GraphQL - A query language for your API

GraphQL is a new style of protocol open-sourced by Facebook, and it is getting popular, especially in Mobile and Single Page Application as the front end. GraphQL provides a complete and understandable description of the data in your API, gives clients the power to ask for exactly what they need and nothing more, makes it easier to evolve APIs over time, and enables powerful developer tools.

Light-graphql-4j is a framework that is designed to work with GraphQL. Similar to other Light frameworks, it provides components and middleware handlers to handle specific use cases for GraphQL.

GraphQL Specific Components

  • graphql-common contains common utilities and static variables that are shared by other components.
  • graphql-router is responsible for handling GraphQL and GraphiQL requests and hooks schema provider.

GraphQL Specific Middleware Handlers

  • graphql-security verifies JWT token in the request header and verifies scopes if it is enabled.
  • graphql-validator validates the path and methods of the request. The GraphQL component handles additional schema validation.

Graphql Router

The Graphql Router is responsible for handling GraphQL and GraphiQL requests while hooking schema providers. It provides RouteHandler and SchemaProvider interfaces and implements both GET and POST handlers for GraphQL. The router is a HandlerProvider that needs to be put into the service.yml config file. This link is an example. The user developed schema needs to be hooked to the GraphqlPostHandler in this module through SchemaProvider interface. The service.yml config file should include the implementation of the com. Read More »

Graphql Security

Graphql Security verifies the JWT token in the request header and verifies scopes if it is enabled. It is very similar to swagger-security / openapi-security but as there is no Swagger specification we cannot verify scopes against the specification. GraphQL recommends authorization outside of schema so that we can only verify query scope and mutation scope for read and write access. This is the handler that should be put before graphql-validator. Read More »

Graphql Common

This module contains common utilities, controls the configuration for GraphQL service and shares some static variables with other modules to make the dependencies much simpler. The significant part of this module is GraphqlConfig, which defines the path for the /graphql endpoint and if GraphiQL is enabled or not. Another part of this module is a utility class that is shared within all graphql modules. Here is an example of graphql.yml Read More »

Graphql Validator

Graphql Validator validates the path and methods of the request. Other schema validation will be handled by the GraphQL component. Basic request validation for the graphql path and methods is done by this middleware handler. It is the first line of validation right after graphql-security and it doesn’t have any knowledge about the graphql query parameter and body. Other schema based validation will be done at GraphQL level. From release 1. Read More »