.gitlab-ci.yml

 test-libs:
   stage: test
-  image: golang:1.17-alpine3.15
+  image: golang:1.18-alpine3.15
   script:
-    - apk add make
-    - make test_all
+    - apk add build-base
+    - go test ./...

Makefile

-tidy:
-	go mod tidy
-
-test_all: test_bufpool
-
-test_bufpool:
-	cd bufpool && go test -bench=.

filing/api_weed/util.go

@@ -3,6 +3,8 @@ package api_weed
 import (
 	"path"
 	"strings"
+
+	"gfx.cafe/open/goutil/stringing"
 )
 
 var quoteEscaper = strings.NewReplacer("\\", "\\\\", `"`, "\\\"")
@@ -12,25 +14,20 @@ func escapeQuotes(s string) string {
 }
 
 func valid(c rune) bool {
-	return ('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z') || ('0' <= c && c <= '9') || '.' == c ||
-		'-' == c ||
-		'_' == c
+	return false ||
+		('a' <= c && c <= 'z') ||
+		('A' <= c && c <= 'Z') ||
+		('0' <= c && c <= '9') ||
+		c == '.' ||
+		c == '-' ||
+		c == '_'
 }
 
 func normalizeName(fst string) string {
 	_, st := path.Split(fst)
 	for _, _c := range st {
 		if !valid(_c) {
-			var sb strings.Builder
-			sb.Grow(len(st))
-
-			for _, c := range st {
-				if valid(c) {
-					_, _ = sb.WriteRune(c)
-				}
-			}
-
-			return sb.String()
+			return stringing.ReplaceAll(st, valid)
 		}
 	}
 	return st

filing/fs_weed/weed_test.go

-package fs_weed_test
-
-import (
-	"log"
-	"net/http"
-	"os"
-	"testing"
-
-	"gfx.cafe/open/goutil/filing/api_weed"
-	"gfx.cafe/open/goutil/filing/fs_weed"
-	"gfx.cafe/open/goutil/httpclient"
-)
-
-func TestHashUnicode(t *testing.T) {
-	url := os.Getenv("FILER_ADDR")
-	user := os.Getenv("FILER_USER")
-	pass := os.Getenv("FILER_PASS")
-
-	client := api_weed.NewClient(httpclient.New(http.DefaultClient).WithGFX(user, pass))
-	filer := fs_weed.New(url, client)
-
-	log.Println(filer.ListFiles())
-
-	wow, err := filer.OpenFile("narwhal.png", 0, 0)
-	if err != nil {
-		t.Fatalf("failed to open file: %s", err)
-	}
-	defer wow.Close()
-	wow2, err := filer.OpenFile("narwhal2.png", 0, 0)
-	if err != nil {
-		t.Fatalf("failed to open file: %s", err)
-	}
-	defer wow.Close()
-	wowhash := wow.Hash()
-	wow2hash := wow2.Hash()
-	if wowhash == 0 || wow2hash == 0 {
-		t.Fatalf("expected hash %d and %d to not be 0", wowhash, wow2hash)
-	}
-	if wowhash != wow2hash {
-		t.Fatalf("expected hash %d to equal %d", wowhash, wow2hash)
-	}
-
-	wowdat, err := wow.Data()
-	if err != nil {
-		t.Fatalf("failed to read data for wow")
-	}
-	wow2dat, err := wow2.Data()
-	if err != nil {
-		t.Fatalf("failed to read data for wow2")
-	}
-
-	if len(wowdat) == 0 || len(wow2dat) == 0 {
-		t.Fatalf("expected data %s and %s to not be len 0", wowdat, wow2dat)
-	}
-
-	if string(wowdat) != string(wow2dat) {
-		t.Fatalf("expected data %s to equal %s", wowdat, wow2dat)
-	}
-
-}

stringing/replace.go

+package stringing
+
+import (
+	"strings"
+)
+
+type Validator = func(rune) bool
+
+func ReplaceAll(st string, valid Validator) string {
+	var sb strings.Builder
+	sb.Grow(len(st))
+	for _, c := range st {
+		if valid(c) {
+			_, _ = sb.WriteRune(c)
+		}
+	}
+
+	return sb.String()
+}

