Create DB session provider(based on xorm) (#13031)

* Create Xorm session provider

This PR creates a Xorm session provider which creates
the appropriate Session table for macaron/session.

Fix #7137

Signed-off-by: Andrew Thornton <art27@cantab.net>

* extraneous l

Signed-off-by: Andrew Thornton <art27@cantab.net>

* fix lint

Signed-off-by: Andrew Thornton <art27@cantab.net>

* use key instead of ID to be compatible with go-macaron/session

Signed-off-by: Andrew Thornton <art27@cantab.net>

* And change the migration too.

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Update spacing of imports

Co-authored-by: 6543 <6543@obermui.de>

* Update modules/session/xorm.go

Co-authored-by: techknowlogick <matti@mdranta.net>

* add xorm provider to the virtual provider

Signed-off-by: Andrew Thornton <art27@cantab.net>

* prep for master merge

* prep for merge master

* As per @lunny

* move migration out of the way

* Move to call this db session as per @lunny

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: techknowlogick <matti@mdranta.net>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

2 files changed, 174 insertions, 0 deletions

diff --git a/modules/session/db.go b/modules/session/db.go
new file mode 100644
index 0000000000..db8c01de95
--- /dev/null
+++ b/modules/session/db.go
@@ -0,0 +1,172 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package session
+
+import (
+	"log"
+	"sync"
+
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/timeutil"
+
+	"gitea.com/go-chi/session"
+)
+
+// DBStore represents a session store implementation based on the DB.
+type DBStore struct {
+	sid  string
+	lock sync.RWMutex
+	data map[interface{}]interface{}
+}
+
+// NewDBStore creates and returns a DB session store.
+func NewDBStore(sid string, kv map[interface{}]interface{}) *DBStore {
+	return &DBStore{
+		sid:  sid,
+		data: kv,
+	}
+}
+
+// Set sets value to given key in session.
+func (s *DBStore) Set(key, val interface{}) error {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	s.data[key] = val
+	return nil
+}
+
+// Get gets value by given key in session.
+func (s *DBStore) Get(key interface{}) interface{} {
+	s.lock.RLock()
+	defer s.lock.RUnlock()
+
+	return s.data[key]
+}
+
+// Delete delete a key from session.
+func (s *DBStore) Delete(key interface{}) error {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	delete(s.data, key)
+	return nil
+}
+
+// ID returns current session ID.
+func (s *DBStore) ID() string {
+	return s.sid
+}
+
+// Release releases resource and save data to provider.
+func (s *DBStore) Release() error {
+	// Skip encoding if the data is empty
+	if len(s.data) == 0 {
+		return nil
+	}
+
+	data, err := session.EncodeGob(s.data)
+	if err != nil {
+		return err
+	}
+
+	return models.UpdateSession(s.sid, data)
+}
+
+// Flush deletes all session data.
+func (s *DBStore) Flush() error {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	s.data = make(map[interface{}]interface{})
+	return nil
+}
+
+// DBProvider represents a DB session provider implementation.
+type DBProvider struct {
+	maxLifetime int64
+}
+
+// Init initializes DB session provider.
+// connStr: username:password@protocol(address)/dbname?param=value
+func (p *DBProvider) Init(maxLifetime int64, connStr string) error {
+	p.maxLifetime = maxLifetime
+	return nil
+}
+
+// Read returns raw session store by session ID.
+func (p *DBProvider) Read(sid string) (session.RawStore, error) {
+	s, err := models.ReadSession(sid)
+	if err != nil {
+		return nil, err
+	}
+
+	var kv map[interface{}]interface{}
+	if len(s.Data) == 0 || s.Expiry.Add(p.maxLifetime) <= timeutil.TimeStampNow() {
+		kv = make(map[interface{}]interface{})
+	} else {
+		kv, err = session.DecodeGob(s.Data)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return NewDBStore(sid, kv), nil
+}
+
+// Exist returns true if session with given ID exists.
+func (p *DBProvider) Exist(sid string) bool {
+	has, err := models.ExistSession(sid)
+	if err != nil {
+		panic("session/DB: error checking existence: " + err.Error())
+	}
+	return has
+}
+
+// Destroy deletes a session by session ID.
+func (p *DBProvider) Destroy(sid string) error {
+	return models.DestroySession(sid)
+}
+
+// Regenerate regenerates a session store from old session ID to new one.
+func (p *DBProvider) Regenerate(oldsid, sid string) (_ session.RawStore, err error) {
+	s, err := models.RegenerateSession(oldsid, sid)
+	if err != nil {
+		return nil, err
+
+	}
+
+	var kv map[interface{}]interface{}
+	if len(s.Data) == 0 || s.Expiry.Add(p.maxLifetime) <= timeutil.TimeStampNow() {
+		kv = make(map[interface{}]interface{})
+	} else {
+		kv, err = session.DecodeGob(s.Data)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return NewDBStore(sid, kv), nil
+}
+
+// Count counts and returns number of sessions.
+func (p *DBProvider) Count() int {
+	total, err := models.CountSessions()
+	if err != nil {
+		panic("session/DB: error counting records: " + err.Error())
+	}
+	return int(total)
+}
+
+// GC calls GC to clean expired sessions.
+func (p *DBProvider) GC() {
+	if err := models.CleanupSessions(p.maxLifetime); err != nil {
+		log.Printf("session/DB: error garbage collecting: %v", err)
+	}
+}
+
+func init() {
+	session.Register("db", &DBProvider{})
+}
diff --git a/modules/session/virtual.go b/modules/session/virtual.go
index 3da499d71a..8402d49a77 100644
--- a/modules/session/virtual.go
+++ b/modules/session/virtual.go
@@ -39,6 +39,8 @@ func (o *VirtualSessionProvider) Init(gclifetime int64, config string) error {
 		o.provider = &session.FileProvider{}
 	case "redis":
 		o.provider = &RedisProvider{}
+	case "db":
+		o.provider = &DBProvider{}
 	case "mysql":
 		o.provider = &mysql.MysqlProvider{}
 	case "postgres":