atomlib.php

<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
/**
 * This library provides functions to generate Atom feeds and tries to follow the same API as lib/rsslib.php
 *
 * @author Matt Clarkson <mattc@catalyst.net.nz>
 * @package oublog
 */


// This function return all the common atom headers.

function atom_standard_header($uniqueid, $link, $updated, $title = null, $description = null) {

    global $CFG, $USER, $OUTPUT;

    static $pixpath = '';

    $status = true;
    $result = "";

    if (!$site = get_site()) {
        $status = false;
    }

    if ($status) {

        // Calculate title, link and description.
        if (empty($title)) {
            $title = format_string($site->fullname);
        }

        // Xml headers.
        $result .= "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n";
        $result .= "<feed xmlns=\"http://www.w3.org/2005/Atom\">\n";

        // Open the channel
        // write channel info.
        $result .= atom_full_tag('id', 1, false, htmlspecialchars($uniqueid));
        $result .= atom_full_tag('updated', 1, false, date_format_rfc3339($updated));
        $result .= atom_full_tag('title', 1, false, htmlspecialchars(html_to_text($title)));
        $result .= atom_full_tag('link', 1, false, null, array('href' => $link, 'rel' => 'self'));
        if (!empty($description)) {
            $result .= atom_full_tag('subtitle', 1, false, $description);
        }
        $result .= atom_full_tag('generator', 1, false, 'Moodle');
        $today = getdate();
        $result .= atom_full_tag('rights', 1, false, '&#169; '. $today['year'] .' '.
                format_string($site->fullname));

        // Write image info.
        $atompix = $OUTPUT->image_url('i/rsssitelogo');

        // Write the info.
        $result .= atom_full_tag('logo', 1, false, $atompix);

    }

    if (!$status) {
        return false;
    } else {
        return $result;
    }
}


function atom_add_items($items) {

    global $CFG;

    $result = '';
    $xhtmlattr = array('type'       => 'xhtml');

    if (!empty($items)) {
        foreach ($items as $item) {
            $result .= atom_start_tag('entry', 1, true);
            $result .= atom_full_tag('title', 2, false, htmlspecialchars(html_to_text($item->title)));
            $result .= atom_full_tag('link', 2, false, null, array('href' => $item->link, 'rel'=>'alternate'));
            $result .= atom_full_tag('updated', 2, false, date_format_rfc3339($item->pubdate));
            // Include the author if exists.
            if (isset($item->author)) {
                $result .= atom_start_tag('author', 2, true);
                $result .= atom_full_tag('name', 3, false, $item->author);
                $result .= atom_end_tag('author', 2, true);
            }
            $result .= atom_full_tag('content', 2, false, '<div xmlns="http://www.w3.org/1999/xhtml">'.
                    clean_text($item->description, FORMAT_HTML).'</div>', $xhtmlattr);
            $result .= atom_full_tag('id', 2, false, $item->link);
            if (isset($item->tags)) {
                $tagdata = array();
                if (isset($item->tagscheme)) {
                    $tagdata['scheme'] = $item->tagscheme;
                }
                foreach ($item->tags as $tag) {
                    $tagdata['term'] = $tag;
                    $result .= atom_full_tag('category', 2, true, false, $tagdata);
                }
            }
            $result .= atom_end_tag('entry', 1, true);

        }
    } else {
        $result = false;
    }
    return $result;
}


// This function return all the common footers for every rss feed in the site.
function atom_standard_footer($title = null, $link = null, $description = null) {

    global $CFG, $USER;

    $status = true;
    $result = '';

    // Close the rss tag.
    $result .= '</feed>';

    return $result;
}



// Return the xml start tag.
function atom_start_tag($tag, $level=0, $endline = false, $attributes = null) {
    if ($endline) {
        $endchar = "\n";
    } else {
        $endchar = "";
    }
    $attrstring = '';
    if (!empty($attributes) && is_array($attributes)) {
        foreach ($attributes as $key => $value) {
            $attrstring .= " ".$key."=\"".htmlspecialchars($value)."\"";
        }
    }
    return str_repeat(" ", $level*2) . "<" . $tag . $attrstring . ">" . $endchar;
}

// Return the xml end tag.
function atom_end_tag($tag, $level = 0, $endline = true) {
    if ($endline) {
        $endchar = "\n";
    } else {
        $endchar = "";
    }
    return str_repeat(" ", $level*2) . "</" . $tag . ">" . $endchar;
}


// Return the start tag, the contents and the end tag.
function atom_full_tag($tag, $level, $endline, $content, $attributes = null) {
    global $CFG;
    $st = atom_start_tag($tag, $level, $endline, $attributes);
    if ($content === false) {
        $st = preg_replace('~>$~', ' />', $st);
        return $st;
    }
    $co="";
    $co = preg_replace("/\r\n|\r/", "\n", $content);
    $et = atom_end_tag($tag, 0, true);

    return $st.$co.$et;
}


function date_format_rfc3339($timestamp=0) {

    $date = date('Y-m-d\TH:i:s', $timestamp);

    $matches = array();

    if (preg_match('/^([\-+])(\d{2})(\d{2})$/', date('O', $timestamp), $matches)) {
        $date .= $matches[1].$matches[2].':'.$matches[3];
    } else {
        $date .= 'Z';
    }
    return $date;
}