Use Go 1.9 multipart.FileHeader.Size attribute

README.md

@@ -39,7 +39,7 @@ Package [check](https://godoc.org/github.com/gowww/check) provides request form
 2. Check data:
 
 	- From a values map, with [Checker.CheckValues](https://godoc.org/github.com/gowww/check#Checker.CheckValues):
-	
+
 		```Go
 		errs := userChecker.CheckValues(map[string][]string{
 			"name":  {"foobar"},
@@ -48,7 +48,7 @@ Package [check](https://godoc.org/github.com/gowww/check) provides request form
 		```
 
 	- From an [http.Request](https://golang.org/pkg/net/http/#Request), with [Checker.CheckRequest](https://godoc.org/github.com/gowww/check#Checker.CheckRequest):
-	
+
 		```Go
 		errs := checker.CheckRequest(r)
 		```

check.go

@@ -7,7 +7,6 @@ import (
 	"io"
 	"mime/multipart"
 	"net/http"
-	"os"
 	"strings"
 )
 
@@ -65,27 +64,6 @@ func (c Checker) CheckRequest(r *http.Request) Errors {
 	return c.Check(form)
 }
 
-func fileSize(file *multipart.FileHeader) (int64, error) {
-	if file == nil {
-		return 0, errNoFileProvided
-	}
-	// TODO: In next Go versions, use new Size attribute (https://go-review.googlesource.com/c/39223).
-	f, err := file.Open()
-	if err != nil {
-		return 0, err
-	}
-	var size int64
-	switch ft := f.(type) {
-	case *os.File:
-		fi, _ := ft.Stat()
-		size = fi.Size()
-	default:
-		size, _ = ft.Seek(0, io.SeekEnd)
-		f.Seek(0, io.SeekStart) // Reset reader.
-	}
-	return size, nil
-}
-
 func fileType(file *multipart.FileHeader) (string, error) {
 	if file == nil {
 		return "", errNoFileProvided

rules.go

@@ -180,11 +180,7 @@ func MaxFileSize(max int64) Rule {
 			return
 		}
 		for _, file := range form.File[key] {
-			size, err := fileSize(file)
-			if err != nil {
-				continue
-			}
-			if size > max {
+			if file != nil && file.Size > max {
 				errs.Add(key, &Error{Error: ErrMaxFileSize, Args: []interface{}{i18n.TransFileSize(max)}})
 				return
 			}
@@ -234,11 +230,7 @@ func MinFileSize(min int64) Rule {
 			return
 		}
 		for _, file := range form.File[key] {
-			size, err := fileSize(file)
-			if err != nil {
-				continue
-			}
-			if size < min {
+			if file != nil && file.Size < min {
 				errs.Add(key, &Error{Error: ErrMinFileSize, Args: []interface{}{i18n.TransFileSize(min)}})
 				return
 			}
@@ -319,15 +311,14 @@ func RangeFileSize(min, max int64) Rule {
 			return
 		}
 		for _, file := range form.File[key] {
-			size, err := fileSize(file)
-			if err != nil {
+			if file == nil {
 				continue
 			}
-			if size > max {
+			if file.Size > max {
 				errs.Add(key, &Error{Error: ErrMaxFileSize, Args: []interface{}{i18n.TransFileSize(max)}})
 				return
 			}
-			if size < min {
+			if file.Size < min {
 				errs.Add(key, &Error{Error: ErrMinFileSize, Args: []interface{}{i18n.TransFileSize(min)}})
 				return
 			}