simplify oauth2 by removing session controller & converting a session…

… to a struct (#241)

_examples/oauth2/example.go

@@ -25,6 +25,7 @@ var (
 	logger       = log.Default()
 	httpClient   = http.DefaultClient
 	client       oauth2.Client
+	sessions     map[string]oauth2.Session
 )
 
 func init() {
@@ -49,8 +50,8 @@ func handleRoot(w http.ResponseWriter, r *http.Request) {
 	var body string
 	cookie, err := r.Cookie("token")
 	if err == nil {
-		session := client.SessionController().GetSession(cookie.Value)
-		if session != nil {
+		session, ok := sessions[cookie.Value]
+		if ok {
 			var user *discord.OAuth2User
 			user, err = client.GetUser(session)
 			if err != nil {
@@ -100,11 +101,12 @@ func handleTryLogin(w http.ResponseWriter, r *http.Request) {
 	)
 	if code != "" && state != "" {
 		identifier := randStr(32)
-		_, err := client.StartSession(code, state, identifier)
+		session, _, err := client.StartSession(code, state)
 		if err != nil {
 			writeError(w, "error while starting session", err)
 			return
 		}
+		sessions[identifier] = session
 		http.SetCookie(w, &http.Cookie{Name: "token", Value: identifier})
 	}
 	http.Redirect(w, r, "/", http.StatusTemporaryRedirect)

oauth2/client.go

@@ -3,6 +3,7 @@ package oauth2
 import (
 	"errors"
 	"fmt"
+	"time"
 
 	"github.com/disgoorg/snowflake/v2"
 
@@ -14,49 +15,71 @@ var (
 	// ErrStateNotFound is returned when the state is not found in the SessionController.
 	ErrStateNotFound = errors.New("state could not be found")
 
-	// ErrAccessTokenExpired is returned when the access token has expired.
-	ErrAccessTokenExpired = errors.New("access token expired. refresh the session")
+	// ErrSessionExpired is returned when the Session has expired.
+	ErrSessionExpired = errors.New("access token expired. refresh the session")
 
 	// ErrMissingOAuth2Scope is returned when a specific OAuth2 scope is missing.
 	ErrMissingOAuth2Scope = func(scope discord.OAuth2Scope) error {
 		return fmt.Errorf("missing '%s' scope", scope)
 	}
 )
 
+// Session represents a discord access token response (https://discord.com/developers/docs/topics/oauth2#authorization-code-grant-access-token-response)
+type Session struct {
+	// AccessToken allows requesting user information
+	AccessToken string `json:"access_token"`
+
+	// RefreshToken allows refreshing the AccessToken
+	RefreshToken string `json:"refresh_token"`
+
+	// Scopes returns the discord.OAuth2Scope(s) of the Session
+	Scopes []discord.OAuth2Scope `json:"scope"`
+
+	// TokenType returns the discord.TokenType of the AccessToken
+	TokenType discord.TokenType `json:"token_type"`
+
+	// Expiration returns the time.Time when the AccessToken expires and needs to be refreshed
+	Expiration time.Time `json:"expiration"`
+}
+
+func (s Session) Expired() bool {
+	return s.Expiration.Before(time.Now())
+}
+
 // Client is a high level wrapper around Discord's OAuth2 API.
 type Client interface {
-	// ID returns the configured client ID
+	// ID returns the configured client ID.
 	ID() snowflake.ID
-	// Secret returns the configured client secret
+	// Secret returns the configured client secret.
 	Secret() string
-	// Rest returns the underlying rest.OAuth2
+	// Rest returns the underlying rest.OAuth2.
 	Rest() rest.OAuth2
 
-	// SessionController returns the configured SessionController
-	SessionController() SessionController
-	// StateController returns the configured StateController
+	// StateController returns the configured StateController.
 	StateController() StateController
 
