Add account

lib/test_phoenix_live_view/accounts.ex

@@ -0,0 +1,353 @@
+defmodule TestPhoenixLiveView.Accounts do
+  @moduledoc """
+  The Accounts context.
+  """
+
+  import Ecto.Query, warn: false
+  alias TestPhoenixLiveView.Repo
+
+  alias TestPhoenixLiveView.Accounts.{User, UserToken, UserNotifier}
+
+  ## Database getters
+
+  @doc """
+  Gets a user by email.
+
+  ## Examples
+
+      iex> get_user_by_email("foo@example.com")
+      %User{}
+
+      iex> get_user_by_email("unknown@example.com")
+      nil
+
+  """
+  def get_user_by_email(email) when is_binary(email) do
+    Repo.get_by(User, email: email)
+  end
+
+  @doc """
+  Gets a user by email and password.
+
+  ## Examples
+
+      iex> get_user_by_email_and_password("foo@example.com", "correct_password")
+      %User{}
+
+      iex> get_user_by_email_and_password("foo@example.com", "invalid_password")
+      nil
+
+  """
+  def get_user_by_email_and_password(email, password)
+      when is_binary(email) and is_binary(password) do
+    user = Repo.get_by(User, email: email)
+    if User.valid_password?(user, password), do: user
+  end
+
+  @doc """
+  Gets a single user.
+
+  Raises `Ecto.NoResultsError` if the User does not exist.
+
+  ## Examples
+
+      iex> get_user!(123)
+      %User{}
+
+      iex> get_user!(456)
+      ** (Ecto.NoResultsError)
+
+  """
+  def get_user!(id), do: Repo.get!(User, id)
+
+  ## User registration
+
+  @doc """
+  Registers a user.
+
+  ## Examples
+
+      iex> register_user(%{field: value})
+      {:ok, %User{}}
+
+      iex> register_user(%{field: bad_value})
+      {:error, %Ecto.Changeset{}}
+
+  """
+  def register_user(attrs) do
+    %User{}
+    |> User.registration_changeset(attrs)
+    |> Repo.insert()
+  end
+
+  @doc """
+  Returns an `%Ecto.Changeset{}` for tracking user changes.
+
+  ## Examples
+
+      iex> change_user_registration(user)
+      %Ecto.Changeset{data: %User{}}
+
+  """
+  def change_user_registration(%User{} = user, attrs \\ %{}) do
+    User.registration_changeset(user, attrs, hash_password: false, validate_email: false)
+  end
+
+  ## Settings
+
+  @doc """
+  Returns an `%Ecto.Changeset{}` for changing the user email.
+
+  ## Examples
+
+      iex> change_user_email(user)
+      %Ecto.Changeset{data: %User{}}
+
+  """
+  def change_user_email(user, attrs \\ %{}) do
+    User.email_changeset(user, attrs, validate_email: false)
+  end
+
+  @doc """
+  Emulates that the email will change without actually changing
+  it in the database.
+
+  ## Examples
+
+      iex> apply_user_email(user, "valid password", %{email: ...})
+      {:ok, %User{}}
+
+      iex> apply_user_email(user, "invalid password", %{email: ...})
+      {:error, %Ecto.Changeset{}}
+
+  """
+  def apply_user_email(user, password, attrs) do
+    user
+    |> User.email_changeset(attrs)
+    |> User.validate_current_password(password)
+    |> Ecto.Changeset.apply_action(:update)
+  end
+
+  @doc """
+  Updates the user email using the given token.
+
+  If the token matches, the user email is updated and the token is deleted.
+  The confirmed_at date is also updated to the current time.
+  """
+  def update_user_email(user, token) do
+    context = "change:#{user.email}"
+
+    with {:ok, query} <- UserToken.verify_change_email_token_query(token, context),
+         %UserToken{sent_to: email} <- Repo.one(query),
+         {:ok, _} <- Repo.transaction(user_email_multi(user, email, context)) do
+      :ok
+    else
+      _ -> :error
+    end
+  end
+
+  defp user_email_multi(user, email, context) do
+    changeset =
+      user
+      |> User.email_changeset(%{email: email})
+      |> User.confirm_changeset()
+
+    Ecto.Multi.new()
+    |> Ecto.Multi.update(:user, changeset)
+    |> Ecto.Multi.delete_all(:tokens, UserToken.by_user_and_contexts_query(user, [context]))
+  end
+
+  @doc ~S"""
+  Delivers the update email instructions to the given user.
