GraphQL SDL tips

benken_parasoft

The SOAtest GraphQL Client has a Form GraphQL view that can be constrained to the fields defined in a GraphQL Schema Definition Language (SDL) document. This simplifies building queries, where the Form GraphQL view is populated with controls to select and configure the available fields, arguments, etc.

A GraphQL SDL may be available in the documentation or source repository of the GraphQL endpoint. Some public examples:
https://raw.githubusercontent.com/graphql/swapi-graphql/master/schema.graphql
https://docs.github.com/public/schema.docs.graphql

What if you do not have access to the GraphQL SDL document? What if it is difficult to obtain? If the GraphQL endpoint has introspection enabled then you can generate a GraphQL SDL document from an introspection result.

First, create a GraphQL Client. On the Resource tab, provide the URL of the GraphQL endpoint. On the Payload tab, configure a GraphQL introspection query:

query IntrospectionQuery {
  __schema {
    queryType {
      name
    }
    mutationType {
      name
    }
    subscriptionType {
      name
    }
    types {
      ...FullType
    }
    directives {
      name
      description
      locations
      args {
        ...InputValue
      }
    }
  }
}

fragment FullType on __Type {
  kind
  name
  description
  fields {
    name
    description
    args {
      ...InputValue
    }
    type {
      ...TypeRef
    }
  }
  inputFields {
    ...InputValue
  }
  interfaces {
    ...TypeRef
  }
  enumValues {
    name
    description
  }
  possibleTypes {
    ...TypeRef
  }
}

fragment InputValue on __InputValue {
  name
  description
  type {
    ...TypeRef
  }
  defaultValue
}

fragment TypeRef on __Type {
  kind
  name
  ofType {
    kind
    name
    ofType {
      kind
      name
      ofType {
        kind
        name
        ofType {
          kind
          name
          ofType {
            kind
            name
            ofType {
              kind
              name
              ofType {
                kind
                name
              }
            }
          }
        }
      }
    }
  }
}

Next, chain an Extension Tool to the GraphQL Client's "Response Traffic" output. Use a script to convert the introspection result:

import com.fasterxml.jackson.core.type.*
import com.fasterxml.jackson.databind.*
import graphql.introspection.*
import graphql.schema.idl.*

String convertToSDL(def resultJson, def context) {
    def mapper = new ObjectMapper()
    def typeRef = new TypeReference<HashMap<String,Object>>() {}
    def introspectionResult = mapper.readValue(resultJson, typeRef).get("data")
    IntrospectionResultToSchema introspectionResultToSchema = new IntrospectionResultToSchema()
    def schemaIDL = introspectionResultToSchema.createSchemaDefinition(introspectionResult)
    def schemaPrinter = new SchemaPrinter()
    def sdlString = schemaPrinter.print(schemaIDL)
    return sdlString
}

Lastly, chain a Write File tool to the Extension Tool's "Return Value" output. In the "Target name" field, type a file name for your GraphQL SDL document (MySDL.graphqls). In the "Target directory" field, type "." to save the file in the same directory as your SOAtest project.

Now, you have a GraphQL SDL document which you can use to build your queries in the Form GraphQL view.

benken_parasoft

GraphQL SDL can also be used for service virtualization.

See GraphQL SDL tips on the Virtualize forum for detail.