PHP Universal Feed Generator
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

883 lines
28 KiB

<?php
namespace FeedWriter;
use \DateTime;
/*
* Copyright (C) 2008 Anis uddin Ahmad <anisniit@gmail.com>
* Copyright (C) 2010-2014 Michael Bemmerl <mail@mx-server.de>
*
* This file is part of the "Universal Feed Writer" project.
*
* This program 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.
*
* This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
*/
// RSS 0.90 Officially obsoleted by 1.0
// RSS 0.91, 0.92, 0.93 and 0.94 Officially obsoleted by 2.0
// So, define constants for RSS 1.0, RSS 2.0 and ATOM
/**
* Universal Feed Writer class
*
* Generate RSS 1.0, RSS2.0 and ATOM Feeds
*
* @package UniversalFeedWriter
* @author Anis uddin Ahmad <anisniit@gmail.com>
* @link http://www.ajaxray.com/projects/rss
*/
abstract class Feed
{
const RSS1 = 'RSS 1.0';
const RSS2 = 'RSS 2.0';
const ATOM = 'ATOM';
/**
* Collection of all channel elements
*/
private $channels = array();
/**
* Collection of items as object of \FeedWriter\Item class.
*/
private $items = array();
/**
* Store some other version wise data
*/
private $data = array();
/**
* The tag names which have to encoded as CDATA
*/
private $CDATAEncoding = array();
/**
* Collection of XML namespaces
*/
private $namespaces = array();
/**
* Contains the format of this feed.
*/
private $version = null;
/**
* Constructor
*
* If no version is given, a feed in RSS 2.0 format will be generated.
*
* @param constant the version constant (RSS1/RSS2/ATOM).
*/
protected function __construct($version = Feed::RSS2)
{
$this->version = $version;
// Setting default encoding
$this->encoding = 'utf-8';
// Setting default value for essential channel elements
$this->channels['title'] = $version . ' Feed';
$this->channels['link'] = 'http://www.ajaxray.com/blog';
// Add some default XML namespaces
$this->namespaces['content'] = 'http://purl.org/rss/1.0/modules/content/';
$this->namespaces['wfw'] = 'http://wellformedweb.org/CommentAPI/';
$this->namespaces['atom'] = 'http://www.w3.org/2005/Atom';
$this->namespaces['rdf'] = 'http://www.w3.org/1999/02/22-rdf-syntax-ns#';
$this->namespaces['rss1'] = 'http://purl.org/rss/1.0/';
$this->namespaces['dc'] = 'http://purl.org/dc/elements/1.1/';
$this->namespaces['sy'] = 'http://purl.org/rss/1.0/modules/syndication/';
// Tag names to encode in CDATA
$this->addCDATAEncoding(array('description', 'content:encoded', 'summary'));
}
// Start # public functions ---------------------------------------------
/**
* Set the URLs for feed pagination.
*
* See RFC 5005, chapter 3. At least one page URL must be specified.
*
* @param string The URL to the next page of this feed. Optional.
* @param string The URL to the previous page of this feed. Optional.
* @param string The URL to the first page of this feed. Optional.
* @param string The URL to the last page of this feed. Optional.
* @link http://tools.ietf.org/html/rfc5005#section-3
* @return self
*/
public function setPagination($nextURL = null, $previousURL = null, $firstURL = null, $lastURL = null)
{
if (empty($nextURL) && empty($previousURL) && empty($firstURL) && empty($lastURL))
die('At least one URL must be specified for pagination to work.');
if (!empty($nextURL))
$this->setAtomLink($nextURL, 'next');
if (!empty($previousURL))
$this->setAtomLink($previousURL, 'previous');
if (!empty($firstURL))
$this->setAtomLink($firstURL, 'first');
if (!empty($lastURL))
$this->setAtomLink($lastURL, 'last');
return $this;
}
/**
* Add a channel element indicating the program used to generate the feed.