+
+  ## Examples
+
+      iex> deliver_user_update_email_instructions(user, current_email, &url(~p"/users/settings/confirm_email/#{&1})")
+      {:ok, %{to: ..., body: ...}}
+
+  """
+  def deliver_user_update_email_instructions(%User{} = user, current_email, update_email_url_fun)
+      when is_function(update_email_url_fun, 1) do
+    {encoded_token, user_token} = UserToken.build_email_token(user, "change:#{current_email}")
+
+    Repo.insert!(user_token)
+    UserNotifier.deliver_update_email_instructions(user, update_email_url_fun.(encoded_token))
+  end
+
+  @doc """
+  Returns an `%Ecto.Changeset{}` for changing the user password.
+
+  ## Examples
+
+      iex> change_user_password(user)
+      %Ecto.Changeset{data: %User{}}
+
+  """
+  def change_user_password(user, attrs \\ %{}) do
+    User.password_changeset(user, attrs, hash_password: false)
+  end
+
+  @doc """
+  Updates the user password.
+
+  ## Examples
+
+      iex> update_user_password(user, "valid password", %{password: ...})
+      {:ok, %User{}}
+
+      iex> update_user_password(user, "invalid password", %{password: ...})
+      {:error, %Ecto.Changeset{}}
+
+  """
+  def update_user_password(user, password, attrs) do
+    changeset =
+      user
+      |> User.password_changeset(attrs)
+      |> User.validate_current_password(password)
+
+    Ecto.Multi.new()
+    |> Ecto.Multi.update(:user, changeset)
+    |> Ecto.Multi.delete_all(:tokens, UserToken.by_user_and_contexts_query(user, :all))
+    |> Repo.transaction()
+    |> case do
+      {:ok, %{user: user}} -> {:ok, user}
+      {:error, :user, changeset, _} -> {:error, changeset}
+    end
+  end
+
+  ## Session
+
+  @doc """
+  Generates a session token.
+  """
+  def generate_user_session_token(user) do
+    {token, user_token} = UserToken.build_session_token(user)
+    Repo.insert!(user_token)
+    token
+  end
+
+  @doc """
+  Gets the user with the given signed token.
+  """
+  def get_user_by_session_token(token) do
+    {:ok, query} = UserToken.verify_session_token_query(token)
+    Repo.one(query)
+  end
+
+  @doc """
+  Deletes the signed token with the given context.
+  """
+  def delete_user_session_token(token) do
+    Repo.delete_all(UserToken.by_token_and_context_query(token, "session"))
+    :ok
+  end
+
+  ## Confirmation
+
+  @doc ~S"""
+  Delivers the confirmation email instructions to the given user.
+
+  ## Examples
+
+      iex> deliver_user_confirmation_instructions(user, &url(~p"/users/confirm/#{&1}"))
+      {:ok, %{to: ..., body: ...}}
+
+      iex> deliver_user_confirmation_instructions(confirmed_user, &url(~p"/users/confirm/#{&1}"))
+      {:error, :already_confirmed}
+
+  """
+  def deliver_user_confirmation_instructions(%User{} = user, confirmation_url_fun)
+      when is_function(confirmation_url_fun, 1) do
+    if user.confirmed_at do
+      {:error, :already_confirmed}
+    else
+      {encoded_token, user_token} = UserToken.build_email_token(user, "confirm")
+      Repo.insert!(user_token)
+      UserNotifier.deliver_confirmation_instructions(user, confirmation_url_fun.(encoded_token))
+    end
+  end
+
+  @doc """
+  Confirms a user by the given token.
+
+  If the token matches, the user account is marked as confirmed
+  and the token is deleted.
