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# Apache PredictionIO Ruby SDK

[![Build Status](https://api.travis-ci.org/apache/predictionio-sdk-ruby.svg?branch=develop)](https://github.com/apache/predictionio-sdk-ruby)
[![Gem Version](https://badge.fury.io/rb/predictionio.svg)](http://badge.fury.io/rb/predictionio)

The Ruby SDK provides a convenient wrapper for PredictionIO Event Server API and
Engine API. It allows you to quickly record your users' behavior and retrieve
personalized predictions for them.

## Documentation

Full Ruby SDK documentation can be found [here](http://www.rubydoc.info/github/apache/incubator-predictionio-sdk-ruby).

Please see the [PredictionIO App Integration
Overview](http://predictionio.apache.org/appintegration/) to
understand how the SDK can be used to integrate PredictionIO Event Server and
Engine with your application.

## Installation

Ruby 2+ required!

The module is published to [RubyGems](http://rubygems.org/gems/predictionio) and
can be installed directly by:

```sh
gem install predictionio
```

Or using [Bundler](http://bundler.io/) with:

```
gem 'predictionio', '0.12.1'
```

## Sending Events to Event Server

Please refer to [Event Server
documentation](http://predictionio.apache.org/datacollection/) for
event format and how the data can be collected from your app.

### Instantiate Event Client and connect to PredictionIO Event Server

```ruby
require 'predictionio'

# Define environment variables.
ENV['PIO_THREADS'] = '50' # For async requests.
ENV['PIO_EVENT_SERVER_URL'] = 'http://localhost:7070'
ENV['PIO_ACCESS_KEY'] = 'YOUR_ACCESS_KEY' # Find your access key with: `$ pio app list`.

# Create PredictionIO event client.
client = PredictionIO::EventClient.new(ENV['PIO_ACCESS_KEY'], ENV['PIO_EVENT_SERVER_URL'], Integer(ENV['PIO_THREADS']))
```

### Create a `$set` user event and send it to Event Server

```ruby
client.create_event(
  '$set',
  'user',
  user_id
)

```

### Create a `$set` item event and send it to Event Server

```ruby
client.create_event(
  '$set',
  'item',
  item_id,
  { 'properties' => { 'categories' => ['Category 1', 'Category 2'] } }
)
```

### Create a `$set` item event and send it to Event Server to specific channel

*NOTE:* channels are supported in PIO version >= 0.9.2 only. Channel must be created first.

```ruby
client.create_event(
  '$set',
  'item',
  item_id,
  { 'properties' => { 'categories' => ['Category 1', 'Category 2'], 'channel' => 'test-channel'} }
)
```

### Create a user 'rate' item event and send it to Event Server

```ruby
client.create_event(
  'rate',
  'user',
  user_id, {
    'targetEntityType' => 'item',
    'targetEntityId' => item_id,
    'properties' => { 'rating' => 10 }
  }
)
```

### Asynchronous request

To send an async request, simply use the `acreate_event` method instead of
`create_event`. Be aware that the asynchronous method does not throw errors.
It's best to use the synchronous method when first getting started.

## Query PredictionIO Engine

### Connect to the Engine:

```ruby
# Define environmental variables.
ENV['PIO_ENGINE_URL'] = 'http://localhost:8000'

# Create PredictionIO engine client.
client = PredictionIO::EngineClient.new(ENV['PIO_ENGINE_URL'])
```

### Send a prediction query to the engine and get the predicted result:

```ruby
# Get 5 recommendations for items similar to 10, 20, 30.
response = client.send_query(items: [10, 20, 30], num: 5)
```

## Mailing List

Please use the Apache mailing lists. Subscription instructions are
[here](http://predictionio.apache.org/support/).

## Issue Tracker

Use [the Apache JIRA](https://issues.apache.org/jira/browse/PIO), and file any
issues under the `Ruby SDK` component.

## Contributing

Please follow these
[instructions](http://predictionio.apache.org/community/contribute-code/).

## License

[Apache License 2.0](http://www.apache.org/licenses/LICENSE-2.0).