如何检查网页是否存在. jQuery和/或PHP [英] How to check if a webpage exists. jQuery and/or PHP

问题描述

我希望能够验证表单以检查网站/网页是否存在.如果返回404错误，则绝对不应该验证.如果有重定向...我愿意接受建议，有时重定向会转到错误页面或主页，有时它们会转到您要查找的页面，所以我不知道.也许对于重定向，可能会有一条特别的提示向用户建议目标地址.

I want to be able to validate a form to check if a website/webpage exists. If it returns a 404 error then that definitely shouldn't validate. If there is a redirect...I'm open to suggestions, sometimes redirects go to an error page or homepage, sometimes they go to the page you were looking for, so I don't know. Perhaps for a redirect there could be a special notice that suggests the destination address to the user.

到目前为止，我发现的最好的事情是这样的:

The best thing I found so far was like this:

$.ajax({url: webpage ,type:'HEAD',error:function(){
    alert('No go.');
}});

这对于404和200来说没有问题，但是如果对URL执行'http://xyz'之类的操作，它只会挂起. 302之类的东西也会触发错误处理程序.

That has no problem with 404's and 200's but if you do something like 'http://xyz' for the url it just hangs. Also 302 and the like trigger the error handler too.

这是一个足够通用的问题，如果有人可以创建一个完整的工作代码示例，我想得到一个完整的示例.对于许多人来说，这可能很方便.

This is a generic enough question I would like a complete working code example if somebody can make one. This could be handy for lots of people to use.

推荐答案

听起来好像您并不在乎网页的内容，只想看看它是否存在.这是我在PHP中的处理方式-我可以阻止PHP占用页面内容的内存.

It sounds like you don't care about the web page's contents, you just want to see if it exists. Here's how I'd do it in PHP - I can stop PHP from taking up memory with the page's contents.

/*
 * Returns false if the page could not be retrieved (ie., no 2xx or 3xx HTTP
 * status code). On success, if $includeContents = false (default), then we
 * return true - if it's true, then we return file_get_contents()'s result (a
 * string of page content).
 */
function getURL($url, $includeContents = false)
{
  if($includeContents)
    return @file_get_contents($url);

  return (@file_get_contents($url, null, null, 0, 0) !== false);
}

为了减少冗长，将上面函数的内容替换为此.

For less verbosity, replace the above function's contents with this.

return ($includeContents) ? 
               @file_get_contents($url) :  
               (@file_get_contents($url, null, null, 0, 0) !== false)
;

有关如何指定HTTP的详细信息，请参见 http://www.php.net/file_get_contents 标头使用流上下文.

See http://www.php.net/file_get_contents for details on how to specify HTTP headers using a stream context.

干杯.

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