sdk-javascript/README.md

246 lines
5.3 KiB
Markdown

[![Codacy Badge](https://api.codacy.com/project/badge/Grade/bd66e7c52002481993cd6d610534b0f7)](https://www.codacy.com/app/fabiojose/sdk-javascript?utm_source=github.com&utm_medium=referral&utm_content=cloudevents/sdk-javascript&utm_campaign=Badge_Grade)
[![Codacy Badge](https://api.codacy.com/project/badge/Coverage/bd66e7c52002481993cd6d610534b0f7)](https://www.codacy.com/app/fabiojose/sdk-javascript?utm_source=github.com&utm_medium=referral&utm_content=cloudevents/sdk-javascript&utm_campaign=Badge_Coverage)
[![Build Status](https://travis-ci.org/cloudevents/sdk-javascript.svg?branch=master)](https://travis-ci.org/cloudevents/sdk-javascript)
# sdk-javascript
Official CloudEvents' SDK for JavaScript.
<img src="https://raw.githubusercontent.com/cncf/artwork/master/cloudevents/horizontal/color/cloudevents-horizontal-color.png" width="300" height="58" alt="CloudEvents logo">
## Installation
This CloudEvents SDK requires nodejs 6.11+
### Nodejs
```sh
npm install cloudevents-sdk
```
## Specification Support
These are the supported specifications by this version.
| **Specifications** | **v0.1** | **v0.2** |
|---------------------------------------|----------|----------|
| CloudEvents | yes | yes |
| HTTP Transport Binding - Structured | yes | yes |
| HTTP Transport Binding - Binary | yes | yes |
| JSON Event Format | yes | yes |
## How to use
The `Cloudevent` constructor arguments.
```js
/*
* spec : if is null, set the spec 0.1 impl
* format: if is null, set the JSON Format 0.1 impl
*/
Cloudevent(spec, format);
```
### Usage
```js
var Cloudevent = require("cloudevents-sdk");
/*
* Constructs a default instance with:
* - Spec 0.1
* - JSON Format 0.1
*/
var cloudevent01 = new Cloudevent();
/*
* Implemented using Builder Design Pattern
*/
cloudevent01
.type("com.github.pull.create")
.source("urn:event:from:myapi/resourse/123");
/*
* Backward compatibility to spec 0.1 by injecting methods from spec implementation
* to Cloudevent
*/
cloudevent01
.eventTypeVersion("1.0");
/*
* Constructs an instance with:
* - Spec 0.2
* - JSON Format 0.1
*/
var cloudevent02 = new Cloudevent(Cloudevent.specs["0.2"]);
/*
* Different specs, but the same API.
*/
cloudevent02
.type("com.github.pull.create")
.source("urn:event:from:myapi/resourse/123");
```
#### Formatting
```js
var Cloudevent = require("cloudevents-sdk");
/*
* Creates an instance with default spec and format
*/
var cloudevent =
new Cloudevent()
.type("com.github.pull.create")
.source("urn:event:from:myapi/resourse/123");
/*
* Format the payload and return it
*/
var formatted = cloudevent.format();
```
#### Emitting
```js
var Cloudevent = require("cloudevents-sdk");
// The event
var cloudevent = new Cloudevent()
.type("com.github.pull.create")
.source("urn:event:from:myapi/resourse/123");
// The binding configuration using POST
var config = {
method: "POST",
url : "https://myserver.com"
};
// The binding instance
var binding = Cloudevent.bindings["http-structured0.1"](config);
// Emit the event using Promise
binding.emit(cloudevent)
.then(response => {
// Treat the response
console.log(response.data);
}).catch(err => {
// Treat the error
console.error(err);
});
```
## Repository Structure
```text
├── index.js
├── lib
│   ├── bindings
│   │   └── http
│   ├── cloudevent.js
│   ├── format
│   └── specs
├── LICENSE
├── package.json
├── README.md
```
- `index.js`: library exports
- `lib/bindings`: every binding implementation goes here
- `lib/bindings/http`: every http binding implementation goes here
- `lib/cloudevent.js`: implementation of Cloudevent, an interface
- `lib/format/`: every format implementation goes here
- `lib/specs/`: every spec implementation goes here
## Unit Testing
The unit test checks the result of formatted payload and the constraints.
```bash
npm test
```
## The API
### `Cloudevent` class
```js
/*
* Format the payload and return an Object.
*/
Object Cloudevent.format()
/*
* Format the payload as String.
*/
String Cloudevent.toString()
```
### `Formatter` classes
Every formatter class must implement these methods to work properly.
```js
/*
* Format the Cloudevent payload argument and return an Object.
*/
Object Formatter.format(payload)
/*
* Format the Cloudevent payload as String.
*/
String Formatter.toString(payload)
```
## `Spec` classes
Every Spec class must implement these methods to work properly.
```js
/*
* The constructor must receives the Cloudevent type.
*/
Spec(Cloudevent)
/*
* Checks the spec constraints, throwing an error if do not pass.
*/
Spec.check()
```
### `Binding` classes
Every Binding class must implement these methods to work properly.
```js
/*
* The constructor must receives the map of configurations.
*/
Binding(config)
/*
* Emits the event using an instance of Cloudevent.
*/
Binding.emit(cloudevent)
```
> See how to implement the method injection [here](lib/specs/spec_0_1.js#L17)
>
> Learn about [Builder Design Pattern](https://en.wikipedia.org/wiki/Builder_pattern)
>
> Check out the produced event payload using this [tool](https://webhook.site)