This article will show how to create a
site-specific search engine. No programming skills will be required to
implement the code presented here but the reader should be familiar
with HTML and would benefit by having some understanding PHP.
Site Search: Quick and Easy
Overview
A site-specific search capability is a nice feature to be able to
add to a website. If a site is large and content-rich such an addition
can be an indispensable aid.
However, the complexity of creating your own search engine can be
intimidating even for an experienced web programmer. This article will
show how to create a site-specific search engine. No programming skills
will be required to implement the code presented here but the reader
should be familiar with HTML and would benefit by having some
understanding of scripting languages.
How We'll Do It
To give a quick overview, we will be using an HTML "form" with a
"text input" box and a "submit" button. This form in conjunction with
the Google API and an open-source PHP script is all that will be
needed. We'll show you how to put these elements together so that a
simple form may be placed on a sidebar, or wherever appropriate, to
assist in searching your site.
There are three steps to creating this site-specific search engine.
1) Get a license key from Google, 2) download the PHP script, "nusoap"
and finally, 3) install a short script to initiate the search and
format the HTML output.
Google API
API stands for "Application Programming Interface" ? it is simply a
means to tap into the Google search engine without having to actually
point your browser at their site. It allows you to perform Google
searches programmatically.
You may find out about the Google API at http://www.google.com/apis/.
You need not download the example code but you will need to create a
Google account and get a license key. This license key will allow you
to initiate 1000 searches per day using the Google API. Check your
website statistics and if you are getting fewer than 500 visits per day
then this number of searches will most likely be more than adequate.
nusoap
nusoap is a PHP script that will facilitate use of the Google API. It is available from the URL, http://sourceforge.net/projects/nusoap/.
Go to this site and find the download link about halfway down the page.
At the time of writing the latest version was 0.6.7. The file is zipped
but don't let that discourage you from using it on a non-Windows
server. It works just as well using Apache and Linux as it does using
Internet Information Server and Windows. You will, of course have to
have PHP installed on your server. If it is not already installed then
it is probably time to find a new web host.
There are a number of files compressed into the zipped file but
"nusoap.php" is the only one we need to be concerned about. If you are
familiar with PHP you may want to have a look at the other files. I
will just mention though that the script we develop is a modification
of the "client3.php" file.
The Code
Let's first create the form that will invoke the search page:
Search this site: <br />
<form method="get" name="search"
action="search.php">
<input type="text" name="criterion" style="width:100px" /><br />
<input style="margin-top:5px" type="submit" value="Submit" />
</form>
Insert this code into the page that you intend to search from ? for
the sake of easy reference let's call that page "searchfrom.html".
The code that actually performs the search is below (based on the "client3.php" file):
<html>
<head>
<title>Site Search Page</title>
</head>
<body>
<?php
require_once("nusoap.php");
$criterion=@$_GET["criterion"];
if(strpos($criterion, """)){
$criterion = stripslashes($criterion);
echo "<b>$criterion</b>";
}else
echo ""<b>$criterion</b>".</p>";
$query=$criterion;
//your site here
$query .= " site:www.yoursite.com";
//your Google key goes here
$key = "yourgooglekey";
//change the value below if you like
$maxresults = 10;
$start = 0;
$parameters = array(
'Googlekey'=>$key,
'queryStr'=>$query,
'startFrom'=>$start,
'maxResults'=>$maxresults,
'filter'=>true,
'restrict'=>'',
'adultContent'=>true,
'language'=>'',
'iencoding'=>'',
'oendcoding'=>''
);
$client = new
soapclient("http://api.google.com/search/beta2");
$result = $client->call("doGoogleSearch", $parameters,
"urn:GoogleSearch");
$searchtime = $result["searchTime"];
$total = $result["estimatedTotalResultsCount"];
if($total > 0){
$rs = $result["resultElements"];
$output="";
for ($i = 0; $i < $total; $i++){
if (!isset($rs[$i])) break;
$element = $rs[$i];
//$title=$element["title"];
$url = $element["URL"];
$snippet = $element["snippet"];
$output.= "<p><a href="$url">".basename($url)."</a> $snippet</p>n";
}
echo $output;
echo "<br /><br />Search time: $searchtime seconds.";
}else
echo "<br /><br />Nothing found.";
?>
</body>
</html>
Save this code as "search.php" making sure that you use the file extension "php".
The changes you need to make to this script are shown in bold.
Substitute your domain name for "www.yoursite.com" and your Google key
for "yourgooglekey" making sure to enclose both items in quotation
marks. Change the value of "$maxresults" if you wish to have fewer or
more results.
To sum up, we now have three files that need to be located in the
same directory, "searchfrom.html", "nusoap.php" and "search.php".
Entering a criterion into the textbox on the "searchfrom.html" page
will open the "search.php" page and display the results of your search
- limited to the specified site. These results will show a snippet of
text and a hyperlink to the page on which your criterion appears.
Visitors to your site can now easily find items of interest and quickly
navigate to them.
Changes & Improvements
Depending upon your knowledge of PHP and HTML this code can be
customised and changed in a number of ways. We have already shown how
the number of results returned can be adjusted but you might also want
to add a pop-up window of search hints for your site visitors. Let them
know that they can search for a single word, or a group of words, or a
specific phrase if they enclose the expression in quotation marks.
Another useful element returned from Google is the page title. I've
put it into the "search.php" page to show how to access it but have
commented it out. One possible use for this piece of information would
be to limit search results to a specifically named page. I'll let you
determine how this might be done.
As you can see our script uses one of the Google advanced search techniques (see http://www.google.com/help/refinesearch.html
), a criterion, the word "site" followed by a semicolon and then a
domain name. In the same way as we have done here, you could easily
change this code to search instead for specific file types by using
something like " filetype:pdf" instead of " site:www.yoursite.com".
You may also want to indicate to visitors that your site search is
Google-based. You may certainly do this but check out the terms and
conditions of use at http://www.google.com/apis/api_terms.html.
Some Limitations
It might be said that any web surfer could do exactly what is
described here by opening a separate instance of their browser and
doing a site-specific search themselves. Quite true, but how many
people would know how to do this and even if they knew, how many would
actually do it? Most web surfers will appreciate the convenience of
being provided with a site-specific search capabilities embedded right
into your site.
As already mentioned, this is not the solution for a high-traffic
site where many searches will be initiated. Nor is it a solution for a
newly posted site. Until a site is indexed by Google no search results
will be returned. Likewise, recent changes to a site will not be found
until the Googlebot visits and registers them.
Additionally, some of the less common character entities are not
rendered correctly. I noticed no problem with common entities such as
"<" and "&" but less common ones such as "…"
were simply rendered as question marks.
That said though, using the Google API in conjunction with the
"nusoap" script is a quick and easy way to implement a site-specific
search. This is particularly useful for sites that are content-rich and
it is an excellent additional service to propose to your clients once
their newly created site shows up on Google.
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