connect2

connect2 is an extensible framework for node using "plugins" known as middleware like connect.

中文版说明

var connect = require('connect2');

var app = connect();

app.use(function(ctx, req, res, next){
  console.log('md1')
  next()
});

app.use(function(ctx, req, res) {
  console.log('md2')
})

function main() {
  let context = {};
  let req = {};
  let res = {};

  app(context, req, res);
}

main();

Getting Started

Connect is a simple framework to glue together various "middleware" to handle something like request, tcp, rpc.

Install Connect

$ npm install connect2

Create an app

The main component is a Connect "app". This will store all the middleware added and is, itself, a function.

var app = connect();

Use middleware

The core of Connect is "using" middleware. Middleware are added as a "stack" where incoming requests will execute each middleware one-by-one until a middleware does not call next() within it.

app.use(function middleware1(ctx, req, res, next) {
  // middleware 1
  next();
});
app.use(function middleware2(ctx, req, res, next) {
  // middleware 2
  next();
});

Mount middleware

The .use() method also takes an optional string that is matched against the beginning of the data.

app.use('afunc', function fooMiddleware(ctx, req, res, next) {
  // req.url starts with "/foo"
  next();
});
app.use('bfunc', function barMiddleware(ctx, req, res, next) {
  // req.url starts with "/bar"
  next();
});

Error middleware

There are special cases of "error-handling" middleware. There are middleware where the function takes exactly 4 arguments. When a middleware passes an error to next, the app will proceed to look for the error middleware that was declared after that middleware and invoke it, skipping any error middleware above that middleware and any non-error middleware below.

// regular middleware
app.use(function (ctx, req, res, next) {
  // i had an error
  next(new Error('boom!'));
});

// error middleware for errors that occurred in middleware
// declared before this
app.use(function onerror(err,ctx, req, res, next) {
  // an error occurred!
});

API

The connect2 API is very similar to connect.

When the connect2 module is required, a function is returned that will construct a new app when called.

// require module
var connect = require('connect2')

// create app
var app = connect([opts])

connect([opts])

The opts object has three functions: finalHandler(ctx, req, res), dispatch(dispatchCtx, route, req) and dispatchContext(). The finalHandle function must be return a function function(err){...}. The returned function is the last function in connect2 middleware. It can handle error. The dispatch function return a Boolean value. if it return true, call this middleware 's handle or fn, else skip. The dispatchContext function return a object what pass to dispatch function as first parameter. You can give some status in it. you can find whole declare in test\server.js. The defaultRoute function set route initial value. The app's default route is empty string ''. You can change it to / or anything you want. Hare are some code:

var app = connect({
  finalHandler: (ctx, req, res) => {
    return function(err) {
      // do something
    }
  },
  dispatch: (ctx, route, req) => {
    return true;
  },
  dispatchContext: function() {
    return {};
  },
  defaultRoute: function() {
    // default value is `empty string`;
    return '/';
  }
})

app(ctx, req, res[, next])

The app itself is a function. This is just an alias to app.handle.

app.handle(ctx, req, res[, out])

Calling the function will run the middleware stack against the given Node.js http request (req) and response (res) objects. An optional function out can be provided that will be called if the request (or error) was not handled by the middleware stack.

app.use(fn)

Use a function on the app, where the function represents a middleware. The function will be invoked for every request in the order that app.use is called. The function is called with three arguments:

app.use(function (ctx, req, res, next) {
})

In addition to a plan function, the fn argument can also be a Node.js HTTP server instance or another Connect app instance.

app.use(route, fn)

Use a function on the app, where the function represents a middleware. The function will be invoked for every request in which the string starts with the given route string in the order that app.use is called. The function is called with three arguments:

app.use('afunc', function (ctx, req, res, next) {
})

License

MIT

Thanks

Thanks for connect.