moodle/blocks/rss_client/block_rss_client.php

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<?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/>.
/**
* Contains block_rss_client
* @package block_rss_client
* @copyright Daryl Hawes
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL
*/
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/**
* A block which displays Remote feeds
*
* @package block_rss_client
* @copyright Daryl Hawes
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL
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*/
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class block_rss_client extends block_base {
/** The maximum time in seconds that cron will wait between attempts to retry failing RSS feeds. */
const CLIENT_MAX_SKIPTIME = 43200; // 60 * 60 * 12 seconds.
function init() {
$this->title = get_string('pluginname', 'block_rss_client');
}
function applicable_formats() {
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return array('all' => true, 'tag' => false); // Needs work to make it work on tags MDL-11960
}
function specialization() {
// After the block has been loaded we customize the block's title display
if (!empty($this->config) && !empty($this->config->title)) {
// There is a customized block title, display it
$this->title = $this->config->title;
} else {
// No customized block title, use localized remote news feed string
$this->title = get_string('remotenewsfeed', 'block_rss_client');
}
}
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/**
* Gets the footer, which is the channel link of the last feed in our list of feeds
*
* @param array $feedrecords The feed records from the database.
* @return block_rss_client\output\footer|null The renderable footer or null if none should be displayed.
*/
protected function get_footer($feedrecords) {
$footer = null;
if ($this->config->block_rss_client_show_channel_link) {
global $CFG;
require_once($CFG->libdir.'/simplepie/moodle_simplepie.php');
$feedrecord = array_pop($feedrecords);
$feed = new moodle_simplepie($feedrecord->url);
$channellink = new moodle_url($feed->get_link());
if (!empty($channellink)) {
$footer = new block_rss_client\output\footer($channellink);
}
}
return $footer;
}
function get_content() {
global $CFG, $DB;
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if ($this->content !== NULL) {
return $this->content;
}
// initalise block content object
$this->content = new stdClass;
$this->content->text = '';
$this->content->footer = '';
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if (empty($this->instance)) {
return $this->content;
}
if (!isset($this->config)) {
// The block has yet to be configured - just display configure message in
// the block if user has permission to configure it
if (has_capability('block/rss_client:manageanyfeeds', $this->context)) {
$this->content->text = get_string('feedsconfigurenewinstance2', 'block_rss_client');
}
return $this->content;
}
// How many feed items should we display?
$maxentries = 5;
if ( !empty($this->config->shownumentries) ) {
$maxentries = intval($this->config->shownumentries);
}elseif( isset($CFG->block_rss_client_num_entries) ) {
$maxentries = intval($CFG->block_rss_client_num_entries);
}
/* ---------------------------------
* Begin Normal Display of Block Content
* --------------------------------- */
$renderer = $this->page->get_renderer('block_rss_client');
$block = new \block_rss_client\output\block();
if (!empty($this->config->rssid)) {
list($rssidssql, $params) = $DB->get_in_or_equal($this->config->rssid);
$rssfeeds = $DB->get_records_select('block_rss_client', "id $rssidssql", $params);
if (!empty($rssfeeds)) {
$showtitle = false;
if (count($rssfeeds) > 1) {
// When many feeds show the title for each feed.
$showtitle = true;
}
foreach ($rssfeeds as $feed) {
if ($renderablefeed = $this->get_feed($feed, $maxentries, $showtitle)) {
$block->add_feed($renderablefeed);
}
}
$footer = $this->get_footer($rssfeeds);
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}
}
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$this->content->text = $renderer->render_block($block);
if (isset($footer)) {
$this->content->footer = $renderer->render_footer($footer);
}
return $this->content;
}
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function instance_allow_multiple() {
return true;
}
function has_config() {
return true;
}
function instance_allow_config() {
return true;
}
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/**
* Returns the html of a feed to be displaed in the block
*
* @param mixed feedrecord The feed record from the database
* @param int maxentries The maximum number of entries to be displayed
* @param boolean showtitle Should the feed title be displayed in html
* @return block_rss_client\output\feed|null The renderable feed or null of there is an error
*/
public function get_feed($feedrecord, $maxentries, $showtitle) {
global $CFG;
require_once($CFG->libdir.'/simplepie/moodle_simplepie.php');
$simplepiefeed = new moodle_simplepie($feedrecord->url);
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if(isset($CFG->block_rss_client_timeout)){
$simplepiefeed->set_cache_duration($CFG->block_rss_client_timeout * 60);
}
if ($simplepiefeed->error()) {
debugging($feedrecord->url .' Failed with code: '.$simplepiefeed->error());
return null;
}
if(empty($feedrecord->preferredtitle)){
$feedtitle = $this->format_title($simplepiefeed->get_title());
}else{
$feedtitle = $this->format_title($feedrecord->preferredtitle);
}
if (empty($this->config->title)){
//NOTE: this means the 'last feed' displayed wins the block title - but
//this is exiting behaviour..
