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Use this static class to extract Text from Pdf files. It supports compressed and uncompressed Pdf (version 1.1 to 1.7) : tested It supports octal encoded (eg : \050) content, but not hexadecimal (eg : <005E>). In some cases, it works better than "pdftotext" binary tool.
<?php
/**
* @file
* Class PdfParser
*
* @author : Sebastien MALOT <sebastien@malot.fr>
* @date : 2013-08-08
*
* References :
* - http://www.mactech.com/articles/mactech/Vol.15/15.09/PDFIntro/index.html
* - http://framework.zend.com/issues/secure/attachment/12512/Pdf.php
* - http://www.php.net/manual/en/ref.pdf.php#74211
*/
class PdfParser
{
/**
* Parse PDF file
*
* @param string $filename
* @return string
*/
public static function parseFile($filename)
{
$content = file_get_contents($filename);
return self::extractText($content);
}
/**
* Parse PDF content
*
* @param string $content
* @return string
*/
public static function parseContent($content)
{
return self::extractText($content);
}
/**
* Convert a PDF into text.
*
* @param string $filename The filename to extract the data from.
* @return string The extracted text from the PDF
*/
protected static function extractText($data)
{
/**
* Split apart the PDF document into sections. We will address each
* section separately.
*/
$a_obj = self::getDataArray($data, 'obj', 'endobj');
$j = 0;
$a_chunks = array();
/**
* Attempt to extract each part of the PDF document into a 'filter'
* element and a 'data' element. This can then be used to decode the
* data.
*/
foreach ($a_obj as $obj) {
$a_filter = self::getDataArray($obj, '<<', '>>');
if (is_array($a_filter) && isset($a_filter[0])) {
$a_chunks[$j]['filter'] = $a_filter[0];
$a_data = self::getDataArray($obj, 'stream', 'endstream');
if (is_array($a_data) && isset($a_data[0])) {
$a_chunks[$j]['data'] = trim(substr($a_data[0], strlen('stream'), strlen($a_data[0]) - strlen('stream') - strlen('endstream')));
}
$j++;
}
}
$result_data = null;
// decode the chunks
foreach ($a_chunks as $chunk) {
// Look at each chunk decide if we can decode it by looking at the contents of the filter
if (isset($chunk['data'])) {
// look at the filter to find out which encoding has been used
if (strpos($chunk['filter'], 'FlateDecode') !== false) {
// Use gzuncompress but suppress error messages.
$data =@ gzuncompress($chunk['data']);
} else {
$data = $chunk['data'];
}
if (trim($data) != '') {
// If we got data then attempt to extract it.
$result_data .= ' ' . self::extractTextElements($data);
}
}
}
/**
* Make sure we don't have large blocks of white space before and after
* our string. Also extract alphanumerical information to reduce
* redundant data.
*/
if (trim($result_data) == '') {
return null;
} else {
// Optimize hyphened words
$result_data = preg_replace('/\s*-[\r\n]+\s*/', '', $result_data);
$result_data = preg_replace('/\s+/', ' ', $result_data);
return $result_data;
}
}
protected static function extractTextElements($content)
{
if (strpos($content, '/CIDInit') === 0) {
return '';
}
$text = '';
$lines = explode("\n", $content);
foreach ($lines as $line) {
$line = trim($line);
$matches = array();
// Parse each lines to extract command and operator values
if (preg_match('/^(?<command>.*[\)\] ])(?<operator>[a-z]+[\*]?)$/i', $line, $matches)) {
$command = trim($matches['command']);
// Convert octal encoding
$found_octal_values = array();
preg_match_all('/\\\\([0-9]{3})/', $command, $found_octal_values);
foreach($found_octal_values[0] as $value) {
$octal = substr($value, 1);
if (intval($octal) < 40) {
// Skips non printable chars
$command = str_replace($value, '', $command);
} else {
$command = str_replace($value, chr(octdec($octal)), $command);
}
}
// Removes encoded new lines, tabs, ...
$command = preg_replace('/\\\\[\r\n]/', '', $command);
$command = preg_replace('/\\\\[rnftb ]/', ' ', $command);
// Force UTF-8 charset
$encoding = mb_detect_encoding($command, array('ASCII', 'UTF-8', 'Windows-1252', 'ISO-8859-1'));
if (strtoupper($encoding) != 'UTF-8') {
if ($decoded = @iconv('CP1252', 'UTF-8//TRANSLIT//IGNORE', $command)) {
$command = $decoded;
}
}
// Removes leading spaces
$operator = trim($matches['operator']);
} else {
$command = $line;
$operator = '';
}
// Handle main operators
switch ($operator) {
// Set character spacing.
case 'Tc':
