GraphQL.Parser

An Elixir binding for libgraphqlparser implemented as a NIF for parsing GraphQL.

Introduction

GraphQL is a query language designed to build client applications by providing an intuitive and flexible syntax and system for describing their data requirements and interactions.

This library is an Elixir interface for the query language parser and not a full implementation of GraphQL. It takes a query string as input and outputs the AST in a format suitable for performing pattern matching. Use this library directly only if you want to write your own implementation of GraphQL or you want to work with AST for something else. For the full Elixir implementation, checkout graphql-elixir. Head here if you are looking out for the full GraphQL specification.

Requirements

A C++ compiler that supports C++11, cmake, and make, for building and installing libgraphqlparser. It also requires Mac OS X or Linux.

Installation

To get started quickly, add GraphQL.Parser to your deps in mix.exs:

defp deps do
  [{:graphql_parser, "~> 0.0.3"}]
end

then, update your deps:

$ mix deps.get

Installing libgraphqlparser

You need to install libgraphqlparser before attemting to compile & run this library. If you're on a mac, you could do brew install libgraphqlparser.

But I'd recommend building and installing from source, because the library is constantly updated with critical bug fixes. It's in pretty early stages, so this is the most recommended approach. To install from source :

$ cd libgraphqlparser/
$ cmake .
$ make
$ make install

Once libgraphqlparser is successfully installed, do a mix compile to compile the NIF and you're good to go!

Examples

iex> GraphQL.Parser.parse "{ hello }"
{:ok,
 %{definitions: [%{directives: nil, kind: "OperationDefinition",
      loc: %{end: 10, start: 1}, name: nil, operation: "query",
      selectionSet: %{kind: "SelectionSet", loc: %{end: 10, start: 1},
        selections: [%{alias: nil, arguments: nil, directives: nil,
           kind: "Field", loc: %{end: 8, start: 3},
           name: %{kind: "Name", loc: %{end: 8, start: 3}, value: "hello"},
           selectionSet: nil}]}, variableDefinitions: nil}], kind: "Document",
   loc: %{end: 10, start: 1}}}

iex> GraphQL.Parser.parse! "{ hello }"
%{definitions: [%{directives: nil, kind: "OperationDefinition",
     loc: %{end: 10, start: 1}, name: nil, operation: "query",
     selectionSet: %{kind: "SelectionSet", loc: %{end: 10, start: 1},
       selections: [%{alias: nil, arguments: nil, directives: nil,
          kind: "Field", loc: %{end: 8, start: 3},
          name: %{kind: "Name", loc: %{end: 8, start: 3}, value: "hello"},
          selectionSet: nil}]}, variableDefinitions: nil}], kind: "Document",
  loc: %{end: 10, start: 1}}

iex> GraphQL.Parser.parse! " hello }"
** (GraphQL.Parser.SyntaxError) 1.2-6: syntax error, unexpected IDENTIFIER, expecting fragment or mutation or query or { on line
    lib/graphql/parser.ex:20: GraphQL.Parser.parse!/1

License

Copyright (c) 2015 Vignesh Rajagopalan

MIT License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.