+  """
+  def confirm_user(token) do
+    with {:ok, query} <- UserToken.verify_email_token_query(token, "confirm"),
+         %User{} = user <- Repo.one(query),
+         {:ok, %{user: user}} <- Repo.transaction(confirm_user_multi(user)) do
+      {:ok, user}
+    else
+      _ -> :error
+    end
+  end
+
+  defp confirm_user_multi(user) do
+    Ecto.Multi.new()
+    |> Ecto.Multi.update(:user, User.confirm_changeset(user))
+    |> Ecto.Multi.delete_all(:tokens, UserToken.by_user_and_contexts_query(user, ["confirm"]))
+  end
+
+  ## Reset password
+
+  @doc ~S"""
+  Delivers the reset password email to the given user.
+
+  ## Examples
+
+      iex> deliver_user_reset_password_instructions(user, &url(~p"/users/reset_password/#{&1}"))
+      {:ok, %{to: ..., body: ...}}
+
+  """
+  def deliver_user_reset_password_instructions(%User{} = user, reset_password_url_fun)
+      when is_function(reset_password_url_fun, 1) do
+    {encoded_token, user_token} = UserToken.build_email_token(user, "reset_password")
+    Repo.insert!(user_token)
+    UserNotifier.deliver_reset_password_instructions(user, reset_password_url_fun.(encoded_token))
+  end
+
+  @doc """
+  Gets the user by reset password token.
+
+  ## Examples
+
+      iex> get_user_by_reset_password_token("validtoken")
+      %User{}
+
+      iex> get_user_by_reset_password_token("invalidtoken")
+      nil
+
+  """
+  def get_user_by_reset_password_token(token) do
+    with {:ok, query} <- UserToken.verify_email_token_query(token, "reset_password"),
+         %User{} = user <- Repo.one(query) do
+      user
+    else
+      _ -> nil
+    end
+  end
+
+  @doc """
+  Resets the user password.
+
+  ## Examples
+
+      iex> reset_user_password(user, %{password: "new long password", password_confirmation: "new long password"})
+      {:ok, %User{}}
+
+      iex> reset_user_password(user, %{password: "valid", password_confirmation: "not the same"})
+      {:error, %Ecto.Changeset{}}
+
+  """
+  def reset_user_password(user, attrs) do
+    Ecto.Multi.new()
+    |> Ecto.Multi.update(:user, User.password_changeset(user, attrs))
+    |> Ecto.Multi.delete_all(:tokens, UserToken.by_user_and_contexts_query(user, :all))
+    |> Repo.transaction()
+    |> case do
+      {:ok, %{user: user}} -> {:ok, user}
+      {:error, :user, changeset, _} -> {:error, changeset}
+    end
+  end
+end

lib/test_phoenix_live_view/accounts/user.ex

@@ -0,0 +1,158 @@
+defmodule TestPhoenixLiveView.Accounts.User do
+  use Ecto.Schema
+  import Ecto.Changeset
+
+  schema "users" do
+    field :email, :string
+    field :password, :string, virtual: true, redact: true
+    field :hashed_password, :string, redact: true
+    field :confirmed_at, :naive_datetime
+
+    timestamps(type: :utc_datetime)
+  end
+
+  @doc """
+  A user changeset for registration.
+
+  It is important to validate the length of both email and password.
+  Otherwise databases may truncate the email without warnings, which
+  could lead to unpredictable or insecure behaviour. Long passwords may
+  also be very expensive to hash for certain algorithms.
+
+  ## Options
+
+    * `:hash_password` - Hashes the password so it can be stored securely
+      in the database and ensures the password field is cleared to prevent
+      leaks in the logs. If password hashing is not needed and clearing the
+      password field is not desired (like when using this changeset for
+      validations on a LiveView form), this option can be set to `false`.
+      Defaults to `true`.
+
+    * `:validate_email` - Validates the uniqueness of the email, in case
+      you don't want to validate the uniqueness of the email (like when
+      using this changeset for validations on a LiveView form before
+      submitting the form), this option can be set to `false`.
+      Defaults to `true`.
