Avro for JavaScript
npm install avscPure JavaScript implementation of the Avro
specification.
+ Blazingly [fast and compact][benchmarks] serialization! Typically faster than
JSON with much smaller encodings.
+ All the Avro goodness and more: [type inference][type-inference], [schema
evolution][schema-evolution], and [remote procedure calls][rpc].
+ Support for [serializing arbitrary JavaScript objects][logical-types].
+ Unopinionated [64-bit integer compatibility][custom-long].
``sh`
$ npm install avsc
avsc is compatible with all versions of [node.js][] since 0.11.
+ [Home][home]
+ API
+ Quickstart
+ Advanced usage
+ [Benchmarks][benchmarks]
Inside a node.js module, or using browserify:
`javascript`
const avro = require('avsc');
+ Encode and decode values from a known schema:
`javascript
const type = avro.Type.forSchema({
type: 'record',
name: 'Pet',
fields: [
{
name: 'kind',
type: {type: 'enum', name: 'PetKind', symbols: ['CAT', 'DOG']}
},
{name: 'name', type: 'string'}
]
});
const buf = type.toBuffer({kind: 'CAT', name: 'Albert'}); // Encoded buffer.
const val = type.fromBuffer(buf); // = {kind: 'CAT', name: 'Albert'}
`
+ Infer a value's schema and encode similar values:
`javascript
const type = avro.Type.forValue({
city: 'Cambridge',
zipCodes: ['02138', '02139'],
visits: 2
});
// We can use type to encode any values with the same structure:`
const bufs = [
type.toBuffer({city: 'Seattle', zipCodes: ['98101'], visits: 3}),
type.toBuffer({city: 'NYC', zipCodes: [], visits: 0})
];
+ Get a [readable stream][readable-stream] of decoded values from an Avro
container file compressed using [Snappy][snappy] (see the [BlockDecoder
API][decoder-api] for an example including checksum validation):
`javascript
const snappy = require('snappy'); // Or your favorite Snappy library.
const codecs = {
snappy: function (buf, cb) {
// Avro appends checksums to compressed blocks, which we skip here.
return snappy.uncompress(buf.slice(0, buf.length - 4), cb);
}
};
avro.createFileDecoder('./values.avro', {codecs})
.on('metadata', function (type) { / type is the writer's type. / })
.on('data', function (val) { / Do something with the decoded value. / });
`
+ Implement a TCP server for an [IDL-defined][idl] protocol:
`javascript
// We first generate a protocol from its IDL specification.
const protocol = avro.readProtocol(
protocol LengthService {
/* Endpoint which returns the length of the input string. /
int stringLength(string str);
}
);
// We then create a corresponding server, implementing our endpoint.
const server = avro.Service.forProtocol(protocol)
.createServer()
.onStringLength(function (str, cb) { cb(null, str.length); });
// Finally, we use our server to respond to incoming TCP connections!
require('net').createServer()
.on('connection', (con) => { server.createChannel(con); })
.listen(24950);
``
[benchmarks]: https://github.com/mtth/avsc/wiki/Benchmarks
[browser-support]: https://github.com/mtth/avsc/wiki#browser-support
[custom-long]: https://github.com/mtth/avsc/wiki/Advanced-usage#custom-long-types
[decoder-api]: https://github.com/mtth/avsc/wiki/API#class-blockdecoderopts
[home]: https://github.com/mtth/avsc/wiki
[idl]: https://avro.apache.org/docs/current/idl.html
[logical-types]: https://github.com/mtth/avsc/wiki/Advanced-usage#logical-types
[node.js]: https://nodejs.org/en/
[readable-stream]: https://nodejs.org/api/stream.html#stream_class_stream_readable
[rpc]: https://github.com/mtth/avsc/wiki/Quickstart#services
[schema-evolution]: https://github.com/mtth/avsc/wiki/Advanced-usage#schema-evolution
[snappy]: https://avro.apache.org/docs/current/spec.html#snappy
[type-inference]: https://github.com/mtth/avsc/wiki/Advanced-usage#type-inference