lifion-aws-event-stream

lifion-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 --save

The 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
  • static
    • .parse(buffer) ⇒ object
  • inner
    • ~Parser ⇐ 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:

• Error Whenever:
  • 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.

lifion-aws-event-stream~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: inner class of lifion-aws-event-stream
Extends: Transform

License

MIT

Changelog

v1.0.5 (2019-07-12)

• #86: Update dependency auto-changelog to ^1.14.1
• #82: Update dependency lint-staged to v9
• #83: Update dependency husky to v3
• #81: Update dependency husky to ^2.7.0
• #80: Update dependency eslint to ^6.0.1
• #78: Update dependency eslint to v6
• #79: Update dependency husky to ^2.5.0
• #73: Update dependency eslint-config-lifion to ^1.2.3
• #74: Update dependency husky to ^2.4.1
• #76: Update dependency prettier to ^1.18.2
• #77: Update dependency lint-staged to ^8.2.1
• #75: Update dependency lint-staged to ^8.2.0
• #72: Update dependency lint-staged to ^8.1.7
• #71: Update dependency codecov to ^3.5.0
• #70: Update dependency husky to ^2.3.0
• #69: Update dependency prettier to ^1.17.1
• #68: Update dependency jsdoc-to-markdown to v5
• #67: Update dependency codecov to ^3.4.0
• #66: Update dependency jest to ^24.8.0
• #65: Update dependency lint-staged to ^8.1.6
• #64: Update dependency jest-junit to ^6.4.0
• #63: Update dependency husky to ^2.2.0
• #62: Update dependency husky to v2
• 470c034: Adopt the latest linter
• 5fd9445: Complete adoption of GitHub Actions
• b887030: Update main.workflow