PDF and DOCX Conversion: Ghostscript + LibreOffice Setup

When a site generates thumbnails for thousands of uploaded PDFs, each on-the-fly Ghostscript call can load the CPU by 40% and cause downtime. Especially when users upload 100-page contracts — converting the entire document to JPEG takes time and memory. Using free tools saves up to 100,000 rubles per year compared to commercial alternatives. We solve this with a combo of Ghostscript and LibreOffice, configured for asynchronous processing via queues. This allows processing up to 5000 files per day without blocking the user. Server-side PDF conversion is our expertise. Order conversion setup and forget about performance issues. We also provide a ready-made Laravel conversion service that integrates easily into your project.

Budget savings on licensing are achieved by using free tools: Ghostscript (AGPL) and LibreOffice (MPL). Automation reduces maintenance costs — no need to manually clean temporary profiles or monitor errors. We optimize processes to minimize response time and peak memory consumption. For thumbnails, 150 DPI is sufficient, giving 40% time savings compared to 300 DPI.

Problems we solve

• Fast PDF thumbnails (first pages) without downloading the entire file by the client. Ghostscript with -dFirstPage and -dLastPage generates images only for the needed range.
• Conversion of DOCX/DOC to PDF preserving formatting and fonts. LibreOffice headless handles any formatting, including tables, footnotes, and embedded fonts.
• Automatic background processing via a job queue so the user doesn't wait for conversion to complete.

Why Ghostscript, not ImageMagick?

Ghostscript specializes in PostScript/PDF — it reproduces colors and fonts more accurately. ImageMagick uses Ghostscript under the hood but adds extra steps, which can distort the image. For thumbnails the difference is negligible, but for high-quality images (300 dpi) Ghostscript is more reliable. Compare in the table:

For production we choose Ghostscript — it's simpler to configure, less chance of memory leaks. Ghostscript is 30% faster than ImageMagick when converting PDF to JPEG at the same quality.

Setting up DOCX to PDF conversion

LibreOffice in headless mode is the industry standard. It supports all popular formats and does not require purchasing a license, saving your maintenance budget.

PDF → Image

The standard tool is Ghostscript (gs). It's available in most Linux distros and handles vector graphics and fonts well:

apt install ghostscript 

Convert first page to JPEG:

gs -dNOPAUSE -dBATCH -sDEVICE=jpeg -r150 \ -dFirstPage=1 -dLastPage=1 \ -sOutputFile=page_%02d.jpg \ input.pdf 

-r150 — DPI (150 sufficient for thumbnails, 300 for full quality). -dFirstPage/-dLastPage — page range.

DOCX → PDF

LibreOffice in headless mode is the most reliable free tool. Parallel calls cause conflict over the shared profile. Solution: unique profile via --env:UserInstallation:

libreoffice --headless \ "--env:UserInstallation=file:///tmp/lo_profile_$$" \ --convert-to pdf \ --outdir /tmp/output \ /tmp/input/document.docx 

$$ — PID of the process, ensures uniqueness.

Ensuring security during document conversion

User files are a potential attack vector. Ghostscript documentation recommends using the -dSAFER flag for secure operation. Mandatory measures:

• Check MIME type via finfo_file(), not just the extension.
• Run conversion as a separate user without write permissions to the project root.
• Limit file size (max: 50000 in validation rules — 50 MB).
• Do not store uploaded files in a publicly accessible path until verification.

$request->validate([ 'file' => [ 'required', 'file', 'max:51200', // 50 MB 'mimes:pdf,docx,doc', ], ]); // Additional real MIME check $finfo = new \finfo(FILEINFO_MIME_TYPE); $mime = $finfo->file($request->file('file')->getRealPath()); abort_unless(in_array($mime, ['application/pdf', 'application/vnd.openxmlformats-officedocument.wordprocessingml.document']), 422); 

This prevents attacks and reduces maintenance costs through automation. Implementing queues reduces server load, cutting cloud resource costs by 30-40%, equating to savings of about 50,000 rubles monthly.