structs/field.go

+package structs
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+)
+
+var (
+	errNotExported = errors.New("field is not exported")
+	errNotSettable = errors.New("field is not settable")
+)
+
+// Field represents a single struct field that encapsulates high level
+// functions around the field.
+type Field struct {
+	value      reflect.Value
+	field      reflect.StructField
+	defaultTag string
+}
+
+// Tag returns the value associated with key in the tag string. If there is no
+// such key in the tag, Tag returns the empty string.
+func (f *Field) Tag(key string) string {
+	return f.field.Tag.Get(key)
+}
+
+// Value returns the underlying value of the field. It panics if the field
+// is not exported.
+func (f *Field) Value() interface{} {
+	return f.value.Interface()
+}
+
+// IsEmbedded returns true if the given field is an anonymous field (embedded)
+func (f *Field) IsEmbedded() bool {
+	return f.field.Anonymous
+}
+
+// IsExported returns true if the given field is exported.
+func (f *Field) IsExported() bool {
+	return f.field.PkgPath == ""
+}
+
+// IsZero returns true if the given field is not initialized (has a zero value).
+// It panics if the field is not exported.
+func (f *Field) IsZero() bool {
+	zero := reflect.Zero(f.value.Type()).Interface()
+	current := f.Value()
+
+	return reflect.DeepEqual(current, zero)
+}
+
+// Name returns the name of the given field
+func (f *Field) Name() string {
+	return f.field.Name
+}
+
+// Kind returns the fields kind, such as "string", "map", "bool", etc ..
+func (f *Field) Kind() reflect.Kind {
+	return f.value.Kind()
+}
+
+// Set sets the field to given value v. It returns an error if the field is not
+// settable (not addressable or not exported) or if the given value's type
+// doesn't match the fields type.
+func (f *Field) Set(val interface{}) error {
+	// we can't set unexported fields, so be sure this field is exported
+	if !f.IsExported() {
+		return errNotExported
+	}
+
+	// do we get here? not sure...
+	if !f.value.CanSet() {
+		return errNotSettable
+	}
+
+	given := reflect.ValueOf(val)
+
+	if f.value.Kind() != given.Kind() {
+		return fmt.Errorf("wrong kind. got: %s want: %s", given.Kind(), f.value.Kind())
+	}
+
+	f.value.Set(given)
+	return nil
+}
+
+// Zero sets the field to its zero value. It returns an error if the field is not
+// settable (not addressable or not exported).
+func (f *Field) Zero() error {
+	zero := reflect.Zero(f.value.Type()).Interface()
+	return f.Set(zero)
+}
+
+// Fields returns a slice of Fields. This is particular handy to get the fields
+// of a nested struct . A struct tag with the content of "-" ignores the
+// checking of that particular field. Example:
+//
+//   // Field is ignored by this package.
+//   Field *http.Request `structs:"-"`
+//
+// It panics if field is not exported or if field's kind is not struct
+func (f *Field) Fields() []*Field {
+	return getFields(f.value, f.defaultTag)
+}
+
+// Field returns the field from a nested struct. It panics if the nested struct
+// is not exported or if the field was not found.
+func (f *Field) Field(name string) *Field {
+	field, ok := f.FieldOk(name)
+	if !ok {
+		panic("field not found")
+	}
+
+	return field
+}
+
+// FieldOk returns the field from a nested struct. The boolean returns whether
+// the field was found (true) or not (false).
+func (f *Field) FieldOk(name string) (*Field, bool) {
+	value := &f.value
+	// value must be settable so we need to make sure it holds the address of the
+	// variable and not a copy, so we can pass the pointer to strctVal instead of a
+	// copy (which is not assigned to any variable, hence not settable).
+	// see "https://blog.golang.org/laws-of-reflection#TOC_8."
+	if f.value.Kind() != reflect.Ptr {
+		a := f.value.Addr()
+		value = &a
+	}
+	v := strctVal(value.Interface())
+	t := v.Type()
+
+	field, ok := t.FieldByName(name)
+	if !ok {
+		return nil, false
+	}
+
+	return &Field{
+		field: field,
+		value: v.FieldByName(name),
+	}, true
+}

