Translate APIs described by OpenAPI Specifications (OAS) into GraphQL
MIT License
Translate APIs described by OpenAPI Specifications (OAS) or Swagger into GraphQL.
OpenAPI-to-GraphQL can be used in two ways:
The Command Line Interface (CLI) provides a convenient way to start a GraphQL server wrapping an API for a given OpenAPI Specification:
npm i -g openapi-to-graphql-cli
openapi-to-graphql <OAS JSON file path or remote url> [options]
For further details, refer to the openapi-to-graphql-cli
documentation.
Use OpenAPI-to-GraphQL as a library in your application to generate GraphQL schemas.
npm i -s openapi-to-graphql
createGraphQLSchema
function:
const { createGraphQLSchema } = require("openapi-to-graphql");
// load or construct OAS (const oas = ...)
const { schema, report } = await createGraphQLSchema(oas);
For further details, refer to the openapi-to-graphql
documentation.
Here are some guides to further help you get started:
link
definitions.Data-centric The GraphQL interface is created around the data definitions in the given OAS, not around the endpoints, leading to a natural use of GraphQL.
Nested data Links defined in the OAS are used to create nested data structures, allowing for (deeply) nested queries.
Automatic query resolution Automatically generated resolvers translate (nested) GraphQL queries to API requests. Request results are translated back to GraphQL responses.
Mutations
Non-safe, non-idempotent API operations (e.g., POST
, PUT
, DELETE
) are translated to GraphQL mutations. Input payload is type-checked.
Subscriptions
GraphQL subscriptions allow clients to receive a stream of events, such as updates whenever data changes on the GraphQL server. OpenAPI-to-GraphQL can create subscriptions based on callback
objects defined in the OAS.
Authentication
OpenAPI-to-GraphQL currently supports authentication via API Key and basic auth. OpenAPI-to-GraphQL wraps secured endpoints into a viewer
, which takes the API key / credentials as input.
API Sanitation
Parts of an API that not compatible with GraphQL are automatically sanitized. For example, API parameters and data definition names with unsupported characters (e.g., -
, .
, ,
, :
, ;
...) are removed. GraphQL queries are desanitized to correctly invoke the REST API and the responses are resanitized to create GraphQL-compliant results.
Custom request options Provide headers and query parameters to send with every API request. This allows, for example, to handle authentication or tag requests from GraphQL.
Swagger and OpenAPI 3 support OpenAPI-to-GraphQL can handle both Swagger (OpenAPI specification 2.0) as well as OpenAPI specification 3.
OpenAPI-to-GraphQL is written in TypeScript. Within each of OpenAPI-to-GraphQL's packages, all source code is contained in the src
folder. Use yarn build
or yarn test
to transpile the source files into the final library in the dist
folder. Entry-point for the library is index.js
in dist
.
Our research paper, "Generating GraphQL-Wrappers for REST(-like) APIs", can be found here. The paper describes the challenges of building OpenAPI-to-GraphQL and an experiment in which we evaluated OpenAPI-to-GraphQL against 959 publicly available OAS, provided by APIs.guru, and successfully created GraphQL interfaces for 89.5% of them.
To run the experiment, in the openapi-to-graphql
package, load APIs.guru specifications, found here, into the /tmp
folder:
npm run guru-load
Then, run tests:
npm run guru-test <number of APIs to test at most>
swagger-to-graphql turns a given Swagger (OpenAPI Specification 2.0) into a GraphQL interface, which resolves against the original API. GraphQL schema is based on endpoints, not on data definitions. No links are considered.
json-to-graphql turns given JSON objects / arrays into a GraphQL schema. resolve
functions need to be provided by the user.
StackOverflow discussion points to the above projects.