Middleware allowing the client to filter the response to only what they need,
reducing the amount of traffic over the wire using the ?filter=foo,bar,baz querystring parameter.
JSONSelect would also be great for this but I find it's a little too complicated for the average use-case, so this is just a simple key filter.
$ npm install koa-json-filter
namequerystring param defaulting to "filter"
You may also set ctx.filter to an array of names to filter on,
for example by using a header field X-Filter: name,email.
Script:
var filter = require('koa-filter');
var koa = require('koa');
var app = koa();
app.use(filter());
app.use(function *(){
this.body = {
name: 'tobi',
email: 'tobi@segment.io',
packages: 5,
friends: ['abby', 'loki', 'jane']
}
});
app.listen(3000);
console.log('app listening on port 3000');Response:
$ GET /?filter=name
{
"name": "tobi"
}
Script:
var filter = require('koa-filter');
var koa = require('koa');
var app = koa();
app.use(filter());
app.use(function *(){
this.body = [
{
name: 'tobi',
email: 'tobi@segment.io',
packages: 5,
friends: ['abby', 'loki', 'jane']
},
{
name: 'loki',
email: 'loki@segment.io',
packages: 2,
friends: ['loki', 'jane']
},
{
name: 'jane',
email: 'jane@segment.io',
packages: 2,
friends: []
},
{
name: 'ewald',
email: 'ewald@segment.io',
packages: 2,
friends: ['tobi']
}
]
});
app.listen(3000);
console.log('app listening on port 3000');Response:
$ GET /?filter=name,email
[
{
"name": "tobi",
"email": "tobi@segment.io"
},
{
"name": "loki",
"email": "loki@segment.io"
},
{
"name": "jane",
"email": "jane@segment.io"
},
{
"name": "ewald",
"email": "ewald@segment.io"
}
]
MIT