lifionlifion-aws-event-stream
Node.js parser for binary streams under the application/vnd.amazon.eventstream content-type.
Getting Started
To install the module:
npm install lifion-aws-event-stream --saveThe module exports a parse function and a Parser stream. To use the parse function:
const { parse } = require('lifion-aws-event-stream');
const buffer = Buffer.from('000000100000000005c248eb7d98c8ff', 'hex');
console.log(parse(buffer)); // { headers: {}, payload: '' }To use the Parser stream:
const { Parser } = require('lifion-aws-event-stream');
const parser = new Parser();
parser.on('data', console.log); // { headers: {}, payload: '' }
const buffer = Buffer.from('000000100000000005c248eb7d98c8ff', 'hex');
parser.write(buffer);Pipe an HTTP response to parse the messages as they arrive:
const got = require('got');
const { Parser } = require('lifion-aws-event-stream');
const { pipeline } = require('stream');
pipeline([
got('/', …),
new Parser(),
new Writable({
objectMode: true,
write(data, encoding, callback) {
console.log(data);
callback();
}
}),
]);This project's implementation is based on:
- https://github.com/aws/aws-sdk-ruby/tree/master/gems/aws-eventstream
- https://github.com/awslabs/aws-c-event-stream
API Reference
- lifion-aws-event-stream
- .Parser ⇐
Transform - .parse(buffer) ⇒
object
- .Parser ⇐
eventStream.Parser ⇐ Transform
A transform stream that calls parse with the binary data written to it. Can be used to pipe a response stream from an AWS service HTTP request. The stream will emit errors thrown during parse calls.
Kind: static class of lifion-aws-event-stream
Extends: Transform
See: https://nodejs.org/dist/latest-v10.x/docs/api/stream.html#stream_class_stream_transform
eventStream.parse(buffer) ⇒ object
Parses the specified buffer with vnd.amazon.eventstream data into an object.
Kind: static method of lifion-aws-event-stream
Returns: object - The parsed vnd.amazon.eventstream object.
Throws:
ErrorWhenever:- The specified buffer has less than 16 bytes. The minimum vnd.amazon.eventstream message should have 4 bytes for the total length of the package, 4 bytes for the length of the headers section, 4 bytes for the checksum of the prelude, and finally 4 more bytes for the checksum of the entire message.
- The total length as specified in the message doesn't matches the bufffer length.
- The checksum of the prelude doesn't matches the calculated checksum.
- The checksum of the message doesn't matches the calculated checksum.
- The header value type is unknown.
| Param | Type | Description |
|---|---|---|
| buffer | Buffer |
The buffer to parse. |