ParamsCollector

Installation

Add this line to your application's Gemfile:

gem 'params_collector'

And then execute:

$ bundle

Or install it yourself as:

$ gem install params_collector

Usage

require 'params_collector'

parser = ParamsCollector.expect do
  # <marshaler> <param_name> <default_value>
  boolean :option1
  boolean :option2, false
  number :num, 4
  string :desc
end

params = ... e.g. from request ...  -> { option1: true, desc: "foo" }

parser.parse(params)

then you can check if all expected parameters were parsed

parser.valid?       # => true

and use that object in the same way as a hash

parser[:option1]    # => true
parser[:option2]    # => false
parser[:num]        # => 4
parser[:desc]       # => "foo"

parser.to_hash      # => { option1: true, desc: "foo" }
parser.merge num: 2 # => { option1: true, page: 2, desc: "foo" }

If you call to_hash method, the output will contain only parameters that are valid, or where the default state was changed.

If you define the default_value (e.g. number :page, 1), then the parser will be valid even if you do not specify e.g.{ page: 123 } to the parse method.

Marshalers

When you call ParamsCollector.expect, you should define, which parameters you expect to be parsed. You can do that by calling:

• boolean :name, [default_value = false] - converts: true|false, "yes|no", "on|off", 1|0 to the TrueClass or FalseClass
• number :name, [default_value = 0] - converts digits and string with digits to the Fixnum or Float
• string :name, [default_value = ""]
• hash :name, [default_value = {}]
• array :name, [default_value = []]

Creating the own marshaler

Marshaler class should respond to:

• .value and return stored value
• .set(value) to set new value

and register self in the ParamsCollector:

ParamsCollector::Parser.register_marshaler("foo", self.name)

so:

class FooMarshaler
  ParamsCollector::Parser.register_marshaler("foo", name)

  attr_reader :value

  def initialize
    @value = nil
  end

  def set(value)
    @value = value
  end
end

Versioning

See semver.org

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request