silverstripe-textextraction/code/extractors/PDFTextExtractor.php

141 lines
3.5 KiB
PHP

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