[Go] Fix for 'Invalid code for files array in multipart/form-data request'… (#8103)

* Fix for 'Invalid code for files array in multipart/form-data request' (OpenAPITools#8093)

* Executed ensure-up-to-date

* Replaced spaces with tabs.

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/GoServerCodegen.java

@@ -228,7 +228,7 @@ public class GoServerCodegen extends AbstractGoCodegen {
         for (CodegenOperation operation : operations) {
             for (CodegenParameter param : operation.allParams) {
                 // import "os" if the operation uses files
-                if (!addedOSImport && "*os.File".equals(param.dataType)) {
+                if (!addedOSImport && ("*os.File".equals(param.dataType) || ("[]*os.File".equals(param.dataType)))) {
                     imports.add(createMapping("import", "os"));
                     addedOSImport = true;
                 }

modules/openapi-generator/src/main/resources/go-server/controller-api.mustache

@@ -66,7 +66,7 @@ func (c *{{classname}}Controller) {{nickname}}(w http.ResponseWriter, r *http.Re
 	}
 	{{/isInteger}}{{^isLong}}{{^isInteger}}
 	{{paramName}} := {{#isArray}}strings.Split({{/isArray}}query.Get("{{paramName}}"){{#isArray}}, ","){{/isArray}}{{/isInteger}}{{/isLong}}{{/isQueryParam}}{{#isFormParam}}{{#isFile}}
-	{{paramName}}, err := ReadFormFileToTempFile(r, "{{paramName}}")
+	{{#isArray}}{{paramName}}, err := ReadFormFilesToTempFiles(r, "{{paramName}}"){{/isArray}}{{^isArray}}{{paramName}}, err := ReadFormFileToTempFile(r, "{{paramName}}"){{/isArray}}
 	if err != nil {
 		w.WriteHeader(500)
 		return

modules/openapi-generator/src/main/resources/go-server/routers.mustache

@@ -7,9 +7,9 @@ import (
 	"net/http"
 	"os"
 	"strconv"
-    {{#featureCORS}}
+	{{#featureCORS}}
 	"github.com/gorilla/handlers"
-    {{/featureCORS}}
+	{{/featureCORS}}
 	"github.com/gorilla/mux"
 )
 
@@ -37,9 +37,9 @@ func NewRouter(routers ...Router) *mux.Router {
 			var handler http.Handler
 			handler = route.HandlerFunc
 			handler = Logger(handler, route.Name)
-            {{#featureCORS}}
+			{{#featureCORS}}
 			handler = handlers.CORS()(handler)
-            {{/featureCORS}}
+			{{/featureCORS}}
 
 			router.
 				Methods(route.Method).
@@ -66,28 +66,61 @@ func EncodeJSONResponse(i interface{}, status *int, w http.ResponseWriter) error
 
 // ReadFormFileToTempFile reads file data from a request form and writes it to a temporary file
 func ReadFormFileToTempFile(r *http.Request, key string) (*os.File, error) {
-	r.ParseForm()
+	_, fileHeader, err := r.FormFile(key)
-	formFile, _, err := r.FormFile(key)
+	if err != nil {
+		return nil, err
+	}
+
+	return readFileHeaderToTempFile(fileHeader)
+}
+
+// ReadFormFilesToTempFiles reads files array data from a request form and writes it to a temporary files
+func ReadFormFilesToTempFiles(r *http.Request, key string) ([]*os.File, error) {
+	if err := r.ParseMultipartForm(32 << 20); err != nil {
+		return nil, err
+	}
+
+	files := make([]*os.File, 0, len(r.MultipartForm.File[key]))
+
+	for _, fileHeader := range r.MultipartForm.File[key] {
+		file, err := readFileHeaderToTempFile(fileHeader)
+		if err != nil {
+			return nil, err
+		}
+
+		files = append(files, file)
+	}
+
+	return files, nil
+}
+
+// readFileHeaderToTempFile reads multipart.FileHeader and writes it to a temporary file
+func readFileHeaderToTempFile(fileHeader *multipart.FileHeader) (*os.File, error) {
+	formFile, err := fileHeader.Open()
 	if err != nil {
 		return nil, err
 	}
 
 	defer formFile.Close()
-	file, err := ioutil.TempFile("tmp", key)
-	if err != nil {
-		return nil, err
-	}
 
-	defer file.Close()
 	fileBytes, err := ioutil.ReadAll(formFile)
 	if err != nil {
 		return nil, err
 	}
 
+	file, err := ioutil.TempFile("", fileHeader.Filename)
+	if err != nil {
+		return nil, err
+	}
+
+	defer file.Close()
+
 	file.Write(fileBytes)
+
 	return file, nil
 }
 
+
 // parseInt64Parameter parses a sting parameter to an int64
 func parseInt64Parameter(param string) (int64, error) {
 	return strconv.ParseInt(param, 10, 64)

samples/server/petstore/go-api-server/go/routers.go

@@ -68,28 +68,61 @@ func EncodeJSONResponse(i interface{}, status *int, w http.ResponseWriter) error
 
 // ReadFormFileToTempFile reads file data from a request form and writes it to a temporary file
 func ReadFormFileToTempFile(r *http.Request, key string) (*os.File, error) {
-	r.ParseForm()
+	_, fileHeader, err := r.FormFile(key)
-	formFile, _, err := r.FormFile(key)
+	if err != nil {
+		return nil, err
+	}
+
+	return readFileHeaderToTempFile(fileHeader)
+}
+
+// ReadFormFilesToTempFiles reads files array data from a request form and writes it to a temporary files
+func ReadFormFilesToTempFiles(r *http.Request, key string) ([]*os.File, error) {
+	if err := r.ParseMultipartForm(32 << 20); err != nil {
+		return nil, err
+	}
+
+	files := make([]*os.File, 0, len(r.MultipartForm.File[key]))
+
+	for _, fileHeader := range r.MultipartForm.File[key] {
+		file, err := readFileHeaderToTempFile(fileHeader)
+		if err != nil {
+			return nil, err
+		}
+
+		files = append(files, file)
+	}
+
+	return files, nil
+}
+
+// readFileHeaderToTempFile reads multipart.FileHeader and writes it to a temporary file
+func readFileHeaderToTempFile(fileHeader *multipart.FileHeader) (*os.File, error) {
+	formFile, err := fileHeader.Open()
 	if err != nil {
 		return nil, err
 	}
 
 	defer formFile.Close()
-	file, err := ioutil.TempFile("tmp", key)
-	if err != nil {
-		return nil, err
-	}
 
-	defer file.Close()
 	fileBytes, err := ioutil.ReadAll(formFile)
 	if err != nil {
 		return nil, err
 	}
 
+	file, err := ioutil.TempFile("", fileHeader.Filename)
+	if err != nil {
+		return nil, err
+	}
+
+	defer file.Close()
+
 	file.Write(fileBytes)
+
 	return file, nil
 }
 
+
 // parseInt64Parameter parses a sting parameter to an int64
 func parseInt64Parameter(param string) (int64, error) {
 	return strconv.ParseInt(param, 10, 64)