Beginners' tutorial: Developing Web service drivers

This is a quick-start guide to getting your first Web service drivers up and running.

Prerequisites

Before you begin, download and install the following tools:

Node.JS v10.19 or later
An editor of your choice, such as VS Code or Webstorm
Siren Platform

Steps

Create and initialize the project by running the following command:
```
mkdir example-web-service-group && cd $_
npm init --yes
```

Add Kibana to the package.json file. Ensure that the file contains the following parameters:

{
  "name": "example-web-service-group",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "kibana": {
    "version": "5.6.10"
  }
}

Add the web-service-interface package by running the following command:
```
npm install @sirensolutions/web-service-interface
```
Open the package.json file to ensure that the @sirensolutions/web-service-interface package is under dependencies.
Create an index.js file by running the following command:
```
touch index.js
```

Copy the following code into the index.js file:

import { registerServices, ServiceDefinition } from '@sirensolutions/web-service-interface';

class StringReverser extends ServiceDefinition { (1)

  name = 'stringreverser';
  inputSchema = { (2)
      message: {
        type: 'text',
        required: true // This defaults to false if you do not set it.
      }
    };
  outputConfiguration = { reversed_message: 'text' }; (3)

  invoke(inputs) { (4)
    // Reverse my input
    const reversed_input = inputs.message.split('').reverse().join();
    return [{
        reversed_message: reversed_input
      }];
  }
}

export default registerServices('example-web-service-group', [StringReverser]); (5)

1	Extends the class, so that it complies with the Web service interface.
2	Specifies the inputs that this Web service accepts and whether or not they are mandatory parameters.
3	Defines the structure and types of the output fields, which are used to create the Elasticsearch field mapping.
4	The function that is called when your Web service is invoked. It receives the parameters that are defined in `inputSchema` and must return an object that has the same structure as the `outputConfiguration`.
5	This export and function call is how you hook the Web service to Siren Investigate.

It’s ready to go! Copy or move the example-service-group folder into the Siren Investigate plugins folder by running the following command:
```
cp -r . /path/to/investigate/plugins
```

Start Elasticsearch and Siren Investigate by running the following commands:

cd path/to/elasticsearch
./bin/elasticseach

cd path/to/investigate
./bin/investigate

To start using the service, copy and paste localhost:5606 into your browser.

Next steps

Intermediate tutorial

Advanced tutorial