Added support for Discord OAuth2 (#25)

* Need a login check

* chore: Add Discord OAuth2 authentication endpoint

chore: Update dependencies and clean up code

chore: Update dependencies, add Discord OAuth2 authentication endpoint, and clean up code

chore: Update dependencies, add Google OAuth2 authentication endpoint, and clean up code

Code clean up

uniqueness on external account id

chore: Add Discord and Google OAuth2 authentication endpoints, and update dependencies

code review fixes

* chore: Update prodHandler to use clienturl flag for Access-Control-Allow-Origin

* chore: Refactor FetchDiscordIdByUsername and FetchGoogleIdByUsername to handle null values

* chore: Set secure and same-site attributes for session cookie

* chore: Set session cookie expiration to 3 months

* Update callback URL for Oauth2 client in docker-compose and rogueserver.go

* Update callback URL for Oauth2 client in docker-compose and rogueserver.go

---------

Co-authored-by: Matthew Olker <matthew.olker@gmail.com>

Dockerfile

@@ -23,6 +23,7 @@ FROM scratch
 WORKDIR /app
 
 COPY --from=builder /src/rogueserver .
+COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
 
 EXPOSE 8001
 

api/account/discord.go

@@ -0,0 +1,104 @@
+/*
+	Copyright (C) 2024  Pagefault Games
+
+	This program is free software: you can redistribute it and/or modify
+	it under the terms of the GNU Affero General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU Affero General Public License for more details.
+
+	You should have received a copy of the GNU Affero General Public License
+	along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package account
+
+import (
+	"encoding/json"
+	"errors"
+	"net/http"
+	"net/url"
+	"os"
+)
+
+func HandleDiscordCallback(w http.ResponseWriter, r *http.Request) (string, error) {
+	code := r.URL.Query().Get("code")
+	gameUrl := os.Getenv("GAME_URL")
+	if code == "" {
+		defer http.Redirect(w, r, gameUrl, http.StatusSeeOther)
+		return "", errors.New("code is empty")
+	}
+
+	discordId, err := RetrieveDiscordId(code)
+	if err != nil {
+		defer http.Redirect(w, r, gameUrl, http.StatusSeeOther)
+		return "", err
+	}
+
+	return discordId, nil
+}
+
+func RetrieveDiscordId(code string) (string, error) {
+	token, err := http.PostForm("https://discord.com/api/oauth2/token", url.Values{
+		"client_id":     {os.Getenv("DISCORD_CLIENT_ID")},
+		"client_secret": {os.Getenv("DISCORD_CLIENT_SECRET")},
+		"grant_type":    {"authorization_code"},
+		"code":          {code},
+		"redirect_uri":  {os.Getenv("DISCORD_CALLBACK_URL")},
+		"scope":         {"identify"},
+	})
+
+	if err != nil {
+		return "", err
+	}
+
+	// extract access_token from token
+	type TokenResponse struct {
+		AccessToken  string `json:"access_token"`
+		TokenType    string `json:"token_type"`
+		ExpiresIn    int    `json:"expires_in"`
+		Scope        string `json:"scope"`
+		RefreshToken string `json:"refresh_token"`
+	}
+
+	var tokenResponse TokenResponse
+	err = json.NewDecoder(token.Body).Decode(&tokenResponse)
+	if err != nil {
+		return "", err
+	}
+
+	access_token := tokenResponse.AccessToken
+	if access_token == "" {
+		return "", errors.New("access token is empty")
+	}
+
+	client := &http.Client{}
+	req, err := http.NewRequest("GET", "https://discord.com/api/users/@me", nil)
+	if err != nil {
+		return "", err
+	}
+
+	req.Header.Set("Authorization", "Bearer "+access_token)
+	resp, err := client.Do(req)
+	if err != nil {
+		return "", err
+	}
+
+	defer resp.Body.Close()
+
+	type User struct {
+		Id string `json:"id"`
+	}
+
+	var user User
+	err = json.NewDecoder(resp.Body).Decode(&user)
+	if err != nil {
+		return "", err
+	}
+
+	return user.Id, nil
+}