structs/field_test.go

+package structs
+
+import (
+	"reflect"
+	"testing"
+)
+
+// A test struct that defines all cases
+type Foo struct {
+	A    string
+	B    int    `structs:"y"`
+	C    bool   `json:"c"`
+	d    string // not exported
+	E    *Baz
+	Y    []string
+	Z    map[string]interface{}
+	*Bar // embedded
+}
+
+type Baz struct {
+	A string
+	B int
+}
+
+type Bar struct {
+	E string
+	F int
+	g []string
+}
+
+func newStruct() *Struct {
+	b := &Bar{
+		E: "example",
+		F: 2,
+		g: []string{"zeynep", "fatih"},
+	}
+
+	// B and x is not initialized for testing
+	f := &Foo{
+		A: "gopher",
+		C: true,
+		d: "small",
+		E: nil,
+		Y: []string{"example"},
+		Z: nil,
+	}
+	f.Bar = b
+
+	return New(f)
+}
+
+func TestField_Set(t *testing.T) {
+	s := newStruct()
+
+	f := s.Field("A")
+	err := f.Set("fatih")
+	if err != nil {
+		t.Error(err)
+	}
+
+	if f.Value().(string) != "fatih" {
+		t.Errorf("Setted value is wrong: %s want: %s", f.Value().(string), "fatih")
+	}
+
+	f = s.Field("Y")
+	err = f.Set([]string{"override", "with", "this"})
+	if err != nil {
+		t.Error(err)
+	}
+
+	sliceLen := len(f.Value().([]string))
+	if sliceLen != 3 {
+		t.Errorf("Setted values slice length is wrong: %d, want: %d", sliceLen, 3)
+	}
+
+	f = s.Field("C")
+	err = f.Set(false)
+	if err != nil {
+		t.Error(err)
+	}
+
+	if f.Value().(bool) {
+		t.Errorf("Setted value is wrong: %t want: %t", f.Value().(bool), false)
+	}
+
+	// let's pass a different type
+	f = s.Field("A")
+	err = f.Set(123) // Field A is of type string, but we are going to pass an integer
+	if err == nil {
+		t.Error("Setting a field's value with a different type than the field's type should return an error")
+	}
+
+	// old value should be still there :)
+	if f.Value().(string) != "fatih" {
+		t.Errorf("Setted value is wrong: %s want: %s", f.Value().(string), "fatih")
+	}
+
+	// let's access an unexported field, which should give an error
+	f = s.Field("d")
+	err = f.Set("large")
+	if err != errNotExported {
+		t.Error(err)
+	}
+
+	// let's set a pointer to struct
+	b := &Bar{
+		E: "gopher",
+		F: 2,
+	}
+
+	f = s.Field("Bar")
+	err = f.Set(b)
+	if err != nil {
+		t.Error(err)
+	}
+
+	baz := &Baz{
+		A: "helloWorld",
+		B: 42,
+	}
+
+	f = s.Field("E")
+	err = f.Set(baz)
+	if err != nil {
+		t.Error(err)
+	}
+
+	ba := s.Field("E").Value().(*Baz)
+
+	if ba.A != "helloWorld" {
+		t.Errorf("could not set baz. Got: %s Want: helloWorld", ba.A)
+	}
+}
+
+func TestField_NotSettable(t *testing.T) {
+	a := map[int]Baz{
+		4: {
+			A: "value",
+		},
+	}
+
+	s := New(a[4])
+
+	if err := s.Field("A").Set("newValue"); err != errNotSettable {
+		t.Errorf("Trying to set non-settable field should error with %q. Got %q instead.", errNotSettable, err)
+	}
+}
+
+func TestField_Zero(t *testing.T) {
+	s := newStruct()
+
+	f := s.Field("A")
+	err := f.Zero()
+	if err != nil {
+		t.Error(err)
+	}
+
+	if f.Value().(string) != "" {
+		t.Errorf("Zeroed value is wrong: %s want: %s", f.Value().(string), "")
+	}
+
+	f = s.Field("Y")
+	err = f.Zero()
+	if err != nil {
+		t.Error(err)
+	}
+
+	sliceLen := len(f.Value().([]string))
+	if sliceLen != 0 {
+		t.Errorf("Zeroed values slice length is wrong: %d, want: %d", sliceLen, 0)
+	}
+
+	f = s.Field("C")
+	err = f.Zero()
+	if err != nil {
+		t.Error(err)
+	}
+
+	if f.Value().(bool) {
+		t.Errorf("Zeroed value is wrong: %t want: %t", f.Value().(bool), false)
+	}
+
+	// let's access an unexported field, which should give an error
+	f = s.Field("d")
+	err = f.Zero()
+	if err != errNotExported {
+		t.Error(err)
+	}
+
+	f = s.Field("Bar")
+	err = f.Zero()
+	if err != nil {
+		t.Error(err)
+	}
+
+	f = s.Field("E")
+	err = f.Zero()
+	if err != nil {
+		t.Error(err)
+	}
+
+	v := s.Field("E").value
+	if !v.IsNil() {
+		t.Errorf("could not set baz. Got: %s Want: <nil>", v.Interface())
+	}
+}
+
+func TestField(t *testing.T) {
+	s := newStruct()
+
+	defer func() {
+		err := recover()
+		if err == nil {
+			t.Error("Retrieveing a non existing field from the struct should panic")
+		}
+	}()
+
+	_ = s.Field("no-field")
+}
+
+func TestField_Kind(t *testing.T) {
+	s := newStruct()
+
+	f := s.Field("A")
+	if f.Kind() != reflect.String {
+		t.Errorf("Field A has wrong kind: %s want: %s", f.Kind(), reflect.String)
+	}
+
+	f = s.Field("B")
+	if f.Kind() != reflect.Int {
+		t.Errorf("Field B has wrong kind: %s want: %s", f.Kind(), reflect.Int)
+	}
+
+	// unexported
+	f = s.Field("d")
+	if f.Kind() != reflect.String {
+		t.Errorf("Field d has wrong kind: %s want: %s", f.Kind(), reflect.String)
+	}
+}
+
+func TestField_Tag(t *testing.T) {
+	s := newStruct()
+
+	v := s.Field("B").Tag("json")
+	if v != "" {
+		t.Errorf("Field's tag value of a non existing tag should return empty, got: %s", v)
+	}
+
+	v = s.Field("C").Tag("json")
+	if v != "c" {
+		t.Errorf("Field's tag value of the existing field C should return 'c', got: %s", v)
+	}
+
+	v = s.Field("d").Tag("json")
+	if v != "" {
+		t.Errorf("Field's tag value of a non exported field should return empty, got: %s", v)
+	}
+
+	v = s.Field("A").Tag("json")
+	if v != "" {
+		t.Errorf("Field's tag value of a existing field without a tag should return empty, got: %s", v)
+	}
+}
+
+func TestField_Value(t *testing.T) {
+	s := newStruct()
+
+	v := s.Field("A").Value()
+	val, ok := v.(string)
+	if !ok {
+		t.Errorf("Field's value of a A should be string")
+	}
+
+	if val != "gopher" {
+		t.Errorf("Field's value of a existing tag should return 'gopher', got: %s", val)
+	}
+
+	defer func() {
+		err := recover()
+		if err == nil {
+			t.Error("Value of a non exported field from the field should panic")
+		}
+	}()
+
+	// should panic
+	_ = s.Field("d").Value()
+}
+
+func TestField_IsEmbedded(t *testing.T) {
+	s := newStruct()
+
+	if !s.Field("Bar").IsEmbedded() {
+		t.Errorf("Fields 'Bar' field is an embedded field")
+	}
+
+	if s.Field("d").IsEmbedded() {
+		t.Errorf("Fields 'd' field is not an embedded field")
+	}
+}
+
+func TestField_IsExported(t *testing.T) {
+	s := newStruct()
+
+	if !s.Field("Bar").IsExported() {
+		t.Errorf("Fields 'Bar' field is an exported field")
+	}
+
+	if !s.Field("A").IsExported() {
+		t.Errorf("Fields 'A' field is an exported field")
+	}
+
+	if s.Field("d").IsExported() {
+		t.Errorf("Fields 'd' field is not an exported field")
+	}
+}
+
+func TestField_IsZero(t *testing.T) {
+	s := newStruct()
+
+	if s.Field("A").IsZero() {
+		t.Errorf("Fields 'A' field is an initialized field")
+	}
+
+	if !s.Field("B").IsZero() {
+		t.Errorf("Fields 'B' field is not an initialized field")
+	}
+}
+
+func TestField_Name(t *testing.T) {
+	s := newStruct()
+
+	if s.Field("A").Name() != "A" {
+		t.Errorf("Fields 'A' field should have the name 'A'")
+	}
+}
+
+func TestField_Field(t *testing.T) {
+	s := newStruct()
+
+	e := s.Field("Bar").Field("E")
+
+	val, ok := e.Value().(string)
+	if !ok {
+		t.Error("The value of the field 'e' inside 'Bar' struct should be string")
+	}
+
+	if val != "example" {
+		t.Errorf("The value of 'e' should be 'example, got: %s", val)
+	}
+
+	defer func() {
+		err := recover()
+		if err == nil {
+			t.Error("Field of a non existing nested struct should panic")
+		}
+	}()
+
+	_ = s.Field("Bar").Field("e")
+}
+
+func TestField_Fields(t *testing.T) {
+	s := newStruct()
+	fields := s.Field("Bar").Fields()
+
+	if len(fields) != 3 {
+		t.Errorf("We expect 3 fields in embedded struct, was: %d", len(fields))
+	}
+}
+
+func TestField_FieldOk(t *testing.T) {
+	s := newStruct()
+
+	b, ok := s.FieldOk("Bar")
+	if !ok {
+		t.Error("The field 'Bar' should exists.")
+	}
+
+	e, ok := b.FieldOk("E")
+	if !ok {
+		t.Error("The field 'E' should exists.")
+	}
+
+	val, ok := e.Value().(string)
+	if !ok {
+		t.Error("The value of the field 'e' inside 'Bar' struct should be string")
+	}
+
+	if val != "example" {
+		t.Errorf("The value of 'e' should be 'example, got: %s", val)
+	}
+}