+  """
+  def registration_changeset(user, attrs, opts \\ []) do
+    user
+    |> cast(attrs, [:email, :password])
+    |> validate_email(opts)
+    |> validate_password(opts)
+  end
+
+  defp validate_email(changeset, opts) do
+    changeset
+    |> validate_required([:email])
+    |> validate_format(:email, ~r/^[^\s]+@[^\s]+$/, message: "must have the @ sign and no spaces")
+    |> validate_length(:email, max: 160)
+    |> maybe_validate_unique_email(opts)
+  end
+
+  defp validate_password(changeset, opts) do
+    changeset
+    |> validate_required([:password])
+    |> validate_length(:password, min: 12, max: 72)
+    # Examples of additional password validation:
+    # |> validate_format(:password, ~r/[a-z]/, message: "at least one lower case character")
+    # |> validate_format(:password, ~r/[A-Z]/, message: "at least one upper case character")
+    # |> validate_format(:password, ~r/[!?@#$%^&*_0-9]/, message: "at least one digit or punctuation character")
+    |> maybe_hash_password(opts)
+  end
+
+  defp maybe_hash_password(changeset, opts) do
+    hash_password? = Keyword.get(opts, :hash_password, true)
+    password = get_change(changeset, :password)
+
+    if hash_password? && password && changeset.valid? do
+      changeset
+      # If using Bcrypt, then further validate it is at most 72 bytes long
+      |> validate_length(:password, max: 72, count: :bytes)
+      # Hashing could be done with `Ecto.Changeset.prepare_changes/2`, but that
+      # would keep the database transaction open longer and hurt performance.
+      |> put_change(:hashed_password, Bcrypt.hash_pwd_salt(password))
+      |> delete_change(:password)
+    else
+      changeset
+    end
+  end
+
+  defp maybe_validate_unique_email(changeset, opts) do
+    if Keyword.get(opts, :validate_email, true) do
+      changeset
+      |> unsafe_validate_unique(:email, TestPhoenixLiveView.Repo)
+      |> unique_constraint(:email)
+    else
+      changeset
+    end
+  end
+
+  @doc """
+  A user changeset for changing the email.
+
+  It requires the email to change otherwise an error is added.
+  """
+  def email_changeset(user, attrs, opts \\ []) do
+    user
+    |> cast(attrs, [:email])
+    |> validate_email(opts)
+    |> case do
+      %{changes: %{email: _}} = changeset -> changeset
+      %{} = changeset -> add_error(changeset, :email, "did not change")
+    end
+  end
+
+  @doc """
+  A user changeset for changing the password.
+
+  ## Options
+
+    * `:hash_password` - Hashes the password so it can be stored securely
+      in the database and ensures the password field is cleared to prevent
+      leaks in the logs. If password hashing is not needed and clearing the
+      password field is not desired (like when using this changeset for
+      validations on a LiveView form), this option can be set to `false`.
+      Defaults to `true`.
+  """
+  def password_changeset(user, attrs, opts \\ []) do
+    user
+    |> cast(attrs, [:password])
+    |> validate_confirmation(:password, message: "does not match password")
+    |> validate_password(opts)
+  end
+
+  @doc """
+  Confirms the account by setting `confirmed_at`.
+  """
+  def confirm_changeset(user) do
+    now = NaiveDateTime.utc_now() |> NaiveDateTime.truncate(:second)
+    change(user, confirmed_at: now)
+  end
+
+  @doc """
+  Verifies the password.
+
+  If there is no user or the user doesn't have a password, we call
+  `Bcrypt.no_user_verify/0` to avoid timing attacks.
+  """
+  def valid_password?(%TestPhoenixLiveView.Accounts.User{hashed_password: hashed_password}, password)
+      when is_binary(hashed_password) and byte_size(password) > 0 do
+    Bcrypt.verify_pass(password, hashed_password)
+  end
+
+  def valid_password?(_, _) do
+    Bcrypt.no_user_verify()
+    false
+  end
+
+  @doc """
+  Validates the current password otherwise adds an error to the changeset.
