includes/specials/SpecialBooksources.php

   1 <?php
   2
   3 /**
   4  * Special page outputs information on sourcing a book with a particular ISBN
   5  * The parser creates links to this page when dealing with ISBNs in wikitext
   6  *
   7  * @author Rob Church <robchur@gmail.com>
   8  * @todo Validate ISBNs using the standard check-digit method
   9  * @ingroup SpecialPage
  10  */
  11 class SpecialBookSources extends SpecialPage {
  12
  13         /**
  14          * ISBN passed to the page, if any
  15          */
  16         private $isbn = '';
  17
  18         /**
  19          * Constructor
  20          */
  21         public function __construct() {
  22                 parent::__construct( 'Booksources' );
  23         }
  24
  25         /**
  26          * Show the special page
  27          *
  28          * @param $isbn ISBN passed as a subpage parameter
  29          */
  30         public function execute( $isbn ) {
  31                 global $wgOut, $wgRequest;
  32                 $this->setHeaders();
  33                 $this->isbn = self::cleanIsbn( $isbn ? $isbn : $wgRequest->getText( 'isbn' ) );
  34                 $wgOut->addWikiMsg( 'booksources-summary' );
  35                 $wgOut->addHTML( $this->makeForm() );
  36                 if( strlen( $this->isbn ) > 0 ) {
  37                         if( !self::isValidISBN( $this->isbn ) ) {
  38                                 $wgOut->wrapWikiMsg( "<div class=\"error\">\n$1\n</div>", 'booksources-invalid-isbn' );
  39                         }
  40                         $this->showList();
  41                 }
  42         }
  43
  44         /**
  45          * Returns whether a given ISBN (10 or 13) is valid.  True indicates validity.
  46          * @param isbn ISBN passed for check
  47          */
  48         public static function isValidISBN( $isbn ) {
  49                 $isbn = self::cleanIsbn( $isbn );
  50                 $sum = 0;
  51                 $check = -1;
  52                 if( strlen( $isbn ) == 13 ) {
  53                         for( $i = 0; $i < 12; $i++ ) {
  54                                 if($i % 2 == 0) {
  55                                         $sum += $isbn{$i};
  56                                 } else {
  57                                         $sum += 3 * $isbn{$i};
  58                                 }
  59                         }
  60
  61                         $check = (10 - ($sum % 10)) % 10;
  62                         if ($check == $isbn{12}) {
  63                                 return true;
  64                         }
  65                 } elseif( strlen( $isbn ) == 10 ) {
  66                         for($i = 0; $i < 9; $i++) {
  67                                 $sum += $isbn{$i} * ($i + 1);
  68                         }
  69
  70                         $check = $sum % 11;
  71                         if($check == 10) {
  72                                 $check = "X";
  73                         }
  74                         if($check == $isbn{9}) {
  75                                 return true;
  76                         }
  77                 }
  78                 return false;
  79         }
  80
  81
  82         /**
  83          * Trim ISBN and remove characters which aren't required
  84          *
  85          * @param $isbn Unclean ISBN
  86          * @return string
  87          */
  88         private static function cleanIsbn( $isbn ) {
  89                 return trim( preg_replace( '![^0-9X]!', '', $isbn ) );
  90         }
  91
  92         /**
  93          * Generate a form to allow users to enter an ISBN
  94          *
  95          * @return string
  96          */
  97         private function makeForm() {
  98                 global $wgScript;
  99                 $title = self::getTitleFor( 'Booksources' );
 100                 $form  = '<fieldset><legend>' . wfMsgHtml( 'booksources-search-legend' ) . '</legend>';
 101                 $form .= Xml::openElement( 'form', array( 'method' => 'get', 'action' => $wgScript ) );
 102                 $form .= Xml::hidden( 'title', $title->getPrefixedText() );
 103                 $form .= '<p>' . Xml::inputLabel( wfMsg( 'booksources-isbn' ), 'isbn', 'isbn', 20, $this->isbn );
 104                 $form .= '&nbsp;' . Xml::submitButton( wfMsg( 'booksources-go' ) ) . '</p>';
 105                 $form .= Xml::closeElement( 'form' );
 106                 $form .= '</fieldset>';
 107                 return $form;
 108         }
 109
 110         /**
 111          * Determine where to get the list of book sources from,
 112          * format and output them
 113          *
 114          * @return string
 115          */
 116         private function showList() {
 117                 global $wgOut, $wgContLang;
 118
 119                 # Hook to allow extensions to insert additional HTML,
 120                 # e.g. for API-interacting plugins and so on
 121                 wfRunHooks( 'BookInformation', array( $this->isbn, &$wgOut ) );
 122
 123                 # Check for a local page such as Project:Book_sources and use that if available
 124                 $title = Title::makeTitleSafe( NS_PROJECT, wfMsgForContent( 'booksources' ) ); # Show list in content language
 125                 if( is_object( $title ) && $title->exists() ) {
 126                         $rev = Revision::newFromTitle( $title );
 127                         $wgOut->addWikiText( str_replace( 'MAGICNUMBER', $this->isbn, $rev->getText() ) );
 128                         return true;
 129                 }
 130
 131                 # Fall back to the defaults given in the language file
 132                 $wgOut->addWikiMsg( 'booksources-text' );
 133                 $wgOut->addHTML( '<ul>' );
 134                 $items = $wgContLang->getBookstoreList();
 135                 foreach( $items as $label => $url )
 136                         $wgOut->addHTML( $this->makeListItem( $label, $url ) );
 137                 $wgOut->addHTML( '</ul>' );
 138                 return true;
 139         }
 140
 141         /**
 142          * Format a book source list item
 143          *
 144          * @param $label Book source label
 145          * @param $url Book source URL
 146          * @return string
 147          */
 148         private function makeListItem( $label, $url ) {
 149                 $url = str_replace( '$1', $this->isbn, $url );
 150                 return '<li><a href="' . htmlspecialchars( $url ) . '">' . htmlspecialchars( $label ) . '</a></li>';
 151         }
 152 }