kartikk221
multipart data parser issues
POST HTTP request results in connection drop (HTTP client gets as response something like: curl: (52) Empty reply from server, err_empty_response, socket hang up), if the request handler contains multidata parsing via req.multipart and it takes a long time to process.
The example server handles 3 requests:
/regular-long -- takes 15s to process, test request is successful. /multipart-fast -- uses hyper-express multipart parser, takes 5s to process, test request is successful. /multipart-long -- uses hyper-express multipart parser, takes 15s to process, test request is unsuccessful.
import { Server } from 'hyper-express';
const app = new Server({
max_body_length: 4 * 1024 * 1024,
});
const PORT = 3000;
app.get('/regular-long', async (_, res) => {
await new Promise((resolve) => setTimeout(resolve, 15000));
res.send('OK');
});
app.post('/multipart-long', async (req, res) => {
const formData = {};
try {
await req.multipart(async (field) => {
if (field.file) {
const chunks = [];
for await (const chunk of field.file.stream) {
chunks.push(chunk);
}
} else {
formData[field.name] = field.value;
}
});
await new Promise((resolve) => setTimeout(resolve, 15000));
res.send(JSON.stringify({ success: true, formData }));
} catch (err) {
console.error('Error:', err);
res.status(500).send(JSON.stringify({ error: err.message }));
}
});
app.post('/multipart-fast', async (req, res) => {
const formData = {};
try {
await req.multipart(async (field) => {
if (field.file) {
const chunks = [];
for await (const chunk of field.file.stream) {
chunks.push(chunk);
}
console.log(`File size: ${Buffer.concat(chunks).length} bytes`);
} else {
formData[field.name] = field.value;
console.log(`Field ${field.name}: ${field.value?.substring(0, 50)}...`);
}
});
await new Promise((resolve) => setTimeout(resolve, 5000));
res.send(JSON.stringify({ success: true, formData }));
} catch (err) {
console.error('Error:', err);
res.status(500).send(JSON.stringify({ error: err.message }));
}
});
app
.listen(PORT)
.then(() => {
console.log(`Server running on http://localhost:${PORT}`);
})
.catch((err) => console.error('Server error:', err));
Another parsers or HTTP libraries do not have this issue.
I have noticed the problem arises when the stream starts to be read by chunks. If the body is downloaded at once everything is fine.
