Output
Every Marble.js listener factory allows you to intercept outgoing messages via dedicated output$ handler.

Building your own output effect

Using HttpOutputEffect you can grab an outgoing Effect response and map it into different one, modifying outgoing data on demand.
type Out = {
request: HttpRequest;
headers: HttpHeaders;
status: HttpStatus;
body: any;
};
HttpOutputEffect :: Observable<Out> -> Observable<Out>
HttpOutputEffect allows you to grab the outgoing response together with corresponding initial request. The output effect works similar to the HttpMiddlewareEffect, but in that case for outgoing responses. Let's build a simple response compression middleware.
output.effect.ts
import { HttpOutputEffect } from '@marblejs/http';
import { map } from 'rxjs/operators';
import * as zlib from 'zlib';
const output$: HttpOutputEffect = res$ =>
res$.pipe(
map(({ request, headers, body, status }) => {
switch(request.headers['accept-encoding']) {
case 'br':
return ({
request,
status,
headers: { ...headers, 'Content-Encoding': 'br' },
body: body.pipe(zlib.createBrotliDecompress()),
});
case 'gzip':
return ({
request,
status,
headers: { ...headers, 'Content-Encoding': 'gzip' },
body: body.pipe(zlib.createGunzip()),
});
case 'deflate':
return ({
request,
status,
headers: { ...headers, 'Content-Encoding': 'deflate' },
body: body.pipe(zlib.createInflate()),
});
default:
return { status, headers, body, request };
}
}),
);
To connect the output effect, all you need to do is to attach it to output$ property in httpListener config object.
import { httpListener } from '@marblejs/http';
import { output$ } from './output.effect';
export const listener = httpListener({
middlewares: [ ... ],
effects: [ ... ],
output$, // 👈
});
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