*: add the ability to define passwords statically

storage/static.go

@@ -0,0 +1,94 @@
+package storage
+
+import (
+	"errors"
+	"strings"
+)
+
+// Tests for this code are in the "memory" package, since this package doesn't
+// define a concrete storage implementation.
+
+// staticClientsStorage is a storage that only allow read-only actions on clients.
+// All read actions return from the list of clients stored in memory, not the
+// underlying
+type staticClientsStorage struct {
+	Storage
+
+	// A read-only set of clients.
+	clients     []Client
+	clientsByID map[string]Client
+}
+
+// WithStaticClients returns a storage with a read-only set of clients. Write actions,
+// such as creating other clients, will fail.
+//
+// In the future the returned storage may allow creating and storing additional clients
+// in the underlying storage.
+func WithStaticClients(s Storage, staticClients []Client) Storage {
+	clientsByID := make(map[string]Client, len(staticClients))
+	for _, client := range staticClients {
+		clientsByID[client.ID] = client
+	}
+	return staticClientsStorage{s, staticClients, clientsByID}
+}
+
+func (s staticClientsStorage) GetClient(id string) (Client, error) {
+	if client, ok := s.clientsByID[id]; ok {
+		return client, nil
+	}
+	return Client{}, ErrNotFound
+}
+
+func (s staticClientsStorage) ListClients() ([]Client, error) {
+	clients := make([]Client, len(s.clients))
+	copy(clients, s.clients)
+	return clients, nil
+}
+
+func (s staticClientsStorage) CreateClient(c Client) error {
+	return errors.New("static clients: read-only cannot create client")
+}
+
+func (s staticClientsStorage) DeleteClient(id string) error {
+	return errors.New("static clients: read-only cannot delete client")
+}
+
+func (s staticClientsStorage) UpdateClient(id string, updater func(old Client) (Client, error)) error {
+	return errors.New("static clients: read-only cannot update client")
+}
+
+type staticPasswordsStorage struct {
+	Storage
+
+	passwordsByEmail map[string]Password
+}
+
+// WithStaticPasswords returns a storage with a read-only set of passwords. Write actions,
+// such as creating other passwords, will fail.
+func WithStaticPasswords(s Storage, staticPasswords []Password) Storage {
+	passwordsByEmail := make(map[string]Password, len(staticPasswords))
+	for _, p := range staticPasswords {
+		p.Email = strings.ToLower(p.Email)
+		passwordsByEmail[p.Email] = p
+	}
+	return staticPasswordsStorage{s, passwordsByEmail}
+}
+
+func (s staticPasswordsStorage) GetPassword(email string) (Password, error) {
+	if password, ok := s.passwordsByEmail[strings.ToLower(email)]; ok {
+		return password, nil
+	}
+	return Password{}, ErrNotFound
+}
+
+func (s staticPasswordsStorage) CreatePassword(p Password) error {
+	return errors.New("static passwords: read-only cannot create password")
+}
+
+func (s staticPasswordsStorage) DeletePassword(id string) error {
+	return errors.New("static passwords: read-only cannot create password")
+}
+
+func (s staticPasswordsStorage) UpdatePassword(id string, updater func(old Password) (Password, error)) error {
+	return errors.New("static passwords: read-only cannot update password")
+}