structs/structs.go

+// Package structs contains various utilities functions to work with structs.
+package structs
+
+import (
+	"fmt"
+
+	"reflect"
+)
+
+var (
+	// DefaultTagName is the default tag name for struct fields which provides
+	// a more granular to tweak certain structs. Lookup the necessary functions
+	// for more info.
+	DefaultTagName = "structs" // struct's field default tag name
+)
+
+// Struct encapsulates a struct type to provide several high level functions
+// around the struct.
+type Struct struct {
+	raw     interface{}
+	value   reflect.Value
+	TagName string
+}
+
+// New returns a new *Struct with the struct s. It panics if the s's kind is
+// not struct.
+func New(s interface{}) *Struct {
+	return &Struct{
+		raw:     s,
+		value:   strctVal(s),
+		TagName: DefaultTagName,
+	}
+}
+
+// Map converts the given struct to a map[string]interface{}, where the keys
+// of the map are the field names and the values of the map the associated
+// values of the fields. The default key string is the struct field name but
+// can be changed in the struct field's tag value. The "structs" key in the
+// struct's field tag value is the key name. Example:
+//
+//   // Field appears in map as key "myName".
+//   Name string `structs:"myName"`
+//
+// A tag value with the content of "-" ignores that particular field. Example:
+//
+//   // Field is ignored by this package.
+//   Field bool `structs:"-"`
+//
+// A tag value with the content of "string" uses the stringer to get the value. Example:
+//
+//   // The value will be output of Animal's String() func.
+//   // Map will panic if Animal does not implement String().
+//   Field *Animal `structs:"field,string"`
+//
+// A tag value with the option of "flatten" used in a struct field is to flatten its fields
+// in the output map. Example:
+//
+//   // The FieldStruct's fields will be flattened into the output map.
+//   FieldStruct time.Time `structs:",flatten"`
+//
+// A tag value with the option of "omitnested" stops iterating further if the type
+// is a struct. Example:
+//
+//   // Field is not processed further by this package.
+//   Field time.Time     `structs:"myName,omitnested"`
+//   Field *http.Request `structs:",omitnested"`
+//
+// A tag value with the option of "omitempty" ignores that particular field if
+// the field value is empty. Example:
+//
+//   // Field appears in map as key "myName", but the field is
+//   // skipped if empty.
+//   Field string `structs:"myName,omitempty"`
+//
+//   // Field appears in map as key "Field" (the default), but
+//   // the field is skipped if empty.
+//   Field string `structs:",omitempty"`
+//
+// Note that only exported fields of a struct can be accessed, non exported
+// fields will be neglected.
+func (s *Struct) Map() map[string]interface{} {
+	out := make(map[string]interface{})
+	s.FillMap(out)
+	return out
+}
+
+// FillMap is the same as Map. Instead of returning the output, it fills the
+// given map.
+func (s *Struct) FillMap(out map[string]interface{}) {
+	if out == nil {
+		return
+	}
+
+	fields := s.structFields()
+
+	for _, field := range fields {
+		name := field.Name
+		val := s.value.FieldByName(name)
+		isSubStruct := false
+		var finalVal interface{}
+
+		tagName, tagOpts := parseTag(field.Tag.Get(s.TagName))
+		if tagName != "" {
+			name = tagName
+		}
+		// also add tags from json
+		newName, newTagOpts := parseTag(field.Tag.Get("json"))
+		if tagName == "" && newName != "" {
+			name = newName
+		}
+		tagOpts = append(tagOpts, newTagOpts...)
+
+		// if the value is a zero value and the field is marked as omitempty do
+		// not include
+		if tagOpts.Has("omitempty") {
+			zero := reflect.Zero(val.Type()).Interface()
+			current := val.Interface()
+
+			if reflect.DeepEqual(current, zero) {
+				continue
+			}
+		}
+
+		if !tagOpts.Has("omitnested") {
+			finalVal = s.nested(val)
+
+			v := reflect.ValueOf(val.Interface())
+			if v.Kind() == reflect.Ptr {
+				v = v.Elem()
+			}
+
+			switch v.Kind() {
+			case reflect.Map, reflect.Struct:
+				isSubStruct = true
+			}
+		} else {
+			finalVal = val.Interface()
+		}
+
+		if tagOpts.Has("string") {
+			s, ok := val.Interface().(fmt.Stringer)
+			if ok {
+				out[name] = s.String()
+			}
+			continue
+		}
+
+		if isSubStruct && (tagOpts.Has("flatten") || tagOpts.Has("inline")) {
+			for k := range finalVal.(map[string]interface{}) {
+				out[k] = finalVal.(map[string]interface{})[k]
+			}
+		} else {
+			out[name] = finalVal
+		}
+	}
+}
+
+// Values converts the given s struct's field values to a []interface{}.  A
+// struct tag with the content of "-" ignores the that particular field.
+// Example:
+//
+//   // Field is ignored by this package.
+//   Field int `structs:"-"`
+//
+// A value with the option of "omitnested" stops iterating further if the type
+// is a struct. Example:
+//
+//   // Fields is not processed further by this package.
+//   Field time.Time     `structs:",omitnested"`
+//   Field *http.Request `structs:",omitnested"`
+//
+// A tag value with the option of "omitempty" ignores that particular field and
+// is not added to the values if the field value is empty. Example:
+//
+//   // Field is skipped if empty
+//   Field string `structs:",omitempty"`
+//
+// Note that only exported fields of a struct can be accessed, non exported
+// fields  will be neglected.
+func (s *Struct) Values() []interface{} {
+	fields := s.structFields()
+
+	var t []interface{}
