Graphql-ruby setup

Documentation

execution docs

https://graphql-ruby.org/queries/executing_queries.html

Sample API

${PROJECT}/lib/graphql_intro.rb

require_relative 'graphql_intro/schema'

${PROJECT}/lib/graphql_intro/schema.rb

# ${PROJECT}/lib/schema.rb
require 'graphql'
require_relative 'query_root'
require_relative 'mutation_root'

class Schema < GraphQL::Schema
  query QueryRoot
  mutation MutationRoot
end

${PROJECT}/lib/graphql_intro/query_root.rb

require 'graphql'

class QueryRoot < GraphQL::Schema::Object
  field :hello, String,
    "Says hello",
    null: false

  def hello
    return "Hi there"
  end
end

${PROJECT}/lib/graphql_intro/mutation_root.rb

require 'graphql'
require_relative 'mutations/write_file'

class MutationRoot < GraphQL::Schema::Object
  field :write_file, mutation: Mutations::WriteFile
end

${PROJECT}/lib/graphql_intro/mutations/write_file.rb

require 'graphql'
require 'digest'

module Mutations
  class WriteFile < GraphQL::Schema::Mutation
    argument :path,     String, required: true
    argument :contents, String, required: true

    field :checksum,             String, null: false
    field :existed_before_write, Boolean, null: false

    def resolve(path:, contents:)
      abspath = File.expand_path(path)
      existed_before_write = File.exist?(abspath)
      write_file(abspath, contents)
      {
        checksum: file_checksum(abspath),
        existed_before_write: existed_before_write,
      }
    end

    private

    def write_file(path, contents)
      dirpath = File.dirname(path)
      Dir.mkdir(dirpath) unless Dir.exist?(dirpath)

      File.open(path, "w") do |fd|
        fd.write(contents)
      end
    end

    def file_checksum(path)
      File.open(path, "r") do |fd|
        Digest::MD5.hexdigest(fd.read)
      end
    end
  end
end

nix project

Include these files in addition to the above sample project to build a contained nix environment.

${PROJECT}/default.nix

# ${package}/default.nix
#
# first run:
#    nix-shell -p bundler --run 'bundle lock'
#    nix-shell -p bundix --run 'bundix -m'
#    nix-shell
#      bundle install
#      bundle exec irb
#        require 'graphql'

{ pkgs ? import <nixpkgs> {} }:
  pkgs.stdenv.mkDerivation {
    pname = "ruby-graphql-intro";
    version = "0.0.1";
    env = pkgs.bundlerEnv {
      name = "ruby-graphql-intro";
      ruby = pkgs.ruby;
      gemdir = ./.;
    };
    buildInputs = [
      pkgs.ruby
      pkgs.bundler
    ];
  }

${PROJECT}/Gemfile

source 'https://rubygems.org'
gem 'graphql'
gem 'pry'

${PROJECT}/Makefile

build: clean
    nix-shell -p bundler --run 'bundle lock'
    nix-shell -p bundix  --run 'bundix -m'
    nix-shell -p bundler --run 'bundle install'
    echo "use_nix" > .envrc
    echo 'PATH=$$PATH:$$PWD/bin' >> .envrc

clean:
    test -d vendor       && rm -rf vendor    || true
    test -d .bundle      && rm -rf .bundle   || true
    test -f gemset.nix   && rm gemset.nix    || true
    test -f Gemfile.lock && rm Gemfile.lock  || true
    test -f .envrc       && rm .envrc        || true

nix-env -i direnv
make
direnv allow
bundle exec pry

require_relative 'lib/graphql_schema'
Schema.execute("query { hello }")