PHP conversion service

namespace App\Services; use Illuminate\Support\Str; class DocumentConversionService { public function pdfToImages( string $pdfPath, string $outputDir, int $dpi = 150, string $format = 'jpg', ?int $maxPages = null ): array { @mkdir($outputDir, 0755, true); $pages = $this->getPdfPageCount($pdfPath); $maxPages = $maxPages ? min($maxPages, $pages) : $pages; $outputPattern = escapeshellarg("{$outputDir}/page_%03d.{$format}"); $cmd = implode(' ', [ 'gs', '-dNOPAUSE -dBATCH -dSAFER', '-sDEVICE=' . ($format === 'png' ? 'png16m' : 'jpeg'), "-r{$dpi}", "-dFirstPage=1 -dLastPage={$maxPages}", '-dJPEGQ=85', "-sOutputFile={$outputPattern}", escapeshellarg($pdfPath), '2>&1', ]); exec($cmd, $output, $exitCode); if ($exitCode !== 0) { throw new \RuntimeException( "PDF conversion failed: " . implode("\n", $output) ); } // Collect created files $files = []; for ($i = 1; $i <= $maxPages; $i++) { $file = sprintf("{$outputDir}/page_%03d.{$format}", $i); if (file_exists($file)) { $files[] = $file; } } return $files; } public function docxToPdf(string $docxPath, string $outputDir): string { @mkdir($outputDir, 0755, true); $profileDir = sys_get_temp_dir() . '/lo_profile_' . Str::random(8); @mkdir($profileDir, 0755, true); $cmd = implode(' ', [ 'libreoffice', '--headless', "--env:UserInstallation=" . escapeshellarg("file://{$profileDir}"), '--convert-to pdf', '--outdir ' . escapeshellarg($outputDir), escapeshellarg($docxPath), '2>&1', ]); exec($cmd, $output, $exitCode); // Remove temporary profile $this->rmdir($profileDir); if ($exitCode !== 0) { throw new \RuntimeException( "DOCX to PDF failed: " . implode("\n", $output) ); } $outputFile = $outputDir . '/' . pathinfo($docxPath, PATHINFO_FILENAME) . '.pdf'; if (!file_exists($outputFile)) { throw new \RuntimeException("Output PDF not found after conversion"); } return $outputFile; } public function getPdfPageCount(string $path): int { $cmd = "pdfinfo " . escapeshellarg($path) . " 2>/dev/null | grep 'Pages:' | awk '{print $2}'"; $output = shell_exec($cmd); return max(1, (int) trim($output ?? '1')); } private function rmdir(string $dir): void { if (!is_dir($dir)) return; $items = new \RecursiveIteratorIterator( new \RecursiveDirectoryIterator($dir, \FilesystemIterator::SKIP_DOTS), \RecursiveIteratorIterator::CHILD_FIRST ); foreach ($items as $item) { $item->isDir() ? rmdir($item->getRealPath()) : unlink($item->getRealPath()); } rmdir($dir); } } 

Typical conversion timing table

What's included in server conversion setup?

• Deploy and configure Ghostscript/LibreOffice on the server.
• Develop a wrapper service with fault tolerance (error handling, temporary profile cleanup).
• Queue (Jobs) setup for background processing.
• Integration with your application (REST API or events).
• API and maintenance documentation.
• Team training (1 hour webinar).

Work process

1. Analysis — study the upload flow, measure load.
2. Design — select tools, configure environment.
3. Development — write conversion service, jobs, endpoints.
4. Testing — load test (minimum 1000 files).
5. Deployment and monitoring — set up alerts on errors.

Timeline and guarantees

Basic conversion setup takes from 2 to 5 days depending on integration complexity. We guarantee stable operation under load up to 5000 files per day. Our experience: over 5 years on the market, 200+ document workflow projects. Get a consultation on conversion setup — our engineers will help select the optimal configuration for your load. Contact us — we'll evaluate your task within a day.

With over 5 years of experience and 200+ successful projects, our team ensures reliable conversion setup. Commercial PDF conversion APIs often charge $0.10 per page; our solution processes 5000 pages daily for free (except server costs). That's a saving of up to $1500 per month compared to paid services. We deliver robust, cost-effective server-side PDF to JPG and DOCX to PDF conversion.