Async I/O

The async.io, async.http, async.net, and async.stream source modules provide task-returning wrappers around file, HTTP, socket, and parser work. They establish the public API for async I/O while the lower-level event-loop runtime is still roadmap work.

Example file reads:

import async.io as aio;
import io;

let configTask = aio.readText("config/app.json");
let templateTask = aio.readText("templates/page.html");

io.println("both reads started");

let config = await configTask;
let template = await templateTask;

async.io functions:

  • readText, writeText, appendText
  • readBytes, writeBytes, appendBytes
  • handle operations: read, readAll, write, writeln, flush, close
  • metadata: stat, listDir

async.http functions:

  • get, post, postJson
  • request, requestWithOptions
  • parseJson

async.net functions:

  • lookupHost
  • TCP: listenTcp, connectTcp, accept, read, write, close
  • UDP: listenUdp, dialUdp, readFrom, writeTo

async.stream functions:

  • jsonStream, jsonReader
  • yamlStream, yamlReader
  • xmlStream, xmlReader
  • csvStream, csvReader

Socket example:

import async;
import async.net as anet;
import bytes;
import net;

let listener = await anet.listenTcp("127.0.0.1:0");
let address = net.localAddr(listener);

let server = async.run(func(): string {
    let conn = await anet.accept(listener);
    let message = await anet.read(conn, 4);
    await anet.write(conn, "pong");
    await anet.close(conn);
    return bytes.toString(message);
});

let client = await anet.connectTcp(address);
await anet.write(client, "ping");
io.println(bytes.toString(await anet.read(client, 4)));
io.println(await server);
← AsyncData Formats →