Node does not send response after child process exits - node.js

Question

I have the following route:
app.get('/downloadSentinel', function (req,res){
var promObj = {};
var data = req.query.data;
var Name = req.query.name;
namesArray = [];
for(var i =0;i<Name.length;i++){
namesArray.push(Name[i]);
}
promObj['Name'] = namesArray;
console.log(promObj.Name);
requestarray = [];
for (i=0; i<data.length;i++) {
requestarray.push(data[i]);
promObj['requestURLS'] = requestarray;
}
createResultFolder(promObj)
.then(downloadSentinel)
.then(resp => {
console.log("THEN:", resp);
res.send(resp);
}).catch((err) => {
console.log("CATCH:", err)
res.send(err);
})
});
The function downloadSentinel calls a Node child process and looks like this:
function downloadSentinel(promObj){
return new Promise((resolve,reject) =>{
var sys = require('util'),
exec = require('child_process').exec,
child;
var urls = parseArrayForBash(promObj.requestURLS);
var names = parseArrayForBash(promObj.Name);
console.log("executing:", './downloadProducts.sh ' + urls + ' ' + names);
child = exec('bash downloadProducts.sh '+ urls + ' ' + names, [{stdio:'inherit'}]);
child.stderr.pipe(process.stderr);
child.stdout.pipe(process.stdout);
child.on("error", function (error) {
console.log("child error:", error);
reject(promObj)
})
child.on('data', function (data) {
console.log(data.toString());
});
child.on('exit', function (exit) {
console.log("child exit:", exit);
resolve(promObj);
})
}
})
}
The output of downloadSentinel is :
child exit: 0
THEN: { Name:
[ 'S2A_MSIL1C_20180315T041541_N0206_R090_T46QEH_20180315T075531',
'S2A_MSIL1C_20180315T041541_N0206_R090_T46QEK_20180315T075531' ],
requestURLS:
[ 'bb5f4946-ce18-4b50-97ba-7ac9a94d9f1e',
'ec15c5d4-0cc6-44d4-a11f-6c2e9055f2e4' ] }
So I think that everything works as expected. But after the child process has exited with code 0, the response res.send(resp); is not sent to the client and I never get the sucess message.
What am I doing wrong?
P.S.: Sorry for the large amount of code, but I don't know what I made wrong so I provided everything.
EDIT
For the client part I am using this jQuery Ajax Request:
function downloadSentinelData(ID,Name){
var url = encodeURI('/downloadSentinel?');
$.ajax({
type: 'GET',
url: url,
timeout:5000,
dataType:'json',
data: {
data: ID,
name: Name
},
success: function(data,status){
console.log(data);
console.log(status);
alert('Products downloaded. Processing now.');
},
error: function (errorMessage) {
}
});
}
Could there be a mistake?

Answer 1

If you are using express.js, you should do res.end() after the res.send