6 files changed, 138 insertions, 1 deletions
diff --git a/README.md b/README.md
index 4015f95..1ea91cb 100644
--- a/README.md
+++ b/README.md
@@ -13,6 +13,7 @@ A personal instance runs at https://trains.adyxax.org/.
 - [Configuration](#configuration)
 - [Usage](#usage)
 - [Building](#building)
+- [Design Choices](#design-choices)
 - [References](#references)
 
 ## Dependencies
@@ -78,6 +79,11 @@ To cross-compile for another os or architecture, use :
 GOOS=openbsd GOARCH=amd64 go build -ldflags="-s -w" ./cmd/trains-webui/
 ```
 
+## Design Choices
+
+- Being a small webapp, the only database supported for now is sqlite3
+- Being a small webapp with no expectation of traffic and for simplicity, the user sessions are currently stored in the database
+
 ## References
 
 - https://www.digital.sncf.com/startup/api
diff --git a/go.mod b/go.mod
index 408cb0c..7d05ed5 100644
--- a/go.mod
+++ b/go.mod
@@ -5,10 +5,11 @@ go 1.16
 require (
 	github.com/DATA-DOG/go-sqlmock v1.5.0
 	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/google/uuid v1.2.0 // indirect
 	github.com/kr/pretty v0.2.1 // indirect
 	github.com/mattn/go-sqlite3 v1.14.6
 	github.com/stretchr/testify v1.7.0
-	golang.org/x/crypto v0.0.0-20210322153248-0c34fe9e7dc2 // indirect
+	golang.org/x/crypto v0.0.0-20210322153248-0c34fe9e7dc2
 	gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 // indirect
 	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b
 )
diff --git a/go.sum b/go.sum
index c5b34c2..cea06dc 100644
--- a/go.sum
+++ b/go.sum
@@ -3,6 +3,8 @@ github.com/DATA-DOG/go-sqlmock v1.5.0/go.mod h1:f/Ixk793poVmq4qj/V1dPUg2JEAKC73Q
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/google/uuid v1.2.0 h1:qJYtXnJRWmpe7m/3XlyhrsLrEURqHRM2kxzoxXqyUDs=
+github.com/google/uuid v1.2.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/kr/pretty v0.2.1 h1:Fmg33tUaq4/8ym9TJN1x7sLJnHVwhP33CNkpYV/7rwI=
 github.com/kr/pretty v0.2.1/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
diff --git a/pkg/database/migrations.go b/pkg/database/migrations.go
index 8cc6420..7de255a 100644
--- a/pkg/database/migrations.go
+++ b/pkg/database/migrations.go
@@ -17,6 +17,12 @@ var allMigrations = []func(tx *sql.Tx) error{
 				email TEXT,
 				created_at DATE DEFAULT (datetime('now')),
 				last_login_at DATE DEFAULT NULL
+			);
+			CREATE TABLE sessions (
+				token TEXT NOT NULL UNIQUE,
+				user_id INTEGER NOT NULL,
+				created_at DATE DEFAULT (datetime('now')),
+				FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
 			);`
 		_, err = tx.Exec(sql)
 		return err
diff --git a/pkg/database/sessions.go b/pkg/database/sessions.go
new file mode 100644
index 0000000..72930f0
--- /dev/null
+++ b/pkg/database/sessions.go
@@ -0,0 +1,33 @@
+package database
+
+import (
+	"git.adyxax.org/adyxax/trains/pkg/model"
+	"github.com/google/uuid"
+)
+
+func (env *DBEnv) CreateSession(user *model.User) (*string, error) {
+	token := uuid.NewString()
+
+	query := `
+		INSERT INTO sessions
+			(token, user_id)
+		VALUES
+			($1, $2);`
+	tx, err := env.db.Begin()
+	if err != nil {
+		return nil, newTransactionError("Could not Begin()", err)
+	}
+	_, err = tx.Exec(
+		query,
+		token,
+		user.Id,
+	)
+	if err != nil {
+		tx.Rollback()
+		return nil, newQueryError("Could not run database query: most likely the token already exists in database, or the user id does not exist", err)
+	}
+	if err := tx.Commit(); err != nil {
+		return nil, newTransactionError("Could not commit transaction", err)
+	}
+	return &token, nil
+}
diff --git a/pkg/database/sessions_test.go b/pkg/database/sessions_test.go
new file mode 100644
index 0000000..0b6a370
--- /dev/null
+++ b/pkg/database/sessions_test.go
@@ -0,0 +1,89 @@
+package database
+
+import (
+	"reflect"
+	"testing"
+
+	"git.adyxax.org/adyxax/trains/pkg/model"
+	"github.com/DATA-DOG/go-sqlmock"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestCreateSession(t *testing.T) {
+	// test db setup
+	db, err := InitDB("sqlite3", "file::memory:?_foreign_keys=on")
+	require.NoError(t, err)
+	err = db.Migrate()
+	require.NoError(t, err)
+	userReg1 := model.UserRegistration{
+		Username: "user1",
+		Password: "user1_pass",
+		Email:    "user1",
+	}
+	user1, err := db.CreateUser(&userReg1)
+	require.NoError(t, err)
+	user2 := *user1
+	user2.Id++ // we want a token request for an invalid user id
+	// Test cases
+	testCases := []struct {
+		name          string
+		input         *model.User
+		expectedError interface{}
+	}{
+		{"Normal user", user1, nil},
+		{"A normal user can request multiple tokens", user1, nil},
+		{"a non existant user id triggers an error", &user2, &QueryError{}},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			valid, err := db.CreateSession(tc.input)
+			if tc.expectedError != nil {
+				require.Error(t, err)
+				assert.Equalf(t, reflect.TypeOf(err), reflect.TypeOf(tc.expectedError), "Invalid error type. Got %s but expected %s", reflect.TypeOf(err), reflect.TypeOf(tc.expectedError))
+				require.Nil(t, valid)
+			} else {
+				require.NoError(t, err)
+				assert.NotNil(t, valid)
+			}
+		})
+	}
+}
+
+func TestCreateSessionWithSQLMock(t *testing.T) {
+	// Transaction begin error
+	dbBeginError, _, err := sqlmock.New()
+	if err != nil {
+		t.Fatalf("an error '%s' was not expected when opening a stub database connection", err)
+	}
+	defer dbBeginError.Close()
+	// Transaction commit error
+	dbCommitError, mockCommitError, err := sqlmock.New()
+	if err != nil {
+		t.Fatalf("an error '%s' was not expected when opening a stub database connection", err)
+	}
+	defer dbCommitError.Close()
+	mockCommitError.ExpectBegin()
+	mockCommitError.ExpectExec(`INSERT INTO`).WillReturnResult(sqlmock.NewResult(1, 1))
+	// Test cases
+	testCases := []struct {
+		name          string
+		db            *DBEnv
+		expectedError interface{}
+	}{
+		{"begin transaction error", &DBEnv{db: dbBeginError}, &TransactionError{}},
+		{"commit transaction error", &DBEnv{db: dbCommitError}, &TransactionError{}},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			valid, err := tc.db.CreateSession(&model.User{})
+			if tc.expectedError != nil {
+				require.Error(t, err)
+				assert.Equalf(t, reflect.TypeOf(err), reflect.TypeOf(tc.expectedError), "Invalid error type. Got %s but expected %s", reflect.TypeOf(err), reflect.TypeOf(tc.expectedError))
+				require.Nil(t, valid)
+			} else {
+				require.NoError(t, err)
+			}
+		})
+	}
+}