add an option to allow to generate only models

cmd/gojsonschema/main.go

@@ -20,6 +20,7 @@ const (
 var (
 	verbose             bool
 	extraImports        bool
+	onlyModels          bool
 	defaultPackage      string
 	defaultOutput       string
 	schemaPackages      []string
@@ -73,6 +74,7 @@ var (
 				YAMLExtensions:      yamlExtensions,
 				StructNameFromTitle: structNameFromTitle,
 				Tags:                tags,
+				OnlyModels:          onlyModels,
 			}
 			for _, id := range allKeys(schemaPackageMap, schemaOutputMap, schemaRootTypeMap) {
 				mapping := generator.SchemaMapping{SchemaID: id}
@@ -136,6 +138,8 @@ func main() {
 		"Verbose output")
 	rootCmd.PersistentFlags().BoolVarP(&extraImports, "extra-imports", "e", false,
 		"Allow extra imports (non standard library)")
+	rootCmd.PersistentFlags().BoolVar(&onlyModels, "only-models", false,
+		"Generate only models (no unmarshal methods, no validation)")
 	rootCmd.PersistentFlags().StringVarP(&defaultPackage, "package", "p", "",
 		`Default name of package to declare Go files under, unless overridden with
 --schema-package`)

pkg/generator/generate.go

@@ -24,6 +24,7 @@ type Config struct {
 	StructNameFromTitle bool
 	Warner              func(string)
 	Tags                []string
+	OnlyModels          bool
 }
 
 type SchemaMapping struct {
@@ -545,6 +546,10 @@ func (g *schemaGenerator) generateDeclaredType(
 
 	g.output.file.Package.AddDecl(&decl)
 
+	if g.config.OnlyModels {
+		return &codegen.NamedType{Decl: &decl}, nil
+	}
+
 	if structType, ok := theType.(*codegen.StructType); ok {
 		var validators []validator
 		for _, f := range structType.RequiredJSONFields {
@@ -1064,57 +1069,58 @@ func (g *schemaGenerator) generateEnumType(
 	g.output.declsByName[enumDecl.Name] = &enumDecl
 	g.output.declsBySchema[t] = &enumDecl
 
-	valueConstant := &codegen.Var{
-		Name:  "enumValues_" + enumDecl.Name,
-		Value: t.Enum,
-	}
-	g.output.file.Package.AddDecl(valueConstant)
+	if !g.config.OnlyModels {
+		valueConstant := &codegen.Var{
+			Name:  "enumValues_" + enumDecl.Name,
+			Value: t.Enum,
+		}
+		g.output.file.Package.AddDecl(valueConstant)
 
