Maple

Master

Maple is an automatic, compile time, client code generator for GraphQL schemas. At best it creates easy to use API functions for use in your code. At worst it can be used as a CLI for a GraphQL API.

Best illustrated by an example - given the following code

defmodule Maple.Examples.Github.Config do
  Application.put_env(:maple, :api_url, "https://api.github.com/graphql")
  Application.put_env(:maple, :additional_headers, %{"Authorization" => "Bearer TOKEN"})
end

defmodule Maple.Examples.Github do
  use Maple
  generate_graphql_functions()
end

generate_graphql_functions will create all the query and mutation functions for the GitHub GraphQL API.

So you can do the following:

iex(1)> c "examples/github.ex", "." # We need to compile the BEAM file to access the documentation
[Maple.Examples.Github, Maple.Examples.Github.Config]

iex(2)> h Maple.Examples.Github.user

                            def user(params, fields)

Lookup a user by login.

Param name: login

  • Description: The user's login.
  • Type: String
  • Required: Yes

iex(3)> Maple.Examples.Github.viewer("login")
%Maple.Response{body: %{"viewer" => %{"login" => "maxneuvians"}}, status: 200}

iex(4)> Maple.Examples.Github.user(%{login: "maxneuvians"}, "name")
%Maple.Response{body: %{"user" => %{"name" => "Max Neuvians"}}, status: 200}

iex(5)> Maple.Examples.Github.user(%{},"name")
{:error, "Query is missing the following required params: login"}

query functions can are either arity /1 or /2 depending if they have required params. mutation functions are always arity /2. Arity /2 functions always take a map as the first argument and a string as the second, which match the GraphQL params and query string concept.

Function names are changed from camel to snake case. ex listUsers becomes list_users.

Take a look at examples/ for more examples.

Installation

def deps do
  [{:maple, git: "https://github.com/maxneuvians/maple"}]
end

or

def deps do
  [{:maple, "~> 0.1.0"}]
end

Configuration

If you only access one GraphQL API you just need to add the following to you config.exs

config :maple,
  api_url: "URL",
  additional_headers: %{"Authorization": "Bearer TOKEN"} # If you have any additional headers

Ramblings

This library is in development.

Maple.generate_graphql_functions can be passed an optional adapter to resolve the GraphQL interaction.

Compare test/support/test_adapter.ex and lib/maple/client.ex to see an example. This will allow you to build clients based on local JSON schema files. ex. test\data\schema.json

The library can also create structs based on GraphQL types (currently commented out). The idea was to parse the result data through the struct for validation.

Contributions and issues welcome!

Also if you think this is a terrible idea, please let me know!

ToDo

  • [X] Refactor macro code
  • [X] Add proper documentation
  • [ ] Support subscriptions
  • [ ] Look into validation through structs
  • [X] Expand help with required attributes
  • [X] Expand help with attribute descriptions

License

MIT

Version

0.1.1