+  """
+  def validate_current_password(changeset, password) do
+    if valid_password?(changeset.data, password) do
+      changeset
+    else
+      add_error(changeset, :current_password, "is not valid")
+    end
+  end
+end

lib/test_phoenix_live_view/accounts/user_notifier.ex

@@ -0,0 +1,79 @@
+defmodule TestPhoenixLiveView.Accounts.UserNotifier do
+  import Swoosh.Email
+
+  alias TestPhoenixLiveView.Mailer
+
+  # Delivers the email using the application mailer.
+  defp deliver(recipient, subject, body) do
+    email =
+      new()
+      |> to(recipient)
+      |> from({"TestPhoenixLiveView", "contact@example.com"})
+      |> subject(subject)
+      |> text_body(body)
+
+    with {:ok, _metadata} <- Mailer.deliver(email) do
+      {:ok, email}
+    end
+  end
+
+  @doc """
+  Deliver instructions to confirm account.
+  """
+  def deliver_confirmation_instructions(user, url) do
+    deliver(user.email, "Confirmation instructions", """
+
+    ==============================
+
+    Hi #{user.email},
+
+    You can confirm your account by visiting the URL below:
+
+    #{url}
+
+    If you didn't create an account with us, please ignore this.
+
+    ==============================
+    """)
+  end
+
+  @doc """
+  Deliver instructions to reset a user password.
+  """
+  def deliver_reset_password_instructions(user, url) do
+    deliver(user.email, "Reset password instructions", """
+
+    ==============================
+
+    Hi #{user.email},
+
+    You can reset your password by visiting the URL below:
+
+    #{url}
+
+    If you didn't request this change, please ignore this.
+
+    ==============================
+    """)
+  end
+
+  @doc """
+  Deliver instructions to update a user email.
+  """
+  def deliver_update_email_instructions(user, url) do
+    deliver(user.email, "Update email instructions", """
+
+    ==============================
+
+    Hi #{user.email},
+
+    You can change your email by visiting the URL below:
+
+    #{url}
+
+    If you didn't request this change, please ignore this.
+
+    ==============================
+    """)
+  end
+end

lib/test_phoenix_live_view/accounts/user_token.ex

@@ -0,0 +1,179 @@
+defmodule TestPhoenixLiveView.Accounts.UserToken do
+  use Ecto.Schema
+  import Ecto.Query
+  alias TestPhoenixLiveView.Accounts.UserToken
+
+  @hash_algorithm :sha256
+  @rand_size 32
+
+  # It is very important to keep the reset password token expiry short,
+  # since someone with access to the email may take over the account.
+  @reset_password_validity_in_days 1
+  @confirm_validity_in_days 7
+  @change_email_validity_in_days 7
+  @session_validity_in_days 60
+
+  schema "users_tokens" do
+    field :token, :binary
+    field :context, :string
+    field :sent_to, :string
+    belongs_to :user, TestPhoenixLiveView.Accounts.User
+
+    timestamps(updated_at: false)
+  end
+
+  @doc """
+  Generates a token that will be stored in a signed place,
+  such as session or cookie. As they are signed, those
+  tokens do not need to be hashed.
+
+  The reason why we store session tokens in the database, even
+  though Phoenix already provides a session cookie, is because
+  Phoenix' default session cookies are not persisted, they are
+  simply signed and potentially encrypted. This means they are
+  valid indefinitely, unless you change the signing/encryption
+  salt.
+
+  Therefore, storing them allows individual user
+  sessions to be expired. The token system can also be extended
+  to store additional data, such as the device used for logging in.
+  You could then use this information to display all valid sessions
+  and devices in the UI and allow users to explicitly expire any
+  session they deem invalid.
+  """
+  def build_session_token(user) do
+    token = :crypto.strong_rand_bytes(@rand_size)
+    {token, %UserToken{token: token, context: "session", user_id: user.id}}
+  end
+
+  @doc """
+  Checks if the token is valid and returns its underlying lookup query.
+
+  The query returns the user found by the token, if any.
+
+  The token is valid if it matches the value in the database and it has
+  not expired (after @session_validity_in_days).
