Migration implementation, auto migrate when starting program

config/config.go

@@ -14,6 +14,7 @@ type Configuration struct {
 		Name        string `json:"DbName"`
 		User        string `json:"DbUser"`
 		Password    string `json:"DbPassword"`
+		AutoMigrate bool   `json:"DbAutoMigrate"`
 	}
 
 	Listen struct {

database/databaseConnection.go

@@ -4,9 +4,8 @@ import (
 	"GoWeb/app"
 	"database/sql"
 	"fmt"
-	"log"
-
 	_ "github.com/lib/pq"
+	"log"
 )
 
 // ConnectDB returns a new database connection

database/migrate.go

@@ -0,0 +1,105 @@
+package database
+
+import (
+	"GoWeb/app"
+	"errors"
+	"fmt"
+	"github.com/lib/pq"
+	"log"
+	"reflect"
+)
+
+// Migrate given a dummy object of any type, it will create a table with the same name as the type and create columns with the same name as the fields of the object
+func Migrate(app *app.App, anyStruct interface{}) error {
+	valueOfStruct := reflect.ValueOf(anyStruct)
+	typeOfStruct := valueOfStruct.Type()
+
+	tableName := typeOfStruct.Name()
+	err := createTable(app, tableName)
+	if err != nil {
+		return err
+	}
+
+	for i := 0; i < valueOfStruct.NumField(); i++ {
+		fieldType := typeOfStruct.Field(i)
+		fieldName := fieldType.Name
+		if fieldName != "Id" && fieldName != "id" {
+			err := createColumn(app, tableName, fieldName, fieldType.Type.Name())
+			if err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}
+
+// createTable creates a table with the given name if it doesn't exist, it is assumed that id will be the primary key
+func createTable(app *app.App, tableName string) error {
+	sanitizedTableQuery := fmt.Sprintf("CREATE TABLE IF NOT EXISTS \"%s\" (\"Id\" serial primary key)", tableName)
+
+	_, err := app.Db.Query(sanitizedTableQuery)
+	if err != nil {
+		log.Println("Error creating table: " + tableName)
+		return err
+	}
+
+	log.Println("Table created successfully (or already exists): " + tableName)
+	return nil
+}
+
+// createColumn creates a column with the given name and type if it doesn't exist
+func createColumn(app *app.App, tableName, columnName, columnType string) error {
+	postgresType, err := getPostgresType(columnType)
+	if err != nil {
+		log.Println("Error creating column: " + columnName + " in table: " + tableName + " with type: " + postgresType)
+		return err
+	}
+
+	sanitizedTableName := pq.QuoteIdentifier(tableName)
+	query := fmt.Sprintf("ALTER TABLE %s ADD COLUMN IF NOT EXISTS \"%s\" %s", sanitizedTableName, columnName, postgresType)
+
+	_, err = app.Db.Query(query)
+	if err != nil {
+		log.Println("Error creating column: " + columnName + " in table: " + tableName + " with type: " + postgresType)
+		return err
+	}
+
+	log.Println("Column created successfully (or already exists):", columnName)
+
+	return nil
+}
+
+// Given a type in Go, return the corresponding type in Postgres
+func getPostgresType(goType string) (string, error) {
+	switch goType {
+	case "int":
+	case "int32":
+	case "uint":
+	case "uint32":
+		return "integer", nil
+	case "int64":
+	case "uint64":
+		return "bigint", nil
+	case "int16":
+	case "int8":
+	case "uint16":
+	case "uint8":
+	case "byte":
+		return "smallint", nil
+	case "string":
+		return "text", nil
+	case "float64":
+		return "double precision", nil
+	case "bool":
+		return "boolean", nil
+	case "time.Time":
+		return "timestamp", nil
+	case "[]byte":
+		return "bytea", nil
+	default:
+		return "text", nil
+	}
+
+	return "", errors.New("Unknown type: " + goType)
+}

env_example.json

@@ -4,7 +4,8 @@
     "DbPort": "5432",
     "DbName": "database",
     "DbUser": "user",
-    "DbPassword": "password"
+    "DbPassword": "password",
+    "AutoMigrate": true
   },
   "Listen": {
     "HttpIp": "127.0.0.1",

main.go

@@ -4,6 +4,7 @@ import (
 	"GoWeb/app"
 	"GoWeb/config"
 	"GoWeb/database"
+	"GoWeb/models"
 	"GoWeb/routes"
 	"embed"
 	"log"
@@ -37,8 +38,15 @@ func main() {
 	file, err := os.OpenFile("logs/"+time.Now().Format("2006-01-02")+".log", os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666)
 	log.SetOutput(file)
 
-	// Connect to database
+	// Connect to database and run migrations
 	appLoaded.Db = database.ConnectDB(&appLoaded)
+	if appLoaded.Config.Db.AutoMigrate {
+		err = models.RunAllMigrations(&appLoaded)
+		if err != nil {
+			log.Println(err)
+			return
+		}
+	}
 
