135 lines
3.7 KiB
Go
135 lines
3.7 KiB
Go
package generate
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import (
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"fmt"
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"strings"
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"github.com/vektah/gqlparser/ast"
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)
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type typeBuilder struct {
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strings.Builder
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schema *ast.Schema
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}
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func (builder *typeBuilder) baseTypeForOperation(operation ast.Operation) *ast.Definition {
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switch operation {
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case ast.Query:
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return builder.schema.Query
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case ast.Mutation:
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return builder.schema.Mutation
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case ast.Subscription:
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return builder.schema.Subscription
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default:
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panic(fmt.Sprintf("unexpected operation: %v", operation))
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}
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}
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func typeForOperation(name string, operation *ast.OperationDefinition, schema *ast.Schema) (string, error) {
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builder := &typeBuilder{schema: schema}
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fmt.Fprintf(builder, "type %s ", name)
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err := builder.writeTypedef(
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builder.baseTypeForOperation(operation.Operation), operation.SelectionSet)
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return builder.String(), err
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}
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func typeForInputType(typ *ast.Type, schema *ast.Schema) (string, error) {
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builder := &typeBuilder{schema: schema}
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// TODO: handle non-scalar types (by passing ...something... as the
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// SelectionSet?)
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err := builder.writeType(typ, nil)
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return builder.String(), err
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}
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func (builder *typeBuilder) writeField(field *ast.Field) error {
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var jsonName string
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if field.Alias != "" {
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jsonName = field.Alias
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} else {
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// TODO: is this case needed? tests don't seem to get here.
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jsonName = field.Name
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}
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// We need an exportable name for JSON-marshaling.
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goName := strings.Title(jsonName)
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builder.WriteString(goName)
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builder.WriteRune(' ')
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if field.Definition == nil {
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// Unclear why gqlparser hasn't already rejected this,
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// but empirically it might not.
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return fmt.Errorf("undefined field %v", field)
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}
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err := builder.writeType(field.Definition.Type, field.SelectionSet)
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if err != nil {
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return err
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}
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if jsonName != goName {
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builder.WriteString("`json:\"")
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builder.WriteString(jsonName)
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builder.WriteString("\"`")
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}
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builder.WriteRune('\n')
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return nil
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}
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var graphQLNameToGoName = map[string]string{
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"Int": "int", // TODO: technically int32 is always enough, use that?
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"Float": "float64",
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"String": "string",
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"Boolean": "bool",
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"ID": "string", // TODO: named type for IDs?
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}
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func (builder *typeBuilder) writeType(typ *ast.Type, selectionSet ast.SelectionSet) error {
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// gqlgen does slightly different things here since it defines names for
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// all the intermediate types, but its implementation may be useful to crib
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// from:
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// https://github.com/99designs/gqlgen/blob/master/plugin/modelgen/models.go#L113
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// TODO: or maybe we should do that?
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if typ.Elem != nil {
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// Type is a list.
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builder.WriteString("[]")
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typ = typ.Elem
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}
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if !typ.NonNull {
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builder.WriteString("*")
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}
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return builder.writeTypedef(builder.schema.Types[typ.Name()], selectionSet)
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}
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func (builder *typeBuilder) writeTypedef(typedef *ast.Definition, selectionSet ast.SelectionSet) error {
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switch typedef.Kind {
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case ast.Object, ast.InputObject:
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builder.WriteString("struct {\n")
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for _, selection := range selectionSet {
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switch selection := selection.(type) {
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case *ast.Field:
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builder.writeField(selection)
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case *ast.FragmentSpread, *ast.InlineFragment:
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return fmt.Errorf("not implemented: %T", selection)
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default:
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return fmt.Errorf("invalid selection type: %v", selection)
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}
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}
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builder.WriteString("}")
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return nil
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case ast.Scalar, ast.Enum:
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goName := graphQLNameToGoName[typedef.Name]
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// TODO(benkraft): Handle custom scalars and enums.
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if goName == "" {
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return fmt.Errorf("unknown scalar name: %s", typedef.Name)
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}
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builder.WriteString(goName)
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return nil
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case ast.Union, ast.Interface:
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return fmt.Errorf("not implemented: %v", typedef.Kind)
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default:
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return fmt.Errorf("unexpected kind: %v", typedef.Kind)
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}
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}
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