$this->title = strip_tags($feedtitle);
}
$feed = new \block_rss_client\output\feed($feedtitle, $showtitle, $this->config->block_rss_client_show_channel_image);
if ($simplepieitems = $simplepiefeed->get_items(0, $maxentries)) {
foreach ($simplepieitems as $simplepieitem) {
try {
$item = new \block_rss_client\output\item(
$simplepieitem->get_id(),
new moodle_url($simplepieitem->get_link()),
$simplepieitem->get_title(),
$simplepieitem->get_description(),
new moodle_url($simplepieitem->get_permalink()),
$simplepieitem->get_date('U'),
$this->config->display_description
);
$feed->add_item($item);
} catch (moodle_exception $e) {
// If there is an error with the RSS item, we don't
// want to crash the page. Specifically, moodle_url can
// throw an exception of the param is an extremely
// malformed url.
debugging($e->getMessage());
}
}
}
// Feed image.
if ($imageurl = $simplepiefeed->get_image_url()) {
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try {
$image = new \block_rss_client\output\channel_image(
new moodle_url($imageurl),
$simplepiefeed->get_image_title(),
new moodle_url($simplepiefeed->get_image_link())
);
$feed->set_image($image);
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} catch (moodle_exception $e) {
// If there is an error with the RSS image, we don'twant to
// crash the page. Specifically, moodle_url can throw an
// exception if the param is an extremely malformed url.
debugging($e->getMessage());
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}
}
return $feed;
}
/**
* Strips a large title to size and adds ... if title too long
*
* @param string title to shorten
* @param int max character length of title
* @return string title s() quoted and shortened if necessary
*/
function format_title($title,$max=64) {
if (core_text::strlen($title) <= $max) {
return s($title);
} else {
return s(core_text::substr($title,0,$max-3).'...');
}
}
/**
* cron - goes through all the feeds. If the feed has a skipuntil value
* that is less than the current time cron will attempt to retrieve it
* with the cache duration set to 0 in order to force the retrieval of
* the item and refresh the cache.
*
* If a feed fails then the skipuntil time of that feed is set to be
* later than the next expected cron time. The amount of time will
* increase each time the fetch fails until the maximum is reached.
*
* If a feed that has been failing is successfully retrieved it will
* go back to being handled as though it had never failed.
*
* CRON should therefor process requests for permanently broken RSS
* feeds infrequently, and temporarily unavailable feeds will be tried
* less often until they become available again.
*
* @return boolean Always returns true
*/
function cron() {
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global $CFG, $DB;
require_once($CFG->libdir.'/simplepie/moodle_simplepie.php');
// Get the legacy cron time, strangely the cron property of block_base
// does not seem to get set. This means we must retrive it here.
$this->cron = $DB->get_field('block', 'cron', array('name' => 'rss_client'));
// We are going to measure execution times
$starttime = microtime();
$starttimesec = time();
// Fetch all site feeds.
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$rs = $DB->get_recordset('block_rss_client');
$counter = 0;
mtrace('');
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foreach ($rs as $rec) {
mtrace(' ' . $rec->url . ' ', '');
// Skip feed if it failed recently.
if ($starttimesec < $rec->skipuntil) {
mtrace('skipping until ' . userdate($rec->skipuntil));
continue;
}
// Fetch the rss feed, using standard simplepie caching
// so feeds will be renewed only if cache has expired
core_php_time_limit::raise(60);
$feed = new moodle_simplepie();
// set timeout for longer than normal to be agressive at
// fetching feeds if possible..
$feed->set_timeout(40);
$feed->set_cache_duration(0);
$feed->set_feed_url($rec->url);
$feed->init();
if ($feed->error()) {
// Skip this feed (for an ever-increasing time if it keeps failing).
$rec->skiptime = $this->calculate_skiptime($rec->skiptime);
$rec->skipuntil = time() + $rec->skiptime;
$DB->update_record('block_rss_client', $rec);
mtrace("Error: could not load/find the RSS feed - skipping for {$rec->skiptime} seconds.");
} else {
mtrace ('ok');
// It worked this time, so reset the skiptime.
if ($rec->skiptime > 0) {
$rec->skiptime = 0;
$rec->skipuntil = 0;
$DB->update_record('block_rss_client', $rec);
}
// Only increase the counter when a feed is sucesfully refreshed.
$counter ++;
}
}
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$rs->close();
// Show times
mtrace($counter . ' feeds refreshed (took ' . microtime_diff($starttime, microtime()) . ' seconds)');
return true;
}
/**
* Calculates a new skip time for a record based on the current skip time.
*
* @param int $currentskip The curreent skip time of a record.
* @return int A new skip time that should be set.
*/
protected function calculate_skiptime($currentskip) {
// The default time to skiptime.
$newskiptime = $this->cron * 1.1;
if ($currentskip > 0) {
// Double the last time.
$newskiptime = $currentskip * 2;
}
if ($newskiptime > self::CLIENT_MAX_SKIPTIME) {
// Do not allow the skip time to increase indefinatly.
$newskiptime = self::CLIENT_MAX_SKIPTIME;
}
return $newskiptime;
}
}