Add Codec interface

Author: alexedwards

codec.go

@@ -0,0 +1,49 @@
+package scs
+
+import (
+	"bytes"
+	"encoding/gob"
+	"time"
+)
+
+// Codec is the interface for encoding/decoding session data to and from a byte
+// slice for use by the session store.
+type Codec interface {
+	Encode(deadline time.Time, values map[string]interface{}) ([]byte, error)
+	Decode([]byte) (deadline time.Time, values map[string]interface{}, err error)
+}
+
+type gobCodec struct{}
+
+func (gobCodec) Encode(deadline time.Time, values map[string]interface{}) ([]byte, error) {
+	aux := &struct {
+		Deadline time.Time
+		Values   map[string]interface{}
+	}{
+		Deadline: deadline,
+		Values:   values,
+	}
+
+	var b bytes.Buffer
+	err := gob.NewEncoder(&b).Encode(&aux)
+	if err != nil {
+		return nil, err
+	}
+
+	return b.Bytes(), nil
+}
+
+func (gobCodec) Decode(b []byte) (time.Time, map[string]interface{}, error) {
+	aux := &struct {
+		Deadline time.Time
+		Values   map[string]interface{}
+	}{}
+
+	r := bytes.NewReader(b)
+	err := gob.NewDecoder(r).Decode(&aux)
+	if err != nil {
+		return time.Time{}, nil, err
+	}
+
+	return aux.Deadline, aux.Values, nil
+}

data.go

@@ -1,11 +1,9 @@
 package scs
 
 import (
-	"bytes"
 	"context"
 	"crypto/rand"
 	"encoding/base64"
-	"encoding/gob"
 	"fmt"
 	"sort"
 	"sync"
@@ -30,18 +28,18 @@ const (
 )
 
 type sessionData struct {
-	Deadline time.Time // Exported for gob encoding.
+	deadline time.Time
 	status   Status
 	token    string
-	Values   map[string]interface{} // Exported for gob encoding.
+	values   map[string]interface{}
 	mu       sync.Mutex
 }
 
 func newSessionData(lifetime time.Duration) *sessionData {
 	return &sessionData{
-		Deadline: time.Now().Add(lifetime).UTC(),
+		deadline: time.Now().Add(lifetime).UTC(),
 		status:   Unmodified,
-		Values:   make(map[string]interface{}),
+		values:   make(map[string]interface{}),
 	}
 }
 
@@ -71,7 +69,7 @@ func (s *SessionManager) Load(ctx context.Context, token string) (context.Contex
 		status: Unmodified,
 		token:  token,
 	}
-	err = sd.decode(b)
+	sd.deadline, sd.values, err = s.Codec.Decode(b)
 	if err != nil {
 		return nil, err
 	}
@@ -104,12 +102,12 @@ func (s *SessionManager) Commit(ctx context.Context) (string, time.Time, error)
 		}
 	}
 
-	b, err := sd.encode()
+	b, err := s.Codec.Encode(sd.deadline, sd.values)
 	if err != nil {
 		return "", time.Time{}, err
 	}
 
-	expiry := sd.Deadline
+	expiry := sd.deadline
 	if s.IdleTimeout > 0 {
 		ie := time.Now().Add(s.IdleTimeout)
 		if ie.Before(expiry) {
@@ -143,9 +141,9 @@ func (s *SessionManager) Destroy(ctx context.Context) error {
 
 	// Reset everything else to defaults.
 	sd.token = ""
-	sd.Deadline = time.Now().Add(s.Lifetime).UTC()
-	for key := range sd.Values {
-		delete(sd.Values, key)
+	sd.deadline = time.Now().Add(s.Lifetime).UTC()
+	for key := range sd.values {
+		delete(sd.values, key)
 	}
 
 	return nil
@@ -158,7 +156,7 @@ func (s *SessionManager) Put(ctx context.Context, key string, val interface{}) {
 	sd := s.getSessionDataFromContext(ctx)
 
 	sd.mu.Lock()
-	sd.Values[key] = val
+	sd.values[key] = val
 	sd.status = Modified
 	sd.mu.Unlock()
 }
@@ -180,7 +178,7 @@ func (s *SessionManager) Get(ctx context.Context, key string) interface{} {
 	sd.mu.Lock()
 	defer sd.mu.Unlock()
 
-	return sd.Values[key]
+	return sd.values[key]
 }
 
 // Pop acts like a one-time Get. It returns the value for a given key from the
@@ -193,11 +191,11 @@ func (s *SessionManager) Pop(ctx context.Context, key string) interface{} {
 	sd.mu.Lock()
 	defer sd.mu.Unlock()
 
-	val, exists := sd.Values[key]
+	val, exists := sd.values[key]
 	if !exists {
 		return nil
 	}
-	delete(sd.Values, key)
+	delete(sd.values, key)
 	sd.status = Modified
 
 	return val
@@ -212,12 +210,12 @@ func (s *SessionManager) Remove(ctx context.Context, key string) {
 	sd.mu.Lock()
 	defer sd.mu.Unlock()
 
-	_, exists := sd.Values[key]
+	_, exists := sd.values[key]
 	if !exists {
 		return
 	}
 
-	delete(sd.Values, key)
+	delete(sd.values, key)
 	sd.status = Modified
 }
 
@@ -230,12 +228,12 @@ func (s *SessionManager) Clear(ctx context.Context) error {
 	sd.mu.Lock()
 	defer sd.mu.Unlock()
 
-	if len(sd.Values) == 0 {
+	if len(sd.values) == 0 {
 		return nil
 	}
 
-	for key := range sd.Values {
-		delete(sd.Values, key)
+	for key := range sd.values {
+		delete(sd.values, key)
 	}
 	sd.status = Modified
 	return nil
@@ -246,7 +244,7 @@ func (s *SessionManager) Exists(ctx context.Context, key string) bool {
 	sd := s.getSessionDataFromContext(ctx)
 
 	sd.mu.Lock()
-	_, exists := sd.Values[key]
+	_, exists := sd.values[key]
 	sd.mu.Unlock()
 
 	return exists
@@ -259,9 +257,9 @@ func (s *SessionManager) Keys(ctx context.Context) []string {
 	sd := s.getSessionDataFromContext(ctx)
 
 	sd.mu.Lock()
-	keys := make([]string, len(sd.Values))
+	keys := make([]string, len(sd.values))
 	i := 0
-	for key := range sd.Values {
+	for key := range sd.values {
 		keys[i] = key
 		i++
 	}
@@ -298,7 +296,7 @@ func (s *SessionManager) RenewToken(ctx context.Context) error {
 	}
 
 	sd.token = newToken
-	sd.Deadline = time.Now().Add(s.Lifetime).UTC()
+	sd.deadline = time.Now().Add(s.Lifetime).UTC()
 	sd.status = Modified
 
 	return nil
@@ -477,21 +475,6 @@ func (s *SessionManager) getSessionDataFromContext(ctx context.Context) *session
 	return c
 }
 
-func (sd *sessionData) encode() ([]byte, error) {
-	var b bytes.Buffer
-	err := gob.NewEncoder(&b).Encode(sd)
-	if err != nil {
-		return nil, err
-	}
-
-	return b.Bytes(), nil
-}
-
-func (sd *sessionData) decode(b []byte) error {
-	r := bytes.NewReader(b)
-	return gob.NewDecoder(r).Decode(sd)
-}
-
 func generateToken() (string, error) {
 	b := make([]byte, 32)
 	_, err := rand.Read(b)