Brothers and sisters, I am building an Express API Endpoint that needs to consume an external API, perform some changing of keys and values, and return to the result to the client. Here is what I have thus far:
const external_endpoint = <external_api_end_point>;
app.get('/', function (req, res, next) {
request({ url: external_endpoint}).pipe(res);
});
This returns the exact payload you would get from hitting the external_endpoint directly.
Isn't there something I can do to change res before it gets sent to the client? I tried a few things but nothings has worked. Any ideas or best practices associated with doing a transform on the incoming payload?
For the sake of simplicity. Lets say this is the payload obj.json:
{
"sad": {
"userid": 5,
"username": "jsmith",
"isAdmin": true
}
}
and I am wanting to change sad to happy.
I know outside of the request I could do something like this:
obj = JSON.parse(JSON.stringify(obj).split('"sad":').join('"happy":'));
but throwing obj in place of res will not work. I have tried assigning the value of this res and res.body but no dice.
Thanks for you help in advance!
If you're using request-promise, you can simply make a new response and send it, or modify the response you got back:
app.get('/', function (req, res, next) {
request({ url: external_endpoint, json: true})
.then(response => res.json({ happy: response.sad })))
.catch(next);
});
(of course, you need to handle errors appropriately)
If you want to process it as a stream (which makes sense if you have a massive amount of data), you can use the original request module, and use event-stream to create your pipe:
const es = require('event-stream');
const swapper = es.through(
function write(data) {
this.emit("data", data.replace("sad", "happy"));
},
function end() {
this.emit("end");
}
);
request({ url: external_endpoint})
.pipe(es.stringify())
.pipe(swapper)
.pipe(es.parse())
.pipe(res);
Here's a sandbox to test the stream processing: https://codesandbox.io/s/3wqx67pq6