147 lines
3.7 KiB
PHP
147 lines
3.7 KiB
PHP
<?php
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namespace SilverStripe\TextExtraction\Extractor;
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use SilverStripe\Assets\File;
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use SilverStripe\TextExtraction\Extractor\FileTextExtractor\Exception;
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/**
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* Text extractor that calls pdftotext to do the conversion.
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* @author mstephens
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*/
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class PDFTextExtractor extends FileTextExtractor
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{
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/**
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* Set to bin path this extractor can execute
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*
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* @var string
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*/
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private static $binary_location = null;
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/**
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* Used if binary_location isn't set.
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* List of locations to search for a given binary in
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*
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* @config
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* @var array
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*/
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private static $search_binary_locations = [
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'/usr/bin',
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'/usr/local/bin',
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];
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public function isAvailable()
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{
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$bin = $this->bin('pdftotext');
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return $bin && file_exists($bin ?? '') && is_executable($bin ?? '');
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}
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public function supportsExtension($extension)
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{
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return strtolower($extension ?? '') === 'pdf';
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}
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public function supportsMime($mime)
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{
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return in_array(
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strtolower($mime ?? ''),
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[
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'application/pdf',
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'application/x-pdf',
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'application/x-bzpdf',
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'application/x-gzpdf'
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]
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);
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}
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/**
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* Accessor to get the location of the binary
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*
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* @param string $program Name of binary
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* @return string
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*/
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protected function bin($program = '')
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{
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// Get list of allowed search paths
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if ($location = $this->config()->get('binary_location')) {
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$locations = [$location];
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} else {
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$locations = $this->config()->get('search_binary_locations');
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}
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// Find program in each path
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foreach ($locations as $location) {
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$path = "{$location}/{$program}";
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if (file_exists($path ?? '')) {
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return $path;
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}
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if (file_exists($path . '.exe')) {
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return $path . '.exe';
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}
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}
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// Not found
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return null;
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}
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public function getContent($file)
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{
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if (!$file || (is_string($file) && !file_exists($file ?? ''))) {
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// no file
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return '';
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}
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$content = $this->getRawOutput($file);
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return $this->cleanupLigatures($content);
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}
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/**
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* Invoke pdftotext with the given File object
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*
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* @param File|string $file
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* @return string Output
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* @throws Exception
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*/
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protected function getRawOutput($file)
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{
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if (!$this->isAvailable()) {
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throw new Exception("getRawOutput called on unavailable extractor");
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}
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$path = $file instanceof File ? $this->getPathFromFile($file) : $file;
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exec(sprintf('%s %s - 2>&1', $this->bin('pdftotext'), escapeshellarg($path ?? '')), $content, $err);
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if ($err) {
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throw new Exception(sprintf(
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'PDFTextExtractor->getContent() failed for %s: %s',
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$path,
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implode(PHP_EOL, $content)
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));
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}
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return implode(PHP_EOL, $content);
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}
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/**
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* Removes utf-8 ligatures.
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*
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* @link http://en.wikipedia.org/wiki/Typographic_ligature#Computer_typesetting
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*
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* @param string $input
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* @return string
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*/
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protected function cleanupLigatures($input)
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{
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$mapping = [
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'ff' => 'ff',
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'fi' => 'fi',
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'fl' => 'fl',
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'ffi' => 'ffi',
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'ffl' => 'ffl',
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'ſt' => 'ft',
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'st' => 'st'
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];
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return str_replace(array_keys($mapping ?? []), array_values($mapping ?? []), $input ?? '');
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}
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}
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