php 检查字符串是否为 URL
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check if a string is a URL
提问by Reham Fahmy
I've seen many questions but wasn't able to understand how it works as I want a more simple case.
我看过很多问题，但无法理解它是如何工作的，因为我想要一个更简单的案例。
If we have text, whatever it is, I'd like to check if it is a URL or not.
如果我们有文本，不管它是什么，我想检查它是否是一个 URL。
$text = "something.com"; //this is a url
if (!IsUrl($text)){
echo "No it is not url";
exit; // die well
}else{
echo "Yes it is url";
// my else codes goes
}
function IsUrl($url){
// ???
}
Is there any other way rather than checking with JavaScript in the case JS is blocked?
在 JS 被阻止的情况下，除了使用 JavaScript 进行检查之外，还有其他方法吗？
回答by enygma
PHP's filter_varfunction is what you need. Look for FILTER_VALIDATE_URL. You can also set flagsto fine-tune your implementation.
No regex needed....
PHP 的filter_var功能正是您所需要的。寻找FILTER_VALIDATE_URL. 您还可以设置flags微调您的实现。
不需要正则表达式....
回答by user3078359
The code below worked for me:
下面的代码对我有用：
if(filter_var($text, FILTER_VALIDATE_URL))
{
echo "Yes it is url";
exit; // die well
}
else
{
echo "No it is not url";
// my else codes goes
}
You can also specify RFCcompliance and other requirements on the URL using flags. See PHP Validate Filtersfor more details.
回答by JKirchartz
http://www.php.net/manual/en/function.preg-match.php#93824
http://www.php.net/manual/en/function.preg-match.php#93824
<?php
$regex = "((https?|ftp)\:\/\/)?"; // SCHEME
$regex .= "([a-z0-9+!*(),;?&=$_.-]+(\:[a-z0-9+!*(),;?&=$_.-]+)?@)?"; // User and Pass
$regex .= "([a-z0-9-.]*)\.([a-z]{2,3})"; // Host or IP
$regex .= "(\:[0-9]{2,5})?"; // Port
$regex .= "(\/([a-z0-9+$_-]\.?)+)*\/?"; // Path
$regex .= "(\?[a-z+&$_.-][a-z0-9;:@&%=+\/$_.-]*)?"; // GET Query
$regex .= "(#[a-z_.-][a-z0-9+$_.-]*)?"; // Anchor
if(preg_match("/^$regex$/i", $url)) // `i` flag for case-insensitive
{
return true;
}
?>
but your example URL is over simplified, (\w+)\.(\w+)would match it. somebody else mentioned filter_varwhich is simply a filter_var($url, FILTER_VALIDATE_URL)but it doesn't seem to like non-asciicharacters so, beware...
但您的示例 URL 过于简化，(\w+)\.(\w+)将匹配它。其他人提到filter_var这只是一个filter_var($url, FILTER_VALIDATE_URL)但它似乎不喜欢非 ascii字符所以，当心......
回答by Sindre
Check if it is a valid url (example.com IS NOTa valid URL)
检查它是否是一个有效的网址（example.com不是一个有效的网址）
function isValidURL($url)
{
return preg_match('|^http(s)?://[a-z0-9-]+(.[a-z0-9-]+)*
(:[0-9]+)?(/.*)?$|i', $url);
}
How to use the function:
如何使用该功能：
if(!isValidURL($fldbanner_url))
{
$errMsg .= "* Please enter valid URL including http://<br>";
}
Source: http://phpcentral.com/208-url-validation-in-php.html
回答by greenie2600
Regexes are a poor way to validate something as complex as a URL.
正则表达式是验证像 URL 这样复杂的东西的糟糕方法。
PHP's filter_var()function offers a much more robust way to validate URLs. Plus, it's faster, since it's native code.
PHP 的filter_var()函数提供了一种更强大的方式来验证 URL。另外，它更快，因为它是本机代码。
回答by kytwb
You could use the following regex pattern to check if your variable is an url or not :
您可以使用以下正则表达式模式来检查您的变量是否为 url：
$pattern = "\b(([\w-]+:\/\/?|www[.])[^\s()<>]+(?:\([\w\d]+\)|([^[:punct:]\s]|\/)))";
回答by Churk
I don't think there is a definitive answer to this. Example of a valid URL:
我不认为对此有明确的答案。有效 URL 示例：
localhost
http://xxx.xxx.xxx/alkjnsdf
abs.com
If you have some text. and not a large amount of it. You can check by doing a CURL request and see if that returns a valid response. Otherwise if I put localhost, it could be a link and it could be something else and you wouldn't be able check it.
如果你有一些文字。而且数量不多。您可以通过执行 CURL 请求来检查它是否返回有效响应。否则，如果我输入 localhost，它可能是一个链接，也可能是其他内容，您将无法检查它。
回答by anubhava
Something like might work for you:
类似的东西可能对你有用：
$arr = array('abc.com/foo',
'localhost',
'abc+def',
'how r u',
'https://how r u',
'ftp://abc.com',
'a.b');
foreach ($arr as $u) {
$url = $u;
if (!preg_match('#^(?:https?|ftp)://#', $url, $m))
$url = 'http://' . $url;
echo "$u => ";
var_dump(filter_var($url, FILTER_VALIDATE_URL));
}
OUTPUT:
输出：
abc.com/foo => string(18) "http://abc.com/foo"
localhost => string(16) "http://localhost"
abc+def => string(14) "http://abc+def"
how r u => bool(false)
https://how r u => bool(false)
ftp://abc.com => string(13) "ftp://abc.com"
a.b => string(10) "http://a.b"
So basically wherever you notice falseas return value that is an INVALID URL for you.
因此，基本上无论您注意到false返回值的任何地方都是无效的 URL。