-	// GenerateAuthorizationURL generates an authorization URL with the given redirect URI, permissions, guildID, disableGuildSelect & scopes. State is automatically generated
+	// GenerateAuthorizationURL generates an authorization URL with the given redirect URI, permissions, guildID, disableGuildSelect & scopes. State is automatically generated.
 	GenerateAuthorizationURL(redirectURI string, permissions discord.Permissions, guildID snowflake.ID, disableGuildSelect bool, scopes ...discord.OAuth2Scope) string
-	// GenerateAuthorizationURLState generates an authorization URL with the given redirect URI, permissions, guildID, disableGuildSelect & scopes. State is automatically generated & returned
+	// GenerateAuthorizationURLState generates an authorization URL with the given redirect URI, permissions, guildID, disableGuildSelect & scopes. State is automatically generated & returned.
 	GenerateAuthorizationURLState(redirectURI string, permissions discord.Permissions, guildID snowflake.ID, disableGuildSelect bool, scopes ...discord.OAuth2Scope) (string, string)
 
-	// StartSession starts a new Session with the given authorization code & state
-	StartSession(code string, state string, identifier string, opts ...rest.RequestOpt) (Session, error)
-	// RefreshSession refreshes the given Session with the refresh token
-	RefreshSession(identifier string, session Session, opts ...rest.RequestOpt) (Session, error)
+	// StartSession starts a new Session with the given authorization code & state.
+	StartSession(code string, state string, opts ...rest.RequestOpt) (Session, *discord.IncomingWebhook, error)
+	// RefreshSession refreshes the given Session with the refresh token.
+	RefreshSession(session Session, opts ...rest.RequestOpt) (Session, error)
+	// VerifySession verifies the given Session & refreshes it if needed.
+	VerifySession(session Session, opts ...rest.RequestOpt) (Session, error)
 
-	// GetUser returns the discord.OAuth2User associated with the given Session. Fields filled in the struct depend on the Session.Scopes
+	// GetUser returns the discord.OAuth2User associated with the given Session. Fields filled in the struct depend on the Session.Scopes.
 	GetUser(session Session, opts ...rest.RequestOpt) (*discord.OAuth2User, error)
 	// GetMember returns the discord.Member associated with the given Session in a specific guild.
 	GetMember(session Session, guildID snowflake.ID, opts ...rest.RequestOpt) (*discord.Member, error)
-	// GetGuilds returns the discord.OAuth2Guild(s) the user is a member of. This requires the discord.OAuth2ScopeGuilds scope in the Session
+	// GetGuilds returns the discord.OAuth2Guild(s) the user is a member of. This requires the discord.OAuth2ScopeGuilds scope in the Session.
 	GetGuilds(session Session, opts ...rest.RequestOpt) ([]discord.OAuth2Guild, error)
-	// GetConnections returns the discord.Connection(s) the user has connected. This requires the discord.OAuth2ScopeConnections scope in the Session
+	// GetConnections returns the discord.Connection(s) the user has connected. This requires the discord.OAuth2ScopeConnections scope in the Session.
 	GetConnections(session Session, opts ...rest.RequestOpt) ([]discord.Connection, error)
-	// GetApplicationRoleConnection returns the discord.ApplicationRoleConnection for the given application. This requires the discord.OAuth2ScopeRoleConnectionsWrite scope in the Session
+	// GetApplicationRoleConnection returns the discord.ApplicationRoleConnection for the given application. This requires the discord.OAuth2ScopeRoleConnectionsWrite scope in the Session.
 	GetApplicationRoleConnection(session Session, applicationID snowflake.ID, opts ...rest.RequestOpt) (*discord.ApplicationRoleConnection, error)
-	// UpdateApplicationRoleConnection updates the discord.ApplicationRoleConnection for the given application. This requires the discord.OAuth2ScopeRoleConnectionsWrite scope in the Session
+	// UpdateApplicationRoleConnection updates the discord.ApplicationRoleConnection for the given application. This requires the discord.OAuth2ScopeRoleConnectionsWrite scope in the Session.
 	UpdateApplicationRoleConnection(session Session, applicationID snowflake.ID, update discord.ApplicationRoleConnectionUpdate, opts ...rest.RequestOpt) (*discord.ApplicationRoleConnection, error)
 }

oauth2/client_impl.go

@@ -35,10 +35,6 @@ func (c *clientImpl) Rest() rest.OAuth2 {
 	return c.config.OAuth2
 }
 