*
* @return self
*/
public function addGenerator()
{
if ($this->version == Feed::ATOM)
$this->setChannelElement('atom:generator', 'FeedWriter', array('uri' => 'https://github.com/mibe/FeedWriter'));
else if ($this->version == Feed::RSS2)
$this->setChannelElement('generator', 'FeedWriter');
else
die('The generator element is not supported in RSS1 feeds.');
return $this;
}
/**
* Add a XML namespace to the internal list of namespaces. After that,
* custom channel elements can be used properly to generate a valid feed.
*
* @access public
* @param string namespace prefix
* @param string namespace name (URI)
* @return self
* @link http://www.w3.org/TR/REC-xml-names/
*/
public function addNamespace($prefix, $uri)
{
$this->namespaces[$prefix] = $uri;
return $this;
}
/**
* Add a channel element to the feed.
*
* @access public
* @param string name of the channel tag
* @param string content of the channel tag
* @param array array of element attributes with attribute name as array key
* @param bool TRUE if this element can appear multiple times
* @return self
*/
public function setChannelElement($elementName, $content, $attributes = null, $multiple = false)
{
$entity['content'] = $content;
$entity['attributes'] = $attributes;
if ($multiple === TRUE)
$this->channels[$elementName][] = $entity;
else
$this->channels[$elementName] = $entity;
return $this;
}
/**
* Set multiple channel elements from an array. Array elements
* should be 'channelName' => 'channelContent' format.
*
* @access public
* @param array array of channels
* @return self
*/
public function setChannelElementsFromArray($elementArray)
{
if (!is_array($elementArray))
return;
foreach ($elementArray as $elementName => $content) {
$this->setChannelElement($elementName, $content);
}
return $this;
}
/**
* Get the appropriate MIME type string for the current feed.
*
* @access public
* @return string The MIME type string.
*/
public function getMIMEType()
{
switch ($this->version) {
case Feed::RSS2 : $mimeType = "application/rss+xml";
break;
case Feed::RSS1 : $mimeType = "application/rdf+xml";
break;
case Feed::ATOM : $mimeType = "application/atom+xml";
break;
default : $mimeType = "text/xml";
}
return $mimeType;
}
/**
* Print the actual RSS/ATOM file
*
* Sets a Content-Type header and echoes the contents of the feed.
* Should only be used in situations where direct output is desired;
* if you need to pass a string around, use generateFeed() instead.
*
* @access public
* @param bool FALSE if the specific feed media type should be sent.
* @return void
*/
public function printFeed($useGenericContentType = false)
{
$contentType = "text/xml";
if (!$useGenericContentType) {
$contentType = $this->getMIMEType();
}
header("Content-Type: " . $contentType);
echo $this->generateFeed();
}
/**
* Generate the feed.
*
* @access public
* @return string The complete feed XML.
*/
public function generateFeed()
{
return $this->makeHeader()
. $this->makeChannels()
. $this->makeItems()
. $this->makeFooter();
}
/**
* Create a new Item.
*
* @access public
* @return Item instance of Item class
*/
public function createNewItem()
{
$Item = new Item($this->version);
return $Item;
}
/**
* Add a properties to be CDATA encoded
*
* @access public
* @param array An array of properties that are merged into the list of properties should be encoded as CDATA
* @return self
*/
public function addCDATAEncoding(Array $property_list)
{
$this->CDATAEncoding = array_merge($this->CDATAEncoding, $property_list);
return $this;
}
/**
* Get list of CDATA encoded properties
*
* @access public
* @return array Return an array of CDATA properties that are to be encoded as CDATA
*/
public function getCDATAEncoding()
{
return $this->CDATAEncoding;
}
/**
* Add a FeedItem to the main class
*
* @access public
* @param Item instance of Item class
* @return self
*/
public function addItem(Item $feedItem)
{
if ($feedItem->getVersion() != $this->version)
die('Feed type mismatch: This instance can handle ' . $this->version . ' feeds only, but item with type ' . $feedItem->getVersion() . ' given.');
$this->items[] = $feedItem;
return $this;
}
// Wrapper functions -------------------------------------------------------------------
/**
* Set the 'encoding' attribute in the XML prolog.
