Add-on Dev: Extending channel->entries and tagdata

Question

I have a search module that grabs locations based on coordinates and estimates distances. I've decided to extend then channel class so I can take advantage of the entries method to display search results. In my method, I use an sql query to find the entry_ids and estimated distance. I then have the following:

public function search_results() {
    ...
    $entry_ids = '4|24|265|23';
    $distances = array(
        1.023536,
        1.254824,
        3.000325,
        4.923142
    );

    ee()->TMPL->tagparams['entry_id'] = $search_ids;
    return parent::entries();
}

This works great with the following code in my template, with one problem:

{exp:module:results}
    <li>
        <span>{distance}</span>
        <h4><a href="/location/{url_title}">{title}</a></h4>
        <div>{my_custom_field}</div>
    </li>
{/exp:module:results}

The "distance" is not a channel field, but that calculated value. Any suggestions on how I can inject that into the parsing per row?

Answer 1

You could create an extension which uses the channel_entries_query_result hook to add your variable to each entry row. That will get parsed along with the native vars. To pass data from your module/plugin file to the extension, you'd need to use the Session cache.

You might be interested to know that Low Search offers a straight forward API for custom filters, which basically extends the channel:entries tag, too. With it, in the same file, you can add your filter rules (which you have in your module/plugin file) and manipulate the output of the results (which you can do with an extension).