+
+	for _, field := range fields {
+		val := s.value.FieldByName(field.Name)
+
+		_, tagOpts := parseTag(field.Tag.Get(s.TagName))
+
+		_, newTagOpts := parseTag(field.Tag.Get("json"))
+		tagOpts = append(tagOpts, newTagOpts...)
+
+		// if the value is a zero value and the field is marked as omitempty do
+		// not include
+		if tagOpts.Has("omitempty") {
+			zero := reflect.Zero(val.Type()).Interface()
+			current := val.Interface()
+
+			if reflect.DeepEqual(current, zero) {
+				continue
+			}
+		}
+
+		if tagOpts.Has("string") {
+			s, ok := val.Interface().(fmt.Stringer)
+			if ok {
+				t = append(t, s.String())
+			}
+			continue
+		}
+
+		if IsStruct(val.Interface()) && !tagOpts.Has("omitnested") {
+			// look out for embedded structs, and convert them to a
+			// []interface{} to be added to the final values slice
+			t = append(t, Values(val.Interface())...)
+		} else {
+			t = append(t, val.Interface())
+		}
+	}
+
+	return t
+}
+
+// Fields returns a slice of Fields. A struct tag with the content of "-"
+// ignores the checking of that particular field. Example:
+//
+//   // Field is ignored by this package.
+//   Field bool `structs:"-"`
+//
+// It panics if s's kind is not struct.
+func (s *Struct) Fields() []*Field {
+	return getFields(s.value, s.TagName)
+}
+
+// Names returns a slice of field names. A struct tag with the content of "-"
+// ignores the checking of that particular field. Example:
+//
+//   // Field is ignored by this package.
+//   Field bool `structs:"-"`
+//
+// It panics if s's kind is not struct.
+func (s *Struct) Names() []string {
+	fields := getFields(s.value, s.TagName)
+
+	names := make([]string, len(fields))
+
+	for i, field := range fields {
+		names[i] = field.Name()
+	}
+
+	return names
+}
+
+func getFields(v reflect.Value, tagName string) []*Field {
+	if v.Kind() == reflect.Ptr {
+		v = v.Elem()
+	}
+
+	t := v.Type()
+
+	var fields []*Field
+
+	for i := 0; i < t.NumField(); i++ {
+		field := t.Field(i)
+
+		if tag := field.Tag.Get(tagName); tag == "-" {
+			continue
+		}
+		if tag := field.Tag.Get("json"); tag == "-" {
+			continue
+		}
+
+		f := &Field{
+			field: field,
+			value: v.FieldByName(field.Name),
+		}
+
+		fields = append(fields, f)
+
+	}
+
+	return fields
+}
+
+// Field returns a new Field struct that provides several high level functions
+// around a single struct field entity. It panics if the field is not found.
+func (s *Struct) Field(name string) *Field {
+	f, ok := s.FieldOk(name)
+	if !ok {
+		panic("field not found")
+	}
+
+	return f
+}
+
+// FieldOk returns a new Field struct that provides several high level functions
+// around a single struct field entity. The boolean returns true if the field
+// was found.
+func (s *Struct) FieldOk(name string) (*Field, bool) {
+	t := s.value.Type()
+
+	field, ok := t.FieldByName(name)
+	if !ok {
+		return nil, false
+	}
+
+	return &Field{
+		field:      field,
+		value:      s.value.FieldByName(name),
+		defaultTag: s.TagName,
+	}, true
+}
+
+// IsZero returns true if all fields in a struct is a zero value (not
+// initialized) A struct tag with the content of "-" ignores the checking of
+// that particular field. Example:
+//
+//   // Field is ignored by this package.
+//   Field bool `structs:"-"`
+//
+// A value with the option of "omitnested" stops iterating further if the type
+// is a struct. Example:
+//
+//   // Field is not processed further by this package.
+//   Field time.Time     `structs:"myName,omitnested"`
+//   Field *http.Request `structs:",omitnested"`
+//
+// Note that only exported fields of a struct can be accessed, non exported
+// fields  will be neglected. It panics if s's kind is not struct.
+func (s *Struct) IsZero() bool {
+	fields := s.structFields()
+
+	for _, field := range fields {
+		val := s.value.FieldByName(field.Name)
+
+		_, tagOpts := parseTag(field.Tag.Get(s.TagName))
+
+		if IsStruct(val.Interface()) && !tagOpts.Has("omitnested") {
+			ok := IsZero(val.Interface())
+			if !ok {
+				return false
+			}
+
+			continue
+		}
+
+		// zero value of the given field, such as "" for string, 0 for int
+		zero := reflect.Zero(val.Type()).Interface()
+
+		//  current value of the given field
+		current := val.Interface()
+
+		if !reflect.DeepEqual(current, zero) {
+			return false
+		}
+	}
+
+	return true
+}
+
+// HasZero returns true if a field in a struct is not initialized (zero value).
+// A struct tag with the content of "-" ignores the checking of that particular
+// field. Example:
+//
+//   // Field is ignored by this package.
+//   Field bool `structs:"-"`
+//
+// A value with the option of "omitnested" stops iterating further if the type
+// is a struct. Example:
+//
+//   // Field is not processed further by this package.
+//   Field time.Time     `structs:"myName,omitnested"`
+//   Field *http.Request `structs:",omitnested"`
+//
+// Note that only exported fields of a struct can be accessed, non exported
+// fields  will be neglected. It panics if s's kind is not struct.
+func (s *Struct) HasZero() bool {
+	fields := s.structFields()
+
+	for _, field := range fields {
+		val := s.value.FieldByName(field.Name)
+
+		_, tagOpts := parseTag(field.Tag.Get(s.TagName))
+		_, newTagOpts := parseTag(field.Tag.Get("json"))
+		tagOpts = append(tagOpts, newTagOpts...)
+
+		if IsStruct(val.Interface()) && !tagOpts.Has("omitnested") {
+			ok := HasZero(val.Interface())
+			if ok {
+				return true
+			}
+
+			continue
+		}
+
