Here is one example of how to parse XML results using PHP.

To provide a specific example, I¡¯ve created a form and code that works with Amazon¡¯s web services. The code below displays a basic form, which queries Amazon, retrieves the XML data, parses the results, and displays them in a nicely formatted table.

Note that in order for this code to work, you will need to obtain your own Access Key ID, which you can easily do here.

• The complete script can be found here
• The XML sample file can be found here

We¡¯ll begin by  a class containing the objects for our xml script:

class OfferList {
var $parser;
var $record;
var $current_field;
var $field_type;
var $ends_record;
var $records;

Next, we need to identify the starting element and the ending element.  Pay close attention the $element variable in both functions.  This means that any tag in the XML document that we reference in this script must be typed in lowercase letters.  So, if there¡¯s a tag we need to use .

function start_element($p,$element,&$attributes){
$element = strtolower($element);
if ($this->field_type[$element] != 0) {
$this->current_field = $element;
} else {
$this->current_field = ¡®¡¯;
}
}

function end_element ($p, $element) {
$element = strtolower($element);
if ($this->ends_record[$element]) {
$this->records[] = $this->record;
$this->record = array();
}
$this->current_field = ¡®¡¯;
}

Here is where we create a new parser, tell it what to parse, and parse it.

function OfferList ($filename) {
$this ->parser = xml_parser_create();
xml_set_object($this->parser, &$this);
xml_set_element_handler($this->parser,¡¯start_element¡¯,'end_element¡¯);
xml_set_character_data_handler($this->parser,¡¯cdata¡¯);

NOTE: The array below should be filled in with the tags from the XML document you are parsing.  Type 1 is a single field and type 2 is an array field.

$this->field_type=array(¡¯asin¡¯ => 1,
¡®detailpageurl¡¯ => 1,
¡®itemattributes¡¯ => 1,
¡®manufacturer¡¯ => 1,
¡®productgroup¡¯ => 1,
¡®title¡¯ => 1);

NOTE: Change ¡®item¡¯ to whatever the closing tag is from your XML document.

$this->ends_record = array(¡¯item¡¯ => true);

$x = join(¡±", file($filename));
xml_parse($this->parser, $x);
xml_parser_free($this->parser);

}

In the event that one of the field_types (set in the OfferList function) is type 2, we¡¯ll tell it where to find the text:

function cdata ($p, $text) {
if($this->field_type[$this->current_field]===2){
$this->record[$this->current_field][]=$text;
}elseif($this->field_type[$this->current_field]===1){
$this->record[$this->current_field].=$text;
}
}

Here is a function to sort the results.  Note that, at least for Amazon, you can specify a parameter in the XML url to sort the results. But, if the url you¡¯ll be using doesn¡¯t have that feature, this is handy.

function resultSort($offer1, $offer2) {
$o1 = $offer1[¡¯title¡¯];
$o2 = $offer2[¡¯title¡¯];

if($o1 == $o2) return 0;
return $o1 < $o2 ? -1 : 1;
}

And this function display the results:

function show_menu() {

if($this->records > 0) {

$color1 = ¡°#EBF0F0¡å;
$color2 = ¡°#C0CACA¡±;
$row_count = 0;
usort($this->records,array($this,¡¯resultSort¡¯));

foreach ($this->records as $offer) {
$pricesub = substr($offer[¡¯price¡¯],-3);
$row_color = ($row_count % 2) ? $color1 : $color2;
$mu = urlencode($offer[¡¯merchanturl¡¯]);
echo ¡±
<tr height=\"35\"
valign=\"top\"
bgcolor=\"$row_color\">¡°;

print(
¡±
<td>¡°.$offer[¡¯title¡¯].¡±</td>
<td>¡°.$offer[¡¯manufacturer¡¯].¡±</td>
<td align=\"center\">¡°.
$offer[¡¯productgroup¡¯].
¡°</td>
<td nowrap><a xhref=\"{$offer['detailpageurl']}\">
More details</a></td>
</tr>
<tr>
<td>No results found</td>
</tr>
<tr>
<td align=\"center\" style=\"font-size:14; font-weight:bold;\" colspan=\"5\">Amazon Search Results</td>
</tr>
</table>

¡°;

If errors were found with the user input, we¡¯ll show how to display the errors and we¡¯ll echo the form with the error messages:

} else {

$strError = ¡®
<dd><font color="red">Please check the following and try your submission again:

</font></dd>
<ul>¡®;

foreach ($oopsie as $error) {
$strError .= ¡±
<li>$error</li>

¡°;
}
$strError .= ¡®</ul>
</div>

¡®;
?>
<form action="<? echo $PHP_SELF; ?>¡± method=¡±POST¡± name=¡±amazon-xml-search¡±>
<? echo $strError; ?>
Enter keyword(s): <input type="text" name="keyword" value="<? echo $_POST['keyword']; ?>¡°>

Select a category:
<select name="searchindex">
<option value="DVD">DVD</option>
<option value="Books">Books</option>
<option value="Video">Video</option>
</select>

<input type="submit" name="finditnow" value="Search Amazon">
</form>

And if the user hasn¡¯t done anything yet, we¡¯ll simply display the form:

<form action="<? echo $PHP_SELF; ?>¡± method=¡±POST¡± name=¡±amazon-xml-search¡±>
Enter keyword(s): <input type="text" name="keyword" value="<? echo $_POST['keyword']; ?>¡°>

Select a category:
<select name="searchindex">

<!-- You can add as many values as you'd like below -->

<option value="DVD">DVD</option>
<option value="Books">Books</option>
<option value="Video">Video</option>
</select>

<input type="submit" name="finditnow" value="Search Amazon">
</form>

I¡¯ve modified this code to include sort functionality and a feature that will display the XML results in a table with alternating row colors. Additionally, this code includes form validation. Much of the code has been borrowed from Programming PHP.