oxc-graphql-parser

A spec-compliant, error-resilient GraphQL lexer and parser for Rust.

Features

Typed GraphQL AST based on the October 2021 specification
Error-resilient lexing and parsing
GraphQL schema and query parsing
Standalone lexer API

Installation

cargo add oxc-graphql-parser

Or add it manually:

[dependencies]
oxc-graphql-parser = "0.0.1"

The Cargo package name uses hyphens. Import it from Rust as oxc_graphql_parser.

Usage

use oxc_graphql_parser::{Allocator, Parser};

let input = "union SearchResult = Photo | Person | Cat | Dog";
let allocator = Allocator::default();
let parser = Parser::new(&allocator, input);
let ast = parser.parse();

assert_eq!(0, ast.errors().len());

Parser::parse always returns an AST, even when lexing or parsing reports errors. Check ast.errors() before walking the document:

use oxc_graphql_parser::{Allocator, Parser};

let input = "union SearchResult = Photo | Person | Cat | Dog";
let allocator = Allocator::default();
let parser = Parser::new(&allocator, input);
let ast = parser.parse();

assert_eq!(0, ast.errors().len());

let document = ast.document();
for definition in &document.definitions {
    println!("{definition:?}");
}

Examples

The examples directory contains integrations for diagnostics and analysis:

Get Field Names In An Object

use oxc_graphql_parser::{Allocator, ast, Parser};

let input = "
type ProductDimension {
  size: String
  weight: Float @tag(name: \"hi from inventory value type field\")
}
";

let allocator = Allocator::default();
let parser = Parser::new(&allocator, input);
let ast = parser.parse();

assert_eq!(0, ast.errors().len());

let document = ast.document();
for definition in &document.definitions {
    if let ast::Definition::ObjectType(object_type) = definition {
        assert_eq!(object_type.name.as_str(), "ProductDimension");

        for field in &object_type.fields {
            println!("{}", field.name);
        }
    }
}

Get Variables Used In A Query

use oxc_graphql_parser::{Allocator, ast, Parser};

let input = "
query GraphQuery($graph_id: ID!, $variant: String) {
  service(id: $graph_id) {
    schema(tag: $variant) {
      document
    }
  }
}
";

let allocator = Allocator::default();
let parser = Parser::new(&allocator, input);
let ast = parser.parse();

assert_eq!(0, ast.errors().len());

let document = ast.document();
for definition in &document.definitions {
    if let ast::Definition::Operation(operation) = definition {
        assert_eq!(operation.name.as_ref().unwrap().as_str(), "GraphQuery");

        let variables: Vec<String> = operation
            .variable_definitions
            .iter()
            .map(|definition| definition.variable.name.to_string())
            .collect();

        assert_eq!(
            variables.as_slice(),
            ["graph_id".to_string(), "variant".to_string()]
        );
    }
}

Rust Versions

oxc-graphql-parser is tested on the latest stable version of Rust. Older versions may or may not be compatible.

License

Licensed under either of:

Apache License, Version 2.0 (LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0)
MIT license (LICENSE-MIT or https://opensource.org/licenses/MIT)

at your option.

oxc-graphql-parser 0.0.4