-func (c *clientImpl) SessionController() SessionController {
-	return c.config.SessionController
-}
-
 func (c *clientImpl) StateController() StateController {
 	return c.config.StateController
 }
@@ -70,74 +66,92 @@ func (c *clientImpl) GenerateAuthorizationURLState(redirectURI string, permissio
 	return discord.AuthorizeURL(values), state
 }
 
-func (c *clientImpl) StartSession(code string, state string, identifier string, opts ...rest.RequestOpt) (Session, error) {
+func (c *clientImpl) StartSession(code string, state string, opts ...rest.RequestOpt) (Session, *discord.IncomingWebhook, error) {
 	redirectURI := c.StateController().ConsumeState(state)
 	if redirectURI == "" {
-		return nil, ErrStateNotFound
+		return Session{}, nil, ErrStateNotFound
 	}
-	exchange, err := c.Rest().GetAccessToken(c.id, c.secret, code, redirectURI, opts...)
+	accessToken, err := c.Rest().GetAccessToken(c.id, c.secret, code, redirectURI, opts...)
 	if err != nil {
-		return nil, err
+		return Session{}, nil, err
 	}
-	return c.SessionController().CreateSessionFromResponse(identifier, *exchange), nil
+
+	return newSession(*accessToken), accessToken.Webhook, nil
 }
 
-func (c *clientImpl) RefreshSession(identifier string, session Session, opts ...rest.RequestOpt) (Session, error) {
-	exchange, err := c.Rest().RefreshAccessToken(c.id, c.secret, session.RefreshToken(), opts...)
+func (c *clientImpl) RefreshSession(session Session, opts ...rest.RequestOpt) (Session, error) {
+	accessToken, err := c.Rest().RefreshAccessToken(c.id, c.secret, session.RefreshToken, opts...)
 	if err != nil {
-		return nil, err
+		return Session{}, err
 	}
-	return c.SessionController().CreateSessionFromResponse(identifier, *exchange), nil
+	return newSession(*accessToken), nil
+}
+
+func (c *clientImpl) VerifySession(session Session, opts ...rest.RequestOpt) (Session, error) {
+	if session.Expired() {
+		return c.RefreshSession(session, opts...)
+	}
+	return session, nil
 }
 
 func (c *clientImpl) GetUser(session Session, opts ...rest.RequestOpt) (*discord.OAuth2User, error) {
 	if err := checkSession(session, discord.OAuth2ScopeIdentify); err != nil {
 		return nil, err
 	}
-	return c.Rest().GetCurrentUser(session.AccessToken(), opts...)
+	return c.Rest().GetCurrentUser(session.AccessToken, opts...)
 }
 
 func (c *clientImpl) GetMember(session Session, guildID snowflake.ID, opts ...rest.RequestOpt) (*discord.Member, error) {
 	if err := checkSession(session, discord.OAuth2ScopeGuildsMembersRead); err != nil {
 		return nil, err
 	}
-	return c.Rest().GetCurrentMember(session.AccessToken(), guildID, opts...)
+	return c.Rest().GetCurrentMember(session.AccessToken, guildID, opts...)
 }
 
 func (c *clientImpl) GetGuilds(session Session, opts ...rest.RequestOpt) ([]discord.OAuth2Guild, error) {
 	if err := checkSession(session, discord.OAuth2ScopeGuilds); err != nil {
 		return nil, err
 	}
-	return c.Rest().GetCurrentUserGuilds(session.AccessToken(), 0, 0, 0, opts...)
+	return c.Rest().GetCurrentUserGuilds(session.AccessToken, 0, 0, 0, opts...)
 }
 
