feat(graphql): support directives

command.go

@@ -203,6 +203,15 @@ func (m *plugin) GenerateCode(data *codegen.Data) error {
 			"gmethod": func(from, to string) string {
 				return m.types.resolver[from][to][2]
 			},
+			"gdpkg": func(name string) string {
+				return m.types.directives["@"+name][0]
+			},
+			"gdtyp": func(name string) string {
+				return m.types.directives["@"+name][1]
+			},
+			"gdmethod": func(name string) string {
+				return m.types.directives["@"+name][2]
+			},
 		},
 		PackageDoc: "//+build !graphql\n",
 		Template: `
@@ -231,6 +240,9 @@ type {{$root.TypeName}} struct {
 			{{lcFirst $root.TypeName}}{{$object.Name}} *{{lcFirst $root.TypeName}}{{$object.Name}}
 		{{- end }}
 	{{- end }}
+	{{ range $directive := .AllDirectives }}
+		{{$directive.Name}}Resolver *{{lookupImport (gdpkg $directive.Name)}}.{{gdtyp $directive.Name}}
+	{{- end }}
 }
 
 func (r *{{$root.TypeName}}) Inject (
@@ -239,12 +251,26 @@ func (r *{{$root.TypeName}}) Inject (
 			{{lcFirst $root.TypeName}}{{$object.Name}} *{{lcFirst $root.TypeName}}{{$object.Name}},
 		{{- end }}
 	{{- end }}
+	{{ range $directive := .AllDirectives }}
+		{{$directive.Name}}Resolver *{{lookupImport (gdpkg $directive.Name)}}.{{gdtyp $directive.Name}},
+	{{- end }}
 ) {
 	{{- range $object := .Objects }}
 		{{- if $object.HasResolvers }}
 			r.{{lcFirst $root.TypeName}}{{$object.Name}} = {{lcFirst $root.TypeName}}{{$object.Name}}
 		{{- end }}
 	{{- end }}
+	{{ range $directive := .AllDirectives }}
+		r.{{$directive.Name}}Resolver = {{$directive.Name}}Resolver
+	{{- end }}
+}
+
+func (r *{{$root.TypeName}}) directives() DirectiveRoot {
+	return DirectiveRoot{
+		{{ range $directive := .AllDirectives -}}
+			{{ucFirst $directive.Name}}: r.{{$directive.Name}}Resolver.{{gdmethod $directive.Name}},
+		{{end}}
+	}
 }
 
 {{ range $object := .Objects -}}

example/graphql/schema/flamingo.me_graphql_example_user_interfaces_graphql-Service.graphql

@@ -4,7 +4,9 @@ type User {
     attributes: User_Attributes!
 }
 
-type User_Attributes {
+directive @userAttributeFilter(prefix: String!) on OBJECT
+
+type User_Attributes @userAttributeFilter(prefix: "secret") {
     keys: [String!]!
     get(key: String!): String!
 }

example/user/infrastructure/user.go

@@ -15,7 +15,8 @@ func (us *UserServiceImpl) UserByID(_ context.Context, id string) (*domain.User,
 		Name:      "User " + id,
 		Nicknames: []string{"nick", id},
 		Attributes: map[string]interface{}{
-			"movie": "starwars",
+			"movie":        "starwars",
+			"secret_crush": "r2d2",
 		},
 	}, nil
 }

example/user/interfaces/graphql/resolver.go

@@ -2,8 +2,11 @@ package graphql
 
 import (
 	"context"
+	"fmt"
+	"strings"
 
 	"flamingo.me/graphql/example/user/domain"
+	"github.com/99designs/gqlgen/graphql"
 )
 
 // UserQueryResolver resolver for the user service
@@ -21,3 +24,21 @@ func (r *UserQueryResolver) Inject(userService domain.UserService) *UserQueryRes
 func (r *UserQueryResolver) User(ctx context.Context, id string) (*domain.User, error) {
 	return r.userService.UserByID(ctx, id)
 }
+
+// UserAttributeFilter directive
+func (r *UserQueryResolver) UserAttributeFilter(ctx context.Context, obj interface{}, next graphql.Resolver, prefix string) (res interface{}, err error) {
+	rawAttributes, err := next(ctx)
+	if err != nil {
+		return nil, err
+	}
+	attributes, ok := rawAttributes.(domain.Attributes)
+	if !ok {
+		return nil, fmt.Errorf("no attributes returned")
+	}
+	for k := range attributes {
+		if strings.HasPrefix(k, prefix) {
+			delete(attributes, k)
+		}
+	}
+	return attributes, nil
+}

example/user/interfaces/graphql/schema.graphql

@@ -4,7 +4,9 @@ type User {
     attributes: User_Attributes!
 }
 
-type User_Attributes {
+directive @userAttributeFilter(prefix: String!) on OBJECT
+
+type User_Attributes @userAttributeFilter(prefix: "secret") {
     keys: [String!]!
     get(key: String!): String!
 }

example/user/interfaces/graphql/service.go

@@ -2,6 +2,7 @@ package graphql
 
 import (
 	// embed schema.grapqhl
+
 	_ "embed"
 
 	"flamingo.me/graphql"
@@ -24,4 +25,6 @@ func (*Service) Types(types *graphql.Types) {
 	types.Map("User", domain.User{})
 	types.Map("User_Attributes", domain.Attributes{})
 	types.Resolve("Query", "User", UserQueryResolver{}, "User")
+
+	types.Directive("@userAttributeFilter", UserQueryResolver{}, "UserAttributeFilter")
 }

helper.go

@@ -7,9 +7,10 @@ import (
 
 // Types represent information on Object->Go type mappings and resolvers
 type Types struct {
-	names    map[string]string
-	resolver map[string]map[string][3]string
-	fields   map[string]map[string]string
+	names      map[string]string
+	resolver   map[string]map[string][3]string
+	fields     map[string]map[string]string
+	directives map[string][3]string
 }
 
 // Map references a graphql type to a go type
@@ -53,6 +54,18 @@ func (tc *Types) GoField(graphqlType, graphqlField, goField string) {
 	tc.fields[graphqlType][graphqlField] = goField
 }
 
+// Directive specifies a directive resolver for a graphql directive
+func (tc *Types) Directive(graphqlDirective string, typ interface{}, method string) {
+	if tc.directives == nil {
+		tc.directives = make(map[string][3]string)
+	}
+	t := reflect.TypeOf(typ)
+	for t.Kind() == reflect.Ptr {
+		t = t.Elem()
+	}
+	tc.directives[graphqlDirective] = [3]string{t.PkgPath(), t.Name(), method}
+}
+
 // FlamingoQueryResolver always resolves to the string "flamingo" for the default schemas.
 type FlamingoQueryResolver struct{}
 

templates/module.go.tpl

@@ -21,7 +21,7 @@ type Module struct{}
 // Configure sets the graphql.ExecutableSchema binding via a provider, passing in the correct root resolver
 func (*Module) Configure(injector *dingo.Injector) {
 	injector.Bind(new(graphql.ExecutableSchema)).ToProvider(func(root *rootResolver) graphql.ExecutableSchema {
-		return NewExecutableSchema(Config{Resolvers: root})
+		return NewExecutableSchema(Config{Resolvers: root, Directives: root.directives()})
 	})
 
 	injector.BindMulti(new(cobra.Command)).ToProvider(func(root *rootResolver) *cobra.Command {