Provides GraphQL support over Publisher REST API [Do not merge]

[wasuradananjith]

Purpose

We can create a GraphQL API by simply using our Publisher REST API, but we cannot do it since we need to have GRAPHQL as a type in our publisher definition. After that change is done we can proceed and create a GraphQL API.
A GraphQL API mainly defined based on a schema file which consists of all the required definitions of queries and mutations which can be used to invoke the particular GraphQL API. So there is a need to handle this schema file through Publisher REST API.

Goals

• Provides functionality to create a GraphQL API through Publisher REST API
• Provides the functionality to add a GraphQL schema for a particular API using our Publisher REST API
• Provides the functionality to retrieve a GraphQL schema of a particular API using our Publisher REST API

Approach

GraphQL is developed by Facebook which is an alternative to REST. It is a query language for APIs where a particular user can specify exactly what data is needed from an API. We know that we can use a Swagger Definition (Open API Specification) to design a REST API. But in GraphQL, we can use Schema Definition Language (SDL) to write the Schema for a GraphQL API. Invoking a GraphQL API simply means fetching data using GraphQL queries and writing data using GraphQL mutations.

We can simply create and publish a GraphQL API using the Publisher REST API which we have in WSO2 API Manager. You just need to change the type of the API as GRAPHQL instead of HTTP/WS/SOAPTOREST and change the apiDefinition as follows (following is the required defintion for a GraphQL API).

"{"swagger": "2.0","info": {"title": "","version": ""},"paths": {"/": {"get": {"responses": {"200": {"description": ""}},"parameters": [{"name": "query","in": "query","required": true,"type": "string","description": " Query to be passed to the GraphQL API"}],"produces": ["application/json"],"consumes": ["application/json"],"summary": "GET method to be used in GraphQL API"},"post": {"parameters": [{"name": "Payload","description": "Query or Mutation to be passed to the GraphQL API","required": false,"in": "body","schema": {"type": "object","properties": {"payload": {"type": "string"}}}}],"responses": {"200": {"description": ""}},"summary": "POST method to be used in GraphQL API","produces": ["application/json"],"consumes": ["application/json"]}}}}"


In we have given support from WSO2 APIM in order to create and publish a GraphQL API in order to invoke it over https/http.
Please refer the mail thread subjected as "[Architecture] GraphQL support for WSO2 APIM" and the Git issue in wso2/product-apim#3184 for more information.

User stories

• Using Publisher APIs in WSO2 someone can
  • Create a GraphQL API
  • Upload a Schema definition for an existing GraphQL API
  • Retrieve a Schema definition of an existing GraphQL API

Documentation

Documentation changes are required.

Automation tests

• Unit tests
  Added few tests in
  • components/apimgt/org.wso2.carbon.apimgt.impl/src/test/java/org/wso2/carbon/apimgt/impl/AbstractAPIManagerTestCase.java
  • components/apimgt/org.wso2.carbon.apimgt.impl/src/test/java/org/wso2/carbon/apimgt/impl/UserAwareAPIProviderTest.java

Test environment

• jdk1.8.0_144
• Ubuntu 16.04 LTS

[bhathiya]

Why shouldn't we merge this? What's pending?

[harsha89]

Closing this as it's not needed now.