GraphQL-Lua

The Roblox Lua reference implementation for GraphQL, a query language for APIs created by Facebook.

See more complete documentation at https://graphql.org/ and https://graphql.org/graphql-js/. GraphQL-Lua has few to no deviations from the upstream documentation and APIs, with the exception of the subscription API (which is stubbed). A quick search for SKIPped tests will highlight current deviations.

Looking for help? Find resources from the community.

Getting Started

A general overview of GraphQL is available in the README for the Specification for GraphQL. That overview describes a simple set of GraphQL examples that exist as tests in this repository. A good way to get started with this repository is to walk through that README and the corresponding tests in parallel.

Using GraphQL-Lua

This repository contains an integration-tested GraphQL implementation, with complete unit and integration tests, written in Roblox Lua that is aligned to the same major.minor version as upstream. See the README.md in each src subdirectory for current status, and run the tests using scripts/ci.sh to see the progress.

GraphQL-Lua provides two important capabilities: building a type schema and serving queries against that type schema.

• In a new project, you can consume this library by adding this line to your rotriever.toml
  • GraphQL = "github.com/Roblox/[email protected]"
• Make sure you are using the latest rotriever 0.5.1 (or later) release
  • you can download the release binary, or add it to your foreman.toml: rotrieve = { source = "roblox/rotriever", version = "0.5.1" }

You'll need rotriever 0.5.1 (or later), so hop over there and make sure you have the latest released version specified in your foreman.toml, or have the latest rotriever version in your PATH. See the rotriever repo for more details on how to install and use rotriever.

The first thing you'll do in GraphQL-Lua is build a GraphQL type schema which maps to your services.

local Workspace = Script.Parent.Parent
local GraphQLModule = require(Workspace.Packages.GraphQL)
local graphql = GraphQLModule.graphql
local GraphQLSchema = GraphQLModule.GraphQLSchema
local GraphQLObjectType = GraphQLModule.GraphQLObjectType
local GraphQLString = GraphQLModule.GraphQLString

local schema = GraphQLSchema.new({
  query = GraphQLObjectType.new({
    name = 'RootQueryType',
    fields = {
      hello = {
        type = GraphQLString,
        resolve = function()
          return 'world';
        end,
      },
    },
  }),
})

This defines a simple schema, with one type and one field, that resolves to a fixed value. The resolve function can return a value, a promise, or an array of promises. (Lua Note: You'll need to use a Promise library compatible with https://github.com/evaera/roblox-lua-promise .) A more complex example, with a Star Wars theme, is included in the top-level tests directory.

Then, serve the result of a query against that type schema.

local source = '{ hello }'

graphql({schema = schema, source = source}):andThen(function (result)
  --[[ Prints:
    world
  ]]
  print(tostring(result.data.hello))
end)

Note: If you're using the luau-polyfill library, you can use the inspect function it exports to pretty-print results and errors.

This runs a query fetching the one field defined. The graphql function will first ensure the query is syntactically and semantically valid before executing it, reporting errors otherwise.

local source = '{ BoyHowdy }'

graphql({schema = schema, source = source}):andThen(function (result)
  --[[ Prints:
    Cannot query field "BoyHowdy" on type "MyRootQueryType".
  ]]
  print(tostring(result.errors[1].message))
end)

Note: Please don't forget to disable the global _G.__DEV__ (the default) if you are running a production server. Enabling _G.__DEV__ has some runtime checks that can provide useful feedback during development, but those extra runtime checks can degrade performance.

Using with GraphiQL and similar tooling

We have ported Apollo GraphQL Client and have both end-to-end tests and benchmarks in that repository that deeply exercises this GraphQL implementation (and its strong Luau types).

Other tooling will likely 'just work', but we will update this documentation with examples of other screenshots of integration with commodity GQL tooling in the future.

Contributing

We actively welcome pull requests. Learn how to contribute.

Changelog

Changes are tracked as GitHub releases.

License

GraphQL-Lua is MIT-licensed.

Credits

The Luau types in this project are based on DefinitelyTyped definitions written by:

• TonyYang https://github.com/TonyPythoneer
• Caleb Meredith https://github.com/calebmer
• Dominic Watson https://github.com/intellix
• Firede https://github.com/firede
• Kepennar https://github.com/kepennar
• Mikhail Novikov https://github.com/freiksenet
• Ivan Goncharov https://github.com/IvanGoncharov
• Hagai Cohen https://github.com/DxCx
• Ricardo Portugal https://github.com/rportugal
• Tim Griesser https://github.com/tgriesser
• Dylan Stewart https://github.com/dyst5422
• Alessio Dionisi https://github.com/adnsio
• Divyendu Singh https://github.com/divyenduz
• Brad Zacher https://github.com/bradzacher
• Curtis Layne https://github.com/clayne11
• Jonathan Cardoso https://github.com/JCMais
• Pavel Lang https://github.com/langpavel
• Mark Caudill https://github.com/mc0
• Martijn Walraven https://github.com/martijnwalraven
• Jed Mao https://github.com/jedmao