*
* @access public
* @param string value of 'encoding' attribute
* @return self
*/
public function setEncoding($encoding)
{
$this->encoding = $encoding;
return $this;
}
/**
* Set the 'title' channel element
*
* @access public
* @param string value of 'title' channel tag
* @return self
*/
public function setTitle($title)
{
return $this->setChannelElement('title', $title);
}
/**
* Set the date when the ATOM feed was lastly updated.
*
* This adds the 'updated' element to the feed. The value of the date parameter
* can be either an instance of the DateTime class, an integer containing a UNIX
* timestamp or a string which is parseable by PHP's 'strtotime' function.
*
* Not supported in RSS1 feeds.
*
* @access public
* @param DateTime|int|string Date which should be used.
* @return self
*/
public function setDate($date)
{
if ($this->version == Feed::RSS1)
die('The publication date is not supported in RSS1 feeds.');
// The feeds have different date formats.
$format = $this->version == Feed::ATOM ? \DATE_ATOM : \DATE_RSS;
if ($date instanceof DateTime)
$date = $date->format($format);
else if(is_numeric($date) && $date >= 0)
$date = date($format, $date);
else if (is_string($date))
$date = date($format, strtotime($date));
else
die('The given date was not an instance of DateTime, a UNIX timestamp or a date string.');
if ($this->version == Feed::ATOM)
$this->setChannelElement('updated', $date);
else
$this->setChannelElement('lastBuildDate', $date);
return $this;
}
/**
* Set the 'description' channel element
*
* @access public
* @param string value of 'description' channel tag
* @return self
*/
public function setDescription($description)
{
if ($this->version != Feed::ATOM)
$this->setChannelElement('description', $description);
return $this;
}
/**
* Set the 'link' channel element
*
* @access public
* @param string value of 'link' channel tag
* @return self
*/
public function setLink($link)
{
if ($this->version == Feed::ATOM)
$this->setChannelElement('link', '', array('href' => $link));
else
$this->setChannelElement('link', $link);
return $this;
}
/**
* Set custom 'link' channel elements.
*
* In ATOM feeds, only one link with alternate relation and the same combination of
* type and hreflang values.
*
* @access public
* @param string URI of this link
* @param string relation type of the resource
* @param string MIME type of the target resource
* @param string language of the resource
* @param string human-readable information about the resource
* @param int length of the resource in bytes
* @link https://www.iana.org/assignments/link-relations/link-relations.xml
* @link https://tools.ietf.org/html/rfc4287#section-4.2.7
* @return self
*/
public function setAtomLink($href, $rel = null, $type = null, $hreflang = null, $title = null, $length = null)
{
$data = array('href' => $href);
if ($rel != null) {
if (!is_string($rel) || empty($rel))
die('rel parameter must be a string and a valid relation identifier.');
$data['rel'] = $rel;
}
if ($type != null) {
// Regex used from RFC 4287, page 41
if (!is_string($type) || preg_match('/.+\/.+/', $type) != 1)
die('type parameter must be a string and a MIME type.');
$data['type'] = $type;
}
if ($hreflang != null) {
// Regex used from RFC 4287, page 41
if (!is_string($hreflang) || preg_match('/[A-Za-z]{1,8}(-[A-Za-z0-9]{1,8})*/', $hreflang) != 1)
die('hreflang parameter must be a string and a valid language code.');
$data['hreflang'] = $hreflang;
}
if ($title != null) {
if (!is_string($title) || empty($title))
die('title parameter must be a string and not empty.');
$data['title'] = $title;
}
if ($length != null) {
if (!is_int($length) || $length < 0)
die('length parameter must be a positive integer.');
$data['length'] = (string) $length;
}
// ATOM spec. has some restrictions on atom:link usage
// See RFC 4287, page 12 (4.1.1)
if ($this->version == Feed::ATOM) {
foreach ($this->channels as $key => $value) {
if ($key != 'atom:link')
continue;
// $value is an array , so check every element
foreach ($value as $linkItem) {
// Only one link with relation alternate and same hreflang & type is allowed.
