[Hapi.js] Route parameters

Routing is a fundamental aspect of any framework. In this lesson, you‘ll learn how to use path parameters in hapi‘s router. We‘ll also touch on how the router uses specificity to order routes internally.

Router Param:

http://localhost:8000/ztw

// Will match any string after /    

    server.route( {
        method: ‘GET‘,
        path: ‘/{name}‘,
        handler: function ( request, reply ) {
            reply( "hello " + request.params.name + "!" ); // hello ztw
        }
    } );

http://localhost:8000/user/ztw:

    server.route( {
        method: ‘GET‘,
        path: ‘/user/{name}‘,
        handler: function ( request, reply ) {
            reply( "hello " + request.params.name + "!" );
        }
    } );

Optional parameters

    server.route( {
        method: ‘GET‘,
        path: ‘/user/{name?}‘,
        handler: function ( request, reply ) {
            var name = request.params.name ? request.params.name : "AAAA";
            reply( "hello " + name + "!" );
        }
    } );

http://localhost:8000/user/ztw:

// hello ztw!

http://localhost:8000/user/:

// hello AAAA!

    server.route( {
        method: ‘GET‘,
        path: ‘/user/{name}/address‘,
        handler: function ( request, reply ) {

            reply( request.params.name + "‘s address: Finland" );
        }
    } );

http://localhost:8000/user/ztw/address:

// ztw‘s address: Finland

Multi-segment parameters

    server.route({
        method: ‘GET‘,
        path: ‘/hello/{user*2}‘,
        handler: function (request, reply) {
            const userParts = request.params.user.split(‘/‘);
            reply(‘Hello ‘ + encodeURIComponent(userParts[0]) + ‘ ‘ + encodeURIComponent(userParts[1]) + ‘!‘);
        }
    });

http://localhost:8000/hello/ztw/twz:

// Hello ztw twz!

If pass the third params, it will report error.

    server.route({
        method: ‘GET‘,
        path: ‘/files/{file*}‘,
        handler: function(request, reply){
            reply(request.params);
        }
    })

http://localhost:8000/files/sky/night/aurora/100.jpg:

// {"file":"sky/night/aurora/100.jpg"}

    server.route({
        method: ‘GET‘,
        path: ‘/files/{file}.jpg‘,
        handler: function(request, reply){
            reply(request.params);
        }
    })

http://localhost:8000/files/100.jpg:

// {"file":"100"}

The last thing I‘d like to cover is path specificity. Hapi‘s router evaluates routes in order from most specific to least specific, which means that the order routes are created does not affect the order they are evaluated.

    server.route({
        method: ‘GET‘,
        path: ‘/files/{file*}‘,
        handler: function(request, reply){
            reply(request.params);
        }
    })

    server.route({
        method: ‘GET‘,
        path: ‘/files/{file}.jpg‘,
        handler: function(request, reply){
            reply(request.params);
        }
    })

If I give the url:

http://localhost:8000/files/100.jpg, it will match the second router instead of the first router.

But if I gave http://localhost:8000/files/b/100.jpg

// {"file":"b/100.jpg"}

It will match the first router.