Expressive HTTP middleware framework for node.js to make web applications and APIs more enjoyable to write. Logoran's middleware stack flows in a stack-like manner, allowing you to perform actions downstream then filter and manipulate the response upstream.

Only methods that are common to nearly all HTTP servers are integrated directly into Logoran's small ~570 SLOC codebase. This includes things like content negotiation, normalization of node inconsistencies, redirection, and a few others.

Logoran is not bundled with any middleware.

Installation

Logoran requires node v7.6.0 or higher for ES2015 and async function support.

$ npm install logoran

Hello Logoran

const Logoran = require('logoran');
const app = new Logoran();

// response
app.use(ctx => {
  ctx.body = 'Hello Logoran';
});

app.listen(3000);

Getting started

• Kick-Off-Logoran - An intro to Logoran via a set of self-guided workshops.
• Workshop - A workshop to learn the basics of Logoran, Express' spiritual successor.
• Introduction Screencast - An introduction to installing and getting started with Logoran

Middleware

Logoran is a middleware framework that can take two different kinds of functions as middleware:

• async function
• common function

Here is an example of logger middleware with each of the different functions:

async functions (node v7.6+)

app.use(async (ctx, next) => {
  const start = Date.now();
  await next();
  const ms = Date.now() - start;
  console.log(`${ctx.method} ${ctx.url} - ${ms}ms`);
});

Common function

// Middleware normally takes two parameters (ctx, next), ctx is the context for one request,
// next is a function that is invoked to execute the downstream middleware. It returns a Promise with a then function for running code after completion.

app.use((ctx, next) => {
  const start = Date.now();
  return next().then(() => {
    const ms = Date.now() - start;
    console.log(`${ctx.method} ${ctx.url} - ${ms}ms`);
  });
});

Logoran v1.x Middleware Signature

The middleware signature changed between v1.x and v2.x. The older signature is deprecated.

Old signature middleware support will be removed in v3

Please see the Migration Guide for more information on upgrading from v1.x and using v1.x middleware with v2.x.

Context, Request and Response

Each middleware receives a Logoran Context object that encapsulates an incoming http message and the corresponding response to that message. ctx is often used as the parameter name for the context object.

app.use(async (ctx, next) => { await next(); });

Logoran provides a Request object as the request property of the Context.
Logoran's Request object provides helpful methods for working with http requests which delegate to an IncomingMessage from the node http module.

Here is an example of checking that a requesting client supports xml.

app.use(async (ctx, next) => {
  ctx.assert(ctx.request.accepts('xml'), 406);
  // equivalent to:
  // if (!ctx.request.accepts('xml')) ctx.throw(406);
  await next();
});

Logoran provides a Response object as the response property of the Context.
Logoran's Response object provides helpful methods for working with http responses which delegate to a ServerResponse .

Logoran's pattern of delegating to Node's request and response objects rather than extending them provides a cleaner interface and reduces conflicts between different middleware and with Node itself as well as providing better support for stream handling. The IncomingMessage can still be directly accessed as the req property on the Context and ServerResponse can be directly accessed as the res property on the Context.

Here is an example using Logoran's Response object to stream a file as the response body.

app.use(async (ctx, next) => {
  await next();
  ctx.response.type = 'xml';
  ctx.response.body = fs.createReadStream('really_large.xml');
});

The Context object also provides shortcuts for methods on its request and response. In the prior examples, ctx.type can be used instead of ctx.request.type and ctx.accepts can be used instead of ctx.request.accepts.

For more information on Request, Response and Context, see the Request API Reference, Response API Reference and Context API Reference.

Logoran Application

The object created when executing new Logoran() is known as the Logoran application object.

The application object is Logoran's interface with node's http server and handles the registration of middleware, dispatching to the middleware from http, default error handling, as well as configuration of the context, request and response objects.

Learn more about the application object in the Application API Reference.

Documentation

• Usage Guide
• Error Handling
• Logoran for Express Users
• FAQ
• API documentation

Babel setup

If you're not using node v7.6+, we recommend setting up babel with babel-preset-env:

$ npm install babel-register babel-preset-env --save

Setup babel-register in your entry file:

require('babel-register');

And have your .babelrc setup:

{
  "presets": [
    ["env", {
      "targets": {
        "node": true
      }
    }]
  ]
}

Troubleshooting

Check the Troubleshooting Guide or Debugging Logoran in the general Logoran guide.

Running tests

$ npm test

Authors

See AUTHORS.

Community

• Badgeboard and list of official modules
• Examples
• Middleware list
• Wiki
• G+ Community
• Reddit Community
• Mailing list
• 中文文档 v1.x
• 中文文档 v2.x
• #logoran on freenode

Job Board

Looking for a career upgrade?

Backers

Support us with a monthly donation and help us continue our activities.

Sponsors

Become a sponsor and get your logo on our README on Github with a link to your site.

License

MIT