Trouble matching Name Servers in PHP with regular expressions

Hi everyone,

I'm having trouble matching Name Servers using regular expressions in PHP. I would greatly appreciate it if someone could help me out with this issue.

To give you a bit of background, I am currently working on a project where I need to validate and extract Name Servers from a given domain name. I have already tried using various regular expressions that I found online, but none of them seem to work properly.

Just to be clear, a typical Name Server looks like this: ns1.example.com or ns2.example.com. I am trying to extract the "ns1" or "ns2" part from the Name Server.

Here is the code I have so far:

```php
$domain = "ns1.example.com";
$pattern = "/^(ns\d+)/";
preg_match($pattern, $domain, $matches);

echo $matches[0];
```

However, when I run this code, it doesn't return anything. It seems like my regular expression is not matching the Name Server correctly.

I have tested my regular expression on online regex testers and it seems to work fine there. But when I try to implement it in my PHP code, it fails to match. I have also tried using different variations of the regular expression, but no luck so far.

I was wondering if anyone has faced a similar issue before or if there is something wrong with my code. Perhaps there is a better regular expression that I can use for matching Name Servers in PHP? Any suggestions or insights would be greatly appreciated.

Thank you in advance for your help!

All Replies

fbalistreri

July 09 2023 at 07:40 PM

User1: Hey there!

I had a similar issue a while back when I was working on a similar project. After some trial and error, I found a regular expression that worked well for matching Name Servers in PHP. Here's what worked for me:

php
$domain = "ns1.example.com";

$pattern = "/^([a-z0-9]+)\./i";

preg_match($pattern, $domain, $matches);



echo $matches[1];

In this case, the regular expression `/^([a-z0-9]+)\./i` matches any combination of lowercase letters and digits before the dot in the domain. It captures the desired part and stores it in `$matches[1]`.

Make sure to use the `i` flag after the pattern to ensure a case-insensitive match. Also, don't forget to escape any special characters if you are using them in your Name Server patterns.

Give it a try and see if it works for you. Let me know if you have any further questions!

Helpful (10)

gladyce48

July 09 2023 at 02:42 PM

User2: Howdy, folks!

I can totally understand the frustration you're experiencing with matching Name Servers in PHP using regular expressions. I recently encountered a similar challenge and came up with a different approach that might help you out.

Instead of relying solely on regular expressions, I used the built-in `parse_url()` function in PHP to extract the hostname from the domain. Then, I used the `explode()` function to split the hostname by the dot and retrieve the desired part of the Name Server. Here's an example:

php
$domain = "ns1.example.com";

$hostname = parse_url($domain, PHP_URL_HOST);

$nameServer = explode(".", $hostname)[0];



echo $nameServer;

In this code snippet, `parse_url()` extracts the hostname from the given domain, and `explode()` splits the hostname on the dot. The `[0]` index retrieves the first part of the resulting array, which represents the Name Server.

Give this method a shot and see if it works better for your use case. Sometimes using a combination of built-in functions can provide a more reliable solution. Let me know if you have any further questions or need additional assistance!

Helpful (9)

Trouble matching Name Servers in PHP with regular expressions

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