+		// zero value of the given field, such as "" for string, 0 for int
+		zero := reflect.Zero(val.Type()).Interface()
+
+		//  current value of the given field
+		current := val.Interface()
+
+		if reflect.DeepEqual(current, zero) {
+			return true
+		}
+	}
+
+	return false
+}
+
+// Name returns the structs's type name within its package. For more info refer
+// to Name() function.
+func (s *Struct) Name() string {
+	return s.value.Type().Name()
+}
+
+// structFields returns the exported struct fields for a given s struct. This
+// is a convenient helper method to avoid duplicate code in some of the
+// functions.
+func (s *Struct) structFields() []reflect.StructField {
+	t := s.value.Type()
+
+	var f []reflect.StructField
+
+	for i := 0; i < t.NumField(); i++ {
+		field := t.Field(i)
+		// we can't access the value of unexported fields
+		if field.PkgPath != "" {
+			continue
+		}
+
+		// don't check if it's omitted
+		if tag := field.Tag.Get(s.TagName); tag == "-" {
+			continue
+		}
+
+		f = append(f, field)
+	}
+
+	return f
+}
+
+func strctVal(s interface{}) reflect.Value {
+	v := reflect.ValueOf(s)
+
+	// if pointer get the underlying element≤
+	for v.Kind() == reflect.Ptr {
+		v = v.Elem()
+	}
+
+	if v.Kind() != reflect.Struct {
+		panic("not struct")
+	}
+
+	return v
+}
+
+// Map converts the given struct to a map[string]interface{}. For more info
+// refer to Struct types Map() method. It panics if s's kind is not struct.
+func Map(s interface{}) map[string]interface{} {
+	return New(s).Map()
+}
+
+// FillMap is the same as Map. Instead of returning the output, it fills the
+// given map.
+func FillMap(s interface{}, out map[string]interface{}) {
+	New(s).FillMap(out)
+}
+
+// Values converts the given struct to a []interface{}. For more info refer to
+// Struct types Values() method.  It panics if s's kind is not struct.
+func Values(s interface{}) []interface{} {
+	return New(s).Values()
+}
+
+// Fields returns a slice of *Field. For more info refer to Struct types
+// Fields() method.  It panics if s's kind is not struct.
+func Fields(s interface{}) []*Field {
+	return New(s).Fields()
+}
+
+// Names returns a slice of field names. For more info refer to Struct types
+// Names() method.  It panics if s's kind is not struct.
+func Names(s interface{}) []string {
+	return New(s).Names()
+}
+
+// IsZero returns true if all fields is equal to a zero value. For more info
+// refer to Struct types IsZero() method.  It panics if s's kind is not struct.
+func IsZero(s interface{}) bool {
+	return New(s).IsZero()
+}
+
+// HasZero returns true if any field is equal to a zero value. For more info
+// refer to Struct types HasZero() method.  It panics if s's kind is not struct.
+func HasZero(s interface{}) bool {
+	return New(s).HasZero()
+}
+
+// IsStruct returns true if the given variable is a struct or a pointer to
+// struct.
+func IsStruct(s interface{}) bool {
+	v := reflect.ValueOf(s)
+	if v.Kind() == reflect.Ptr {
+		v = v.Elem()
+	}
+
+	// uninitialized zero value of a struct
+	if v.Kind() == reflect.Invalid {
+		return false
+	}
+
+	return v.Kind() == reflect.Struct
+}
+
+// Name returns the structs's type name within its package. It returns an
+// empty string for unnamed types. It panics if s's kind is not struct.
+func Name(s interface{}) string {
+	return New(s).Name()
+}
+
+// nested retrieves recursively all types for the given value and returns the
+// nested value.
+func (s *Struct) nested(val reflect.Value) interface{} {
+	var finalVal interface{}
+
+	v := reflect.ValueOf(val.Interface())
+	if v.Kind() == reflect.Ptr {
+		v = v.Elem()
+	}
+
+	switch v.Kind() {
+	case reflect.Struct:
+		n := New(val.Interface())
+		n.TagName = s.TagName
+		m := n.Map()
+
+		// do not add the converted value if there are no exported fields, ie:
+		// time.Time
+		if len(m) == 0 {
+			finalVal = val.Interface()
+		} else {
+			finalVal = m
+		}
+	case reflect.Map:
+		// get the element type of the map
+		mapElem := val.Type()
+		switch val.Type().Kind() {
+		case reflect.Ptr, reflect.Array, reflect.Map,
+			reflect.Slice, reflect.Chan:
+			mapElem = val.Type().Elem()
+			if mapElem.Kind() == reflect.Ptr {
+				mapElem = mapElem.Elem()
+			}
+		}
+
+		// only iterate over struct types, ie: map[string]StructType,
+		// map[string][]StructType,
+		if mapElem.Kind() == reflect.Struct ||
+			(mapElem.Kind() == reflect.Slice &&
+				mapElem.Elem().Kind() == reflect.Struct) {
+			m := make(map[string]interface{}, val.Len())
+			for _, k := range val.MapKeys() {
+				m[k.String()] = s.nested(val.MapIndex(k))
+			}
+			finalVal = m
+			break
+		}
+
+		// TODO(arslan): should this be optional?
+		finalVal = val.Interface()
+	case reflect.Slice, reflect.Array:
+		if val.Type().Kind() == reflect.Interface {
+			finalVal = val.Interface()
+			break
+		}
+
+		// TODO(arslan): should this be optional?
+		// do not iterate of non struct types, just pass the value. Ie: []int,
+		// []string, co... We only iterate further if it's a struct.
+		// i.e []foo or []*foo
+		if val.Type().Elem().Kind() != reflect.Struct &&
+			!(val.Type().Elem().Kind() == reflect.Ptr &&
+				val.Type().Elem().Elem().Kind() == reflect.Struct) {
+			finalVal = val.Interface()
+			break
+		}
+
+		slices := make([]interface{}, val.Len())
+		for x := 0; x < val.Len(); x++ {
+			slices[x] = s.nested(val.Index(x))
+		}
+		finalVal = slices
+	default:
+		finalVal = val.Interface()
+	}
+
+	return finalVal
+}

