Intended audience
Background
Getting results from a database
Highlighting search criteria
Getting a search result synopsis
Conclusion
About the author

Intended audience

The purpose of this article is to show how to build two functions that help make search results from a database look more appealing to users.

Background

Most people are familiar with doing searches on Google, and how Google formats search results. First, the search criteria text appears in a bold font. Second, the text of the search results ends with an ellipsis (...) to let the user know that there is more information where that came from. These little UI features make it easy for readers to find what they are looking for.

Getting results from a database

There's no doubt that one of PHP's strongest features is its ability to interact with various databases. For this article we will be using MySQL but the code presented here can be modified to support other databases with little effort.

By way of a primer, here's a sample script that you could use to query a database:

<?php
$query = "
    SELECT id, title, author, body
    FROM article
    WHERE author='John Doe'
";
$result = mysql_query($query);
$row = mysql_fetch_array($result, MYSQL_ASSOC);
$body = $row['body'];
?>

Highlighting search criteria

On of the handy things many web sites do with their search results is highlight in some way the search criteria in the search results. As mentioned before, Google does this by making the search criteria text bold as seen in the following example:



In our example we will change the background color of the text.

Highlighting text involves changing the style of the text using the CSS 'background-color' property. This can easily be done using the style parameter of many tags. In this case we'll use the <span> tag:

<span style="background-color: Yellow;">this is some sample text.</span>


Obviously we need to be able to dynamically change the background color using PHP:

<span style="background-color: <?php echo $bgcolor; ?>">this is some sample text.</span>

We will get the value of $bgcolor later in the article.

So now, how do we put our search criteria in between the <span> tags? One way is to store the start and end tags in their own PHP variables. Then we can concatenate everything together using PHP’s concatenation operator.

<?php
$start_tag = "<span style='background-color: $bgcolor '>";
$end_tag = '</span>';
$highlighted_results = $start_tag . $criteria . $end_tag;
?>


Next we need some way to highlight the criteria only, without highlighting the rest of the result text. The best and most portable way to make any changes to the search results is by using a function.

<?php

function highlight_search_criteria($search_criteria, $bgcolor='Yellow')
{
    $start_tag = "<span style=' background-color: $bgcolor'>";
    $end_tag = '</span>';

    $highlighted_results = $start_tag . $search_criteria . $end_tag;

    return $highlighted_results;
}

?>


This function takes as its parameters the search criteria text and an optional background color. Here's an example of how you might use this function:

<?php

$highlighted_criteria = highlight_search_criteria('John Doe');
echo $highlighted_criteria;

?>


This would produce the following text:

John Doe

Notice that we left out the second parameter of the function. Since the second parameter is defined with a default value, it can be left blank and the default value will be used. If you wanted to change the background color, from Yellow to Green for example, you would provide 'Green' as the second parameter when calling the function.

Now all this is nice and it does the job, but we can take it even further. Wouldn't it be nice if we could provide the complete text as well as the search criteria and have the criteria automatically highlighted inline? With a little more work to our function we can do just that.

<?php

function highlight_search_criteria($search_results, $search_criteria, $bgcolor='Yellow')
{
    $start_tag = ';';

    $highlighted_results = $start_tag . $search_criteria . $end_tag;

    return eregi_replace($search_criteria, $highlighted_results, $search_results);
}

?>


This function adds the full search results text as the first parameter. Then, using the eregi_replace() function built-in to PHP, we can replace all occurrences of $search_criteria throughout $search_results with $highlighted_results.

Our function is nearly complete but we still have one last thing to do. What would happen if the search criteria are not found anywhere in the search results? You might find some unexpected things happen if you replace nothing with something throughout your search results. Because of this, we need to check that we actually have search criteria to highlight inside our function.

