Skip to content

fix: add PDF-only file type validation to multer upload middleware #461

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
ChetanSenta wants to merge 2 commits into
base: master
Choose a base branch
from
Open

fix: add PDF-only file type validation to multer upload middleware #461

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
dec6e8e
fix: add PDF-only file type validation to multer upload middleware
Jun 1, 2026
46bc979
fix: use crypto.randomUUID() for collision-resistant upload filenames
Jun 2, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
44 changes: 22 additions & 22 deletions server.js
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@ require("dotenv").config();
const express = require("express");
const cors = require("cors");
const multer = require("multer");
const crypto = require('crypto');
const axios = require("axios");
const fs = require("fs");
const fsPromises = require("fs/promises");
Expand Down Expand Up @@ -446,32 +447,24 @@ const startUploadsCleanup = () => {
};

const storage = multer.diskStorage({
destination: (req, file, cb) => {
cb(null, UPLOADS_DIR);
},
destination: (req, file, cb) => cb(null, 'uploads/'),
filename: (req, file, cb) => {
cb(null, `${crypto.randomUUID()}.pdf`);
},
const unique = `${Date.now()}-${crypto.randomUUID()}`;
const ext = path.extname(file.originalname).toLowerCase();
cb(null, unique + ext);
},
});

const upload = multer({
storage,
limits: {
fileSize: MAX_PDF_SIZE_BYTES,
// Additional limits to prevent abuse
files: 1, // Only allow one file per request
},
fileFilter: (req, file, cb) => {
const isPdfMime = file.mimetype === "application/pdf";
const isPdfExtension = file.originalname.toLowerCase().endsWith(".pdf");

if (!isPdfMime || !isPdfExtension) {
return cb(new Error("Only PDF files are allowed."));
}

const fileFilter = (req, file, cb) => {
const ext = path.extname(file.originalname).toLowerCase();
if (file.mimetype === 'application/pdf' && ext === '.pdf') {
cb(null, true);
},
});
} else {
cb(new Error('Only PDF files are allowed.'), false);
}
};

const upload = multer({ storage, fileFilter });

const cleanupFile = async (filePath) => {
if (!filePath) return;
Expand Down Expand Up @@ -1129,6 +1122,13 @@ app.get("/health", (req, res) => {
res.json({ status: "ok" });
});

app.use((err, req, res, next) => {
if (err.message === 'Only PDF files are allowed.') {
return res.status(400).json({ error: err.message });
}
next(err);
});

app.use((req, res, next) => {
res.status(404).json({ error: "Not found" });
});
Expand Down
Loading