Remove the Gorp dependency

Removed the underlying Gorp package as a dependency & replaced with use of the standard database/sql driver.

This removes a dependency and makes this package very lightweight and makes database interactions very transparent. Lastly, from the standpoint of unit testing where you want to mock the database layer instead of requiring a real database, you can now easily use a package like [go-SQLMock](https://github.com/DATA-DOG/go-sqlmock) to do just that.

The tests may/not pass for Golang 1.5; it appears that the problem is Travis need to install a linter.

pgstore.go

@@ -3,11 +3,12 @@ package pgstore
 import (
 	"database/sql"
 	"encoding/base32"
+	"errors"
+	"fmt"
 	"net/http"
 	"strings"
 	"time"
 
-	"github.com/coopernurse/gorp"
 	"github.com/gorilla/securecookie"
 	"github.com/gorilla/sessions"
 
@@ -19,18 +20,18 @@ import (
 type PGStore struct {
 	Codecs  []securecookie.Codec
 	Options *sessions.Options
-	path    string
-	DbMap   *gorp.DbMap
+	Path    string
+	DbPool  *sql.DB
 }
 
-// Session type
-type Session struct {
-	Id         int64     `db:"id"`
-	Key        string    `db:"key"`
-	Data       string    `db:"data"`
-	CreatedOn  time.Time `db:"created_on"`
-	ModifiedOn time.Time `db:"modified_on"`
-	ExpiresOn  time.Time `db:"expires_on"`
+// PGSession type
+type PGSession struct {
+	ID         int64
+	Key        string
+	Data       string
+	CreatedOn  time.Time
+	ModifiedOn time.Time
+	ExpiresOn  time.Time
 }
 
 // NewPGStore creates a new PGStore instance and a new database/sql pool.
@@ -38,7 +39,7 @@ type Session struct {
 func NewPGStore(dbURL string, keyPairs ...[]byte) (*PGStore, error) {
 	db, err := sql.Open("postgres", dbURL)
 	if err != nil {
-		// Ignore PGStore value and return nil.
+		// Ignore and return nil.
 		return nil, err
 	}
 	return NewPGStoreFromPool(db, keyPairs...)
@@ -46,25 +47,20 @@ func NewPGStore(dbURL string, keyPairs ...[]byte) (*PGStore, error) {
 
 // NewPGStoreFromPool creates a new PGStore instance from an existing
 // database/sql pool.
-// This will also create in the database the schema needed by pgstore.
+// This will also create the database schema needed by pgstore.
 func NewPGStoreFromPool(db *sql.DB, keyPairs ...[]byte) (*PGStore, error) {
-	dbmap := &gorp.DbMap{Db: db, Dialect: gorp.PostgresDialect{}}
-
 	dbStore := &PGStore{
 		Codecs: securecookie.CodecsFromPairs(keyPairs...),
 		Options: &sessions.Options{
 			Path:   "/",
 			MaxAge: 86400 * 30,
 		},
-		DbMap: dbmap,
+		DbPool: db,
 	}
 
 	// Create table if it doesn't exist
-	dbmap.AddTableWithName(Session{}, "http_sessions").SetKeys(true, "Id")
-	err := dbmap.CreateTablesIfNotExists()
-
+	err := dbStore.createSessionsTable()
 	if err != nil {
-		// Ignore PGStore value and return nil.
 		return nil, err
 	}
 
@@ -73,7 +69,7 @@ func NewPGStoreFromPool(db *sql.DB, keyPairs ...[]byte) (*PGStore, error) {
 
 // Close closes the database connection.
 func (db *PGStore) Close() {
-	db.DbMap.Db.Close()
+	db.DbPool.Close()
 }
 
 // Get Fetches a session for a given name after it has been added to the
@@ -171,8 +167,9 @@ func (db *PGStore) MaxAge(age int) {
 // load fetches a session by ID from the database and decodes its content
 // into session.Values.
 func (db *PGStore) load(session *sessions.Session) error {
-	var s Session
-	err := db.DbMap.SelectOne(&s, "SELECT * FROM http_sessions WHERE key = $1", session.ID)
+	var s PGSession
+
+	err := db.selectOne(&s, session.ID)
 	if err != nil {
 		return err
 	}
@@ -207,7 +204,7 @@ func (db *PGStore) save(session *sessions.Session) error {
 		}
 	}
 
-	s := Session{
+	s := PGSession{
 		Key:        session.ID,
 		Data:       encoded,
 		CreatedOn:  createdOn,
@@ -216,15 +213,58 @@ func (db *PGStore) save(session *sessions.Session) error {
 	}
 
 	if session.IsNew {
-		return db.DbMap.Insert(&s)
+		return db.insert(&s)
 	}
 
-	_, err = db.DbMap.Exec("update http_sessions set data=$1, modified_on=$2, expires_on=$3 where key=$4", s.Data, s.ModifiedOn, s.ExpiresOn, s.Key)
-	return err
+	return db.update(&s)
 }
 
 // Delete session
 func (db *PGStore) destroy(session *sessions.Session) error {
-	_, err := db.DbMap.Db.Exec("DELETE FROM http_sessions WHERE key = $1", session.ID)
+	_, err := db.DbPool.Exec("DELETE FROM http_sessions WHERE key = $1", session.ID)
+	return err
+}
+
+func (db *PGStore) createSessionsTable() error {
+	stmt := "CREATE TABLE IF NOT EXISTS http_sessions (" +
+		"id BIGSERIAL PRIMARY KEY," +
+		"key BYTEA," +
+		"data BYTEA," +
+		"created_on TIMESTAMPTZ DEFAULT CURRENT_TIMESTAMP," +
+		"modified_on TIMESTAMPTZ," +
+		"expires_on TIMESTAMPTZ);"
+
+	_, err := db.DbPool.Exec(stmt)
+	if err != nil {
+		msg := fmt.Sprintf("Unable to create http_sessions table in the database: %s\n", err.Error())
+		return errors.New(msg)
+	}
+
+	return nil
+}
+
+func (db *PGStore) selectOne(s *PGSession, key string) error {
+	stmt := "SELECT id, key, data, created_on, modified_on, expires_on FROM http_sessions WHERE key = $1"
+	err := db.DbPool.QueryRow(stmt, key).Scan(&s.ID, &s.Key, &s.Data, &s.CreatedOn, &s.ModifiedOn, &s.ExpiresOn)
+	if err != nil {
+		msg := fmt.Sprintf("Unable to find session in the database: %s\n", err.Error())
+		return errors.New(msg)
+	}
+
+	return nil
+}
+
+func (db *PGStore) insert(s *PGSession) error {
+	stmt := `INSERT INTO http_sessions (key, data, created_on, modified_on, expires_on)
+           VALUES ($1, $2, $3, $4, $5)`
+	_, err := db.DbPool.Exec(stmt, s.Key, s.Data, s.CreatedOn, s.ModifiedOn, s.ExpiresOn)
+
+	return err
+}
+
+func (db *PGStore) update(s *PGSession) error {
+	stmt := `UPDATE http_sessions SET data=$1, modified_on=$2, expires_on=$3 WHERE key=$4`
+	_, err := db.DbPool.Exec(stmt, s.Data, s.ModifiedOn, s.ExpiresOn, s.Key)
+
 	return err
 }