Zeromatter

Framework for ØMQ request-response modeled servers.

Best used in tandem with the zquest client.

Usage

Zeromatter is influenced heavily by the koa framework, and is used best in tandem with the zquest client. It is designed to be a drop-in replacement for existing http frameworks utilizing ØMQ as the means of communication. The framework is designed to use request-router communication, but supports intermediary routers for load balancing purposes.

Examples

Generator

let zeromatter = require('zeromatter');
let app = zeromatter();

app.use(function *(ctx, next) {
  ctx.shortId = ctx.id.split('-')[0];
  console.log(`[${ctx.shortId}] --> `);
  yield next();
  console.log(`[${ctx.shortId}] <--`);
});

app.use(function *(ctx) {
  console.log(`[${ctx.shortId}]   ${ctx.message}`);
  ctx.response = {
    text: 'Hello World!',
    echo: ctx.data
  }
});

app.listen();

Promise

let app = Zeromatter();

app.use((ctx, next) => {
  ctx.shortId = ctx.id.split('-')[0];
  console.log(`[${ctx.shortId}] --> `);
  return next().then(() => {
    console.log(`[${ctx.shortId}] <--`);
  });
});

app.use(function () {
  return new Promise((resolve, reject) => {
    console.log(`[${ctx.shortId}]   ${ctx.message}`);
    ctx.response = {
      text: 'Hello World!',
      echo: ctx.data
    };
    resolve();
  });
});

app.listen();

Key

• Examples
  • Generator
  • Promise
• Documentation
  • Defaults
  • zeromatter(opts)
  • app.use(func)
  • app.useAll(func)
  • app.listen(opts)
  • app.close()

Documentation

Defaults

defaults used by zeromatter

{
  protocol: "amqp", // protocol for comm (SHOULD NOT CHANGE)
  host: "127.0.0.1", // host to bind to
  port: 5555 // port to bind to
}

zeromatter(opts)

• Application builder
• Accepts
  • Object to override defaults
• Returns
  • instance of zeromatter

let app = zeromatter({
  host: 'localhost',
  port: '1991'
});

app.use(func)

• Push middleware function onto the chain of execution
• Accepts
  • Generator || Function returning Promise
    • Accept promise next representing the next step in the middleware
    • Errors or rejecting a promise will bubble up the middleware
    • The value of ctx.response when the final promise is resolved will be the value returned to the client
    • The context of ctx is an instance of Message

app.use(function *(ctx, next) {
  console.log(this);
  // {
  //   message: String || Object // message content, parsed if json. aliases: body, data
  //   data: String || Object // // message content, parsed if json. aliases: message, data
  //   body: String || Object // // message content, parsed if json. aliases: body, message
  //   id: String // request UUID
  //   raw: Buffer // encoded buffer content of the message
  //   res: String || Object // Value to be stringified and sent to the client. alias: response
  //   response: String || Object // Value to be stringified and sent to the client. alias res
  // }

  yield next();
  this.response = this.response || 'Hello World!';
});

// OR

app.use(function (ctx, next) {
  return new Promise((resolve, reject) => {
    console.log(this);
    // {
    //   message: String || Object // message content, parsed if json. aliases: body, data
    //   data: String || Object // message content, parsed if json. aliases: message, data
    //   body: String || Object // message content, parsed if json. aliases: body, message
    //   id: String // request UUID
    //   raw: Buffer // encoded buffer content of the message
    //   res: String || Object // Value to be stringified and sent to the client. alias: response
    //   response: String || Object // Value to be stringified and sent to the client. alias res
    // }

    next().then(() => {
      this.response = this.response || 'Hello World!';
      resolve();
    }).catch(reject);
  });
});

app.useAll(func)

• Push array of middleware function onto the chain of execution
• Accepts
  • Array of functions to be passed to app.use(func)

app.useAll([
  function *(ctx, next) { yield next(); },
  function *(ctx, next) { yield next(); },
  function (ctx, next) {
    return new Promise((resolve, reject) => {
      this.response = 'Hello World';
      resolve();
    });
  }
])

app.listen(opts)

• Bind the server and listen for messages
• Accepts
  • Object to override defaults

app.listen({
  host: 'localhost',
  port: '1991'
});

app.close()

• Close the bound socket

app.close();

Authors

• John Hofrichter