package auth import ( "context" "errors" "io/ioutil" "net/http" "strings" "github.com/aerogo/aero" "github.com/animenotifier/arn" "github.com/animenotifier/notify.moe/utils" jsoniter "github.com/json-iterator/go" "golang.org/x/oauth2" "golang.org/x/oauth2/facebook" ) // FacebookUser is the user data we receive from Facebook type FacebookUser struct { ID string `json:"id"` Email string `json:"email"` FirstName string `json:"first_name"` LastName string `json:"last_name"` Gender string `json:"gender"` } // InstallFacebookAuth enables Facebook login for the app. func InstallFacebookAuth(app *aero.Application) { // OAuth2 configuration defines the API keys, // scopes of required data and the redirect URL // that Facebook should send the user to after // a successful login on their pages. config := &oauth2.Config{ ClientID: arn.APIKeys.Facebook.ID, ClientSecret: arn.APIKeys.Facebook.Secret, RedirectURL: "https://" + app.Config.Domain + "/auth/facebook/callback", Scopes: []string{ "public_profile", "email", }, Endpoint: facebook.Endpoint, } // When a user visits /auth/facebook, we ask OAuth2 config for a URL // to redirect the user to. Once the user has logged in on that page, // he'll be redirected back to our servers to the callback page. app.Get("/auth/facebook", func(ctx *aero.Context) string { state := ctx.Session().ID() url := config.AuthCodeURL(state) return ctx.Redirect(url) }) // This is the redirect URL that we specified in the OAuth2 config. // The user has successfully completed the login on Facebook servers. // Now we have to check for fraud requests and request user information. // If both Facebook ID and email can't be found in our DB, register a new user. // Otherwise, log in the user with the given Facebook ID or email. app.Get("/auth/facebook/callback", func(ctx *aero.Context) string { if !ctx.HasSession() { return ctx.Error(http.StatusUnauthorized, "Facebook login failed", errors.New("Session does not exist")) } session := ctx.Session() if session.ID() != ctx.Query("state") { return ctx.Error(http.StatusUnauthorized, "Facebook login failed", errors.New("Incorrect state")) } // Handle the exchange code to initiate a transport token, err := config.Exchange(context.Background(), ctx.Query("code")) if err != nil { return ctx.Error(http.StatusBadRequest, "Could not obtain OAuth token", err) } // Construct the OAuth client client := config.Client(context.Background(), token) // Fetch user data from Facebook resp, err := client.Get("https://graph.facebook.com/me?fields=email,first_name,last_name,gender") if err != nil { return ctx.Error(http.StatusBadRequest, "Failed requesting user data from Facebook", err) } defer resp.Body.Close() body, _ := ioutil.ReadAll(resp.Body) // Construct a FacebookUser object fbUser := FacebookUser{} err = jsoniter.Unmarshal(body, &fbUser) if err != nil { return ctx.Error(http.StatusBadRequest, "Failed parsing user data (JSON)", err) } // Change googlemail.com to gmail.com fbUser.Email = strings.Replace(fbUser.Email, "googlemail.com", "gmail.com", 1) // Is this an existing user connecting another social account? user := utils.GetUser(ctx) if user != nil { // Add FacebookToUser reference user.ConnectFacebook(fbUser.ID) // Save in DB user.Save() // Log authLog.Info("Added Facebook ID to existing account", user.ID, user.Nick, ctx.RealIP(), user.Email, user.RealName()) return ctx.Redirect("/") } var getErr error // Try to find an existing user via the Facebook user ID user, getErr = arn.GetUserByFacebookID(fbUser.ID) if getErr == nil && user != nil { authLog.Info("User logged in via Facebook ID", user.ID, user.Nick, ctx.RealIP(), user.Email, user.RealName()) user.LastLogin = arn.DateTimeUTC() user.Save() session.Set("userId", user.ID) return ctx.Redirect("/") } // Try to find an existing user via the associated e-mail address user, getErr = arn.GetUserByEmail(fbUser.Email) if getErr == nil && user != nil { authLog.Info("User logged in via Email", user.ID, user.Nick, ctx.RealIP(), user.Email, user.RealName()) user.LastLogin = arn.DateTimeUTC() user.Save() session.Set("userId", user.ID) return ctx.Redirect("/") } // Register new user user = arn.NewUser() user.Nick = "fb" + fbUser.ID user.Email = fbUser.Email user.FirstName = fbUser.FirstName user.LastName = fbUser.LastName user.Gender = fbUser.Gender user.LastLogin = arn.DateTimeUTC() // Save basic user info already to avoid data inconsistency problems user.Save() // Register user arn.RegisterUser(user) // Connect account to a Facebook account user.ConnectFacebook(fbUser.ID) // Save user object again with updated data user.Save() // Login session.Set("userId", user.ID) // Log authLog.Info("Registered new user via Facebook", user.ID, user.Nick, ctx.RealIP(), user.Email, user.RealName()) // Redirect to starting page for new users return ctx.Redirect(newUserStartRoute) }) }