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219e10c270
Modified addon. The addon used to generate a large system load and led to the server being unavailable. The changes help to make better use of system resources. - Creates and removes tesseract-limited.sh to limit the system resources for tesseract (timeout/resource limits). - Checks permitted formats to avoid wasting resources.
115 lines
No EOL
3.3 KiB
PHP
115 lines
No EOL
3.3 KiB
PHP
<?php
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/**
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* Name: Tesseract OCR
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* Description: Use OCR to extract text from images (with timeout, resource limits, alt-text & format checks)
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* Version: 0.2
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* Author: Michael Vogel <http://pirati.ca/profile/heluecht>
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* * Modified by: Matthias Ebers <http://loma.ml/profile/feb>
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*/
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use Friendica\Core\Hook;
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use Friendica\Core\System;
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use Friendica\DI;
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use thiagoalessio\TesseractOCR\TesseractOCR;
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require_once __DIR__ . DIRECTORY_SEPARATOR . 'vendor' . DIRECTORY_SEPARATOR . 'autoload.php';
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/**
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* Called when the addon is enabled
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*/
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function tesseract_install()
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{
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Hook::register('ocr-detection', __FILE__, 'tesseract_ocr_detection');
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$wrapperPath = __DIR__ . '/tesseract-limited.sh';
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// Create a wrapper script with timeout and resource constraints
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if (!file_exists($wrapperPath)) {
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$script = <<<BASH
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#!/bin/bash
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# Wrapper for tesseract with timeout and resource limits
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timeout 5s nice -n 10 ionice -c3 /usr/bin/tesseract "\$@"
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BASH;
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file_put_contents($wrapperPath, $script);
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chmod($wrapperPath, 0755);
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DI::logger()->notice('Tesseract wrapper script created', ['path' => $wrapperPath]);
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} else {
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DI::logger()->info('Tesseract wrapper script already exists', ['path' => $wrapperPath]);
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}
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DI::logger()->notice('Tesseract OCR addon installed');
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}
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/**
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* Called when the addon is disabled
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*/
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function tesseract_uninstall()
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{
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$wrapperPath = __DIR__ . '/tesseract-limited.sh';
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if (file_exists($wrapperPath)) {
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unlink($wrapperPath);
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DI::logger()->notice('Tesseract wrapper script removed', ['path' => $wrapperPath]);
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}
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Hook::unregister('ocr-detection', __FILE__, 'tesseract_ocr_detection');
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DI::logger()->notice('Tesseract OCR addon uninstalled');
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}
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/**
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* Main OCR processing hook for incoming images
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*/
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function tesseract_ocr_detection(&$media)
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{
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// Skip OCR if image already contains an alt-text
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if (!empty($media['description'])) {
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DI::logger()->debug('Image already has description, skipping OCR');
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return;
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}
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// Only allow specific MIME types for OCR
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$allowedTypes = ['image/jpeg', 'image/png', 'image/bmp', 'image/tiff'];
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if (!empty($media['type']) && !in_array($media['type'], $allowedTypes)) {
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DI::logger()->debug('Unsupported image type for OCR', ['type' => $media['type']]);
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return;
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}
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// Alternatively skip GIF files based on filename
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if (empty($media['type']) && !empty($media['filename']) && preg_match('/\.gif$/i', $media['filename'])) {
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DI::logger()->debug('GIF image detected via filename, skipping OCR');
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return;
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}
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$ocr = new TesseractOCR();
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try {
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// Use wrapper script with timeout and niceness
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$ocr->executable(__DIR__ . '/tesseract-limited.sh');
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// Detect and set available languages
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$languages = $ocr->availableLanguages();
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if ($languages) {
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$ocr->lang(implode('+', $languages));
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}
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// Use Friendica's temporary path
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$ocr->tempDir(System::getTempPath());
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// Provide raw image data to Tesseract
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$ocr->imageData($media['img_str'], strlen($media['img_str']));
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// Run OCR and assign description if text is found
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$text = trim($ocr->run());
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if (!empty($text)) {
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$media['description'] = $text;
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DI::logger()->debug('OCR text detected', ['text' => $text]);
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} else {
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DI::logger()->debug('No text detected in image');
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}
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} catch (\Throwable $th) {
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DI::logger()->info('Error calling TesseractOCR', ['message' => $th->getMessage()]);
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}
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} |