api/account/google.go

@@ -0,0 +1,97 @@
+/*
+	Copyright (C) 2024  Pagefault Games
+
+	This program is free software: you can redistribute it and/or modify
+	it under the terms of the GNU Affero General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU Affero General Public License for more details.
+
+	You should have received a copy of the GNU Affero General Public License
+	along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package account
+
+import (
+	"encoding/json"
+	"errors"
+	"net/http"
+	"net/url"
+	"os"
+
+	"github.com/golang-jwt/jwt/v5"
+)
+
+func HandleGoogleCallback(w http.ResponseWriter, r *http.Request) (string, error) {
+	code := r.URL.Query().Get("code")
+	gameUrl := os.Getenv("GAME_URL")
+	if code == "" {
+		defer http.Redirect(w, r, gameUrl, http.StatusSeeOther)
+		return "", errors.New("code is empty")
+	}
+
+	googleId, err := RetrieveGoogleId(code)
+	if err != nil {
+		defer http.Redirect(w, r, gameUrl, http.StatusSeeOther)
+		return "", err
+	}
+
+	return googleId, nil
+}
+
+func RetrieveGoogleId(code string) (string, error) {
+	token, err := http.PostForm("https://oauth2.googleapis.com/token", url.Values{
+		"client_id":     {os.Getenv("GOOGLE_CLIENT_ID")},
+		"client_secret": {os.Getenv("GOOGLE_CLIENT_SECRET")},
+		"code":          {code},
+		"grant_type":    {"authorization_code"},
+		"redirect_uri":  {os.Getenv("GOOGLE_CALLBACK_URL")},
+	})
+
+	if err != nil {
+		return "", err
+	}
+	defer token.Body.Close()
+	type TokenResponse struct {
+		AccessToken  string `json:"access_token"`
+		TokenType    string `json:"token_type"`
+		ExpiresIn    int    `json:"expires_in"`
+		IdToken      string `json:"id_token"`
+		RefreshToken string `json:"refresh_token"`
+		Scope        string `json:"scope"`
+	}
+	var tokenResponse TokenResponse
+	err = json.NewDecoder(token.Body).Decode(&tokenResponse)
+	if err != nil {
+		return "", err
+	}
+
+	userId, err := parseJWTWithoutValidation(tokenResponse.IdToken)
+	if err != nil {
+		return "", err
+	}
+
+	return userId, nil
+}
+
+func parseJWTWithoutValidation(idToken string) (string, error) {
+	parser := jwt.NewParser()
+
+	// Use ParseUnverified to parse the token without validation
+	parsedJwt, _, err := parser.ParseUnverified(idToken, jwt.MapClaims{})
+	if err != nil {
+		return "", err
+	}
+
+	claims, ok := parsedJwt.Claims.(jwt.MapClaims)
+	if !ok {
+		return "", errors.New("invalid token claims")
+	}
+
+	return claims.GetSubject()
+}

api/account/info.go

@@ -23,12 +23,19 @@ import (
 
 type InfoResponse struct {
 	Username        string `json:"username"`
+	DiscordId       string `json:"discordId"`
+	GoogleId        string `json:"googleId"`
 	LastSessionSlot int    `json:"lastSessionSlot"`
 }
 
 // /account/info - get account info
-func Info(username string, uuid []byte) (InfoResponse, error) {
+func Info(username string, discordId string, googleId string, uuid []byte) (InfoResponse, error) {
 	slot, _ := db.GetLatestSessionSaveDataSlot(uuid)
-
-	return InfoResponse{Username: username, LastSessionSlot: slot}, nil
+	response := InfoResponse{
+		Username:        username,
+		LastSessionSlot: slot,
+		DiscordId:       discordId,
+		GoogleId:        googleId,
+	}
+	return response, nil
 }

api/account/login.go

@@ -55,18 +55,25 @@ func Login(username, password string) (LoginResponse, error) {
 		return response, fmt.Errorf("password doesn't match")
 	}
 
-	token := make([]byte, TokenSize)
-	_, err = rand.Read(token)
+	response.Token, err = GenerateTokenForUsername(username)
+
 	if err != nil {
 		return response, fmt.Errorf("failed to generate token: %s", err)
 	}
 
-	err = db.AddAccountSession(username, token)
+	return response, nil
+}
+
+func GenerateTokenForUsername(username string) (string, error) {
+	token := make([]byte, TokenSize)
+	_, err := rand.Read(token)
 	if err != nil {
-		return response, fmt.Errorf("failed to add account session")
+		return "", fmt.Errorf("failed to generate token: %s", err)
 	}
 
-	response.Token = base64.StdEncoding.EncodeToString(token)
-
-	return response, nil
+	err = db.AddAccountSession(username, token)
+	if err != nil {
+		return "", fmt.Errorf("failed to add account session")
+	}
+	return base64.StdEncoding.EncodeToString(token), nil
 }

api/common.go

@@ -63,6 +63,9 @@ func Init(mux *http.ServeMux) error {
 	mux.HandleFunc("GET /daily/rankings", handleDailyRankings)
 	mux.HandleFunc("GET /daily/rankingpagecount", handleDailyRankingPageCount)
 
+	// auth
+	mux.HandleFunc("/auth/{provider}/callback", handleProviderCallback)
+	mux.HandleFunc("/auth/{provider}/logout", handleProviderLogout)
 	return nil
 }