 func (c *clientImpl) GetConnections(session Session, opts ...rest.RequestOpt) ([]discord.Connection, error) {
 	if err := checkSession(session, discord.OAuth2ScopeConnections); err != nil {
 		return nil, err
 	}
-	return c.Rest().GetCurrentUserConnections(session.AccessToken(), opts...)
+	return c.Rest().GetCurrentUserConnections(session.AccessToken, opts...)
 }
 
 func (c *clientImpl) GetApplicationRoleConnection(session Session, applicationID snowflake.ID, opts ...rest.RequestOpt) (*discord.ApplicationRoleConnection, error) {
 	if err := checkSession(session, discord.OAuth2ScopeRoleConnectionsWrite); err != nil {
 		return nil, err
 	}
-	return c.Rest().GetCurrentUserApplicationRoleConnection(session.AccessToken(), applicationID, opts...)
+	return c.Rest().GetCurrentUserApplicationRoleConnection(session.AccessToken, applicationID, opts...)
 }
 
 func (c *clientImpl) UpdateApplicationRoleConnection(session Session, applicationID snowflake.ID, update discord.ApplicationRoleConnectionUpdate, opts ...rest.RequestOpt) (*discord.ApplicationRoleConnection, error) {
 	if err := checkSession(session, discord.OAuth2ScopeRoleConnectionsWrite); err != nil {
 		return nil, err
 	}
-	return c.Rest().UpdateCurrentUserApplicationRoleConnection(session.AccessToken(), applicationID, update, opts...)
+	return c.Rest().UpdateCurrentUserApplicationRoleConnection(session.AccessToken, applicationID, update, opts...)
 }
 
 func checkSession(session Session, scope discord.OAuth2Scope) error {
-	if session.Expiration().Before(time.Now()) {
-		return ErrAccessTokenExpired
+	if session.Expired() {
+		return ErrSessionExpired
 	}
-	if !discord.HasScope(scope, session.Scopes()...) {
+	if !discord.HasScope(scope, session.Scopes...) {
 		return ErrMissingOAuth2Scope(scope)
 	}
 	return nil
 }
+
+func newSession(accessToken discord.AccessTokenResponse) Session {
+	return Session{
+		AccessToken:  accessToken.AccessToken,
+		RefreshToken: accessToken.RefreshToken,
+		Scopes:       accessToken.Scope,
+		TokenType:    accessToken.TokenType,
+		Expiration:   time.Now().Add(accessToken.ExpiresIn * time.Second),
+	}
+}

oauth2/config.go

@@ -9,8 +9,7 @@ import (
 // DefaultConfig is the configuration which is used by default
 func DefaultConfig() *Config {
 	return &Config{
-		Logger:            log.Default(),
-		SessionController: NewSessionController(),
+		Logger: log.Default(),
 	}
 }
 
@@ -20,7 +19,6 @@ type Config struct {
 	RestClient                rest.Client
 	RestClientConfigOpts      []rest.ConfigOpt
 	OAuth2                    rest.OAuth2
-	SessionController         SessionController
 	StateController           StateController
 	StateControllerConfigOpts []StateControllerConfigOpt
 }
@@ -72,13 +70,6 @@ func WithOAuth2(oauth2 rest.OAuth2) ConfigOpt {
 	}
 }
 
-// WithSessionController applies a custom SessionController to the OAuth2 client
-func WithSessionController(sessionController SessionController) ConfigOpt {
-	return func(config *Config) {
-		config.SessionController = sessionController
-	}
-}
-
 // WithStateController applies a custom StateController to the OAuth2 client
 func WithStateController(stateController StateController) ConfigOpt {
 	return func(config *Config) {