Chinese Documentation : Add a custom Express route

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Prerequisite: Install StrongLoop software as described in 安装 StrongLoop.

Recommended: Read LoopBack 核心概念.

Because LoopBack is built on Express, you can add custom routes just as you do in Express.



In this part of the tutorial, you're going to add a new custom route.

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If you followed the previous steps in the tutorial, skip down to Introducing boot scripts.

If you're just jumping in, follow the steps below to catch up...

Get the app (in the state following the last article) from GitHub and install all its dependencies:

$ git clone https://github.com/strongloop/loopback-getting-started.git
$ cd loopback-getting-started
$ git checkout step4
$ npm install

Introducing boot scripts

When a LoopBack application starts (or "bootstraps"), it runs the scripts in the /server/boot directory, known as boot scripts.  By default, LoopBack loads boot scripts in alphabetical order.   

The standard scaffolded LoopBack application created by the application generator contains the following standard boot scripts (in /server/boot) that perform basic initialization:

  • authentication.js - Enables authentication for the application by calling app.enableAuth().
  • explorer.js - Enables API Explorer.  Delete or change the extension of this file to disable API Explorer.
  • rest-api.js - Exposes the application's models over REST using loopback.rest() middleware.

For more information on boot scripts, see 定义启动脚本(boot script).

Add a new boot script

For example, add a new boot script named routes.js in /server/boot directory, with this code:

/server/boot/routes.js
module.exports = function(app) {
  // Install a "/ping" route that returns "pong"
  app.get('/ping', function(req, res) {
    res.send('pong');
  });
}

As an aside, you could have just as well used Express router middleware instead, like this:

/server/boot/routes.js
module.exports = function(app) {
  var router = app.loopback.Router();
    router.get('/ping', function(req, res) {
      res.send('pongaroo');
    });
    app.use(router);
}

In fact you can also add routes right in sever.js using the Express API.  For example, add this call to app.use() just before the call to app.start():

server/server.js
...
app.use('/express-status', function(req, res, next) {
  res.json({ running: true });
});

// start the server if `$ node server.js`
if (require.main === module) {
  app.start();
}

The point is that a LoopBack application can easily do all the things that an Express application can.  If you're familiar with Express, this will make LoopBack easier to learn and use.

Run the boot script

Now, run the application again:

$ slc run

Load http://0.0.0.0:3000/ping.  You'll see "pong" as the response. 

Next: Check out Next steps for information on what to read next.