implement new field: x-go-type-import (#633)

* implement new field: x-go-type-import

* implement getting of request bodies imports

* implement getting of responses imports

* refactoring: rename GetImportsFromSchema to GetImports

* refactoring: add error wrapping

* update README

* fix: generate import only if define x-go-type and x-go-type-import

* fix: bug of import generation

* fix: remove useless checking

* docs: add description for 'name' field

* test: add tests for x-go-type-import into codegen_test

* docs: fix README.md

* refactor: fix error msg

* refactor: use existing importMap type

* refactor: fix error msg

Co-authored-by: Vladimir Stepanov <v.stepanov@redmadrobot.com>

README.md

@@ -574,7 +574,59 @@ which help you to use the various OpenAPI 3 Authentication mechanism.
   ```
   Name string `json:"name" tag1:"value1" tag2:"value2"`
   ```
-
+- `x-go-type-import`: adds extra Go imports to your generated code. It can help you, when you want to
+   choose your own import package for `x-go-type`.
+
+  ```yaml
+    schemas:
+      Pet:
+        properties:
+          age:
+            x-go-type: myuuid.UUID
+            x-go-type-import:
+              name: myuuid
+              path: github.com/google/uuid
+  ```
+  After code generation you will get this:
+  ```go
+    import (
+        ...
+        myuuid "github.com/google/uuid"
+    )
+
+  //Pet defines model for Pet.
+    type Pet struct {
+        Age *myuuid.UUID `json:"age,omitempty"`
+    }
+
+  ```
+  `name` is an optional parameter. Example:
+
+  ```yaml
+  components:
+  schemas:
+    Pet:
+      properties:
+        age:
+          x-go-type: uuid.UUID
+          x-go-type-import:
+            path: github.com/google/uuid
+      required:
+        - age
+  ```
+
+  After code generation you will get this result:
+
+  ```go
+  import (
+	  "github.com/google/uuid"
+  )
+
+  // Pet defines model for Pet.
+  type Pet struct {
+	  Age uuid.UUID `json:"age"`
+  }
+  ```
 
 
 ## Using `oapi-codegen`

pkg/codegen/codegen.go

@@ -139,6 +139,7 @@ func Generate(spec *openapi3.T, opts Configuration) (string, error) {
 	}
 
 	var typeDefinitions, constantDefinitions string
+	var xGoTypeImports map[string]goImport
 	if opts.Generate.Models {
 		typeDefinitions, err = GenerateTypeDefinitions(t, spec, ops, opts.OutputOptions.ExcludeSchemas)
 		if err != nil {
@@ -150,6 +151,10 @@ func Generate(spec *openapi3.T, opts Configuration) (string, error) {
 			return "", fmt.Errorf("error generating constants: %w", err)
 		}
 
+		xGoTypeImports, err = GetTypeDefinitionsImports(spec, opts.OutputOptions.ExcludeSchemas)
+		if err != nil {
+			return "", fmt.Errorf("error getting type definition imports: %w", err)
+		}
 	}
 
 	var echoServerOut string
@@ -228,7 +233,7 @@ func Generate(spec *openapi3.T, opts Configuration) (string, error) {
 	var buf bytes.Buffer
 	w := bufio.NewWriter(&buf)
 
