Responding with data to a Slack url in Express - angularjs

Question

I have the following route in my Node backend with express middleware. My app uses the Slack backslash api to post a link to a user's channel. When user clicks it opens a form on an angular app hosted on heroku.
What I am looking to do is update the Slack user when the form get submitted.
So the question, how can I send a post request to slack url when the route below gets triggered(obviously the res is pointing to the /update). I've researched quite a bit and tried rewriting headers and using low level http methods, but I have a feeling there is a better solution to this. Many thanks for your help.
app.post("/update", function(req,res,next) {
res url -> http://slackapi/12345/
res.json({"text":"hello":}
})

Answer 1

res is not supposed to be sent to slack, this is the response to whoever contacted you. you need to send a different request to slack, and return whatever you want with res.
You can use request module to generate a http request to slack.
var request = require('request');
app.post("/update", function(req,res,next) {
request('http://slackapi/12345/', function (error, response, body) {
if (!error && response.statusCode == 200) {
console.log(body);
res.json({"text":"some answer to the requester"});
} else {
res.json({"text":"notify requester sending to slack falied"});
}
});
});