GraphQL::Constraint::Directive

Allows using @constraint as a directive to validate input data. Inspired by Constraints Directives RFC and OpenAPI.
This gem is an implementation of graphql-constraint-directive in Ruby.

Installation

Install the gem and add to the application's Gemfile by executing:

$ bundle add graphql-constraint-directive

Usage

This gem is an implemented as a plugin of graphql-ruby. Attach to your schema as follows:

class MySchema < GraphQL::Schema
  use GraphQL::Constraint::Directive
end

Then, set the directive to the argument for which you want to set validation:

class CreateBook < BaseMutation
  argument :title, String,
           required: true,
           directives: { GraphQL::Constraint::Directive::Constraint => { min_length: 1, max_length: 200 } }

  field :book, Book, null: false

  def resolve(title:)
    # ...some codes
    {
      book: book
    }
  end
end

This will dump the following schema:

input CreateBookInput {
  title: String! @constraint(minLength: 1, maxLength: 200)
}

type Mutation {
  createBook(
    input: CreateBookInput!
  ): CreateBookPayload
}

tips: You can use shorthand constraints: option if you let your argument class include GraphQL::Constraint::Directive::ConstraintArgumentKeyword helper.

# optional
# in your argument class
require 'graphql/constraint/directive/constraint_argument_keyword'

module Types
  class BaseArgument < GraphQL::Schema::Argument
    include GraphQL::Constraint::Directive::ConstraintArgumentKeyword
  end
end

# optional
class CreateBook < BaseMutation
  argument :title, String,
           required: true,
           # shorthand for `directives: { GraphQL::Constraint::Directive::Constraint =>...`
           constraints: { min_length: 1, max_length: 200 }

API

String

minLength

@constraint(minLength: 5) Restrict to a minimum length

maxLength

@constraint(maxLength: 5) Restrict to a maximum length

startsWith(unimplemented)

@constraint(startsWith: "foo") Ensure value starts with foo

endsWith(unimplemented)

@constraint(endsWith: "foo") Ensure value ends with foo

contains(unimplemented)

@constraint(contains: "foo") Ensure value contains foo

notContains(unimplemented)

@constraint(notContains: "foo") Ensure value does not contain foo

pattern

@constraint(pattern: "^[0-9a-zA-Z]*$") Ensure value matches regex, e.g. alphanumeric

Warning

Unlike others, actual validation of pattern is not implemented. You need to implement it on your application side.

Int/Float

min

@constraint(min: 3) Ensure value is greater than or equal to

max

@constraint(max: 3) Ensure value is less than or equal to

exclusiveMin(unimplemented)

@constraint(exclusiveMin: 3) Ensure value is greater than

exclusiveMax(unimplemented)

@constraint(exclusiveMax: 3) Ensure value is less than

multipleOf(unimplemented)

@constraint(multipleOf: 10) Ensure value is a multiple

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/mh4gf/graphql-ruby-constraint-directive. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

License

The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the Graphql::Ruby::Constraint::Directive project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.