37

GitHub - francisrstokes/hexnut: ? Hexnut is a middleware based, express/koa lik...

 5 years ago
source link: https://github.com/francisrstokes/hexnut
Go to the source link to view the article. You can view the picture content, updated content and better typesetting reading experience. If the link is broken, please click the button below to view the snapshot at that time.

readme.md

Hexnut

logo.png

Hexnut is a middleware based, express/koa like framework for web sockets.

npm version license CircleCI

For an introduction, and API documentation, please check out the docs.

Middleware

Client side

You can use hexnut as a client in the frontend with hexnut-client. It is also middleware based and can use many of the server middlewares directly, such as hexnut-bodyparser and hexnut-sequence.

Examples

Trivial Example

const Hexnut = require('hexnut');
const errorService = require(/* some error logging service */);
const app = new Hexnut({ port: 8080 });

app.onerror = async (err, ctx) => {
  await errorService(err);
  ctx.send(`Error! ${err.message}`);
};

app.use(ctx => {
  if (ctx.isConnection) {
    ctx.state = { count: 0 };
    return ctx.send('Hello, and welcome to the socket!');
  }

  ctx.state.count++;
  ctx.send(`Message No. ${ctx.state.count}: ${ctx.message}`);
});

app.start();

Parsing JSON automatically

const Hexnut = require('hexnut');
const bodyParser = require('hexnut-bodyparser');
const app = new Hexnut({ port: 8080 });

app.use(bodyParser.json());

app.use(ctx => {
  if (ctx.isConnection) {
    ctx.state = { count: 0 };
    return ctx.send('Hello, and welcome to the socket!');
  }

  if (ctx.message.type) {
    ctx.state.count++;
    ctx.send(`Message No. ${ctx.state.count}: ${ctx.message.type}`);
  } else {
    ctx.send(`Invalid message format, expecting JSON with a "type" key`);
  }
});

app.start();

Handling messages by type

const Hexnut = require('hexnut');
const handle = require('hexnut-handle');
const app = new Hexnut({ port: 8080 });

app.use(handle.connect(ctx => {
  ctx.count = 0;
}));

app.use(handle.matchMessage(
  msg => msg === 'incCount',
  ctx => ctx.count++
));

app.use(handle.matchMessage(
  msg => msg === 'decCount',
  ctx => ctx.count--
));

app.use(handle.matchMessage(
  msg => msg === 'getCount',
  ctx => ctx.send(ctx.count)
));

app.start();

Sequencing Interactions

const Hexnut = require('hexnut');
const bodyParser = require('hexnut-bodyparser');
const sequence = require('hexnut-sequence');
const app = new Hexnut({ port: 8080 });

app.use(bodyParser.json());

// This sequence happens when the user connects
app.use(sequence.onConnect(function* (ctx) {
  ctx.send(`Welcome, ${ctx.ip}`);
  const name = yield sequence.getMessage();
  ctx.clientName = name;
  return;
}));

app.use(sequence.interruptible(function* (ctx) {
  // In order to use this sequence, we assert that we must have a clientName on the ctx
  yield sequence.assert(() => 'clientName' in ctx);

  // We first expect a message with type == greeting
  const greeting = yield sequence.matchMessage(msg => msg.type === 'greeting');

  // Then a message that has type == timeOfDay
  const timeOfDay = yield sequence.matchMessage(msg => msg.type === 'timeOfDay');

  return ctx
    .send(`And a ${greeting.value} to you too, ${ctx.clientName} on this fine ${timeOfDay.value}`);
}));

app.start();

Integrating with rxjs

const Hexnut = require('hexnut');
const { withObservable, filterMessages } = require('hexnut-with-observable');

const { tap, filter } = require('rxjs/operators');
const { pipe } = require('rxjs');

const app = new Hexnut({ port: 8181 });

app.use(withObservable(pipe(
  // Do setup operations here...
  tap(({ctx}) => {
    if (ctx.isConnection) {
      console.log(`[${ctx.ip}] Connection started`);
    }
  }),

  // Filter to only messages
  filterMessages(msg => msg !== 'skip'),

  // Process messages
  tap(({ctx, next}) => {
    ctx.send(`You sent: ${ctx.message}`);
  })
)));


app.start();

About Joyk


Aggregate valuable and interesting links.
Joyk means Joy of geeK