Feature/secure print

api/main_endpoints/routes/Printer.js

@@ -7,6 +7,8 @@ const fs = require('fs');
 const path = require('path');
 const { MetricsHandler, register } = require('../../util/metrics.js');
 const { cleanUpChunks, cleanUpExpiredChunks, recordPrintingFolderSize } = require('../util/Printer.js');
+const { PDFDocument, StandardFonts } = require('pdf-lib');
+const {subtractUserPages} = require('../util/userHelpers');
 
 const {
   decodeToken,
@@ -113,16 +115,25 @@ router.post('/sendPrintRequest', upload.single('chunk'), async (req, res) => {
       return res.sendStatus(SERVER_ERROR);
     }
   }
-
-  const stream = await fs.createReadStream(assembledPdfFromChunks);
+  const stream = await fs.promises.readFile(assembledPdfFromChunks); // Buffer
   const data = new FormData();
   data.append('file', stream, {filename: id, type: 'application/pdf'});
   data.append('copies', copies);
   data.append('sides', sides);
 
   try {
+    const pdfDoc = await PDFDocument.load(stream); // load PDF
+    const numpages = pdfDoc.getPages().length; // get number of pages
+    const copiesInt = parseInt(copies || 1, 10);
+    const totalPages = numpages * copiesInt; // updates users printcount
+    const pagesRemaining = await subtractUserPages(user.id, totalPages);
+    if (pagesRemaining === null) {
+      await cleanUpChunks(dir, id);
+      return res.status(400).json({ error: 'Page limit exceeded or user not found' });
+    }
     // full pdf can be sent to quasar no problem
     const printRes = await axios.post(PRINTER_URL + '/print', data, {
+
       headers: {
         ...data.getHeaders(),
       },

api/main_endpoints/util/userHelpers.js

@@ -202,6 +202,26 @@ function checkIfPageCountResets(lastLogin) {
 
   return lastLoginWasOverOneWeekAgo || aSundayHasPassedSinceLastLogin;
 }
+// updates users available pages
+async function subtractUserPages(userId, pagesToPrint){
+  const user = await User.findById(userId);
+  if(!user){
+    logger.error(`User not found ID: ${userId}`);
+    return null; // checks user
+  }
+  if(!Number.isInteger(pagesToPrint) || pagesToPrint <= 0){
+    logger.error(`Invalid pagesToPrint value: ${pagesToPrint}.`);
+    return null;
+  }
+  if (user.pagesPrinted < pagesToPrint) {
+    logger.error(`User has insufficient pages remaining. Requested: ${pagesToPrint}. Available:${user.pagesPrinted}`);
+    return null;
+  }
+
+  user.pagesPrinted -= pagesToPrint;
+  await user.save();
+  return user.pagesPrinted;
+}
 
 module.exports = {
   registerUser,
@@ -211,4 +231,5 @@ module.exports = {
   userWithEmailExists,
   checkIfPageCountResets,
   findPasswordReset,
+  subtractUserPages,
 };