package auth import ( "net/http" "os" "codeberg.org/u1f320/pronouns.cc/backend/db" "codeberg.org/u1f320/pronouns.cc/backend/log" "codeberg.org/u1f320/pronouns.cc/backend/server" "emperror.dev/errors" "github.com/bwmarrin/discordgo" "github.com/go-chi/render" "github.com/mediocregopher/radix/v4" "golang.org/x/oauth2" ) var discordOAuthConfig = oauth2.Config{ ClientID: os.Getenv("DISCORD_CLIENT_ID"), ClientSecret: os.Getenv("DISCORD_CLIENT_SECRET"), Endpoint: oauth2.Endpoint{ AuthURL: "https://discord.com/api/oauth2/authorize", TokenURL: "https://discord.com/api/oauth2/token", AuthStyle: oauth2.AuthStyleInParams, }, Scopes: []string{"identify"}, } type oauthCallbackRequest struct { CallbackDomain string `json:"callback_domain"` Code string `json:"code"` State string `json:"state"` } type discordCallbackResponse struct { HasAccount bool `json:"has_account"` // if true, Token and User will be set. if false, Ticket and Discord will be set Token string `json:"token,omitempty"` User *userResponse `json:"user,omitempty"` Discord string `json:"discord,omitempty"` // username, for UI purposes Ticket string `json:"ticket,omitempty"` RequireInvite bool `json:"require_invite"` // require an invite for signing up } func (s *Server) discordCallback(w http.ResponseWriter, r *http.Request) error { ctx := r.Context() decoded, err := Decode[oauthCallbackRequest](r) if err != nil { return server.APIError{Code: server.ErrBadRequest} } // if the state can't be validated, return if valid, err := s.validateCSRFState(ctx, decoded.State); !valid { if err != nil { return err } return server.APIError{Code: server.ErrInvalidState} } cfg := discordOAuthConfig cfg.RedirectURL = decoded.CallbackDomain + "/login/discord" token, err := cfg.Exchange(r.Context(), decoded.Code) if err != nil { log.Errorf("exchanging oauth code: %v", err) return server.APIError{Code: server.ErrInvalidOAuthCode} } dg, _ := discordgo.New(token.Type() + " " + token.AccessToken) du, err := dg.User("@me") if err != nil { return err } u, err := s.DB.DiscordUser(ctx, du.ID) if err == nil { err = u.UpdateFromDiscord(ctx, s.DB, du) if err != nil { log.Errorf("updating user %v with Discord info: %v", u.ID, err) } token, err := s.Auth.CreateToken(u.ID) if err != nil { return err } render.JSON(w, r, discordCallbackResponse{ HasAccount: true, Token: token, User: dbUserToUserResponse(u), }) return nil } else if err != db.ErrUserNotFound { // internal error return err } // no user found, so save a ticket + save their Discord info in Redis ticket := RandBase64(32) err = s.DB.SetJSON(ctx, "discord:"+ticket, du, "EX", "600") if err != nil { log.Errorf("setting Discord user for ticket %q: %v", ticket, err) return err } render.JSON(w, r, discordCallbackResponse{ HasAccount: false, Discord: du.String(), Ticket: ticket, RequireInvite: s.RequireInvite, }) return nil } type signupRequest struct { Ticket string `json:"ticket"` Username string `json:"username"` InviteCode string `json:"invite_code"` } type signupResponse struct { User userResponse `json:"user"` Token string `json:"token"` } func (s *Server) discordSignup(w http.ResponseWriter, r *http.Request) error { ctx := r.Context() req, err := Decode[signupRequest](r) if err != nil { return server.APIError{Code: server.ErrBadRequest} } if s.RequireInvite && req.InviteCode == "" { return server.APIError{Code: server.ErrInviteRequired} } valid, taken, err := s.DB.UsernameTaken(ctx, req.Username) if err != nil { return err } if !valid { return server.APIError{Code: server.ErrInvalidUsername} } if taken { return server.APIError{Code: server.ErrUsernameTaken} } tx, err := s.DB.Begin(ctx) if err != nil { return errors.Wrap(err, "beginning transaction") } defer tx.Rollback(ctx) du := new(discordgo.User) err = s.DB.GetJSON(ctx, "discord:"+req.Ticket, &du) if err != nil { log.Errorf("getting discord user for ticket: %v", err) return server.APIError{Code: server.ErrInvalidTicket} } u, err := s.DB.CreateUser(ctx, tx, req.Username) if err != nil { return errors.Wrap(err, "creating user") } err = u.UpdateFromDiscord(ctx, tx, du) if err != nil { if errors.Cause(err) == db.ErrUsernameTaken { return server.APIError{Code: server.ErrUsernameTaken} } return errors.Wrap(err, "updating user from discord") } if s.RequireInvite { valid, used, err := s.DB.InvalidateInvite(ctx, tx, req.InviteCode) if err != nil { return errors.Wrap(err, "checking and invalidating invite") } if !valid { return server.APIError{Code: server.ErrInviteRequired} } if used { return server.APIError{Code: server.ErrInviteAlreadyUsed} } } // delete sign up ticket err = s.DB.Redis.Do(ctx, radix.Cmd(nil, "DEL", "discord:"+req.Ticket)) if err != nil { return errors.Wrap(err, "deleting signup ticket") } // commit transaction err = tx.Commit(ctx) if err != nil { return errors.Wrap(err, "committing transaction") } // create token token, err := s.Auth.CreateToken(u.ID) if err != nil { return errors.Wrap(err, "creating token") } // return user render.JSON(w, r, signupResponse{ User: *dbUserToUserResponse(u), Token: token, }) return nil } func Decode[T any](r *http.Request) (T, error) { decoded := *new(T) return decoded, render.Decode(r, &decoded) }