BigML.io Ruby bindings

In this repository you'll find an open source Ruby module that gives you a simple binding to interact with BigML. You can use it to easily create, retrieve, list, update, and delete BigML resources (i.e., sources, datasets, models and, predictions).

This module is licensed under the Apache License, Version 2.0.

Support

Please, report problems and bugs to our BigML.io issue tracker

Discussions about the different bindings take place in the general BigML mailing list. Or join us in our Campfire chatroom

Requirements

The only mandatory dependencies are the json and [rest-client] (http://rubygems.org/gems/rest-client) gems. Installation of bigml gem checks its existence on your system and installs them also when needed.

Installation

To install:

Build your own gem

$ gem build bigml.gemspec

and install the bindings

$ gem install bigml-0.0.1.gem

Importing the module

require 'rubygems'
require 'bigml'

Authentication

All the requests to BigML.io must be authenticated using your username and API key and are always transmitted over HTTPS.

This module will look for your username and API key in the environment variables BIGML_USERNAME and BIGML_API_KEY respectively. You can add the following lines to your .bashrc or .bash_profile to set those variables automatically when you log in:

export BIGML_USERNAME=myusername
export BIGML_API_KEY=ae579e7e53fb9abd646a6ff8aa99d4afe83ac291

With that environment set up, connection to BigML will be automatically initialized when needed. Otherwise, you can set your authentication explicitly by instantiating the BigML class as follows.

connection = BigML.instance.authenticate('myusername',
                   'ae579e7e53fb9abd646a6ff8aa99d4afe83ac291')

Running the Tests

To run the tests you just have to

$ bundle install

which manages dependencies. You also will need to set up your authentication via environment variables, as explained above. With that in place, you can run the test suite simply by:

$ cd tests
$ bundle exec cucumber
$ bundle exec ruby ts_bigml.rb

Quick Start

Imagine that you want to use this csv file containing the Iris flower dataset to predict the species of a flower whose sepal length is 5 and whose sepal width is 2.5. A preview of the dataset is shown below. It has 4 numeric fields: sepal length, sepal width, petal length, petal width and a categorical field: species. By default, BigML considers the last field in the dataset as the objective field (i.e., the field that you want to generate predictions for).

sepal length,sepal width,petal length,petal width,species
5.1,3.5,1.4,0.2,Iris-setosa
4.9,3.0,1.4,0.2,Iris-setosa
4.7,3.2,1.3,0.2,Iris-setosa
...
5.8,2.7,3.9,1.2,Iris-versicolor
6.0,2.7,5.1,1.6,Iris-versicolor
5.4,3.0,4.5,1.5,Iris-versicolor
...
6.8,3.0,5.5,2.1,Iris-virginica
5.7,2.5,5.0,2.0,Iris-virginica
5.8,2.8,5.1,2.4,Iris-virginica

You can easily generate a prediction following these steps:

require 'rubygems'
require 'bigml'

source = BigMLSource.create_resource('./data/iris.csv')
dataset = BigMLDataset.create_resource(source)
model = BigMLModel.create_resource(dataset)
prediction = BigMLPrediction.create_resource(model, {'sepal length' => 5, 
                                            'sepal width' => 2.5})

where the static methods return the object properties in a hash format. Either the hash or the resource id can be used as the parameter for the next create_resource call.

You might as well instantiate source, dataset, model and prediction objects for further use

require 'rubygems'
require 'bigml'

source = BigMLSource.create('./data/iris.csv')
dataset = BigMLDataset.create(source)
model = BigMLModel.create(dataset)
prediction = BigMLPrediction.create(model, {'sepal length' => 5, 
                                            'sepal width' => 2.5})

In this case, as you see, the source object itself can also be used as input for the next BigMLDataset.create call, but you might also use the previously discussed properties hash or the resource id.

Fields

BigML automatically generates identifiers for each field. To see the fields and the ids and types that have been assigned to a source you can use fields:

require 'rubygems'
require 'bigml'
require 'pp'

source = BigMLSource.create_resource('./data/iris.csv')
pp BigMLSource.fields(source)

or using objects' syntax

require 'rubygems'
require 'bigml'
require 'pp'

source = BigMLSource.create('./data/iris.csv')
pp source.fields

and you'll get:

{:"000001"=>{:column_number=>1, :optype=>"numeric", :name=>"sepal width"},
 :"000002"=>{:column_number=>2, :optype=>"numeric", :name=>"petal length"},
 :"000003"=>{:column_number=>3, :optype=>"numeric", :name=>"petal width"},
 :"000000"=>{:column_number=>0, :optype=>"numeric", :name=>"sepal length"},
 :"000004"=>{:column_number=>4, :optype=>"categorical", :name=>"species"}}
=> nil

