Module: Grape::DSL::Parameters

Included in:
Validations::ParamsScope
Defined in:
lib/grape/dsl/parameters.rb

Overview

Defines DSL methods, meant to be applied to a ParamsScope, which define and describe the parameters accepted by an endpoint, or all endpoints within a namespace.

Constant Summary collapse

EmptyOptionalValue = 
Object.new.freeze

Instance Method Summary collapse

Instance Method Details

#build_with(build_with) ⇒ Object

Set the module used to build the request.params.

Examples:


require 'grape/extenstions/hashie_mash'
class API < Grape::API
  desc "Get collection"
  params do
    build_with :hashie_mash
    requires :user_id, type: Integer
  end
  get do
    params['user_id']
  end
end

Parameters:

  • build_with —

    the ParamBuilder module to use when building request.params Available builders are:

    * Grape::Extensions::ActiveSupport::HashWithIndifferentAccess::ParamBuilder (default)
* Grape::Extensions::Hash::ParamBuilder
* Grape::Extensions::Hashie::Mash::ParamBuilder


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# File 'lib/grape/dsl/parameters.rb', line 31

def build_with(build_with)
  @api.inheritable_setting.build_params_with = build_with
end

#declared_param?(param) ⇒ Boolean

Test for whether a certain parameter has been defined in this params block yet.

Returns:

  • (Boolean) —

    whether the parameter has been defined



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# File 'lib/grape/dsl/parameters.rb', line 175

def declared_param?(param)
  # Elements of @declared_params of lateral scope are pushed in @parent. So check them in @parent.
  return @parent.declared_param?(param) if lateral?

  # @declared_params also includes hashes of options and such, but those
  # won't be flattened out.
  @declared_params.flatten.any? do |declared_param_attr|
    first_hash_key_or_param(declared_param_attr.key) == param
  end
end

#given(*attrs) { ... } ⇒ Object

Define a block of validations which should be applied if and only if the given parameter is present. The parameters are not nested.

Parameters:

  • attr (Symbol) —

    the parameter which, if present, triggers the validations

Yields:

  • a parameter definition DSL

Raises:

  • Grape::Exceptions::UnknownParameter if attr has not been defined in this scope yet



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# File 'lib/grape/dsl/parameters.rb', line 164

def given(*attrs, &)
  attrs.each do |attr|
    proxy_attr = first_hash_key_or_param(attr)
    raise Grape::Exceptions::UnknownParameter.new(proxy_attr) unless declared_param?(proxy_attr)
  end
  new_lateral_scope(dependent_on: attrs, &)
end

#optional(*attrs, using: nil, except: nil, as: nil, **opts) ⇒ Object

Allow, but don't require, one or more parameters for the current endpoint.

Parameters:

  • attrs —

    list of parameters names, or, if :using is passed as an option, which keys to include (:all or :none) from the :using hash. Passing the options as a trailing positional Hash is deprecated; pass them as keyword arguments instead.

Options Hash (*attrs):

  • :type (Class) —

    the type to coerce this parameter to before passing it to the endpoint. See Validations::Types for a list of types that are supported automatically. Custom classes may be used where they define a class-level ::parse method, or in conjunction with the :coerce_with parameter. JSON may be supplied to denote JSON-formatted objects or arrays of objects. Array[JSON] accepts the same values as JSON but will wrap single objects in an Array.

  • :types (Array<Class>) —

    may be supplied in place of :type to declare an attribute that has multiple allowed types. See Validations::Types::MultipleTypeCoercer for more details on coercion and validation rules for variant-type parameters.

  • :desc (String) —

    description to document this parameter

  • :default (Object) —

    default value, if parameter is optional

  • :values (Array) —

    permissable values for this field. If any other value is given, it will be handled as a validation error

  • :using (Hash[Symbol => Hash]) —

    a hash defining keys and options, like that returned by Entity#documentation. The value of each key is an options hash accepting the same parameters

  • :except (Array[Symbol]) —

    a list of keys to exclude from the :using Hash. The meaning of this depends on if :all or :none was passed; :all + :except will make the :except fields optional, whereas :none + :except will make the :except fields required

  • :coerce_with (#parse, #call) —

    method to be used when coercing the parameter to the type named by attrs[:type]. Any class or object that defines ::parse or ::call may be used.



