2   Stylesheet to convert a Facebook public page to RSS.
 
   4   Copyright (C) 2015  Antonio Ospite <ao2@ao2.it>
 
   6   This file is part of tweeper.
 
   8   This program is free software: you can redistribute it and/or modify
 
   9   it under the terms of the GNU General Public License as published by
 
  10   the Free Software Foundation, either version 3 of the License, or
 
  11   (at your option) any later version.
 
  13   This program is distributed in the hope that it will be useful,
 
  14   but WITHOUT ANY WARRANTY; without even the implied warranty of
 
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 
  16   GNU General Public License for more details.
 
  18   You should have received a copy of the GNU General Public License
 
  19   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
  23   Since June 23rd, 2015 facebook.com deprecated the RSS feed endpoint for public pages:
 
  24   https://developers.facebook.com/docs/apps/changelog#v2_3_90_day_deprecations
 
  26   They suggest to use the Graph API but they fail to mention that it does not
 
  27   work anymore without authentication, so it cannot be considered an
 
  28   _equivalent_ solution.
 
  30   Luckily we've got Tweeper!
 
  33 <xsl:stylesheet version="1.0"
 
  34     xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
 
  35     xmlns:php="http://php.net/xsl"
 
  36     xsl:extension-element-prefixes="php"
 
  37     exclude-result-prefixes="php">
 
  39     <xsl:output method="xml" indent="yes"/>
 
  41     <xsl:variable name="BaseURL">
 
  42         <xsl:text>https://facebook.com</xsl:text>
 
  46          Extract the page id from an element like:
 
  47         <meta property="al:android:url" content="fb://page/793837197390834">
 
  49         The page id will be used to build the permalink.
 
  53         select="substring-after(//meta[@property='al:android:url']/@content, 'fb://page/')"/>
 
  55     <xsl:template match="//div[contains(@class, 'userContentWrapper')]">
 
  56         <xsl:variable name="story-id" select=".//input[@name='ft_ent_identifier']/@value"/>
 
  59             select="concat($BaseURL, '/permalink.php?id=', $page-id, '&story_fbid=', $story-id)"/>
 
  61         <!-- Get only the first child in order to skip the footer of the content -->
 
  62         <xsl:variable name="item-content" select="div[1]"/>
 
  66                 <xsl:variable name="item-title" select="$item-content//p"/>
 
  67                 <xsl:variable name="title-length" select="140"/>
 
  68                 <!-- ellipsize, inspired from http://stackoverflow.com/questions/13622338 -->
 
  70                     <xsl:when test="string-length($item-title) > $title-length">
 
  71                         <xsl:variable name="truncated-length" select="$title-length - 3"/>
 
  72                         <xsl:value-of select="substring($item-title, 1, $truncated-length)"/>
 
  73                         <xsl:text>...</xsl:text>
 
  76                         <xsl:value-of select="$item-title"/>
 
  81                 <xsl:value-of select="$item-permalink"/>
 
  84                 <xsl:value-of select="$item-permalink"/>
 
  87                 <xsl:variable name="timestamp" select=".//abbr[@data-shorten]/@data-utime"/>
 
  88                 <xsl:value-of select="php:functionString('Tweeper::epochToRssDate', number($timestamp))"/>
 
  93                      Get only the children starting from the one with class="userContent",
 
  94                      this way the content header is skipped
 
  97                     name="usercontent-position"
 
  98                     select="count($item-content/div[contains(@class, 'userContent')]/preceding-sibling::*) + 1"/>
 
 100                 <xsl:text disable-output-escaping="yes"><![CDATA[</xsl:text>
 
 101                 <xsl:copy-of select="$item-content/div[position() >= $usercontent-position]"/>
 
 102                 <xsl:text disable-output-escaping="yes">]]></xsl:text>
 
 107     <xsl:template match="/">
 
 108         <xsl:variable name="channel-title" select="//title"/>
 
 109         <xsl:variable name="channel-link" select="//div[contains(@class, 'userContentWrapper')][1]//a[1]/@href"/>
 
 112             <xsl:attribute name="xml:base"><xsl:value-of select="$BaseURL" /></xsl:attribute>
 
 114                 <generator>Tweeper</generator>
 
 116                     <xsl:value-of select="$channel-title"/>
 
 119                     <xsl:value-of select="$channel-link"/>
 
 122                     <xsl:text disable-output-escaping="yes"><![CDATA[</xsl:text>
 
 123                     <xsl:copy-of select="//div[@data-id='1']/node()"/>
 
 124                     <xsl:text disable-output-escaping="yes">]]></xsl:text>
 
 128                         <xsl:value-of select="$channel-title"/>
 
 131                         <xsl:value-of select="$channel-link"/>
 
 134                         <xsl:value-of select="//img[@class='profilePic img']/@src"/>
 
 137                 <xsl:apply-templates select="//div[contains(@class, 'userContentWrapper')]"/>