Parsing a Pinboard feed

I’ve tried it again with

Xpath to posts: item

No custom namespaces specified

title->post_title
link->guid
description -> post_content

and still “No items in feed” when there should be two.

I rolled my own in PHP5.4 and got the two elements I expected:

$html = "";
$url = "https://feeds.pinboard.in/rss/u:berendes/t:gas_pressure/";
$xml = simplexml_load_file($url);
for($i = 0; $i < 3; $i++){
        $title = $xml->item[$i]->title;
        $link = $xml->item[$i]->link;
        $description = $xml->item[$i]->description;
        $html .= "<a href='$link'><h3>$title</h3></a>";
        $html .= "$description";
}
echo $html;

Solved.

The key thing is that the pinboard feed has a default namespace:
<rdf:RDF xmlns="https://purl.org/rss/1.0/" ....>
rather than just named workspaces, as in the other feed, which worked smoothly:
<rss xmlns:content="https://purl.org/rss/1.0/modules/content/" xmlns:dc="https://purl.org/dc/elements/1.1/" xmlns:atom="https://www.w3.org/2005/Atom" version="2.0">

so the xpath expression for the feed elements is //default:item and
the field mappings are default:title => post_title, default:link=>guid, and default:description=>post_content

This works as expected.