Link or image preg/ereg replace?

Question

Heres my issue. I'm building a website where you can share links/pictures. Now heres what I want to do. If the link is a link to a site, then display a link such as:

<a href="http://example.com" target="_blank">http://example.com</a>

But heres my downfall, if it a picture(jpg, gif, png, ect) I want to display that on the page instead of the link. How do I go about doing that?

-- Forgot to add:

$profile_post_post = ereg_replace("[[:alpha:]]+://[^<>[:space:]]+[[:alnum:]/]","<a href=\"\\0\" target=\"_blank\">\\0</a>", $profile_post_post);

Thats the code that makes the link.

an img just uses the if you link an image you would just do Can you elaborate more on what you already have in place? — cwhelms, Jul 06 '11 at 18:59
Please share the code how you do it already for the normal link. — hakre, Jul 06 '11 at 19:00
Blimey; I haven't seen `ereg_replace` in years! Is there any particular reason, @JakeAero, that you ignored that **massive red warning** on its manual page, stating that "this function has been DEPRECATED as of PHP 5.3.0", and that "relying on this feature is highly discouraged"? Or the long-standing tip at the bottom that reads "`preg_replace()`, which uses a Perl-compatible regular expression syntax, is often a faster alternative to `ereg_replace()`"? — Lightness Races in Orbit, Jul 06 '11 at 19:03

score 0 · Accepted Answer · answered Jul 06 '11 at 19:06

0

Use preg_replace_callback, providing a callback that selects the link contents conditionally based on its format. i.e. if it ends in .jpg, render an img tag. If it ends in anything other than a typical image file extension, print its name.

answered Jul 06 '11 at 19:06

Lightness Races in Orbit

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score 0 · Answer 2 · answered Jul 06 '11 at 19:15

Assuming you are using PHP, and the URL is stored in $url:

if (!preg_match("@^https?\:\/\/@", $url)
{
    $url = "http://$url";
}

if (preg_match("@\.(gif|jpe?g|png)$@", $url))
{
   echo '<img src="' . $url . '" />"';
}
else
{
   echo '<a href="' . $url . '" target="_blank">' . $url . </a>;
}

This is not an exact method, as some pictures may be served with the correct MIME type without bearing a gif, jpeg, jpg or png extension.

This is a far better method to check if a link refers to a picture, but it is time- and bandwith consuming. As such, it would be better to store the result in a database at the same time $url is, for later reuses:

if (!preg_match("@^https?\:\/\/@", $url)
{
    $url = "http://$url";
}

$headers = get_headers($url, 1);
$mime_type = isset($headers["Content-Type"])  ?  $headers["Content-Type"]  :  "";

if (preg_match("@\.(gif|jpe?g|png)$@", $url)  ||  preg_match("@^image\/@", $mime_type))
{
   $html = '<img src="' . $url . '" />"';
}
else
{
   $html = '<a href="' . $url . '" target="_blank">' . $url . '</a>';
}

Link or image preg/ereg replace?

2 Answers2