how to add offset and limit to my php rss parser? - php

Question

how to add an offset and limit to my PHP rss parser that returns the result as an object ?, here is what i have at the moment. it doesn't have any offset nor limit, how to approach this ?
class Rss
{
/*
*#access public
*#params url,int ''=default,int ''=default
*#usage input url,offset and limit,
*#returns content based onf the offset/limit input
*/
public function getFeed($url,$offset='',$limit=''){
$object = array();
$rss = simplexml_load_file($url);
foreach($rss->channel->item as $item){
$object[] = $item->title;
$object[] = $item->description;
$object[] = $item->link;
}
return $object;
}
}

Answer 1

Simpliest way
$limit = 10; $offset = 5;
$i=0; $taken=0;
foreach($rss->channel->item as $item){
if ($i>=$offset && $taken<$limit){
++$taken;
$object[] = $item->title;
$object[] = $item->description;
$object[] = $item->link;
}
//little optimization here
if ($taken == $limit)
break;
++$i;
}
Of course you can store $limit and $offset as object properties, or get them elsewhere.

Answer 2

how about a single counter thing? set offset/limit as needed
public function getFeed($url,$offset='',$limit=''){
$object = array();
$rss = simplexml_load_file($url);
$offset = 3; $limit = 8; $counter = 0;
foreach($rss->channel->item as $item){
$counter++;
if ($counter > $offset && $counter < $limit) {
$object[] = $item->title;
$object[] = $item->description;
$object[] = $item->link;
}
}
return $object;
}

Answer 3

You can use SimpleXMLElement::xpath. This way you don't have to traverse all items just for counting things.
public function getFeed($url, $offset = 1, $limit = -1){
$object = array();
$rss = simplexml_load_file($url);
$limitCriteria = '';
if ($limit > 0) {
$limitCriteria = 'and position() <= ' . ((int)$offset + (int)$limit + 1);
}
foreach($rss->xpath(sprintf('//item[position() >= %s %s]', (int)$offset, $limitCriteria)) as $item){
$object[] = $item->title;
$object[] = $item->description;
$object[] = $item->link;
}
return $object;
}