GoWeb/database/models/user.go

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package models
import (
"GoWeb/app"
"bytes"
"crypto/rand"
"database/sql"
"encoding/gob"
"encoding/hex"
"golang.org/x/crypto/bcrypt"
"log"
"math"
"net/http"
"strconv"
"time"
)
type User struct {
Id int64
Username string
Password string
CreatedAt string
UpdatedAt string
}
// GetUserById finds a users table row in the database by id and returns a struct representing this row
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)
if err != nil {
log.Println("Error querying user row with id: " + strconv.FormatInt(id, 10))
return User{}, err
}
defer func(row *sql.Rows) {
err := row.Close()
if err != nil {
log.Println("Error closing database row")
log.Println(err)
}
}(row)
// Feed row data into user struct
row.Next()
err = row.Scan(&user.Id, &user.Username, &user.Password, &user.CreatedAt, &user.UpdatedAt)
if err != nil {
log.Println("Error reading queried row from database")
log.Println(err)
return User{}, err
}
return user, nil
}
// CreateUser creates a users table row in the database
func CreateUser(app *app.App, username string, password string, createdAt time.Time, updatedAt time.Time) (User, error) {
// Hash password
hash, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
if err != nil {
log.Println("Error hashing password when creating user")
return User{}, err
}
var lastInsertId int64
sqlStatement := "INSERT INTO users (username, password, created_at, updated_at) 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")
log.Println(err)
return User{}, err
}
return GetUserById(app, lastInsertId)
}
// AuthenticateUser validates the password for the specified user if it matches a session cookie is created and returned
func AuthenticateUser(app *app.App, username string, password string) (string, error) {
var hashedPassword []byte
// Query row by username, scan password column
err := app.Db.QueryRow("SELECT password FROM users WHERE username = $1", username).Scan(&hashedPassword)
if err != nil {
log.Println("Unable to find row with username: " + username)
log.Println(err)
return "", err
}
// Convert passed password to []byte
passwordBuffer := &bytes.Buffer{}
err = gob.NewEncoder(passwordBuffer).Encode(password)
if err != nil {
log.Println("Unable to convert passed password to []byte")
log.Println(err)
return "", err
}
passwordByteSlice := passwordBuffer.Bytes()
// Validate password
err = bcrypt.CompareHashAndPassword(hashedPassword, passwordByteSlice)
if err != nil { // Failed to validate password, doesn't match
log.Println("Authentication error (incorrect password) for user:" + username)
log.Println(err)
return "", err
} else {
return createSessionCookie(app, username)
}
}
// CreateSessionCookie creates a new session token and cookie and returns the token value
func createSessionCookie(app *app.App, username string) (string, error) {
// Generate random 64 character string (alpha-numeric)
buff := make([]byte, int(math.Ceil(float64(64)/2)))
_, err := rand.Read(buff)
if err != nil {
log.Println("Error creating random buffer for token value")
log.Println(err)
return "", err
}
str := hex.EncodeToString(buff)
token := str[:64]
// Store token in auth_token column of users table
sqlStatement := "UPDATE users SET auth_token = $1 WHERE username = $2"
err = app.Db.QueryRow(sqlStatement, token, username).Scan()
if err != nil {
log.Println("Error setting auth_token column in users table")
log.Println(err)
return "", err
}
// Create session cookie, containing token
cookie := &http.Cookie{
Name: "",
Value: token,
Path: "/",
MaxAge: 86400,
}
http.SetCookie(w, cookie)
return token, nil
}