How to make Node.js wait for response from a large request
Question
I am posting a large number of files that can take potentially minutes to upload. I using a multi-part form to post the files and then waiting for a response from the POST, but this can take several minutes.
How do I make Node/Express wait for this response? As of now, it seems like the request is "timing out" and Node or the browser is re-POSTing the files because it is taking so long. I can see this because my middleware functions are being called multiple times for requests that take too long.
Is there a library to make Node not timeout? Should I be attempting to POST these files in a different fashion? Thanks
var mid = function(req,res,next) {
console.log('Called');
next();
};
app.post('/api/GROBID', mid, authenticate, PDFupload.return_GROBID, PDFupload.post_doc, function(req, res) {
if (res.locals.body == 400) res.send(400);
/*if (process.env.TEST_ENV == 'unit-testing') {
res.send(res.locals.body);
}*/
res.render('uploads', {files : res.locals.body});
});
Edit: This mid middleware (used as an example) is being called twice. This means the route is being posted to twice. How do I make sure this does not happen?
1 answers
solution1
3 2018-01-19 23:51:59
Is there a library to make Node not timeout?
Express sits on top of Node.js' built-in HTTP server . By default, the timeout is 2 minutes. You can modify its default timeout as below:
var express = require('express');
var app = express();
var port = process.env.PORT || 3000;
app.get('/', function(req, res) {
res.send('<html><head></head><body><h1>Hello world!</h1></body></html>');
});
var server = app.listen(port);
server.timeout = 1000 * 60 * 10; // 10 minutes
Should I be attempting to POST these files in a different fashion?
Yes, you can use Multer , a node.js middleware for handling multipart/form-data, which is primarily used for uploading files.
And with Multer, you don't have to worry about the timeout anymore. Event the upload time is longer than the timeout, say 2 minutes by default, Express just won't timeout.
Here is the sample code:
app.js
var express = require('express');
var app = express();
var path = require('path');
var multer = require('multer');
const storage = multer.diskStorage({
destination: function (req, file, cb) {
cb(null, '/your/path/to/store/uploaded/files/')
},
filename: function (req, file, cb) {
// Keep original file names
cb(null, file.originalname)
}
})
var upload = multer({ storage: storage })
// files is the name of the input html element
// 12 is the maximum number of files to upload
app.post('/upload', upload.array('files', 12), async (req, res) => {
res.send('File uploaded!');
})
app.get('/', function (req, res) {
res.sendFile(path.join(__dirname + '/index.html'));
});
app.listen(3000);
index.html
<html>
<body>
<form ref='uploadForm' id='uploadForm'
action='http://localhost:3000/upload'
method='post'
encType="multipart/form-data">
<input type='file' name='files' multiple/>
<input type='submit' value='Upload!' />
</form>
</body>
</html>
Now try starting the web server:
node app.js
Then open your browser and go to http://localhost:3000
You can now upload a number of big files, which you can find later on in folder /your/path/to/store/uploaded/files/
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