Using the Node.js event library

Installation

You can install the generated Node.js event library locally with

npm install PATH

Package organization

Each event in your specification will be added as a submodule in the package. For example, if you have two events, basic and advanced, in your generator specifcation, your package structure look as follows:

mypackage/
    Basic/
        ...
    Advanced/
        ...
    index.js
    package.json
    README.md
    ...

The events themselves will be parsed into a Node.js class. Additionally, each object type attribute will also be parsed into a Node.js class. For example, if the advanced event has two object type attributes, name and address, the package structure looks as follows:

mypackage/
    Basic/
        # Event class
        Basic.js
    Advanced/
        # Event class
        Advanced.js
        # Data classes
        Name.js
        Address.js
    # Other files
    ...

When you import the event library above, it will return an object as follows:

// pkg = require('mypackage')
pkg = {
    Basic: {
        Event: [Function Basic]
        DataClasses: {}
    },
    Advanced: {
        Event: [Function Event]
        DataClasses: {
            Name: [Function Name],
            Address: [Function Address]
        }
    }
}

To use the advanced event, refer to the function in the required package. Initialize it with an object of attribute names and values (if no default values are provided). Your event library will validate the input values as specified.

event = new pkg.Advanced.Event({
    id: 'my-id',
    source: 'my-source'
})

Similarly, to use the data classes:

name = new pkg.Advanced.DataClasses.Name()
address = new pkg.Advanced.DataClasses.Address()

Important: All the class names are cast in camel case.

Using the JSON binding

To serialize an event into a JSON string with your event library, call the toJSON method on an event instance:

event = new pkg.Advanced.Event()
jsonStr = event.toJSON()

To deserialize an event from a JSON string with your event library, call the from_JSON method on an event class:

event = pkg.Advanced.Event.fromJSON(json_str)

Using the HTTP binding

To send an event via HTTP, call the sendHTTP method. This method takes two parameters, url and mode, the latter of which accepts two values, structured (using the structured mapping mode, default) and binary (using the binary mapping mode).

Note: See Transport Bindings for more information about bindings and mapping modes.

// pkg = require('mypackage')
event = pkg.Advanced.Event()
event.sendHTTP('http://my-endpoint.com')
# or
# event.sendHTTP('http://my-endpoint.com', 'binary')

In the background your event library uses request (synchronized) to send the HTTP request. This command returns a Promise with response and body.

To receive an event via HTTP, extract headers and payload (body) from your HTTP framework or application and pass it to the receiveHTTP method in the event class. The headers must be an object and the payload (body) must be a UTF-8 encoded string.

event = pkg.Advanced.Event.receiveHTTP(headers, payload)

Note: If you are using the binary mode and some of your attribute names are not in lower case, double check that the headers object you pass switch cases automatically. HTTP headers are case-insensitive, and your event library queries the headers object using the names exactly as you provides.