| import express from 'express'; |
| import multer from 'multer'; |
| import { exec as execCallback } from 'child_process'; |
| import { promisify } from 'util'; |
| import fs from 'fs/promises'; |
| import crypto from 'crypto'; |
|
|
| const exec = promisify(execCallback); |
| const app = express(); |
| const upload = multer({ storage: multer.memoryStorage() }); |
|
|
| app.post('/process', upload.single('file'), async (req, res) => { |
| const file = req.file; |
| const format = (req.query.format || 'pdf').toLowerCase(); |
| const page = parseInt(req.query.page || '1'); |
| const quality = parseInt(req.query.quality || '80'); |
|
|
| if (!file) return res.status(400).json({ error: 'No file provided' }); |
|
|
| const id = crypto.randomBytes(16).toString('hex'); |
| const tmpPdf = `/tmp/${id}.pdf`; |
| let outputFiles = [tmpPdf]; |
|
|
| try { |
| |
| const formData = new FormData(); |
| const fileBlob = new Blob([file.buffer], { type: file.mimetype }); |
| formData.append('files', fileBlob, file.originalname); |
| formData.append('pdfa', 'PDF/A-1b'); |
|
|
| const gotenbergRes = await fetch('http://127.0.0.1:3000/forms/libreoffice/convert', { |
| method: 'POST', |
| body: formData, |
| }); |
|
|
| if (!gotenbergRes.ok) throw new Error(`Gotenberg Error: ${await gotenbergRes.text()}`); |
| |
| const pdfBuffer = await gotenbergRes.arrayBuffer(); |
| await fs.writeFile(tmpPdf, Buffer.from(pdfBuffer)); |
|
|
| |
| const { stdout: pdfInfoStdout } = await exec(`pdfinfo ${tmpPdf}`); |
| const pagesMatch = pdfInfoStdout.match(/Pages:\s+(\d+)/); |
| const totalPages = pagesMatch ? parseInt(pagesMatch[1], 10) : 1; |
|
|
| |
| let targetPage = page; |
| if (page > totalPages) { |
| targetPage = ((page - 1) % totalPages) + 1; |
| } |
|
|
| |
| res.setHeader('X-Total-Pages', totalPages.toString()); |
| res.setHeader('X-Actual-Page', targetPage.toString()); |
|
|
| |
| if (format === 'pdf') { |
| res.setHeader('Content-Type', 'application/pdf'); |
| return res.send(Buffer.from(pdfBuffer)); |
| } |
|
|
| |
| let finalOutput = ''; |
| let mimeType = ''; |
|
|
| if (format === 'svg') { |
| finalOutput = `/tmp/${id}.svg`; |
| outputFiles.push(finalOutput); |
| await exec(`pdftocairo -svg -f ${targetPage} -l ${targetPage} ${tmpPdf} ${finalOutput}`); |
| mimeType = 'image/svg+xml'; |
| |
| } else if (format === 'png' || format === 'jpeg' || format === 'webp' || format === 'avif') { |
| const tmpImg = `/tmp/${id}`; |
| |
| if (format === 'jpeg') { |
| finalOutput = `/tmp/${id}.jpg`; |
| outputFiles.push(finalOutput); |
| await exec(`pdftocairo -jpeg -singlefile -f ${targetPage} -l ${targetPage} ${tmpPdf} ${tmpImg}`); |
| mimeType = 'image/jpeg'; |
| } else { |
| const intermediatePng = `/tmp/${id}.png`; |
| outputFiles.push(intermediatePng); |
| await exec(`pdftocairo -png -singlefile -f ${targetPage} -l ${targetPage} ${tmpPdf} ${tmpImg}`); |
| |
| if (format === 'png') { |
| finalOutput = intermediatePng; |
| mimeType = 'image/png'; |
| } else if (format === 'webp') { |
| finalOutput = `/tmp/${id}.webp`; |
| outputFiles.push(finalOutput); |
| await exec(`cwebp -q ${quality} ${intermediatePng} -o ${finalOutput}`); |
| mimeType = 'image/webp'; |
| } else if (format === 'avif') { |
| finalOutput = `/tmp/${id}.avif`; |
| outputFiles.push(finalOutput); |
| await exec(`avifenc -q ${quality} ${intermediatePng} ${finalOutput}`); |
| mimeType = 'image/avif'; |
| } |
| } |
| } else { |
| throw new Error('Unsupported format'); |
| } |
|
|
| const finalBuffer = await fs.readFile(finalOutput); |
| res.setHeader('Content-Type', mimeType); |
| res.setHeader('Cache-Control', 'public, max-age=31536000'); |
| res.send(finalBuffer); |
|
|
| } catch (error) { |
| console.error(error); |
| res.status(500).json({ error: error.message }); |
| } finally { |
| for (const f of outputFiles) { |
| fs.unlink(f).catch(() => {}); |
| } |
| } |
| }); |
|
|
| app.listen(7860, () => console.log('Extractor API running on 7860')); |
