Chronos - An efficient library for asynchronous programming

Introduction

Chronos is an efficient async/await framework for Nim. Features include:

• Asynchronous socket and process I/O
• HTTP server with SSL/TLS support out of the box (no OpenSSL needed)
• Synchronization primitivies like queues, events and locks
• Cancellation
• Efficient dispatch pipeline with excellent multi-platform support
• Exceptional error handling features, including raises tracking

Getting started

Install chronos using nimble:

nimble install chronos

or add a dependency to your .nimble file:

requires "chronos"

and start using it:

import chronos/apps/http/httpclient

proc retrievePage(uri: string): Future[string] {.async.} =
  # Create a new HTTP session
  let httpSession = HttpSessionRef.new()
  try:
    # Fetch page contents
    let resp = await httpSession.fetch(parseUri(uri))
    # Convert response to a string, assuming its encoding matches the terminal!
    bytesToString(resp.data)
  finally: # Close the session
    await noCancel(httpSession.closeWait())

echo waitFor retrievePage(
  "https://raw.githubusercontent.com/status-im/nim-chronos/master/README.md")

Documentation

See the user guide.

Projects using chronos

• libp2p - Peer-to-Peer networking stack implemented in many languages
• presto - REST API framework
• Scorper - Web framework
• 2DeFi - Decentralised file system
• websock - WebSocket library with lots of features

chronos is available in the Nim Playground

Submit a PR to add yours!

TODO

• Multithreading Stream/Datagram servers

Contributing

When submitting pull requests, please add test cases for any new features or fixes and make sure nimble test is still able to execute the entire test suite successfully.

chronos follows the Status Nim Style Guide.

License

Licensed and distributed under either of

• MIT license: LICENSE-MIT or http://opensource.org/licenses/MIT

or

• Apache License, Version 2.0, (LICENSE-APACHEv2 or http://www.apache.org/licenses/LICENSE-2.0)

at your option. These files may not be copied, modified, or distributed except according to those terms.