-	externalImports := importMapping.GoImports()
+	externalImports := append(importMapping.GoImports(), importMap(xGoTypeImports).GoImports()...)
 	importsOut, err := GenerateImports(t, externalImports, opts.PackageName)
 	if err != nil {
 		return "", fmt.Errorf("error generating imports: %w", err)
@@ -787,3 +792,97 @@ func LoadTemplates(src embed.FS, t *template.Template) error {
 		return nil
 	})
 }
+
+func GetTypeDefinitionsImports(swagger *openapi3.T, excludeSchemas []string) (map[string]goImport, error) {
+	res := map[string]goImport{}
+	schemaImports, err := GetSchemaImports(swagger.Components.Schemas, excludeSchemas)
+	if err != nil {
+		return nil, err
+	}
+
+	reqBodiesImports, err := GetRequestBodiesImports(swagger.Components.RequestBodies)
+	if err != nil {
+		return nil, err
+	}
+
+	responsesImports, err := GetResponsesImports(swagger.Components.Responses)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, imprts := range []map[string]goImport{schemaImports, reqBodiesImports, responsesImports} {
+		for k, v := range imprts {
+			res[k] = v
+		}
+	}
+	return res, nil
+}
+
+func GetSchemaImports(schemas map[string]*openapi3.SchemaRef, excludeSchemas []string) (map[string]goImport, error) {
+	var err error
+	res := map[string]goImport{}
+	excludeSchemasMap := make(map[string]bool)
+	for _, schema := range excludeSchemas {
+		excludeSchemasMap[schema] = true
+	}
+	for _, schemaName := range SortedSchemaKeys(schemas) {
+		if _, ok := excludeSchemasMap[schemaName]; ok {
+			continue
+		}
+		schema := schemas[schemaName].Value
+
+		if schema == nil || schema.Properties == nil {
+			continue
+		}
+
+		res, err = GetImports(schema.Properties)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return res, nil
+}
+
+func GetRequestBodiesImports(bodies map[string]*openapi3.RequestBodyRef) (map[string]goImport, error) {
+	var res map[string]goImport
+	var err error
+	for _, requestBodyName := range SortedRequestBodyKeys(bodies) {
+		requestBodyRef := bodies[requestBodyName]
+		response := requestBodyRef.Value
+		jsonBody, found := response.Content["application/json"]
+		if found {
+			schema := jsonBody.Schema
+			if schema == nil || schema.Value == nil || schema.Value.Properties == nil {
+				continue
+			}
+
+			res, err = GetImports(schema.Value.Properties)
+			if err != nil {
+				return nil, err
+			}
+		}
+	}
+	return res, nil
+}
+
+func GetResponsesImports(responses map[string]*openapi3.ResponseRef) (map[string]goImport, error) {
+	var res map[string]goImport
+	var err error
+	for _, responseName := range SortedResponsesKeys(responses) {
+		responseOrRef := responses[responseName]
+		response := responseOrRef.Value
+		jsonResponse, found := response.Content["application/json"]
+		if found {
+			schema := jsonResponse.Schema
+			if schema == nil || schema.Value == nil || schema.Value.Properties == nil {
+				continue
+			}
+
+			res, err = GetImports(schema.Value.Properties)
+			if err != nil {
+				return nil, err
+			}
+		}
+	}
+	return res, nil
+}

pkg/codegen/codegen_test.go

@@ -8,6 +8,10 @@ import (
 	"net/http"
 	"testing"
 
+	"github.com/stretchr/testify/require"
+
+	"github.com/deepmap/oapi-codegen/pkg/util"
+
 	"github.com/getkin/kin-openapi/openapi3"
 	"github.com/golangci/lint-1"
 	"github.com/stretchr/testify/assert"
@@ -16,6 +20,13 @@ import (
 	examplePetstore "github.com/deepmap/oapi-codegen/examples/petstore-expanded/echo/api"
 )
 
+func checkLint(t *testing.T, filename string, code []byte) {
+	linter := new(lint.Linter)
+	problems, err := linter.Lint("test.gen.go", code)
+	assert.NoError(t, err)
+	assert.Len(t, problems, 0)
+}
+
 func TestExamplePetStoreCodeGeneration(t *testing.T) {
 
 	// Input vars for code generation:
@@ -58,10 +69,7 @@ func TestExamplePetStoreCodeGeneration(t *testing.T) {
 `)
 
 	// Make sure the generated code is valid:
-	linter := new(lint.Linter)
-	problems, err := linter.Lint("test.gen.go", []byte(code))
-	assert.NoError(t, err)
-	assert.Len(t, problems, 0)
+	checkLint(t, "test.gen.go", []byte(code))
 }
 
 func TestExamplePetStoreCodeGenerationWithUserTemplates(t *testing.T) {
@@ -179,10 +187,42 @@ type GetTestByNameResponse struct {
 	assert.Contains(t, code, "DeadSince *time.Time    `json:\"dead_since,omitempty\" tag1:\"value1\" tag2:\"value2\"`")
 