<?php

function highlight_search_criteria($search_results, $search_criteria, $bgcolor='Yellow')
{
    if (empty($criteria)) {
        return $search_results;
    } else {
        $start_tag = '<span style='background-color: $bgcolor'>';
        $end_tag = '</span>';

        $highlighted_results = $start_tag . $search_criteria . $end_tag;

        return eregi_replace($search_criteria, $highlighted_results, $search_results);
    }
}

?>


And here's an example of how to use the function:

<?php

$db_result_text = "The users with the most points in this game were John Doe,
Jane Smith, and Bill Bobbins.";
$result_text = highlight_search_criteria($db_result_text, 'John Doe');

echo $db_result_text;

?>


This results in:

The users with the most points in this game were John Doe, Jane Smith, and Bill Bobbins.

There are a few more things you could do to this function. For example, you could provide the option of either highlighting the background color or making the criteria bold. You might even extend it so that it automatically picks a random background color each time it is used. I'm sure you'll think of a million other features to add to this function that will make it even more useful.

Getting a search result synopsis

As a companion to the highlight_search_criteria()function we built above, the following function can allow you to easily summarize your search results.
When you are listing several results you probably don't want to display the full results, because your users might end up with a annoyingly long pages that require a lot of scrolling.

The most common way to “summarize” text (which is not really “summarizing” but simply “truncating”) is to quote the first few words followed by an ellipsis. An example of this might be:

We hold these truths to be self-evident...

In order to do this we need to reduce the text from a variable number of words to a manageable number, say 10. We'll use the explode() function to do this.

explode() takes a string and breaks it up into an array using a specified delimiter. This is preferable over using a regular expression, as it scales better and doesn't look like a rash of cartoon profanity. Here is what explode() looks like in action.

<?php

$text_array = explode(' ', 'This is just a test');

print_r($expl_array);

?>


In this example we are splitting the string "This is just a test." using the space character as a delimiter. Here is the output of the script.

Array
(
    [0] => This
    [1] => is
    [2] => just
    [3] => a
    [4] => test
)


Now that we have all the words of our result text inside an array we can easily get the first 10 words. This is how it looks in the function:

<?php

function summarize_search_result($result_text, $num_words=10) {
    $text_array = explode(' ', $result_text, $num_words +  1);

    return implode(' ', array_slice($text_array, 0, $num_words). '...';
}

?>


Here we have a function that accepts the result text as its first parameter as well as an option integer representing the number of words in the summary. In the function we first get the array of words using explode() up to the desired number of words (third parameter to explode()).

Finally, we use the implode() function to bring the words back together, and append the ellipsis to the result.

Here’s an example of how to use it:

<?php

$some_text = "WHEN in the Course of human Events, it becomes necessary for 
one People to dissolve the political bands which have connected them with another
, and to assume among the Powers of the Earth, the separate and equal Station to 
which the Laws of Nature and Nature's God entitle them, a decent Respect to the Opinions 
of Mankind requires that they should declare the causes which impel them to the Separation.";

$summary_text = summarize_search_result($some_text, 15);

echo $summary_text;

?>


This results in:

WHEN in the Course of human Events, it becomes necessary for one People to dissolve...

As with highlight_search_criteria() you can probably find many more ways to extend this function.

Conclusion

Using these two functions together you can get results very similar to Google Groups where the search criteria is not only bold but is highlighted.

<?php

$some_text = "WHEN in the Course of human Events, it becomes necessary for 
one People to dissolve the political bands which have connected them with another, 
and to assume among the Powers of the Earth, the separate and equal Station to which 
the Laws of Nature and Nature's God entitle them, a decent Respect to the Opinions of 
Mankind requires that they should declare the causes which impel them to the Separation.";

$searched = highlight_search_criteria($some_text, 'Events');

$summarized = summarize_search_result($searched, 15);

echo $summarized;

?>


This will give you:

WHEN in the Course of human Events, it becomes necessary for one People to dissolve...

The functions covered here are far from complex or advanced PHP but I think you will agree that they are very handy functions to have in any web developer's toolkit. They also do a great job of showing off the power of PHP!

About the author

Darrell Brogdon is an independent consultant specializing in Web Application development. He can be reached at darrell@brogdon.net.