Hello Service (parameter parsing)

This example is a more elaborate version of our original hello-world example that illustrates the use of parameter and response definitions.

The code defining the service is located in lib/HelloService.js and uses a simple Endpoint object to implement an HTTP GET at the path /hello.

Recall that our original, bare-bones hello-world service looked like this:

__(function() {
  module.exports = o({
    _type: carbon.carbond.Service,
    port: 8888,
    endpoints : {
      hello: o({
        _type: carbon.carbond.Endpoint,
        get: function(req, res) {
          return { msg: "Hello world!" }
        }
      })
    }
  })
})

This example illustrates formally defining the parameters taken and responses returned by our hello endpoint.

__(function() {
  module.exports = o({
    _type: carbon.carbond.Service,
    port: 8888,
    endpoints : {
      hello: o({
        _type: carbon.carbond.Endpoint,

        get: {
          parameters: {
            who: {
              location: 'query', // one of 'path', 'query', 'header', or 'body'
              required: false,
              default: 'world',
              schema: { type: 'string' } // drives parsing and validation (which can also help prevent injection attacks)
            }
          },
          responses: [
            {
              statusCode: 200,
              description: "Success",
              schema: {
                type: 'object',
                properties: {
                  msg: { type: 'string' }
                },
                required: [ 'msg' ],
                additionalProperties: false
              }
            }
          ],
          
          service: function(req, res) {
            return { msg: `Hello ${req.parameters.who}!` }
          }
        }
      })
    }
  })
})

Installing the service

We encourage you to clone the git repository so you can play around with the code.

$ git clone -b carbon-0.7 git@github.com:carbon-io-examples/example__hello-world-service-parameter-parsing.git
$ cd example__hello-world-service-parameter-parsing
$ npm install

Running the service

To run the service:

$ node lib/HelloService

For cmdline help:

$ node lib/HelloService -h

Accessing the service

To access the /hello endpoint:

$ curl localhost:8888/hello
{ msg: "Hello world!" }

$ curl localhost:8888/hello?who=Addison
{ msg: "Hello Addison!" }

Running the unit tests

This example comes with a simple unit test written in Carbon.io's test framework called TestTube. It is located in the test directory.

$ node test/HelloServiceTest

or

$ npm test

Generating API documentation (aglio flavor)

To generate documentation using aglio, install it as a devDependency:

$ npm install -D --no-optional aglio

Using --no-optional speeds up aglio's install time significantly. Then generate the docs using this command:

$ node lib/HelloService gen-static-docs --flavor aglio --out docs/index.html

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