 	// Make sure the generated code is valid:
-	linter := new(lint.Linter)
-	problems, err := linter.Lint("test.gen.go", []byte(code))
+	checkLint(t, "test.gen.go", []byte(code))
+}
+
+func TestXGoTypeImport(t *testing.T) {
+	packageName := "api"
+	opts := Configuration{
+		PackageName: packageName,
+		Generate: GenerateOptions{
+			Models: true,
+		},
+	}
+	spec := "test_specs/x-go-type-import-pet.yaml"
+	swagger, err := util.LoadSwagger(spec)
+	require.NoError(t, err)
+
+	// Run our code generation:
+	code, err := Generate(swagger, opts)
 	assert.NoError(t, err)
-	assert.Len(t, problems, 0)
+	assert.NotEmpty(t, code)
+
+	// Check that we have valid (formattable) code:
+	_, err = format.Source([]byte(code))
+	assert.NoError(t, err)
+
+	// Check that we have a package:
+	assert.Contains(t, code, "package api")
+
+	// Check import
+	assert.Contains(t, code, `myuuid "github.com/google/uuid"`)
+
+	// Check generated struct
+	assert.Contains(t, code, "type Pet struct {\n\tAge myuuid.UUID `json:\"age\"`\n}")
+
+	// Make sure the generated code is valid:
+	checkLint(t, "test.gen.go", []byte(code))
+
 }
 
 //go:embed test_spec.yaml

pkg/codegen/test_specs/x-go-type-import-pet.yaml

@@ -0,0 +1,47 @@
+openapi: "3.0.0"
+info:
+  version: 1.0.0
+  title: Swagger Petstore
+  description: A sample API that uses a petstore as an example to demonstrate features in the OpenAPI 3.0 specification
+  termsOfService: http://swagger.io/terms/
+  contact:
+    name: Swagger API Team
+    email: apiteam@swagger.io
+    url: http://swagger.io
+  license:
+    name: Apache 2.0
+    url: https://www.apache.org/licenses/LICENSE-2.0.html
+servers:
+  - url: http://petstore.swagger.io/api
+paths:
+  /pets/{id}:
+    get:
+      summary: Returns a pet by ID
+      description: Returns a pet based on a single ID
+      operationId: findPetByID
+      parameters:
+        - name: id
+          in: path
+          description: ID of pet to fetch
+          required: true
+          schema:
+            type: integer
+            format: int64
+      responses:
+        '200':
+          description: pet response
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Pet'
+components:
+  schemas:
+    Pet:
+      properties:
+        age:
+          x-go-type: myuuid.UUID
+          x-go-type-import:
+            path: github.com/google/uuid
+            name: myuuid
+      required:
+        - age

pkg/codegen/utils.go

@@ -14,6 +14,7 @@
 package codegen
 
 import (
+	"encoding/json"
 	"fmt"
 	"net/url"
 	"regexp"
@@ -801,3 +802,28 @@ func findSchemaNameByRefPath(refPath string, spec *openapi3.T) (string, error) {
 	}
 	return "", nil
 }
+
+func GetImports(dict map[string]*openapi3.SchemaRef) (map[string]goImport, error) {
+	res := map[string]goImport{}
+	for _, v := range dict {
+		if v == nil || v.Value == nil {
+			continue
+		}
+
+		if v.Value.Extensions["x-go-type-import"] == nil || v.Value.Extensions["x-go-type"] == nil {
+			continue
+		}
+		goTypeImportExt := v.Value.Extensions["x-go-type-import"]
+
+		if raw, ok := goTypeImportExt.(json.RawMessage); ok {
+			gi := goImport{}
+			if err := json.Unmarshal(raw, &gi); err != nil {
+				return nil, err
+			}
+			res[gi.String()] = gi
+		} else {
+			continue
+		}
+	}
+	return res, nil
+}