if (@$linkItem['rel'] == 'alternate' && @$linkItem['hreflang'] == $hreflang && @$linkItem['type'] == $type)
die('The feed must not contain more than one link element with a relation of "alternate"'
. ' that has the same combination of type and hreflang attribute values.');
}
}
}
return $this->setChannelElement('atom:link', '', $data, true);
}
/**
* Set an 'atom:link' channel element with relation=self attribute.
* Needs the full URL to this feed.
*
* @link http://www.rssboard.org/rss-profile#namespace-elements-atom-link
* @access public
* @param string URL to this feed
* @return self
*/
public function setSelfLink($url)
{
return $this->setAtomLink($url, 'self', $this->getMIMEType());
}
/**
* Set the 'image' channel element
*
* @access public
* @param string title of image
* @param string link url of the image
* @param string path url of the image
* @return self
*/
public function setImage($title, $link, $url)
{
return $this->setChannelElement('image', array('title'=>$title, 'link'=>$link, 'url'=>$url));
}
/**
* Set the 'about' channel element. Only for RSS 1.0
*
* @access public
* @param string value of 'about' channel tag
* @return self
*/
public function setChannelAbout($url)
{
$this->data['ChannelAbout'] = $url;
return $this;
}
/**
* Generate an UUID.
*
* The UUID is based on an MD5 hash. If no key is given, a unique ID as the input
* for the MD5 hash is generated.
*
* @author Anis uddin Ahmad <admin@ajaxray.com>
* @param string optional key on which the UUID is generated
* @param string an optional prefix
* @return string the formated UUID
*/
public static function uuid($key = null, $prefix = '')
{
$key = ($key == null) ? uniqid(rand()) : $key;
$chars = md5($key);
$uuid = substr($chars,0,8) . '-';
$uuid .= substr($chars,8,4) . '-';
$uuid .= substr($chars,12,4) . '-';
$uuid .= substr($chars,16,4) . '-';
$uuid .= substr($chars,20,12);
return $prefix . $uuid;
}
/**
* Replace invalid xml utf-8 chars.
*
* See utf8_for_xml() function at
* http://www.phpwact.org/php/i18n/charsets#xml and
* http://www.w3.org/TR/REC-xml/#charsets
*
* @param string
* @return string
*/
public static function utf8_for_xml($string)
{
return preg_replace('/[^\x{0009}\x{000a}\x{000d}\x{0020}-\x{D7FF}\x{E000}-\x{FFFD}]+/u', ' ', $string);
}
// End # public functions ----------------------------------------------
// Start # private functions ----------------------------------------------
/**
* Returns all used XML namespace prefixes in this instance.
* This includes all channel elements and feed items.
* Unfortunately some namespace prefixes are not included,
* because they are hardcoded, e.g. rdf.
*
* @access private
* @return array Array with namespace prefix as value.
*/
private function getNamespacePrefixes()
{
$prefixes = array();
// Get all tag names from channel elements...
$tags = array_keys($this->channels);
// ... and now all names from feed items
foreach ($this->items as $item)
$tags = array_merge($tags, array_keys($item->getElements()));
// Look for prefixes in those tag names
foreach ($tags as $tag) {
$elements = explode(':', $tag);
if (count($elements) != 2)
continue;
$prefixes[] = $elements[0];
}
return array_unique($prefixes);
}
/**
* Returns the XML header and root element, depending on the feed type.
*
* @access private
* @return string The XML header of the feed.
