Express Partial Response Middleware NPM version
This Express Middleware will allow you to send a subset of a JSON object
instead of the entire object from your HTTP services. To do so, your services
will begin accepting the ?fields= query-string that, using a simple language,
will specify which fields and sub-fields to keep and which to ignore.
If you've used the Google APIs, provided a ?fields= query-string to get a
Partial Response,
and wanted to do the same for your own server, now you can do so with this
middleware.
Underneath, this middleware uses json-mask. Use it directly without this middleware if you need more flexibility.
npm install express-partial-response
const express = require('express'); const partialResponse = require('express-partial-response'); const app = express(); app.use(partialResponse()); app.get('/', (req, res) => { res.json({ firstName: 'Mohandas', lastName: 'Gandhi', aliases: [ { firstName: 'Mahatma', lastName: 'Gandhi' }, { firstName: 'Bapu' } ] }); }); app.listen(4000);
Let's test it:
$ curl 'http://localhost:4000'
{"firstName":"Mohandas","lastName":"Gandhi","aliases":[{"firstName":"Mahatma","lastName":"Gandhi"},{"firstName":"Bapu"}]}
$ # Let's just get the first name
$ curl 'http://localhost:4000?fields=lastName'
{"lastName":"Gandhi"}
$ # Now, let's just get the first names directly as well as from aliases
$ curl 'http://localhost:4000?fields=firstName,aliases(firstName)'
{"firstName":"Mohandas","aliases":[{"firstName":"Mahatma"},{"firstName":"Bapu"}]}
Note: take a look at /example.
Look at json-mask for the available syntax of the fields param.
query specifies the query-string to use. Defaults to fields
app.use( partialResponse({ query: 'filter' }) );
MIT. See LICENSE