Dataset

If you want to get some basic statistics for each field you can retrieve the fields from the dataset as follows:

dataset = BigMLDataset.get(dataset)
pp BigMLDataset.fields(dataset)

or using instantiated objects

dataset = BigMLDataset.new('dataset/4fcfd1a515526871bb00008c')
pp dataset.fields

You will get a dictionary keyed by field id:

{:"000001"=>
  {:column_number=>1,
   :optype=>"numeric",
   :summary=>
    {:sum_squares=>1430.4,
     :median=>3.02044,
     :counts=>
      [[2, 1],
       [2.2, 3],
       [2.3, 4],
       [2.4, 3],
       [2.5, 8],
       [2.6, 5],
       [2.7, 9],
       [2.8, 14],
       [2.9, 10],
       [3, 26],
       [3.1, 11],
       [3.2, 13],
       [3.3, 6],
       [3.4, 12],
       [3.5, 6],
       [3.6, 4],
       [3.7, 3],
       [3.8, 6],
       [3.9, 2],
       [4, 1],
       [4.1, 1],
       [4.2, 1],
       [4.4, 1]],
     :minimum=>2,
     :missing_count=>0,
     :population=>150,
     :sum=>458.6,
     :maximum=>4.4},
   :name=>"sepal width",
   :datatype=>"double"},
 :"000002"=>
  {:column_number=>2,
   :optype=>"numeric",
   :summary=>
    {:sum_squares=>2582.71,
     :median=>4.34142,
     :minimum=>1,
     :missing_count=>0,
     :population=>150,
     :sum=>563.7,
     :splits=>
      [1.25138,
       1.32426,
       1.37171,
       1.40962,
       1.44567,
       1.48173,
       1.51859,
       1.56301,
       1.6255,

        ...  (snippet) ...

 :"000004"=>
  {:column_number=>4,
   :optype=>"categorical",
   :summary=>
    {:categories=>
      [["Iris-versicolor", 50], ["Iris-setosa", 50], ["Iris-virginica", 50]],
     :missing_count=>0},
   :name=>"species",
   :datatype=>"string"}}
=> nil

Model

One of the greatest things about BigML is that the models that it generates for you are fully white-boxed. To get the model for the example above you can retrieve it as follows:

model = BigMLModel.get(model)
pp model[:object][:model][:root]

or using objects

model = BigMLModel.new('model/4fcfd178035d0742cc000087')
pp model.get[:object][:model][:root]

You will get a explicit tree-like predictive model:

{:count=>150,
 :distribution=>
  [["Iris-virginica", 50], ["Iris-versicolor", 50], ["Iris-setosa", 50]],
 :children=>
  [{:count=>100,
    :distribution=>[["Iris-virginica", 50], ["Iris-versicolor", 50]],
    :children=>
     [{:count=>48,
       :distribution=>[["Iris-virginica", 46], ["Iris-versicolor", 2]],
       :children=>
        [{:count=>38,
          :distribution=>[["Iris-virginica", 38]],
          :leaf=>true,
          :predicate=>{:value=>5.05, :field=>"000002", :operator=>">"},
          :output=>"Iris-virginica"},
         {:count=>10,
          :distribution=>[["Iris-virginica", 8], ["Iris-versicolor", 2]],
          :children=>
           [{:count=>4,
             :distribution=>[["Iris-virginica", 2], ["Iris-versicolor", 2]],
             :children=>
              [{:count=>3,
                :distribution=>[["Iris-virginica", 2], ["Iris-versicolor", 1]],
                :children=> ... (snippet) ...            

(Note that we have abbreviated the output in the snippet above for readability: the full predictive model you'll get is going to contain much more details).

Creating Resources

Newly-created resources are returned in a dictionary with the following keys:

• code: If the request is successful you will get a BigML::HTTP_CREATED (201) status code. Otherwise, it will be one of the standard HTTP error codes detailed in the documentation.
• resource: The identifier of the new resource.
• location: The location of the new resource.
• object: The resource itself, as computed by BigML.
• error: If an error occurs and the resource cannot be created, it will contain an additional code and a description of the error. In this case, location, and resource will be nil.

Statuses

Please, bear in mind that resource creation is almost always asynchronous (predictions are the only exception). Therefore, when you create a new source, a new dataset or a new model, even if you receive an immediate response from the BigML servers, the full creation of the resource can take from a few seconds to a few days, depending on the size of the resource and BigML's load. A resource is not fully created until its status is BigML::FINISHED. See the documentation on status codes for the listing of potential states and their semantics. So depending on your application you might need to use the following constants.

