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 HTTP response and map it into different response, modifying outgoing data on demand.

HttpOutputEffect :: Observable<{ req: HttpRequest; res: HttpEffectResponse }>
-> Observable<HttpEffectResponse>

HttpOutputEffect allows you to grab the outgoing response together with corresponding initial request. Lets build a simple response compression middleware.

output.effect.ts
output.effect.ts
import { HttpOutputEffect } from '@marblejs/core';
import { map } from 'rxjs/operators';
import * as zlib from 'zlib';
const output$: HttpOutputEffect = res$ =>
res$.pipe(
map(({ res, req }) => {
switch(req.headers['accept-encoding']) {
case 'br':
return ({
...res,
headers: { ...res.headers, 'Content-Encoding': 'br' },
body: res.body.pipe(zlib.createBrotliDecompress()),
});
case 'gzip':
return ({
...res,
headers: { ...res.headers, 'Content-Encoding': 'gzip' },
body: res.body.pipe(zlib.createGunzip()),
});
case 'deflate':
return ({
...res,
headers: { ...res.headers, 'Content-Encoding': 'deflate' },
body: res.body.pipe(zlib.createInflate()),
});
default:
return res;
}
}),
);

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/core';
import { output$ } from './output.effect';
export const listener = httpListener({
middlewares: [ ... ],
effects: [ ... ],
output$, // 👈
});