How to fix improperly formatted URL strings entered by members

Question

I allow members to enter their web address, facebook address, etc. for their member profiles as well as in directory listing entries. I instruct them to always include "http://" at the beginning of the URL but of course they don't always listen. So in many cases I'm getting URL formatted with no "http://" or "https://" which create bad links.

Is there a way I can essentially do a find a replace for NOT found? So if the URL string does not contain "http://" or "https://" then I can add it back in so the link isn't broken?

I use CE String plugin for other things and I have been trying to work out a way to use it for this purpose but haven't had any luck yet.

Here's the related part of my template:

{if website}<li class="web"><a href="{website}">{exp:low_replace multiple="yes" find="http://|https://"}{website}{/exp:low_replace}</a></li>{/if}
{if facebook}<li class="facebook"><a href="{facebook}">{exp:low_replace multiple="yes" find="http://|https://"}{facebook}{/exp:low_replace}</a></li>{/if}

I need to enter some logic at the beginning of each link's href to add in the "http://" if the member has not included it in their URL string. Would appreciate any help on how to achieve this.

Answer 1

The EECMS has a "first party" plugin for this, but it isn't included in ExpressionEngine by default. You have to download it.

From the own add-on file:

Makes sure that a URL has a protocol, that ampersands are converted to entities, and all other characters are properly URL encoded.

{if website}
    <li class="web">
        <a href="{exp:valid_url}{website}{/exp:valid_url}">
            {website}
        </a>
    </li>
{/if}
{if facebook}
    <li class="facebook">
        <a href="{exp:valid_url}{facebook}{/exp:valid_url}">
            {facebook}
        </a>
    </li>
{/if}

There's some useful add-ons available for download on the User Guide. They're all maintained by EllisLab itself.