Add authserver module

authserver/internal/auth/jwt.go

@@ -0,0 +1,114 @@
+package auth
+
+import (
+	"errors"
+	"time"
+
+	"github.com/golang-jwt/jwt/v5"
+)
+
+type Claims struct {
+	UserID   uint64 `json:"uid"`
+	Username string `json:"username"`
+	Email    string `json:"email"`
+	IsAdmin  bool   `json:"admin"`
+	jwt.RegisteredClaims
+}
+
+type OAuthCodeClaims struct {
+	UserID      uint64 `json:"uid"`
+	ClientID    string `json:"client_id"`
+	RedirectURI string `json:"redirect_uri"`
+	jwt.RegisteredClaims
+}
+
+func Sign(secret, issuer string, ttl time.Duration, userID uint64, username, email string, isAdmin bool) (string, string, time.Time, error) {
+	now := time.Now()
+	expiresAt := now.Add(ttl)
+	tokenID := randomID()
+	claims := Claims{
+		UserID:   userID,
+		Username: username,
+		Email:    email,
+		IsAdmin:  isAdmin,
+		RegisteredClaims: jwt.RegisteredClaims{
+			ID:        tokenID,
+			Issuer:    issuer,
+			Subject:   username,
+			Audience:  []string{"authserver"},
+			IssuedAt:  jwt.NewNumericDate(now),
+			ExpiresAt: jwt.NewNumericDate(expiresAt),
+		},
+	}
+	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
+	signed, err := token.SignedString([]byte(secret))
+	return signed, tokenID, expiresAt, err
+}
+
+func SignOAuthCode(secret, issuer string, ttl time.Duration, userID uint64, clientID, redirectURI string) (string, string, time.Time, error) {
+	now := time.Now()
+	expiresAt := now.Add(ttl)
+	codeID := randomID()
+	claims := OAuthCodeClaims{
+		UserID:      userID,
+		ClientID:    clientID,
+		RedirectURI: redirectURI,
+		RegisteredClaims: jwt.RegisteredClaims{
+			ID:        codeID,
+			Issuer:    issuer,
+			Subject:   clientID,
+			Audience:  []string{"oauth-code"},
+			IssuedAt:  jwt.NewNumericDate(now),
+			ExpiresAt: jwt.NewNumericDate(expiresAt),
+		},
+	}
+	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
+	signed, err := token.SignedString([]byte(secret))
+	return signed, codeID, expiresAt, err
+}
+
+func Parse(secret string, tokenValue string) (*Claims, error) {
+	token, err := jwt.ParseWithClaims(tokenValue, &Claims{}, func(token *jwt.Token) (any, error) {
+		if token.Method != jwt.SigningMethodHS256 {
+			return nil, errors.New("unexpected jwt signing method")
+		}
+		return []byte(secret), nil
+	})
+	if err != nil {
+		return nil, err
+	}
+	claims, ok := token.Claims.(*Claims)
+	if !ok || !token.Valid {
+		return nil, errors.New("invalid jwt claims")
+	}
+	return claims, nil
+}
+
+func ParseOAuthCode(secret string, tokenValue string) (*OAuthCodeClaims, error) {
+	token, err := jwt.ParseWithClaims(tokenValue, &OAuthCodeClaims{}, func(token *jwt.Token) (any, error) {
+		if token.Method != jwt.SigningMethodHS256 {
+			return nil, errors.New("unexpected jwt signing method")
+		}
+		return []byte(secret), nil
+	})
+	if err != nil {
+		return nil, err
+	}
+	claims, ok := token.Claims.(*OAuthCodeClaims)
+	if !ok || !token.Valid {
+		return nil, errors.New("invalid oauth code claims")
+	}
+	if !claimStringsContains(claims.Audience, "oauth-code") {
+		return nil, errors.New("invalid oauth code audience")
+	}
+	return claims, nil
+}
+
+func claimStringsContains(values jwt.ClaimStrings, target string) bool {
+	for _, value := range values {
+		if value == target {
+			return true
+		}
+	}
+	return false
+}