📝 My notes for understanding the internals of the library

[tiagonuneslx]

GraphQL Schema Object (top-level class)

• Schema (DefaultSchema)
  • Contains:
    • a SchemaConfiguration
    • a SchemaModel
    • an Executor
    • a RequestInterpreter
  • Receives a request (+ variables, context, options)
  • Parses variables JSON using VariablesJson
  • Parses GraphQL request using Parser
  • Creates an ExecutionPlan using RequestInterpreter
  • Executes the request using Executor

Building a GraphQL Schema

• SchemaBuilder
  • Used to build a SchemaDefinition (with TypeDefs)
  • Compiles SchemaDefinition using SchemaCompilation
• TypeDef
  • Contains information about a GraphQL type, including instructions on how to transform an instance into a JsonNode
• Type
  • Contains:
    • all the information about a GraphQL type
    • definition: TypeDef, which contains additional information, including instructions on how to transform an instance into a JsonNode
• SchemaCompilation
  • Contains:
    • a SchemaDefinition
  • Based on SchemaDefinition (with TypeDefs), and on the return types of the Resolvers, creates a SchemaModel (with Types).
  • Creates a Schema

Parsing a GraphQL request

• Lexer transforms input into Tokens
• Parser transforms Tokens into Nodes
  • Uses Lexer
• Variables are parsed from JSON using Jackson (VariablesJson)

Executing a GraphQL request

• RequestInterpreter
  • Prepares the request for execution
  • Creates a ExecutionPlan (list of Execution.Nodes)
• Executor
  • Converts all Execution.Nodes to JsonNodes
  • Converts JsonNodes to String