.com/path/to/dir/index.php" string(44) "http://www.example.com/path/to/dir/index.php" string(44) "http://www.example.com/path/to/dir/index.php" string(44) "http://www.example.com/path/to/dir/index.php" bool(false)
网址：http://www.example.com/path/to/dir/index.php?test=y
var_dump(filter_var('http://www.example.com/path/to/dir/index.php?test=y', FILTER_VALIDATE_URL));
var_dump(filter_var('http://www.example.com/path/to/dir/index.php?test=y', FILTER_VALIDATE_URL, FILTER_FLAG_SCHEME_REQUIRED));
var_dump(filter_var('http://www.example.com/path/to/dir/index.php?test=y', FILTER_VALIDATE_URL, FILTER_FLAG_HOST_REQUIRED));
var_dump(filter_var('http://www.example.com/path/to/dir/index.php?test=y', FILTER_VALIDATE_URL, FILTER_FLAG_PATH_REQUIRED));
var_dump(filter_var('http://www.example.com/path/to/dir/index.php?test=y', FILTER_VALIDATE_URL, FILTER_FLAG_QUERY_REQUIRED));结果：
string(51) "http://www.example.com/path/to/dir/index.php?test=y" string(51) "http://www.example.com/path/to/dir/index.php?test=y" string(51) "http://www.example.com/path/to/dir/index.php?test=y" string(51) "http://www.example.com/path/to/dir/index.php?test=y" string(51) "http://www.example.com/path/to/dir/index.php?test=y"
警告：您必须检查协议以保护自己免受XSS攻击：
var_dump(filter_var('javascript://comment%0Aalert(1)', FILTER_VALIDATE_URL));
// string(31) "javascript://comment%0Aalert(1)"