preg_match:确保开始和结束包含某些内容

Question

我希望有一个正则表达式,确保字符串的开头包含'http://'和'/'以及结尾.

这是我提出的更长的版本,

if(!preg_match("/(^http:\/\//", $site_http)) 
{
 $error = true;
 echo '<error elementid="site_http" message="site_http - Your link appears to be invalid. Please confirm that your link contains http:// at the start."/>';
}
elseif (!preg_match("/\/$/", $site_http)) 
{
 $error = true;
 echo '<error elementid="site_http" message="site_http - Your link appears to be invalid. Please confirm that your link has ended with a /."/>';
}

但我认为这两个表达式可以像下面这样放在一起,但它不会起作用,

if(!preg_match("/(^http:\/\/)&(\/$)/", $site_http)) 
{
 $error = true;
 echo '<error elementid="site_http" message="site_http - Your link appears to be invalid. Please confirm that your link contains http:// at the start and a / at the end."/>';
}

我试图结合的多个表达式一定是错的!任何的想法？

谢谢,刘

Answer 1

if(preg_match('/^http:\/\/.*\/$/', $site_http)) 
{
  ...
}

该^http:\/\/部队http://在正面的\/$力量在最后一个斜杠,并.*让一切(也可能没有)之间.

例如:

<?php

foreach (array("http://site.com.invalid/", "http://") as $site_http) {
  echo "$site_http - ";
  if (preg_match('/^http:\/\/.*\/$/', $site_http)) {
    echo "match\n";
  }
  else {
    echo "no match\n";
  }
}
?>

生成以下输出:

http://site.com.invalid/ - match
http:// - no match