Introduction to Node.js open source application framework HapiJS

This article mainly introduces the introduction of HapiJS, the Node.js open source application framework. This article explains the introduction of HapiJS, HapiJS installation, project configuration and development examples. Friends in need can refer to it.

1. Introduction to HapiJS

HapiJS is an open source, Node.js-based application framework, which is suitable for building applications The design goal of programs and services is to allow developers to focus on developing reusable application business logic and to provide developers with the infrastructure required to build application business logic. The latest version of HapiJS is currently version 7.2.0.

2. HapiJS installation and project configuration

1. Install Hapi library
The installation of HapiJS is very simple, execute the following command:

$ sudo npm install hapi -g
hapi@7.2.0 /usr/local/lib/node_modules/hapi
├── cryptiles@2.0.4
├── heavy@1.0.0
├── topo@1.0.2
├── accept@1.0.0
├── items@1.1.0
├── kilt@1.1.1
├── catbox-memory@1.1.0
├── boom@2.5.1
├── qs@2.2.4
├── call@1.0.0
├── statehood@1.2.0
├── h2o2@2.0.1
├── iron@2.1.2
├── shot@1.3.5
├── glue@1.0.0
├── wreck@5.0.1
├── hoek@2.8.0
├── catbox@4.0.3
├── vision@1.1.0
├── mimos@1.0.0 (mime-db@1.1.1)
├── rejoice@1.0.0 (bossy@1.0.2)
├── inert@1.1.0 (lru-cache@2.5.0)
├── joi@4.7.0 (isemail@1.1.1)
└── subtext@1.0.1 (content@1.0.1, pez@1.0.0)

2. Configure the project

1) Create a new directory named myproject

$ mkdir myproject
$ cd myproject

2) In the directory Run the initialization command

$ npm init

This command will generate the package.json file, which is the metadata of the project.
Then execute the command:

$ npm install --save hapi

It will install the hapi library to the project and write the dependencies of hapi into package.json.

At this point, everything needed for project development has been prepared.

3. Development Example

1. Create a server

// server.js
var Hapi = require('hapi');
var server = new Hapi.Server(3000);
server.start(function(){
console.log('Server running at: ', server.info.uri);
});

First, we need the Hapi library.

Secondly, we create a new hapi server object and pass the port number to listen to the server object.

Finally, the server object starts and outputs log information.

To explain, when we create a server object, we can provide the host name, IP address, or even a Unix socket file, or a Windows system bound to the named pipe of the server.

2. Start the server

Execute the command:

$ node server.js

Visit http://127.0.0.1:3000/, the browser displays the following content:

{"statusCode":404,"error":"Not Found"}

This is normal because there is no content on the server itself. Let’s add the routing logic.

3. Routing logic

// server.js
var Hapi = require('hapi');
var server = new Hapi.Server(3000);
server.route({
method: 'GET',
path: '/',
handler: function(request, reply){
reply('Hello, world!');
}
});
server.route({
method: 'GET',
path: '/{name}',
handler: function(request, reply){
reply('Hello, ' + encodeURIComponent(request.params.name) + "!");
}
});
server.start(function(){
console.log('Server running at: ', server.info.uri);
});

Start the server again:

$ node server.js

and visit http://127.0.0.1:3000/, the browser displays the following content :

Hello, world!

Visit http://127.0.0.1:3000/Zhang San, the browser displays the following content:

Hello, Zhang San!

It can be seen that the routing logic is running normally.

Note: The parameter of
method can be any valid HTTP method, or it can be an asterisk * (indicating any HTTP method).
The parameter of path defines the access path, which can contain parameters, optional parameters, and even wildcards.

4. Using plug-ins

When creating web applications, we usually need to access logs. To add basic logging output to the application, we can load the good plugin on the server.

1. Install the good plug-in

$ sudo npm install --save good
good@3.1.1 node_modules/good
├── json-stringify-safe@5.0.0
├── good-reporter@2.0.0
├── async@0.9.0
├── hoek@2.8.1
├── moment@2.8.3
├── good-file@2.0.0 (items@1.1.0)
└── joi@4.7.0 (topo@1.0.2, isemail@1.1.1)

2. Update the code of server.js

// server.js
var Hapi = require('hapi');
var Good = require('good');
var server = new Hapi.Server(3000);
server.route({
method: 'GET',
path: '/',
handler: function(request, reply){
reply('Hello, world!');
}
});
server.route({
method: 'GET',
path: '/{name}',
handler: function(request, reply){
reply('Hello, ' + encodeURIComponent(request.params.name) + "!");
}
});
server.pack.register(Good, function(err){
if(err){
// something bad happened loading the plugin
throw err;
}
server.start(function(){
server.log('info', 'Server running at: ' + server.info.uri);
});
});

Run server.js, the console output:

141102/161007.644, info, Server running at: http://localhost:3000

If we then visit: http://127.0.0.1:3000

The console will continue to output:

141102/161150.689, request, http://Thinker-LQ:3000: get /liqiang {} 200 (37ms) 
141102/161155.812, request, http://Thinker-LQ:3000: get / {} 200 (4ms)

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