108 lines
2.3 KiB
Go
108 lines
2.3 KiB
Go
package models
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import (
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"crypto/rand"
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"crypto/sha256"
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"database/sql"
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"encoding/base64"
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"fmt"
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)
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func RandBytes(n int) ([]byte, error) {
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b := make([]byte, n)
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nRead, err := rand.Read(b)
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if err != nil {
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return nil, fmt.Errorf("bytes: %w", err)
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}
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if nRead < n {
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return nil, fmt.Errorf("bytes: didn't read enough random bytes")
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}
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return b, nil
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}
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func RandString(n int) (string, error) {
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b, err := RandBytes(n)
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if err != nil {
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return "", fmt.Errorf("string: %w", err)
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}
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return base64.URLEncoding.EncodeToString(b), nil
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}
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const SessionTokenBytes = 32
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func SessionToken() (string, error) {
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return RandString(SessionTokenBytes)
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}
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func hash(token string) string {
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tokenHash := sha256.Sum256([]byte(token))
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return base64.StdEncoding.EncodeToString(tokenHash[:])
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}
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type Session struct {
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ID int
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UserID int
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TokenHash string
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// Token is only set when creating a new session. When looking up a session
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// this will be left empty, as we only store the hash of a session token
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// in our database and we cannot reverse it into a raw token.
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Token string
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}
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type SessionService struct {
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DB *sql.DB
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}
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func (ss *SessionService) Create(userID int) (*Session, error) {
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token, err := SessionToken()
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if err != nil {
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return nil, fmt.Errorf("create: %w", err)
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}
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session := Session{
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UserID: userID,
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Token: token,
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TokenHash: hash(token),
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}
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row := ss.DB.QueryRow(`
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UPDATE sessions
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SET token_hash = $2
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WHERE user_id = $1
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RETURNING id;
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`, session.UserID, session.TokenHash)
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err = row.Scan(&session.ID)
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if err == sql.ErrNoRows {
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row = ss.DB.QueryRow(`
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INSERT INTO sessions (user_id, token_hash)
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VALUES ($1, $2)
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RETURNING id;
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`, session.UserID, session.TokenHash)
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err = row.Scan(&session.ID)
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}
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if err != nil {
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return nil, fmt.Errorf("create: %w", err)
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}
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return &session, nil
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}
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func (ss *SessionService) User(token string) (*User, error) {
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token_hash := hash(token)
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var user User
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row := ss.DB.QueryRow(`
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SELECT (user_id) FROM sessions WHERE token_hash = $1;
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`, token_hash)
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err := row.Scan(&user.ID)
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if err != nil {
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return nil, fmt.Errorf("user: %w", err)
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}
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row = ss.DB.QueryRow(`
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SELECT email, password_hash
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FROM users WHERE id = $1;
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`, user.ID)
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err = row.Scan(&user.Email, &user.PasswordHash)
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if err != nil {
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return nil, fmt.Errorf("user: %w", err)
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}
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return &user, err
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}
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