-	if wrapInStruct {
+		if wrapInStruct {
+			g.output.file.Package.AddImport("encoding/json", "")
+			g.output.file.Package.AddDecl(&codegen.Method{
+				Impl: func(out *codegen.Emitter) {
+					out.Comment("MarshalJSON implements json.Marshaler.")
+					out.Printlnf("func (j *%s) MarshalJSON() ([]byte, error) {", enumDecl.Name)
+					out.Indent(1)
+					out.Printlnf("return json.Marshal(j.Value)")
+					out.Indent(-1)
+					out.Printlnf("}")
+				},
+			})
+		}
+
+		g.output.file.Package.AddImport("fmt", "")
+		g.output.file.Package.AddImport("reflect", "")
 		g.output.file.Package.AddImport("encoding/json", "")
 		g.output.file.Package.AddDecl(&codegen.Method{
 			Impl: func(out *codegen.Emitter) {
-				out.Comment("MarshalJSON implements json.Marshaler.")
-				out.Printlnf("func (j *%s) MarshalJSON() ([]byte, error) {", enumDecl.Name)
+				out.Comment("UnmarshalJSON implements json.Unmarshaler.")
+				out.Printlnf("func (j *%s) UnmarshalJSON(b []byte) error {", enumDecl.Name)
 				out.Indent(1)
-				out.Printlnf("return json.Marshal(j.Value)")
+				out.Printf("var v ")
+				enumType.Generate(out)
+				out.Newline()
+				varName := "v"
+				if wrapInStruct {
+					varName += ".Value"
+				}
+				out.Printlnf("if err := json.Unmarshal(b, &%s); err != nil { return err }", varName)
+				out.Printlnf("var ok bool")
+				out.Printlnf("for _, expected := range %s {", valueConstant.Name)
+				out.Printlnf("if reflect.DeepEqual(%s, expected) { ok = true; break }", varName)
+				out.Printlnf("}")
+				out.Printlnf("if !ok {")
+				out.Printlnf(`return fmt.Errorf("invalid value (expected one of %%#v): %%#v", %s, %s)`,
+					valueConstant.Name, varName)
+				out.Printlnf("}")
+				out.Printlnf(`*j = %s(v)`, enumDecl.Name)
+				out.Printlnf(`return nil`)
 				out.Indent(-1)
 				out.Printlnf("}")
 			},
 		})
 	}
-
-	g.output.file.Package.AddImport("fmt", "")
-	g.output.file.Package.AddImport("reflect", "")
-	g.output.file.Package.AddImport("encoding/json", "")
-	g.output.file.Package.AddDecl(&codegen.Method{
-		Impl: func(out *codegen.Emitter) {
-			out.Comment("UnmarshalJSON implements json.Unmarshaler.")
-			out.Printlnf("func (j *%s) UnmarshalJSON(b []byte) error {", enumDecl.Name)
-			out.Indent(1)
-			out.Printf("var v ")
-			enumType.Generate(out)
-			out.Newline()
-			varName := "v"
-			if wrapInStruct {
-				varName += ".Value"
-			}
-			out.Printlnf("if err := json.Unmarshal(b, &%s); err != nil { return err }", varName)
-			out.Printlnf("var ok bool")
-			out.Printlnf("for _, expected := range %s {", valueConstant.Name)
-			out.Printlnf("if reflect.DeepEqual(%s, expected) { ok = true; break }", varName)
-			out.Printlnf("}")
-			out.Printlnf("if !ok {")
-			out.Printlnf(`return fmt.Errorf("invalid value (expected one of %%#v): %%#v", %s, %s)`,
-				valueConstant.Name, varName)
-			out.Printlnf("}")
-			out.Printlnf(`*j = %s(v)`, enumDecl.Name)
-			out.Printlnf(`return nil`)
-			out.Indent(-1)
-			out.Printlnf("}")
-		},
-	})
-
 	// TODO: May be aliased string type.
 	if prim, ok := enumType.(codegen.PrimitiveType); ok && prim.Type == "string" {
 		for _, v := range t.Enum {

tests/data/onlyModels/onlyModel.json

@@ -0,0 +1,29 @@
+{
+  "$schema": "http://json-schema.org/draft-04/schema#",
+  "id": "https://example.com/primitives",
+  "type": "object",
+  "properties": {
+    "myString": {
+      "type": "string"
+    },
+    "myNumber": {
+      "type": "number"
+    },
+    "myInteger": {
+      "type": "integer"
+    },
+    "myBoolean": {
+      "type": "boolean"
+    },
+    "myNull": {
+      "type": "null"
+    },
+    "myEnum": {
+      "type": "string",
+      "enum": [
+        "x",
+        "y"
+      ]
+    }
+  }
+}

tests/integration_test.go

@@ -172,6 +172,15 @@ func TestRegressions(t *testing.T) {
 	testExamples(t, basicConfig, "./data/regressions")
 }
 
+func TestOnlyModels(t *testing.T) {
+	t.Parallel()
+
+	cfg := basicConfig
+	cfg.OnlyModels = true
+
+	testExamples(t, cfg, "./data/onlyModels")
+}
+
 func testExampleFile(t *testing.T, cfg generator.Config, fileName string) {
 	t.Helper()