feat: add IsLink, FileMode, MiMeType funcs for file

.gitignore

@@ -4,5 +4,6 @@
 cryptor/*.txt
 fileutil/*.txt
 fileutil/*.zip
+fileutil/*.link
 fileutil/unzip/*
 cryptor/*.pem

fileutil/file.go

@@ -9,7 +9,9 @@ import (
 	"bufio"
 	"errors"
 	"io"
+	"io/fs"
 	"io/ioutil"
+	"net/http"
 	"os"
 	"path/filepath"
 	"strings"
@@ -240,3 +242,57 @@ func UnZip(zipFile string, destPath string) error {
 	}
 	return nil
 }
+
+// IsLink checks if a file is symbol link or not
+func IsLink(path string) bool {
+	fi, err := os.Lstat(path)
+	if err != nil {
+		return false
+	}
+	return fi.Mode()&os.ModeSymlink != 0
+}
+
+// FileMode return file's mode and permission
+func FileMode(path string) (fs.FileMode, error) {
+	fi, err := os.Lstat(path)
+	if err != nil {
+		return 0, err
+	}
+	return fi.Mode(), nil
+}
+
+// MiMeType return file mime type
+// file should be string or *os.File
+func MiMeType(file interface{}) string {
+	var mediatype string
+
+	readBuffer := func(f *os.File) ([]byte, error) {
+		buffer := make([]byte, 512)
+		_, err := f.Read(buffer)
+		if err != nil {
+			return nil, err
+		}
+		return buffer, nil
+	}
+
+	if filePath, ok := file.(string); ok {
+		f, err := os.Open(filePath)
+		if err != nil {
+			return mediatype
+		}
+		buffer, err := readBuffer(f)
+		if err != nil {
+			return mediatype
+		}
+		return http.DetectContentType(buffer)
+	}
+
+	if f, ok := file.(*os.File); ok {
+		buffer, err := readBuffer(f)
+		if err != nil {
+			return mediatype
+		}
+		return http.DetectContentType(buffer)
+	}
+	return mediatype
+}

fileutil/file_test.go

@@ -181,3 +181,53 @@ func TestZipAndUnZip(t *testing.T) {
 	os.Remove(zipFile)
 	os.RemoveAll(unZipPath)
 }
+
+func TestFileMode(t *testing.T) {
+	srcFile := "./text.txt"
+	CreateFile(srcFile)
+
+	mode, err := FileMode(srcFile)
+	if err != nil {
+		t.Fail()
+	}
+	t.Log(mode)
+
+	os.Remove(srcFile)
+}
+
+func TestIsLink(t *testing.T) {
+	srcFile := "./text.txt"
+	CreateFile(srcFile)
+
+	linkFile := "./text.link"
+	if !IsExist(linkFile) {
+		_ = os.Symlink(srcFile, linkFile)
+	}
+	if !IsLink(linkFile) {
+		internal.LogFailedTestInfo(t, "IsLink", linkFile, "true", "false")
+		t.FailNow()
+	}
+
+	if IsLink("./file.go") {
+		internal.LogFailedTestInfo(t, "IsLink", "./file.go", "false", "true")
+		t.FailNow()
+	}
+	os.Remove(srcFile)
+	os.Remove(linkFile)
+}
+
+func TestMiMeType(t *testing.T) {
+	mt1 := MiMeType("./file.go")
+	expected := "text/plain; charset=utf-8"
+
+	if mt1 != expected {
+		internal.LogFailedTestInfo(t, "MiMeType", "./file.go", expected, mt1)
+		t.FailNow()
+	}
+	f, _ := os.Open("./file.go")
+	mt2 := MiMeType(f)
+	if mt2 != expected {
+		internal.LogFailedTestInfo(t, "MiMeType", "./file.go", expected, mt2)
+		t.FailNow()
+	}
+}