BigML::WAITING
BigML::QUEUED
BigML::STARTED
BigML::IN_PROGRESS
BigML::SUMMARIZED
BigML::FINISHED
BigML::FAULTY
BigML::UNKNOWN
BigML::RUNNABLE

You can query the status of any resource with the status method.

BigMLSource.status(source)
BigMLDataset.status(dataset)
BigMLModel.status(model)
BigMLPrediction.status(prediction)

or using objects' status method

source.status
dataset.status
model.status
prediction.status

Before invoking the creation of a new resource, the library checks that the status of the resource that is passed as a parameter is FINISHED. You can change how often the status will be checked with the wait_time argument. By default, it is set to 3 seconds.

Creating sources

To create a source from a local data file, you can use the create_resource method. The only required parameter is the path to the data file. You can use a second optional parameter to specify any of the options for source creation described in the BigML API documentation.

Here's a sample invocation:

require 'rubygems'
require 'bigml'

source = BigMLSource.create_resource('./data/iris.csv',
    {:name => 'my source', :source_parser => {:missing_tokens => ['?']}})

It's result would be a hash with the source's properties. As already mentioned, source creation is asynchronous: the initial resource status code will be either WAITING or QUEUED. You can retrieve the updated status at any time using the corresponding get method. For example, to get the status of our source we would use:

BigMLSource.status(source)

You can also achieve the same results by creating a new instance of BigMLSource.

In this case, the invocation would be as follows:

require 'rubygems'
require 'bigml'

source = BigMLSource.create('./data/iris.csv',
            {:name => 'my source', :source_parser => {:missing_tokens => ['?']}})

and to check it's status we could use

source.status

You can always create a new instance for a previously existing source by calling the constructor with another source instance, a source properties hash or a source id string.

source = BigMLSource.new('source/4fd12cfb1552682fd1000156')

Creating datasets

Once you have created a source, you can create a dataset. The only required argument to create a dataset is a source id. You can add all the additional arguments accepted by BigML and documented here.

For example, to create a dataset named "my dataset" with the first 1024 bytes of a source, you can submit the following request:

dataset = BigMLDataset.create_resource(source, {:name => "my dataset", :size => 1024})

A hash of dataset's properties will be returned. Upon success, the dataset creation job will be queued for execution, and you can follow its evolution using BigMLDataset.status(dataset).

Again, you could also define a dataset object calling create. Then, the previous example would read:

dataset = BigMLDataset.create(source, {:name => "my dataset", :size => 1024})

where source can be a source object, a source properties hash or a source id string and it's status would be obtained by asking for dataset.status.

To obtain an instance of a previously created database, you just have to call the BigMLDatabase constructor with a database object, a database properties hash or a database id.

database = BigMLDatabase.new('database/4fd12cfb1552682fd1000156')

Creating models

Once you have created a dataset, you can create a model. The only required argument to create a model is a dataset id. You can also include in the request all the additional arguments accepted by BigML and documented here.

For example, to create a model only including the first two fields and the first 10 instances in the dataset, you can use the following invocation:

model = BigMLModel.create_resource(dataset, {
    :name => "my model", 
    :input_fields => ["000000", "000001"], 
    :range => [1, 10]})

Again, the model is scheduled for creation, and you can retrieve its status at any time by means of BigMLModel.status(model) .

Or you could create a BigMLModel instance by providing the dataset. Then the previous example would be:

model = BigMLModel.create(dataset, {
    :name => "my model", 
    :input_fields => ["000000", "000001"], 
    :range => [1, 10]})

where dataset can be a dataset object, a dataset properties hash or a dataset id string.

and it's status could be checked by using model.status.

Also, new instances can be constructed for previously existing models by passing as argument a model object, a model properties hash or a model id string.

model = BigMLModel.new('model/4fd12cfb1552682fd1000156')

Creating predictions

You can now use the model resource identifier together with some input parameters to ask for predictions, using the create method. You can also give the prediction a name.

prediction = BigMLPrediction.create_resource(model,
                                             {'sepal length' => 5,
                                              'sepal width' => 2.5},
                                              {:name => "my prediction"})

To see the prediction you can use pp:

pp prediction

And to use object instantiation, call create with the same list of arguments. Then, prediction creation would read:

prediction = BigMLPrediction.create(model,{'sepal length' => 5,
                                           'sepal width' => 2.5},
                                          {:name => "my prediction"})

where model can be a model object, a model properties hash or a model id string. To see the prediction you can use pp:

pp prediction.get

Instances of previously existing predictions can be created by calling the constructor with a prediction object, a prediction properties hash or a prediction id string

prediction = BigMLPrediction.new('prediction/4fd12cfb1552682fd1000156')

Reading Resources

When retrieved individually, resources are returned as a dictionary identical to the one you get when you create a new resource. However, the status code will be BigML::HTTP_OK if the resource can be retrieved without problems, or one of the HTTP standard error codes otherwise.

