feat(session): add initial session engine structure

Refs: #8

session/session.go

@@ -0,0 +1,131 @@
+package session
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"time"
+)
+
+type Engine interface {
+	Read(string, any) error
+	Start() error
+	Stop() error
+	Store(string, any) error
+	Encode() error
+	Decode() error
+}
+
+type FileEngine struct {
+	Dir string
+	Encoder
+	PurgeDuration time.Duration
+}
+
+func NewFileEngine() *FileEngine {
+	dir := filepath.Join(os.TempDir(), "httpok", "sess")
+	return &FileEngine{
+		Dir:           dir,
+		Encoder:       &JsonEncoder{},
+		PurgeDuration: 2 * time.Minute,
+	}
+}
+
+func (e *FileEngine) Read(sess string, v any) error {
+	sessFile := filepath.Join(e.Dir, fmt.Sprintf("%s.sess", sess))
+	file, err := os.Open(sessFile)
+	if err != nil {
+		return err
+	}
+
+	defer file.Close()
+
+	buffer := make([]byte, 1024)
+	n, err := file.Read(buffer)
+
+	if err != nil {
+		return err
+	}
+	err = e.Encoder.Decode(buffer[:n], v)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (e *FileEngine) Start() error {
+	fileInfo, err := os.Stat(e.Dir)
+	if err != nil {
+		if os.IsNotExist(err) {
+			err := os.MkdirAll(e.Dir, 0o774)
+			if err != nil {
+				return errors.New(
+					fmt.Sprintf("error creating session dir %s: %v", e.Dir,
+						err),
+				)
+			}
+			return nil
+		}
+		return errors.New(
+			fmt.Sprintf("error stating session dir %s: %v", e.Dir, err),
+		)
+	}
+
+	if fileInfo.Mode().IsRegular() {
+		return errors.New(
+			fmt.Sprintf("there is a file named as %s it is not possible to "+
+				"create the sesssion dir", e.Dir),
+		)
+	}
+
+	return nil
+}
+
+func (e *FileEngine) Stop() error {
+	return nil
+}
+
+func (e *FileEngine) Store(sess string, v any) error {
+	sessFile := filepath.Join(e.Dir, fmt.Sprintf("%s.sess", sess))
+	file, err := os.OpenFile(sessFile, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	data, err := e.Encoder.Encode(v)
+
+	_, err = file.Write(data)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (e *FileEngine) Encode() error {
+	return nil
+}
+
+func (e *FileEngine) Decode() error {
+	return nil
+}
+
+type Encoder interface {
+	Encode(any) ([]byte, error)
+	Decode([]byte, any) error
+}
+
+type JsonEncoder struct {
+}
+
+func (e *JsonEncoder) Encode(v any) ([]byte, error) {
+	return json.Marshal(v)
+}
+
+func (e *JsonEncoder) Decode(data []byte, v any) error {
+	return json.Unmarshal(data, v)
+}

session/session_test.go

@@ -0,0 +1,59 @@
+// Copyright 2023-2025 Flavio Garcia
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package session
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/candango/httpok/util"
+	"github.com/stretchr/testify/assert"
+)
+
+// TODO: We need to keep building the session engine tests
+func TestSessionServer(t *testing.T) {
+	engine := NewFileEngine()
+	err := engine.Start()
+	if err != nil {
+		t.Error(err)
+	}
+
+	sess := util.RandomString(16)
+
+	err = engine.Store(sess, map[string]interface{}{
+		"key": "value",
+	})
+	if err != nil {
+		t.Error(err)
+	}
+	var sessData map[string]interface{}
+
+	err = engine.Read(sess, &sessData)
+	if err != nil {
+		t.Error(err)
+	}
+
+	assert.Equal(t, "value", sessData["key"])
+	defer func() {
+		sessFile := filepath.Join(engine.Dir, fmt.Sprintf("%s.sess", sess))
+		err := os.Remove(sessFile)
+		if err != nil {
+			t.Error(err)
+		}
+
+	}()
+}