textract/lib/extractors/pptx.js

Extracting text from files of various type including html, pdf, doc, docx, xls, xlsx, csv, pptx, png, jpg, gif, rtf, text/*, and various open office.

var xpath = require( 'xpath' )
  , Dom = require( 'xmldom' ).DOMParser
  , yauzl = require( 'yauzl' )
  , util = require( '../util' )
  , slideMatch = /^ppt\/slides\/slide/
  , noteMatch = /^ppt\/notesSlides\/notesSlide/
  ;

function _compareSlides( a, b ) {
  if ( a.slide < b.slide ) {
    return -1;
  }
  if ( a.slide > b.slide ) {
    return 1;
  }
  return 0;
}

function _calculateExtractedText( slideText ) {
  var doc = new Dom().parseFromString( slideText )
    , ps = xpath.select( "//*[local-name()='p']", doc )
    , text = ''
    ;

  ps.forEach( function( paragraph ) {
    var ts
      , localText = ''
      ;

    paragraph = new Dom().parseFromString( paragraph.toString() );
    ts = xpath.select( "//*[local-name()='t' or local-name()='tab' or local-name()='br']",
      paragraph );
    ts.forEach( function( t ) {
      if ( t.localName === 't' && t.childNodes.length > 0 ) {
        localText += t.childNodes[0].data;
      } else {
        if ( t.localName === 'tab' || t.localName === 'br' ) {
          localText += '';
        }
      }
    });
    text += localText + '\n';
  });

  return text;
}

function extractText( filePath, options, cb ) {
  var slides = [];

  yauzl.open( filePath, function( err, zipfile ) {
    if ( err ) {
      util.yauzlError( err, cb );
      return;
    }

    zipfile.on( 'end', function() {
      var slidesText, text;
      if ( slides.length ) {
        slides.sort( _compareSlides );
        slidesText = slides.map( function( slide ) {
          return slide.text;
        }).join( '\n' );
        text = _calculateExtractedText( slidesText );
        cb( null, text );
      } else {
        cb(
          new Error( 'Extraction could not find slides in file, are you' +
            ' sure it is the mime type it says it is?' ),
          null );
      }
    });

    zipfile.on( 'entry', function( entry ) {
      if ( slideMatch.test( entry.fileName ) || noteMatch.test( entry.fileName ) ) {
        util.getTextFromZipFile( zipfile, entry, function( err2, text ) {
          var slide = +entry.fileName.replace( 'ppt/slides/slide', '' ).replace( '.xml', '' );
          slides.push({ slide: slide, text: text });
        });
      }
    });

    zipfile.on( 'error', function( err3 ) {
      cb( err3 );
    });
  });
}

module.exports = {
  types: [
    'application/vnd.openxmlformats-officedocument.presentationml.presentation',
    'application/vnd.openxmlformats-officedocument.presentationml.template'],
  extract: extractText
};