Await for function before end()

Question

edit: added a bit more code.

    const express = require('express');
    var bodyParser = require('body-parser');
    const app = express();

    var urlencodedParser = bodyParser.urlencoded({extended: false})

    const {google} = require('googleapis');
    const {PubSub} = require('@google-cloud/pubsub');
    const iot = require('@google-cloud/iot');
    const API_VERSION = 'v1';

    const DISCOVERY_API = 'https://cloudiot.googleapis.com/$discovery/rest';
    app.get('/', urlencodedParser, (req, res) => {

    const projectId = req.query.proyecto;
    const cloudRegion = req.query.region;
    const registryId = req.query.registro;
    const numSerie = req.query.numSerie;
    const command = req.query.command;

    const client = new iot.v1.DeviceManagerClient();
    if (client === undefined) {
        console.log('Did not instantiate client.');
    } else {
        console.log('Did instantiate client.');
        sendCom();
    }

    async function sendCom() {
        const formattedName = await client.devicePath(projectId, cloudRegion, registryId, numSerie)
        const binaryData = Buffer.from(command);
        const request = {
            name: formattedName,
            binaryData: binaryData,
        };
        return client.sendCommandToDevice(request).then(responses => res.status(200).send(JSON.stringify({
            data: OK
        }))).catch(err => res.status(404).send('Could not send command. Is the device connected?'));
    }
});

const PORT = process.env.PORT || 8080;
app.listen(PORT, () => {
    console.log(`App listening on port ${PORT}`);
    console.log('Press Ctrl+C to quit.');
});

module.exports = app;

I have this function, that I call after the client initiate: sendCom();

     async function sendCom() {
        const formattedName = await client.devicePath(projectId, cloudRegion, registryId, deviceId)
        const binaryData = Buffer.from(command);            
        const request = { name: formattedName, binaryData: binaryData, };

        client.sendCommandToDevice(request)
        .then(responses => {
            res.status(200).send(JSON.stringify({ data: OK })).end();                
        })
        .catch(err => {
            res.status(404).send('Could not send command. Is the device connected?').end();             
        });
    }

My problem is that sendCommandToDevice gets executed perfectly, however I get the catch error. As I understand it, it's because in the .then ends the connection.

I've looked at this and thats's what I tried, however I'm not sure I understand what's going on.

you are using `res.status....` while your lambda get `responses`. where is `res` come from? — Omri Attiya, Apr 06 '20 at 08:48
@OmriAttiya its in app.get('/', urlencodedParser, (req, res) => {} All the code I posted above is here. — 1x2x3x4x, Apr 06 '20 at 09:03
@Farrukh Yeah, as I said I think that's the problem. But I'm not sure where or how should I .end() it? — 1x2x3x4x, Apr 06 '20 at 09:04
Well for this case you don't need to call .end() because there is no buffer you are making to send the response plus @OmriAttiya is right about res.status it should be responses.status... — Farrukh, Apr 06 '20 at 09:19
@Farrukh I've updated the post with a more comprehesive code, if that helps. I've changed to what you and OmriAttiya said. Still no success. — 1x2x3x4x, Apr 06 '20 at 09:28

score 0 · Answer 1 · answered Apr 06 '20 at 09:08

0

You can not use send with end.

end() is used when you want to end the request and want to respond with no data.
send() is used to end the request and respond with some data.

You can found more about it here.

answered Apr 06 '20 at 09:08

ziishaned

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Thanks. I removed the .end() However I face the same problem. Even if the try is succesful and the sendCommandToDevice works, I still get as repsonse the catch. – 1x2x3x4x Apr 06 '20 at 09:15

Await for function before end()

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