feat(fileutil): add ReadFile func (#140)

fileutil/file.go

@@ -22,6 +22,8 @@ import (
 	"path/filepath"
 	"runtime"
 	"strings"
+
+	"github.com/duke-git/lancet/v2/validator"
 )
 
 // IsExist checks if a file or directory exists.
@@ -624,3 +626,24 @@ func WriteBytesToFile(filepath string, content []byte) error {
 	_, err = f.Write(content)
 	return err
 }
+
+// ReadFile get file reader by a url or a local file
+// Play: todo
+func ReadFile(path string) (reader io.ReadCloser, closeFn func(), err error) {
+	switch {
+	case validator.IsUrl(path):
+		resp, err := http.Get(path)
+		if err != nil {
+			return nil, func() {}, err
+		}
+		return resp.Body, func() { resp.Body.Close() }, nil
+	case IsExist(path):
+		reader, err := os.Open(path)
+		if err != nil {
+			return nil, func() {}, err
+		}
+		return reader, func() { reader.Close() }, nil
+	default:
+		return nil, func() {}, errors.New("unknown file type")
+	}
+}