feat: rate limiter, users table, validation, servers split up, graceful quit, user functions
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@@ -0,0 +1,215 @@
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package data
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import (
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"context"
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"database/sql"
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"errors"
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"time"
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"golang.org/x/crypto/bcrypt"
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"greenlight.debuggingjon.dev/internal/validator"
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)
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// Define a custom ErrDuplicateEmail error.
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var (
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ErrDuplicateEmail = errors.New("duplicate email")
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)
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// Define a User struct to represent an individual user. Importantly, notice how we are
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// using the json:"-" struct tag to prevent the Password and Version fields appearing in
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// any output when we encode it to JSON. Also notice that the Password field uses the
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// custom password type defined below.
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type User struct {
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ID int64 `json:"id"`
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CreatedAt time.Time `json:"created_at"`
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Name string `json:"name"`
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Email string `json:"email"`
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Password password `json:"-"`
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Activated bool `json:"activated"`
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Version int `json:"-"`
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}
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// Create a custom password type which is a struct containing the plaintext and hashed
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// versions of the password for a user. The plaintext field is a *pointer* to a string,
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// so that we're able to distinguish between a plaintext password not being present in
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// the struct at all, versus a plaintext password which is the empty string "".
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type password struct {
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plaintext *string
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hash []byte
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}
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// The Set() method calculates the bcrypt hash of a plaintext password, and stores both
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// the hash and the plaintext versions in the struct.
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func (p *password) Set(plaintextPassword string) error {
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hash, err := bcrypt.GenerateFromPassword([]byte(plaintextPassword), 12)
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if err != nil {
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return err
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}
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p.plaintext = &plaintextPassword
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p.hash = hash
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return nil
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}
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// The Matches() method checks whether the provided plaintext password matches the
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// hashed password stored in the struct, returning true if it matches and false
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// otherwise.
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func (p *password) Matches(plaintextPassword string) (bool, error) {
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err := bcrypt.CompareHashAndPassword(p.hash, []byte(plaintextPassword))
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if err != nil {
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switch {
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case errors.Is(err, bcrypt.ErrMismatchedHashAndPassword):
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return false, nil
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default:
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return false, err
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}
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}
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return true, nil
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}
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func ValidateEmail(v *validator.Validator, email string) {
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v.Check(email != "", "email", "must be provided")
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v.Check(validator.Matches(email, validator.EmailRX), "email", "must be a valid email address")
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}
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func ValidatePasswordPlaintext(v *validator.Validator, password string) {
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v.Check(password != "", "password", "must be provided")
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v.Check(len(password) >= 8, "password", "must be at least 8 bytes long")
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v.Check(len(password) <= 72, "password", "must not be more than 72 bytes long")
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}
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func ValidateUser(v *validator.Validator, user *User) {
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v.Check(user.Name != "", "name", "must be provided")
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v.Check(len(user.Name) <= 500, "name", "must not be more than 500 bytes long")
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// Call the standalone ValidateEmail() helper.
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ValidateEmail(v, user.Email)
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// If the plaintext password is not nil, call the standalone
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// ValidatePasswordPlaintext() helper.
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if user.Password.plaintext != nil {
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ValidatePasswordPlaintext(v, *user.Password.plaintext)
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}
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// If the password hash is ever nil, this will be due to a logic error in our
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// codebase (probably because we forgot to set a password for the user). It's a
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// useful sanity check to include here, but it's not a problem with the data
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// provided by the client. So rather than adding an error to the validation map we
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// raise a panic instead.
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if user.Password.hash == nil {
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panic("missing password hash for user")
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}
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}
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// Create a UserModel struct which wraps the connection pool.
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type UserModel struct {
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DB *sql.DB
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}
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// Insert a new record in the database for the user. Note that the id, created_at and
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// version fields are all automatically generated by our database, so we use the
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// RETURNING clause to read them into the User struct after the insert, in the same way
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// that we did when creating a movie.
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func (m UserModel) Insert(user *User) error {
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query := `
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INSERT INTO users (name, email, password_hash, activated)
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VALUES ($1, $2, $3, $4)
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RETURNING id, created_at, version`
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args := []any{user.Name, user.Email, user.Password.hash, user.Activated}
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ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
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defer cancel()
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// If the table already contains a record with this email address, then when we try
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// to perform the insert there will be a violation of the UNIQUE "users_email_key"
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// constraint that we set up in the previous chapter. We check for this error
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// specifically, and return custom ErrDuplicateEmail error instead.
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err := m.DB.QueryRowContext(ctx, query, args...).Scan(&user.ID, &user.CreatedAt, &user.Version)
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if err != nil {
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switch {
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case err.Error() == `pq: duplicate key value violates unique constraint "users_email_key"`:
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return ErrDuplicateEmail
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default:
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return err
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}
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}
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return nil
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}
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// Retrieve the User details from the database based on the user's email address.
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// Because we have a UNIQUE constraint on the email column, this SQL query will only
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// return one record (or none at all, in which case we return a ErrRecordNotFound error).
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func (m UserModel) GetByEmail(email string) (*User, error) {
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query := `
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SELECT id, created_at, name, email, password_hash, activated, version
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FROM users
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WHERE email = $1`
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var user User
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ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
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defer cancel()
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err := m.DB.QueryRowContext(ctx, query, email).Scan(
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&user.ID,
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&user.CreatedAt,
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&user.Name,
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&user.Email,
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&user.Password.hash,
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&user.Activated,
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&user.Version,
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)
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if err != nil {
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switch {
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case errors.Is(err, sql.ErrNoRows):
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return nil, ErrRecordNotFound
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default:
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return nil, err
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}
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}
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return &user, nil
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}
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// Update the details for a specific user. Notice that we check against the version
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// field to help prevent any race conditions during the request cycle, just like we did
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// when updating a movie. And we also check for a violation of the "users_email_key"
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// constraint when performing the update, just like we did when inserting the user
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// record originally.
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func (m UserModel) Update(user *User) error {
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query := `
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UPDATE users
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SET name = $1, email = $2, password_hash = $3, activated = $4, version = version + 1
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WHERE id = $5 AND version = $6
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RETURNING version`
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args := []any{
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user.Name,
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user.Email,
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user.Password.hash,
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user.Activated,
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user.ID,
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user.Version,
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}
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ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
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defer cancel()
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err := m.DB.QueryRowContext(ctx, query, args...).Scan(&user.Version)
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if err != nil {
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switch {
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case err.Error() == `pq: duplicate key value violates unique constraint "users_email_key"`:
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return ErrDuplicateEmail
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case errors.Is(err, sql.ErrNoRows):
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return ErrEditConflict
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default:
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return err
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}
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}
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return nil
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}
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