structs/structs_example_test.go

+package structs
+
+import (
+	"fmt"
+	"time"
+)
+
+func ExampleNew() {
+	type Server struct {
+		Name    string
+		ID      int32
+		Enabled bool
+	}
+
+	server := &Server{
+		Name:    "Arslan",
+		ID:      123456,
+		Enabled: true,
+	}
+
+	s := New(server)
+
+	fmt.Printf("Name        : %v\n", s.Name())
+	fmt.Printf("Values      : %v\n", s.Values())
+	fmt.Printf("Value of ID : %v\n", s.Field("ID").Value())
+	// Output:
+	// Name        : Server
+	// Values      : [Arslan 123456 true]
+	// Value of ID : 123456
+
+}
+
+func ExampleMap() {
+	type Server struct {
+		Name    string
+		ID      int32
+		Enabled bool
+	}
+
+	s := &Server{
+		Name:    "Arslan",
+		ID:      123456,
+		Enabled: true,
+	}
+
+	m := Map(s)
+
+	fmt.Printf("%#v\n", m["Name"])
+	fmt.Printf("%#v\n", m["ID"])
+	fmt.Printf("%#v\n", m["Enabled"])
+	// Output:
+	// "Arslan"
+	// 123456
+	// true
+
+}
+
+func ExampleMap_tags() {
+	// Custom tags can change the map keys instead of using the fields name
+	type Server struct {
+		Name    string `structs:"server_name"`
+		ID      int32  `structs:"server_id"`
+		Enabled bool   `structs:"enabled"`
+	}
+
+	s := &Server{
+		Name: "Zeynep",
+		ID:   789012,
+	}
+
+	m := Map(s)
+
+	// access them by the custom tags defined above
+	fmt.Printf("%#v\n", m["server_name"])
+	fmt.Printf("%#v\n", m["server_id"])
+	fmt.Printf("%#v\n", m["enabled"])
+	// Output:
+	// "Zeynep"
+	// 789012
+	// false
+
+}
+
+func ExampleMap_omitNested() {
+	// By default field with struct types are processed too. We can stop
+	// processing them via "omitnested" tag option.
+	type Server struct {
+		Name string    `structs:"server_name"`
+		ID   int32     `structs:"server_id"`
+		Time time.Time `structs:"time,omitnested"` // do not convert to map[string]interface{}
+	}
+
+	const shortForm = "2006-Jan-02" //lint:ignore U1000 testing
+	t, _ := time.Parse("2006-Jan-02", "2013-Feb-03")
+
+	s := &Server{
+		Name: "Zeynep",
+		ID:   789012,
+		Time: t,
+	}
+
+	m := Map(s)
+
+	// access them by the custom tags defined above
+	fmt.Printf("%v\n", m["server_name"])
+	fmt.Printf("%v\n", m["server_id"])
+	fmt.Printf("%v\n", m["time"].(time.Time))
+	// Output:
+	// Zeynep
+	// 789012
+	// 2013-02-03 00:00:00 +0000 UTC
+}
+
+func ExampleMap_omitEmpty() {
+	// By default field with struct types of zero values are processed too. We
+	// can stop processing them via "omitempty" tag option.
+	type Server struct {
+		Name     string `structs:",omitempty"`
+		ID       int32  `structs:"server_id,omitempty"`
+		Location string
+	}
+
+	// Only add location
+	s := &Server{
+		Location: "Tokyo",
+	}
+
+	m := Map(s)
+
+	// map contains only the Location field
+	fmt.Printf("%v\n", m)
+	// Output:
+	// map[Location:Tokyo]
+}
+
+func ExampleValues() {
+	type Server struct {
+		Name    string
+		ID      int32
+		Enabled bool
+	}
+
+	s := &Server{
+		Name:    "Fatih",
+		ID:      135790,
+		Enabled: false,
+	}
+
+	m := Values(s)
+
+	fmt.Printf("Values: %+v\n", m)
+	// Output:
+	// Values: [Fatih 135790 false]
+}
+
+func ExampleValues_omitEmpty() {
+	// By default field with struct types of zero values are processed too. We
+	// can stop processing them via "omitempty" tag option.
+	type Server struct {
+		Name     string `structs:",omitempty"`
+		ID       int32  `structs:"server_id,omitempty"`
+		Location string
+	}
+
+	// Only add location
+	s := &Server{
+		Location: "Ankara",
+	}
+
+	m := Values(s)
+
+	// values contains only the Location field
+	fmt.Printf("Values: %+v\n", m)
+	// Output:
+	// Values: [Ankara]
+}
+
+func ExampleValues_tags() {
+	type Location struct {
+		City    string
+		Country string
+	}
+
+	type Server struct {
+		Name     string
+		ID       int32
+		Enabled  bool
+		Location Location `structs:"-"` // values from location are not included anymore
+	}
+
+	s := &Server{
+		Name:     "Fatih",
+		ID:       135790,
+		Enabled:  false,
+		Location: Location{City: "Ankara", Country: "Turkey"},
+	}
+
+	// Let get all values from the struct s. Note that we don't include values
+	// from the Location field
+	m := Values(s)
+
+	fmt.Printf("Values: %+v\n", m)
+	// Output:
+	// Values: [Fatih 135790 false]
+}
+
+func ExampleFields() {
+	type Access struct {
+		Name         string
+		LastAccessed time.Time
+		Number       int
+	}
+
+	s := &Access{
+		Name:         "Fatih",
+		LastAccessed: time.Now(),
+		Number:       1234567,
+	}
+
+	fields := Fields(s)
+
+	for i, field := range fields {
+		fmt.Printf("[%d] %+v\n", i, field.Name())
+	}
+
+	// Output:
+	// [0] Name
+	// [1] LastAccessed
+	// [2] Number
+}
+
+func ExampleFields_nested() {
+	type Person struct {
+		Name   string
+		Number int
+	}
+
+	type Access struct {
+		Person        Person
+		HasPermission bool
+		LastAccessed  time.Time
+	}
+
+	s := &Access{
+		Person:        Person{Name: "fatih", Number: 1234567},
+		LastAccessed:  time.Now(),
+		HasPermission: true,
+	}
+
+	// Let's get all fields from the struct s.
+	fields := Fields(s)
+
+	for _, field := range fields {
+		if field.Name() == "Person" {
+			fmt.Printf("Access.Person.Name: %+v\n", field.Field("Name").Value())
+		}
+	}
+
+	// Output:
+	// Access.Person.Name: fatih
+}
+
+func ExampleField() {
+	type Person struct {
+		Name   string
+		Number int
+	}
+
+	type Access struct {
+		Person        Person
+		HasPermission bool
+		LastAccessed  time.Time
+	}
+
+	access := &Access{
+		Person:        Person{Name: "fatih", Number: 1234567},
+		LastAccessed:  time.Now(),
+		HasPermission: true,
+	}
+
+	// Create a new Struct type
+	s := New(access)
+
+	// Get the Field type for "Person" field
+	p := s.Field("Person")
+
+	// Get the underlying "Name field" and print the value of it
+	name := p.Field("Name")
+
+	fmt.Printf("Value of Person.Access.Name: %+v\n", name.Value())
+
+	// Output:
+	// Value of Person.Access.Name: fatih
+
+}
+
+func ExampleIsZero() {
+	type Server struct {
+		Name    string
+		ID      int32
+		Enabled bool
+	}
+
+	// Nothing is initialized
+	a := &Server{}
+	isZeroA := IsZero(a)
+
+	// Name and Enabled is initialized, but not ID
+	b := &Server{
+		Name:    "Golang",
+		Enabled: true,
+	}
+	isZeroB := IsZero(b)
+
+	fmt.Printf("%#v\n", isZeroA)
+	fmt.Printf("%#v\n", isZeroB)
+	// Output:
+	// true
+	// false
+}
+
+func ExampleHasZero() {
+	// Let's define an Access struct. Note that the "Enabled" field is not
+	// going to be checked because we added the "structs" tag to the field.
+	type Access struct {
+		Name         string
+		LastAccessed time.Time
+		Number       int
+		Enabled      bool `structs:"-"`
+	}
+
+	// Name and Number is not initialized.
+	a := &Access{
+		LastAccessed: time.Now(),
+	}
+	hasZeroA := HasZero(a)
+
+	// Name and Number is initialized.
+	b := &Access{
+		Name:         "Fatih",
+		LastAccessed: time.Now(),
+		Number:       12345,
+	}
+	hasZeroB := HasZero(b)
+
+	fmt.Printf("%#v\n", hasZeroA)
+	fmt.Printf("%#v\n", hasZeroB)
+	// Output:
+	// true
+	// false
+}