break;
// Move text current point.
case 'Td':
$values = explode(' ', $command);
$y = array_pop($values);
$x = array_pop($values);
if ($x > 0) {
$text .= ' ';
}
if ($y < 0) {
$text .= ' ';
}
break;
// Move text current point and set leading.
case 'TD':
$values = explode(' ', $command);
$y = array_pop($values);
if ($y < 0) {
$text .= "\n";
}
break;
// Set font name and size.
case 'Tf':
$text.= ' ';
break;
// Display text, allowing individual character positioning
case 'TJ':
$start = mb_strpos($command, '[', null, 'UTF-8') + 1;
$end = mb_strrpos($command, ']', null, 'UTF-8');
$text.= self::parseTextCommand(mb_substr($command, $start, $end - $start, 'UTF-8'));
break;
// Display text.
case 'Tj':
$start = mb_strpos($command, '(', null, 'UTF-8') + 1;
$end = mb_strrpos($command, ')', null, 'UTF-8');
$text.= mb_substr($command, $start, $end - $start, 'UTF-8'); // Removes round brackets
break;
// Set leading.
case 'TL':
// Set text matrix.
case 'Tm':
// $text.= ' ';
break;
// Set text rendering mode.
case 'Tr':
break;
// Set super/subscripting text rise.
case 'Ts':
break;
// Set text spacing.
case 'Tw':
break;
// Set horizontal scaling.
case 'Tz':
break;
// Move to start of next line.
case 'T*':
$text.= "\n";
break;
// Internal use
case 'g':
case 'gs':
case 're':
case 'f':
// Begin text
case 'BT':
// End text
case 'ET':
break;
case '':
break;
default:
}
}
$text = str_replace(array('\\(', '\\)'), array('(', ')'), $text);
return $text;
}
/**
* Strip out the text from a small chunk of data.
*
* @param string $text
* @param int $font_size Currently not used
*
* @return string
*/
protected static function parseTextCommand($text, $font_size = 0) {
$result = '';
$cur_start_pos = 0;
while (($cur_start_text = mb_strpos($text, '(', $cur_start_pos, 'UTF-8')) !== false) {
// New text element found
if ($cur_start_text - $cur_start_pos > 8) {
$spacing = ' ';
} else {
$spacing_size = mb_substr($text, $cur_start_pos, $cur_start_text - $cur_start_pos, 'UTF-8');
if ($spacing_size < -50) {
$spacing = ' ';
} else {
$spacing = '';
}
}
$cur_start_text++;
$start_search_end = $cur_start_text;
while (($cur_start_pos = mb_strpos($text, ')', $start_search_end, 'UTF-8')) !== false) {
if (mb_substr($text, $cur_start_pos - 1, 1, 'UTF-8') != '\\') {
break;
}
$start_search_end = $cur_start_pos + 1;
}
// something wrong happened
if ($cur_start_pos === false) {
break;
}
// Add to result
$result .= $spacing . mb_substr($text, $cur_start_text, $cur_start_pos - $cur_start_text, 'UTF-8');
$cur_start_pos++;
}
return $result;
}
/**
* Convert a section of data into an array, separated by the start and end words.
*
* @param string $data The data.
* @param string $start_word The start of each section of data.
* @param string $end_word The end of each section of data.
* @return array The array of data.
*/
protected static function getDataArray($data, $start_word, $end_word)
{
$start = 0;
$end = 0;
$a_results = array();
while ($start !== false && $end !== false) {
$start = strpos($data, $start_word, $end);
$end = strpos($data, $end_word, $start);
if ($end !== false && $start !== false) {
// data is between start and end
$a_results[] = substr($data, $start, $end - $start + strlen($end_word));
}
}
return $a_results;
}
}
@cobbrg

Looks very promising. It doesn't seem to preserve carriage returns? Thanks!

@alpeshkasodariya

Hello,

We are using above static class to extract Text from Pdf files.
But This class does not support pdf version of 1.4.

Could you please help us ?

Thanks..

@smalot
Owner

This class is useful but, I agree, really elementary.

I'm currently working on a more complex standalone php lib which will support mac charset encoding, hexa and octale encoding, character translation, carriage returns ...
Many of those specifications are available from very low pdf version.

https://github.com/smalot/pdfparser

To help me in my developments, could you send me some pdf sample file that I could include in my unit tests ?
email : sebastien@malot.fr

Thanks for all !

@smalot
Owner

I've just made a first release (v0.9.0)
https://github.com/smalot/pdfparser/tree/v0.9.0

Don't hesitate to test it and report me any issue.

@alexglue

Parsing of this http://economics.ihbt.ifmo.ru/file/article/263.pdf was failed (bad content).

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