Sans-Server-Router

A router middleware built for Sans-Server.

Table of Contents

• Example
• Router Options
• Defining Routes
• Paths

Example

const Router        = require('sans-server-router');
const SansServer    = require('sans-server');

// define the server instance
const server = SansServer();

// define the router
const router = Router();

// add the router as middleware
server.use(router);

// define a route with a parameter
router.get('/api/content/:contentId', function(req, res) {
    res.send('You selected content: ' + req.params.contentId);
});

// make a request
server.request({ method: 'GET', path: '/api/content/1234' })
    .then(function(res) {
        console.log(res.body);      // "You selected content: 1234"
    });

Define a Router

A router can take an optional configuration with these options:

• caseInsensitive - Setting this option to false will require that the letter case (upper or lower) must match the defined path. Defaults to true.

• paramFormat - This option affects how you write your path parameters. Defaults to colon. Possible values include:

  • colon - '/path/:param1'

  • handlebar - '/path/{param1}'

  • doubleHandlebar - '/path/{{param1}}'

Example

const Router        = require('sans-server-router');
const router = Router({
    ignoreCase: true,
    paramFormat: 'colon'
});

Defining Routes

Routes can be defined for the following methods: delete, get, head, options, patch, post, put. There is also a method all that allows you to define a route for each of those methods.

Each of these methods has the same signature. The get method is demonstrated here:

Signature: get ( path : String|RegExp, ...callback : Function ) : SansServer

Parameters:

• path - The path definition. This can be a static path, a path with parameters, or a regular expression.

  This can be a string or a regular expression. If a string then parameters can be defined and when the route is run those parameters will exist on the request object at req.params. If a regular expression is passed in then the match results for that regular expression will be stored on the req.params property.

• callback - This is a middleware function that takes up to three parameters: req the request object, res the response object, and next a function to call to pass the request down the line to the next handler.

  You can pass any additional callbacks as additional parameters. They will be called so long as next() was called by the middleware that proceeded.

  If the last callback calls next() then other routes that also match the incoming path will execute. If there are no other matching routes then any remaining middleware functions will execute.

Example: Static Path

const Router        = require('sans-server-router');
const SansServer    = require('sans-server');

const router = Router();
const server = SansServer();

server.use(router);

// define static path for GET method
server.get('/path', function(req, res, next) {
    res.send('You hit the endpoint GET /path');
});

Example: Path with Parameters

router.post('/path/:param1', function(req, res, next) {
    res.send('You hit the endpoint POST /path/:param1 where param1=' + req.params.param1);
});

Example: Path with Chained Middlewares

router.put('/path',
    function(req, res, next) {
        next();
    },
    function(req, res, next) {
        res.send('Done');
    }
);

Example: Multiple Path Matches

Both of these routes will run their associated middleware functions when a request to GET /path/foo is made.

// because this is defined first /path/foo will go here first, but only /path/foo
router.get('/path/foo', function(req, res, next) {
    req.isFoo = true;
    next();
});

// this will match many paths
router.get('/path/:name', function(req, res, next) {
    res.send('Path ' + req.params.name + ' is foo? ' + req.isFoo);
});

Example: Router Declines to Respond

Because the router is calling middleware functions, the middleware function does not need to provide a response. It can call the next() function instead.

const Router        = require('sans-server-router');
const SansServer    = require('sans-server');

const server = SansServer();
const router = Router();
server.use(router);

// because this middleware is added after the router middleware, it won't be called unless
// the router passes the request through with next()
server.use(function(req, res, next) {
    res.send(req.foo);  // "bar"
});

// route gets everything but just calls next()
router.get('*', function(req, res, next) {
    req.foo = 'bar';
    next();
});

Paths

When a path matches it will begin to call each middleware that is assigned to that route. Before it calls each middleware it will add a property to the request object req.params that will be an object containing information about the path's parameter values.

Static Paths

Static paths have no parameters and must match the incoming request path exactly. The req.params object will be an empty object {}.

Parameter Paths

Paths can have parameters defined in three formats: colon the default, handlebar, or doubleHandlebar. The format must be consistent for each router instance and is defined with the instantiation of the middleware. Regardless of the format used, the paths are parsed the same.

Once a route is selected, the values for the parameters are stored on an object in the request: req.params. This object's properties are the names of the parameters and it's values are taken from the path.

Parameter Formats

• colon - /path/:param - The parameter is defined with a colon.
• handlebar - /path/{param} - The parameter is surrounded by handlebars.
• doubleHandlebar - /path/{{param}} - The parameter is surrounded by double handlebars.

Wildcards

Use wildcards to allow matching across path delimiters.

• * will match everything.
• /path/* will match /path/foo, /path/bar, etc. but will not match just /path.
• /path/:foo* will match /path/abc/def etc.
• :lead*/dest will match /abc/xyz/dest or anything else that ends with dest.

Optional Parameters

A parameter name followed by a ? is an optional parameter.

• /path/:optParam? will match /path and /path/foo.
• /:param?/path will match /path and abc/path.

Regular Expressions

In place of using strings to define the route path you can instead define a regular expression. If the regular expression matches an incoming request then the matched results will be set into the req.params property.

router.get(/(\d+)/, function(req, res, next) {
    res.send('Path parameter: ' + req.params[0]);
});