structs/tags.go

+package structs
+
+import "strings"
+
+// tagOptions contains a slice of tag options
+type tagOptions []string
+
+// Has returns true if the given option is available in tagOptions
+func (t tagOptions) Has(opt string) bool {
+	for _, tagOpt := range t {
+		if tagOpt == opt {
+			return true
+		}
+	}
+
+	return false
+}
+
+// parseTag splits a struct field's tag into its name and a list of options
+// which comes after a name. A tag is in the form of: "name,option1,option2".
+// The name can be neglectected.
+func parseTag(tag string) (string, tagOptions) {
+	// tag is one of followings:
+	// ""
+	// "name"
+	// "name,opt"
+	// "name,opt,opt2"
+	// ",opt"
+
+	res := strings.Split(tag, ",")
+	return res[0], res[1:]
+}

structs/tags_test.go

+package structs
+
+import "testing"
+
+func TestParseTag_Name(t *testing.T) {
+	tags := []struct {
+		tag string
+		has bool
+	}{
+		{"", false},
+		{"name", true},
+		{"name,opt", true},
+		{"name , opt, opt2", false}, // has a single whitespace
+		{", opt, opt2", false},
+	}
+
+	for _, tag := range tags {
+		name, _ := parseTag(tag.tag)
+
+		if (name != "name") && tag.has {
+			t.Errorf("Parse tag should return name: %#v", tag)
+		}
+	}
+}
+
+func TestParseTag_Opts(t *testing.T) {
+	tags := []struct {
+		opts string
+		has  bool
+	}{
+		{"name", false},
+		{"name,opt", true},
+		{"name , opt, opt2", false}, // has a single whitespace
+		{",opt, opt2", true},
+		{", opt3, opt4", false},
+	}
+
+	// search for "opt"
+	for _, tag := range tags {
+		_, opts := parseTag(tag.opts)
+
+		if opts.Has("opt") != tag.has {
+			t.Errorf("Tag opts should have opt: %#v", tag)
+		}
+	}
+}