GraphQLSchema

public protocol GraphQLSchema

GraphQL Schema

A GraphQL Schema describes the entire API that is available. It’s basically only a name space for your Query and Mutation Types.

Your Query and Mutation Types have to be Root Types with the same Viewer Context.

  • A Query Type is mandatory.
  • A Mutation Type is optional.

Examples

If you only want to offer a Query Type, you only need to implement that class:

enum MySchema {

   class Query: QueryType {
       func greeting(name: String = "World") -> String {
           return "Hello, \(name)!"
       }

       init(viewerContext: ()) { ... }
   }

}

that gets translated to the following schema:

type Query {
   greeting(name: String! = "World"): String!
}

Alternatively you can also specify a Mutation Type:

enum MySchema {
   class Query: QueryType {
       func greeting(name: String = "World") -> String {
           return "Hello, \(name)!"
       }

       init(viewerContext: ()) { ... }
   }

   class Mutation: MutationType {
       func store(status: String) -> String { ... }

       init(viewerContext: ()) { ... }
   }
}

Which would generate this Schema:

type Query {
   greeting(name: String! = "World"): String!
}

type Mutation {
   store(status: String!): String!
}

If your types need to have a context for the current user, they need to use the exact same ViewerContext:

enum MySchema {
   typealias ViewerContext = User

   class Query: QueryType {
       let user: User

       var greeting: String {
           return "Hello, \(user.name)!"
       }

       init(viewerContext: User) { ... }
   }

   class Mutation: MutationType {
       let user: User

       func store(status: String) -> String { ... }

       init(viewerContext: User) { ... }
   }
}

  • Type of the Response of the Schema

    Declaration

    Swift

    typealias Result = GraphQLResult

  • Type of an Empty Mutation Type. Signals GraphZahl that no mutations are allowed

    Declaration

    Swift

    typealias None = EmptyRootType<ViewerContext>

  • Type that tells the Query/Mutation type everything about the User. This defaults to Void, to signal that all requests are treated the same, and this API does not compute anything different on a by user basis.

    Declaration

    Swift

    associatedtype ViewerContext = Void where Self.ViewerContext == Self.Mutation.ViewerContext

  • Type of the Query for this Schema. Should conform to QueryType. And should have the same Viewer Context as the Schema

    Declaration

    Swift

    associatedtype Query : MandatoryRootType

  • Type of the Mutation for this Schema. Should conform to MutationType. And should have the same Viewer Context as the Schema. Defaults to None signalling GraphZahl that no mutations are allowed.

    Declaration

    Swift

    associatedtype Mutation : GraphQLRootType = Self.None where Self.Mutation.ViewerContext == Self.Query.ViewerContext
  • prepare(viewerContext:) Extension method

    Undocumented

    Declaration

    Swift

    public static func prepare(viewerContext: ViewerContext? = nil) throws

  • Performs a GraphQL Request

    Declaration

    Swift

    public static func perform(request: String,
                           viewerContext: ViewerContext,
                           variableValues: [String : Map] = [:],
                           eventLoopGroup: EventLoopGroup? = nil) throws -> Future<GraphQLResult>

    Parameters

    request

    Query Text
    viewerContext

    Viewer Context

    Return Value

    A future with the result with data and errors for the query

  • viewerContext Extension method

    Undocumented

    Declaration

    Swift

    public static var viewerContext: Context.Key<ViewerContext> { get }

Available where ViewerContext == Void

  • Performs a GraphQL Request

    Declaration

    Swift

    public static func perform(request: String,
                           variableValues: [String : Map] = [:],
                           eventLoopGroup: EventLoopGroup? = nil) throws -> Future<GraphQLResult>

    Parameters

    request

    Query Text

    Return Value

    A future with the result with data and errors for the query