+  """
+  def verify_session_token_query(token) do
+    query =
+      from token in by_token_and_context_query(token, "session"),
+        join: user in assoc(token, :user),
+        where: token.inserted_at > ago(@session_validity_in_days, "day"),
+        select: user
+
+    {:ok, query}
+  end
+
+  @doc """
+  Builds a token and its hash to be delivered to the user's email.
+
+  The non-hashed token is sent to the user email while the
+  hashed part is stored in the database. The original token cannot be reconstructed,
+  which means anyone with read-only access to the database cannot directly use
+  the token in the application to gain access. Furthermore, if the user changes
+  their email in the system, the tokens sent to the previous email are no longer
+  valid.
+
+  Users can easily adapt the existing code to provide other types of delivery methods,
+  for example, by phone numbers.
+  """
+  def build_email_token(user, context) do
+    build_hashed_token(user, context, user.email)
+  end
+
+  defp build_hashed_token(user, context, sent_to) do
+    token = :crypto.strong_rand_bytes(@rand_size)
+    hashed_token = :crypto.hash(@hash_algorithm, token)
+
+    {Base.url_encode64(token, padding: false),
+     %UserToken{
+       token: hashed_token,
+       context: context,
+       sent_to: sent_to,
+       user_id: user.id
+     }}
+  end
+
+  @doc """
+  Checks if the token is valid and returns its underlying lookup query.
+
+  The query returns the user found by the token, if any.
+
+  The given token is valid if it matches its hashed counterpart in the
+  database and the user email has not changed. This function also checks
+  if the token is being used within a certain period, depending on the
+  context. The default contexts supported by this function are either
+  "confirm", for account confirmation emails, and "reset_password",
+  for resetting the password. For verifying requests to change the email,
+  see `verify_change_email_token_query/2`.
+  """
+  def verify_email_token_query(token, context) do
+    case Base.url_decode64(token, padding: false) do
+      {:ok, decoded_token} ->
+        hashed_token = :crypto.hash(@hash_algorithm, decoded_token)
+        days = days_for_context(context)
+
+        query =
+          from token in by_token_and_context_query(hashed_token, context),
+            join: user in assoc(token, :user),
+            where: token.inserted_at > ago(^days, "day") and token.sent_to == user.email,
+            select: user
+
+        {:ok, query}
+
+      :error ->
+        :error
+    end
+  end
+
+  defp days_for_context("confirm"), do: @confirm_validity_in_days
+  defp days_for_context("reset_password"), do: @reset_password_validity_in_days
+
+  @doc """
+  Checks if the token is valid and returns its underlying lookup query.
+
+  The query returns the user found by the token, if any.
+
+  This is used to validate requests to change the user
+  email. It is different from `verify_email_token_query/2` precisely because
+  `verify_email_token_query/2` validates the email has not changed, which is
+  the starting point by this function.
+
+  The given token is valid if it matches its hashed counterpart in the
+  database and if it has not expired (after @change_email_validity_in_days).
+  The context must always start with "change:".
+  """
+  def verify_change_email_token_query(token, "change:" <> _ = context) do
+    case Base.url_decode64(token, padding: false) do
+      {:ok, decoded_token} ->
+        hashed_token = :crypto.hash(@hash_algorithm, decoded_token)
+
+        query =
+          from token in by_token_and_context_query(hashed_token, context),
+            where: token.inserted_at > ago(@change_email_validity_in_days, "day")
+
+        {:ok, query}
+
+      :error ->
+        :error
+    end
+  end
+
+  @doc """
+  Returns the token struct for the given token value and context.
+  """
+  def by_token_and_context_query(token, context) do
+    from UserToken, where: [token: ^token, context: ^context]
+  end
+
+  @doc """
+  Gets all tokens for the given user for the given contexts.
+  """
+  def by_user_and_contexts_query(user, :all) do
+    from t in UserToken, where: t.user_id == ^user.id
+  end
+
+  def by_user_and_contexts_query(user, [_ | _] = contexts) do
+    from t in UserToken, where: t.user_id == ^user.id and t.context in ^contexts
+  end
+end