Apollo_Code_Generation [en]

Transcript

1. Apollo Code Generation
   

   View Slide

2. Introduction
   Yuya Horita
   iOS Engineer @CyberAgent, 2017/4 ~ 2019/5
   Software Engineer @M3, 2019/5 ~
   GitHub: https://github.com/horita-yuya
   Twitter: https://twitter.com/horita_yuya
   Medium: https://medium.com/@yuyaHorita
   

   View Slide

3. View Slide

4. schema.json
   *.graphql
   ʴ
   

   View Slide

5. schema.json
   File contains the results of an introspection query, or query information
   > Conventionally this file is called schema.json
   Reference: https://www.apollographql.com/docs/ios/downloading-schema/
   

   View Slide

6. *.graphql
   Query definition file
   

   View Slide

7. schema.json
   *.graphql
   ʴ
   

   View Slide

8. schema.json
   *.graphql
   Token AST IR
   →
   

   View Slide

9. Lexer
   .graphql to Tokens
   

   View Slide

10. User.graphql
    

    View Slide

11. User.graphql
    Tokens
    query
    User
    (
    $
    id
    email
    @
    include
    …
    AddressFragment
    Debug
    :
    response
    ~~~~~
    ~~~~~
    ~~~~~
    ~~~~~
    ~~~~~
    ~~~~~
    ~~~~~
    ~~~~~
    

    View Slide

12. query User
    (
    $
    @
    …
    AddressFragment
    NAME
    Kind Value
    undefined
    undefined
    undefined
    undefined
    COMMENT Debug
    Ignoring on parsing phase
    name
    : undefined
    

    View Slide

13. `#` itself is not a token kind.
    -> Other ways to comment out, like `/**/`?
    

    View Slide

14. https://github.com/graphql/graphql-js/blob/master/src/language/lexer.js#L187
    https://github.com/graphql/graphql-spec/issues/276
    Reading implementation of lexer, it seems only `#` indicates comment.
    

    View Slide

15. Parser
    Tokens to AST
    

    View Slide

16. query
    User
    AddressFragment
    NAME
    NAME
    NAME
    Operation definition
    name
    NAME
    Tokens Semantics
    Operation name
    field name
    Fragment name
    

    View Slide

17. (
    $
    @
    …
    Beginning of definition of arguments, etc.
    Variable
    Directive
    Fragment/Inline Fragment Spread
    Tokens
    : Argument, Alias, etc.
    Semantics
    

    View Slide

18. NAME Token: Semantics depends on syntax and value.
    Punctuator Token: Semantics is fixed or depends on syntax
    ( $ : @
    

    View Slide

19. View Slide

20. Document
    Hoge parsing operation
    function parseHoge is defined in graphql/language/parser.js
    =
    OperationDefinition
    OperationType Name VariableDefinitions
    VariableDefinition
    SelectionSet
    VariableDefinition
    Recursive Descent Parsing
    

    View Slide

21. Tokens
    Rules
    +
    Starts with operation definition keyword `query`. The next `User` is
    operation name. If `(` exists in just after `User`, variable definitions
    starts. It will end with `)`. Next `{` means the beginning of definition
    of SelectionSet ……
    

    View Slide

22. VariableDefinitions
    Document
    OperationDefinition FragmentDefinition
    AST
    OperationType
    VariableDefinition
    VariableDefinition
    

    View Slide

23. IR Generator
    AST to IR
    

    View Slide

24. View Slide

25. View Slide

26. View Slide

27. VariableDefinition
    Type
    Variable
    Name
    value: string
    Name
    value: string
    

    View Slide

28. Type
    Variable
    Name
    value: id
    Name
    value: Int!
    VariableDefinitions
    VariableDefinition VariableDefinition
    Type
    Variable
    Name
    value: withEmail
    Name
    value: Boolean!
    

    View Slide

29. VariableDefinitions
    VariableDefinition VariableDefinition
    + schema.json
    GraphQLType
    GraphQLType
    Type
    Variable
    Name
    value: id
    Name
    value: Int!
    Type
    Variable
    Name
    value: withEmail
    Name
    value: Boolean!
    

    View Slide

30. IR
    

    View Slide

31. IR
    CompilerContext LegacyCompilerContext
    

    View Slide

32. Summary
    1. AST from *.graphql.
    2. IR from ast and schema.json.
    3. .swift, .ts, .scala from IR
    4. It seems .kt doesn’t use apollo-tooling. All implementations
    are in apollo-android.
    

    View Slide

33. Appendix
    

    View Slide

34. Lexer
    Lexer: https://github.com/graphql/graphql-js/blob/master/src/language/lexer.js
    Token Kind: https://github.com/graphql/graphql-js/blob/master/src/language/tokenKind.js
    

    View Slide

35. Parser
    Parser: https://github.com/graphql/graphql-js/blob/master/src/language/parser.js

    AST: https://github.com/graphql/graphql-js/blob/master/src/language/ast.js
    AST Kind: https://github.com/graphql/graphql-js/blob/master/src/language/kinds.js
    

    View Slide

36. IR
    Compiler:
    https://github.com/apollographql/apollo-tooling/blob/master/packages/apollo-codegen-
    core/src/compiler/index.ts
    

    View Slide