oxc-graphql-parser

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

Features

Typed GraphQL concrete syntax tree 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::Parser;

let input = "union SearchResult = Photo | Person | Cat | Dog";
let parser = Parser::new(input);
let cst = parser.parse();

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

Parser::parse always returns a concrete syntax tree, even when lexing or parsing reports errors. Check cst.errors() before walking the document:

use oxc_graphql_parser::Parser;

let input = "union SearchResult = Photo | Person | Cat | Dog";
let parser = Parser::new(input);
let cst = parser.parse();

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

let document = cst.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::{cst, Parser};

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

let parser = Parser::new(input);
let cst = parser.parse();

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

let document = cst.document();
for definition in document.definitions() {
    if let cst::Definition::ObjectTypeDefinition(object_type) = definition {
        assert_eq!(object_type.name().unwrap().text(), "ProductDimension");

        for field in object_type.fields_definition().unwrap().field_definitions() {
            println!("{}", field.name().unwrap().text());
        }
    }
}

Get Variables Used In A Query

use oxc_graphql_parser::{cst, Parser};

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

let parser = Parser::new(input);
let cst = parser.parse();

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

let document = cst.document();
for definition in document.definitions() {
    if let cst::Definition::OperationDefinition(operation) = definition {
        assert_eq!(operation.name().unwrap().text(), "GraphQuery");

        let variables: Vec<String> = operation
            .variable_definitions()
            .iter()
            .flat_map(|definitions| definitions.variable_definitions())
            .filter_map(|definition| Some(definition.variable()?.text().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 0.0.1