 	// Define Routes
 	routes.GetRoutes(&appLoaded)

models/migrations.go

@@ -0,0 +1,21 @@
+package models
+
+import (
+	"GoWeb/app"
+	"GoWeb/database"
+)
+
+// RunAllMigrations defines the structs that should be represented in the database
+func RunAllMigrations(app *app.App) error {
+	// Declare new dummy user for reflection
+	user := User{
+		Id:        1, // Id is handled automatically, but it is added here to show it will be skipped during column creation
+		Username:  "migrate",
+		Password:  "migrate",
+		AuthToken: "migrate",
+		CreatedAt: "2021-01-01 00:00:00",
+		UpdatedAt: "2021-01-01 00:00:00",
+	}
+
+	return database.Migrate(app, user)
+}

models/user.go

@@ -18,6 +18,7 @@ type User struct {
 	Id        int64
 	Username  string
 	Password  string
+	AuthToken string
 	CreatedAt string
 	UpdatedAt string
 }
@@ -34,7 +35,7 @@ func GetCurrentUser(app *app.App, r *http.Request) (User, error) {
 	var userId int64
 
 	// Query row by session cookie
-	err = app.Db.QueryRow("SELECT user_id FROM sessions WHERE session = $1", cookie.Value).Scan(&userId)
+	err = app.Db.QueryRow("SELECT Id FROM User WHERE session = $1", cookie.Value).Scan(&userId)
 	if err != nil {
 		log.Println("Error querying session row with session: " + cookie.Value)
 		return User{}, err
@@ -48,7 +49,7 @@ func GetUserById(app *app.App, id int64) (User, error) {
 	user := User{}
 
 	// Query row by id
-	row, err := app.Db.Query("SELECT id, username, password, created_at, updated_at FROM users WHERE id = $1", id)
+	row, err := app.Db.Query("SELECT Id, Username, Password, AuthToken, CreatedAt, UpdatedAt FROM User WHERE Id = $1", id)
 	if err != nil {
 		log.Println("Error querying user row with id: " + strconv.FormatInt(id, 10))
 		return User{}, err
@@ -85,7 +86,7 @@ func CreateUser(app *app.App, username string, password string, createdAt time.T
 
 	var lastInsertId int64
 
-	sqlStatement := "INSERT INTO users (username, password, created_at, updated_at) VALUES ($1, $2, $3, $4) RETURNING id"
+	sqlStatement := "INSERT INTO User (Username, Password, CreatedAt, UpdatedAt) VALUES ($1, $2, $3, $4) RETURNING Id"
 	err = app.Db.QueryRow(sqlStatement, username, string(hash), createdAt, updatedAt).Scan(&lastInsertId)
 	if err != nil {
 		log.Println("Error creating user row")
@@ -101,7 +102,7 @@ func AuthenticateUser(app *app.App, w http.ResponseWriter, username string, pass
 	var hashedPassword []byte
 
 	// Query row by username, scan password column
-	err := app.Db.QueryRow("SELECT password FROM users WHERE username = $1", username).Scan(&hashedPassword)
+	err := app.Db.QueryRow("SELECT Password FROM User WHERE Username = $1", username).Scan(&hashedPassword)
 	if err != nil {
 		log.Println("Unable to find row with username: " + username)
 		log.Println(err)
@@ -134,7 +135,7 @@ func createSessionCookie(app *app.App, w http.ResponseWriter, username string) (
 
 	// If the auth_token column for any user matches the token, set existingAuthToken to true
 	var existingAuthToken bool
-	err = app.Db.QueryRow("SELECT EXISTS(SELECT 1 FROM users WHERE auth_token = $1)", token).Scan(&existingAuthToken)
+	err = app.Db.QueryRow("SELECT EXISTS(SELECT 1 FROM User WHERE AuthToken = $1)", token).Scan(&existingAuthToken)
 	if err != nil {
 		log.Println("Error checking for existing auth token")
 		log.Println(err)
@@ -148,7 +149,7 @@ func createSessionCookie(app *app.App, w http.ResponseWriter, username string) (
 	}
 
 	// Store token in auth_token column of the users table
-	_, err = app.Db.Exec("UPDATE users SET auth_token = $1 WHERE username = $2", token, username)
+	_, err = app.Db.Exec("UPDATE User SET AuthToken = $1 WHERE Username = $2", token, username)
 	if err != nil {
 		log.Println("Error setting auth_token column in users table")
 		log.Println(err)
@@ -182,7 +183,7 @@ func ValidateSessionCookie(app *app.App, r *http.Request) (string, error) {
 
 	// Query row by token
 	var username string
-	err = app.Db.QueryRow("SELECT username FROM users WHERE auth_token = $1", cookie.Value).Scan(&username)
+	err = app.Db.QueryRow("SELECT Username FROM User WHERE AuthToken = $1", cookie.Value).Scan(&username)
 	if err != nil {
 		log.Println("Error querying row by token")
 		log.Println(err)
@@ -203,7 +204,7 @@ func LogoutUser(app *app.App, w http.ResponseWriter, r *http.Request) {
 	}
 
 	// Set token to empty string
-	sqlStatement := "UPDATE users SET auth_token = $1 WHERE auth_token = $2"
+	sqlStatement := "UPDATE User SET AuthToken = $1 WHERE AuthToken = $2"
 	_, err = app.Db.Exec(sqlStatement, "", cookie.Value)
 	if err != nil {
 		log.Println("Error setting auth_token column in users table")