*/
private function makeHeader()
{
$out = '<?xml version="1.0" encoding="'.$this->encoding.'" ?>' . PHP_EOL;
$prefixes = $this->getNamespacePrefixes();
$attributes = array();
$tagName = '';
$defaultNamespace = '';
if ($this->version == Feed::RSS2) {
$tagName = 'rss';
$attributes['version'] = '2.0';
} elseif ($this->version == Feed::RSS1) {
$tagName = 'rdf:RDF';
$prefixes[] = 'rdf';
$defaultNamespace = $this->namespaces['rss1'];
} elseif ($this->version == Feed::ATOM) {
$tagName = 'feed';
$defaultNamespace = $this->namespaces['atom'];
// Ugly hack to remove the 'atom' value from the prefixes array.
$prefixes = array_flip($prefixes);
unset($prefixes['atom']);
$prefixes = array_flip($prefixes);
}
// Iterate through every namespace prefix and add it to the element attributes.
foreach ($prefixes as $prefix) {
if (!isset($this->namespaces[$prefix]))
die('Unknown XML namespace prefix: \'' . $prefix . '\'. Use the addNamespace method to add support for this prefix.');
else
$attributes['xmlns:' . $prefix] = $this->namespaces[$prefix];
}
// Include default namepsace, if required
if (!empty($defaultNamespace))
$attributes['xmlns'] = $defaultNamespace;
$out .= $this->makeNode($tagName, '', $attributes, true);
return $out;
}
/**
* Closes the open tags at the end of file
*
* @access private
* @return string The XML footer of the feed.
*/
private function makeFooter()
{
if ($this->version == Feed::RSS2) {
return '</channel>' . PHP_EOL . '</rss>';
} elseif ($this->version == Feed::RSS1) {
return '</rdf:RDF>';
} elseif ($this->version == Feed::ATOM) {
return '</feed>';
}
}
/**
* Creates a single node in XML format
*
* @access private
* @param string name of the tag
* @param mixed tag value as string or array of nested tags in 'tagName' => 'tagValue' format
* @param array Attributes (if any) in 'attrName' => 'attrValue' format
* @param string True if the end tag should be omitted. Defaults to false.
* @return string formatted xml tag
*/
private function makeNode($tagName, $tagContent, $attributes = null, $omitEndTag = false)
{
$nodeText = '';
$attrText = '';
if (is_array($attributes) && count($attributes) > 0) {
foreach ($attributes as $key => $value) {
$value = self::utf8_for_xml($value);
$value = htmlspecialchars($value);
$attrText .= " $key=\"$value\"";
}
}
if (is_array($tagContent) && $this->version == Feed::RSS1) {
$attrText = ' rdf:parseType="Resource"';
}
$attrText .= (in_array($tagName, $this->CDATAEncoding) && $this->version == Feed::ATOM) ? ' type="html"' : '';
$nodeText .= "<{$tagName}{$attrText}>";
$nodeText .= (in_array($tagName, $this->CDATAEncoding)) ? '<![CDATA[' : '';
if (is_array($tagContent)) {
foreach ($tagContent as $key => $value) {
$nodeText .= $this->makeNode($key, $value);
}
} else {
$tagContent = self::utf8_for_xml($tagContent);
$nodeText .= (in_array($tagName, $this->CDATAEncoding)) ? $this->sanitizeCDATA($tagContent) : htmlspecialchars($tagContent);
}
$nodeText .= (in_array($tagName, $this->CDATAEncoding)) ? ']]>' : '';
if (!$omitEndTag)
$nodeText .= "</$tagName>";
$nodeText .= PHP_EOL;
return $nodeText;
}
/**
* Make the channels.
*
* @access private
* @return string The feed header as XML containing all the feed metadata.
