Format some data as RSS that is currently only available as JSON

format-json-as-rss.php

#!/usr/bin/php
<?php

    date_default_timezone_set("GMT");

    $type = "a type";
    $key = "some identifier";
    $json = "canonical url of this json stuff";

    $entries = json_decode(file_get_contents("php://stdin"));
    $len = sizeof($entries);
    $rss = '';
    $now = new DateTime();
    if ($len) {
        $rss  = '<?xml version="1.0"?><rss version="2.0">';
        $rss .= ' <channel><title>Site Name ' . $type . ': ' . $key . '</title>';
        $rss .= ' <link>' . htmlentities ( $json ) . '</link>';
        $rss .= ' <pubDate>' . $now->format(DATE_RSS ) . '</pubDate>';
 
        for ($i=0; $i<$len; $i++) {
        
            $sender = $entries[$i]->user->screen_name;
            $payload  = htmlentities ( $entries[$i]->text );

            $created_at = new DateTime($entries[$i]->created_at);
            $created_at = $created_at->format(DATE_RSS);
        
            $rss .= "<item>\n<title>" . $sender . ": " . $payload . "</title>\n";
            $rss .= " <author>" . $entries[$i]->user->name . " (@" . $sender . ")</author>\n";
            $rss .= " <pubDate>" . $created_at . "</pubDate>\n";
            $rss .= " <guid isPermaLink='false'>" . $entries[$i]->id_str . "</guid>\n";
            $rss .= " <link>https://example.com/" . $sender . "/statuses/" . $entries[$i]->id_str . "</link>\n";
            $rss .= " <description>" . $payload . "</description>\n";
            $rss .= "</item>\n";
        }
      
        $rss .= "</channel></rss>";
    }
    print $rss;