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# File 'lib/grape/dsl/parameters.rb', line 137

def optional(*attrs, using: nil, except: nil, as: nil, **opts, &)
  return redispatch_legacy_options(:optional, attrs, { using:, except:, as: }.compact.merge(opts), &) if legacy_options?(attrs)

  declare(attrs, opts, required: false, using:, except:, as:, &)
end

#params(params) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns hash of parameters relevant for the current scope.

Parameters:

  • params (Hash) —

    initial hash of parameters

Returns:

  • hash of parameters relevant for the current scope



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# File 'lib/grape/dsl/parameters.rb', line 193

def params(params)
  scoped = @parent ? (@parent.qualifying_params.presence || @parent.params(params)) : params
  @element ? map_params(scoped, @element) : scoped
end

#requires(*attrs, using: nil, except: nil, as: nil, **opts) ⇒ Object Also known as: group

Require one or more parameters for the current endpoint.

Examples:


params do
  # Basic usage: require a parameter of a certain type
  requires :user_id, type: Integer

  # You don't need to specify type; String is default
  requires :foo

  # Multiple params can be specified at once if they share
  # the same options.
  requires :x, :y, :z, type: Date

  # Nested parameters can be handled as hashes. You must
  # pass in a block, within which you can use any of the
  # parameters DSL methods.
  requires :user, type: Hash do
    requires :name, type: String
  end
end

Parameters:

  • attrs —

    list of parameters names, or, if :using is passed as an option, which keys to include (:all or :none) from the :using hash. Passing the options as a trailing positional Hash is deprecated; pass them as keyword arguments instead.

Options Hash (*attrs):

  • :type (Class) —

    the type to coerce this parameter to before passing it to the endpoint. See Validations::Types for a list of types that are supported automatically. Custom classes may be used where they define a class-level ::parse method, or in conjunction with the :coerce_with parameter. JSON may be supplied to denote JSON-formatted objects or arrays of objects. Array[JSON] accepts the same values as JSON but will wrap single objects in an Array.

  • :types (Array<Class>) —

    may be supplied in place of :type to declare an attribute that has multiple allowed types. See Validations::Types::MultipleTypeCoercer for more details on coercion and validation rules for variant-type parameters.

  • :desc (String) —

    description to document this parameter

  • :default (Object) —

    default value, if parameter is optional

  • :values (Array) —

    permissable values for this field. If any other value is given, it will be handled as a validation error

  • :using (Hash[Symbol => Hash]) —

    a hash defining keys and options, like that returned by Entity#documentation. The value of each key is an options hash accepting the same parameters

  • :except (Array[Symbol]) —

    a list of keys to exclude from the :using Hash. The meaning of this depends on if :all or :none was passed; :all + :except will make the :except fields optional, whereas :none + :except will make the :except fields required

  • :coerce_with (#parse, #call) —

    method to be used when coercing the parameter to the type named by attrs[:type]. Any class or object that defines ::parse or ::call may be used.



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# File 'lib/grape/dsl/parameters.rb', line 127

def requires(*attrs, using: nil, except: nil, as: nil, **opts, &)
  return redispatch_legacy_options(:requires, attrs, { using:, except:, as: }.compact.merge(opts), &) if legacy_options?(attrs)

  declare(attrs, opts, required: true, using:, except:, as:, &)
end

#use(*names, **options) ⇒ Object Also known as: use_scope, includes

Include reusable params rules among current. You can define reusable params with helpers method.

Examples:


class API < Grape::API
  helpers do
    params :pagination do
      optional :page, type: Integer
      optional :per_page, type: Integer
    end
  end

  desc "Get collection"
  params do
    use :pagination
  end
  get do
    Collection.page(params[:page]).per(params[:per_page])
  end
end


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# File 'lib/grape/dsl/parameters.rb', line 56

def use(*names, **options)
  return redispatch_legacy_options(:use, names, options) if legacy_options?(names)

  named_params = @api.inheritable_setting.named_params || {}
  names.each do |name|
    params_block = named_params.fetch(name) do
      raise "Params :#{name} not found!"
    end

    if options.empty?
      instance_exec(options, &params_block)
    else
      instance_exec(**options, &params_block)
    end
  end
end

#with(**opts) ⇒ Object

Define common settings for one or more parameters

Parameters:

  • attrs —

    list of parameters names, or, if :using is passed as an option, which keys to include (:all or :none) from the :using hash. Passing the options as a trailing positional Hash is deprecated; pass them as keyword arguments instead.



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# File 'lib/grape/dsl/parameters.rb', line 146

def with(**opts, &)
  new_group_attrs = @group&.deep_merge(opts) || opts
  new_group_scope(new_group_attrs, &)
end