*/
private function makeChannels()
{
$out = '';
//Start channel tag
switch ($this->version) {
case Feed::RSS2:
$out .= '<channel>' . PHP_EOL;
break;
case Feed::RSS1:
$out .= (isset($this->data['ChannelAbout']))? "<channel rdf:about=\"{$this->data['ChannelAbout']}\">" : "<channel rdf:about=\"{$this->channels['link']}\">";
break;
}
//Print Items of channel
foreach ($this->channels as $key => $value) {
// In ATOM feeds, strip all ATOM namespace prefixes from the tag name. They are not needed here,
// because the ATOM namespace name is set as default namespace.
if ($this->version == Feed::ATOM && strncmp($key, 'atom', 4) == 0) {
$key = substr($key, 5);
}
// The channel element can occur multiple times, when the key 'content' is not in the array.
if (!isset($value['content'])) {
// If this is the case, iterate through the array with the multiple elements.
foreach ($value as $singleElement) {
$out .= $this->makeNode($key, $singleElement['content'], $singleElement['attributes']);
}
} else {
$out .= $this->makeNode($key, $value['content'], $value['attributes']);
}
}
if ($this->version == Feed::RSS1) {
//RSS 1.0 have special tag <rdf:Seq> with channel
$out .= "<items>" . PHP_EOL . "<rdf:Seq>" . PHP_EOL;
foreach ($this->items as $item) {
$thisItems = $item->getElements();
$out .= "<rdf:li resource=\"{$thisItems['link']['content']}\"/>" . PHP_EOL;
}
$out .= "</rdf:Seq>" . PHP_EOL . "</items>" . PHP_EOL . "</channel>" . PHP_EOL;
} else if ($this->version == Feed::ATOM) {
// ATOM feeds have a unique feed ID. This is generated from the 'link' channel element.
$out .= $this->makeNode('id', Feed::uuid($this->channels['link']['attributes']['href'], 'urn:uuid:'));
}
return $out;
}
/**
* Prints formatted feed items
*
* @access private
* @return string The XML of every feed item.
*/
private function makeItems()
{
$out = '';
foreach ($this->items as $item) {
$thisItems = $item->getElements();
// the argument is printed as rdf:about attribute of item in rss 1.0
$out .= $this->startItem($thisItems['link']['content']);
foreach ($thisItems as $feedItem) {
$name = $feedItem['name'];
// Strip all ATOM namespace prefixes from tags when feed is an ATOM feed.
// Not needed here, because the ATOM namespace name is used as default namespace.
if ($this->version == Feed::ATOM && strncmp($name, 'atom', 4) == 0)
$name = substr($name, 5);
$out .= $this->makeNode($name, $feedItem['content'], $feedItem['attributes']);
}
$out .= $this->endItem();
}
return $out;
}
/**
* Make the starting tag of channels
*
* @access private
* @param string The vale of about tag which is used for RSS 1.0 only.
* @return string The starting XML tag of an feed item.
*/
private function startItem($about = false)
{
$out = '';
if ($this->version == Feed::RSS2) {
$out .= '<item>' . PHP_EOL;
} elseif ($this->version == Feed::RSS1) {
if ($about) {
$out .= "<item rdf:about=\"$about\">" . PHP_EOL;
} else {
throw new \Exception("link element is not set - It's required for RSS 1.0 to be used as the about attribute of the item tag.");
}
} elseif ($this->version == Feed::ATOM) {
$out .= "<entry>" . PHP_EOL;
}
return $out;
}
/**
* Closes feed item tag
*
* @access private
* @return string The ending XML tag of an feed item.
*/
private function endItem()
{
if ($this->version == Feed::RSS2 || $this->version == Feed::RSS1) {
return '</item>' . PHP_EOL;
} elseif ($this->version == Feed::ATOM) {
return '</entry>' . PHP_EOL;
}
}
/**
* Sanitizes data which will be later on returned as CDATA in the feed.
*
* A "]]>" respectively "<![CDATA" in the data would break the CDATA in the
* XML, so the brackets are converted to a HTML entity.
*
* @access private
* @param string Data to be sanitized
* @return string Sanitized data
*/
private function sanitizeCDATA($text)
{
$text = str_replace("]]>", "]]&gt;", $text);
$text = str_replace("<![CDATA[", "&lt;![CDATA[", $text);
return $text;
}
// End # private functions ----------------------------------------------
} // end of class Feed