Listing Resources

You can list resources with the appropriate api method:

BigMLSource.list()
BigMLDataset.list()
BigMLModel.list()
BigMLPredictions.list()

you will receive a dictionary with the following keys:

• code: If the request is successful you will get a BigML::HTTP_OK (200) status code. Otherwise, it will be one of the standard HTTP error codes. See BigML documentation on status codes for more info.
• meta: A dictionary including the following keys that can help you paginate listings:
  • previous: Path to get the previous page or nil if there is no previous page.
  • next: Path to get the next page or nil if there is no next page.
  • offset: How far off from the first entry in the resources is the first one listed in the resources key.
  • limit: Maximum number of resources that you will get listed in the resources key.
  • total_count: The total number of resources in BigML.
• objects: A list of resources as returned by BigML.
• error: If an error occurs and the resource cannot be created, it will contain an additional code and a description of the error. In this case, meta, and resources will be nil.

Filtering Resources

You can filter resources in listings using the syntax and fields labeled as filterable in the BigML documentation for each resource.

A few examples:

Ids of the first 5 sources created before April 1st, 2012

sources = []
list = BigMLSource.list("limit=5;created__lt=2012-04-1")[:objects]
if not list.nil?
  sources = list.map{ |source| source[:resource] }
end

Name of the first 10 datasets bigger than 1MB

datasets = []
list = BigMLDataset.list("limit=10;size__gt=1048576")[:objects]
if not list.nil?
  datasets = list.map{ |dataset| dataset[:resource] }
end

Name of models with more than 5 fields (columns)

models = []
list = BigMLModel.list("columns__gt=5")[:objects]
if not list.nil?
  models = list.map{ |model| model[:resource] }
end

Ids of predictions whose model has not been deleted

predictions = []
list = BigMLPrediction.list("model_status=true")[:objects]
if not list.nil?
  predictions = list.map{ |prediction| prediction[:resource] }
end

Ordering Resources

You can order resources in listings using the syntax and fields labeled as sortable in the BigML documentation for each resource.

A few examples:

Name of sources ordered by size

sources = []
list = BigMLSource.list("order_by=size")[:objects]
if not list.nil?
  sources = list.map{ |source| source[:name] }
end

Number of instances in datasets created before April 1st, 2012 ordered by size

datasets = []
list = BigMLDataset.list("created__lt=2012-04-1;order_by=size")[:objects]
if not list.nil?
  datasets = list.map{ |dataset| dataset[:rows] }
end

Model ids ordered by number of predictions (in descending order).

models = []
list = BigMLModel.list("order_by=-number_of_predictions")[:objects]
if not list.nil?
  models = list.map{ |model| model[:resource] }
end

Name of predictions ordered by name.

predictions = []
list = BigMLPrediction.list("order_by=name")[:objects]
if not list.nil?
  predictions = list.map{ |prediction| prediction[:name] }
end

Updating Resources

When you update a resource, it is returned in a dictionary exactly like the one you get when you create a new one. However the status code will be BigML::HTTP_ACCEPTED if the resource can be updated without problems or one of the HTTP standard error codes otherwise.

BigMLSource.update(source, {:name => "new name"})
BigMLDataset.update(dataset, {:name => "new name"})
BigMLModel.update(model, {:name => "new name"})
BigMLPrediction.update(prediction, {:name => "new name"})

or if using instances

source.update({:name => "new name"})
dataset.update({:name => "new name"})
model.update({:name => "new name"})
prediction.update({:name => "new name"})

Deleting Resources

Resources can be deleted individually using the corresponding method for each type of resource.

BigMLSource.delete(source)
BigMLDataset.delete(dataset)
BigMLModel.delete(model)
BigMLPrediction.delete(prediction)

or if using instances

source.delete
dataset.delete
model.delete
prediction.delete

Each of the calls above will return a dictionary with the following keys:

• code If the request is successful, the code will be a BigML::HTTP_NO_CONTENT (204) status code. Otherwise, it wil be one of the standard HTTP error codes. See the documentation on status codes for more info.
• error If the request does not succeed, it will contain a dictionary with an error code and a message. It will be nil otherwise.