feat: api key authentication (#291)

Co-authored-by: Elias Schneider <login@eliasschneider.com>

backend/internal/middleware/auth_middleware.go

@@ -0,0 +1,89 @@
+package middleware
+
+import (
+	"github.com/gin-gonic/gin"
+	"github.com/pocket-id/pocket-id/backend/internal/service"
+)
+
+// AuthMiddleware is a wrapper middleware that delegates to either API key or JWT authentication
+type AuthMiddleware struct {
+	apiKeyMiddleware *ApiKeyAuthMiddleware
+	jwtMiddleware    *JwtAuthMiddleware
+	options          AuthOptions
+}
+
+type AuthOptions struct {
+	AdminRequired   bool
+	SuccessOptional bool
+}
+
+func NewAuthMiddleware(
+	apiKeyService *service.ApiKeyService,
+	jwtService *service.JwtService,
+) *AuthMiddleware {
+	return &AuthMiddleware{
+		apiKeyMiddleware: NewApiKeyAuthMiddleware(apiKeyService, jwtService),
+		jwtMiddleware:    NewJwtAuthMiddleware(jwtService),
+		options: AuthOptions{
+			AdminRequired:   true,
+			SuccessOptional: false,
+		},
+	}
+}
+
+// WithAdminNotRequired allows the middleware to continue with the request even if the user is not an admin
+func (m *AuthMiddleware) WithAdminNotRequired() *AuthMiddleware {
+	// Create a new instance to avoid modifying the original
+	clone := &AuthMiddleware{
+		apiKeyMiddleware: m.apiKeyMiddleware,
+		jwtMiddleware:    m.jwtMiddleware,
+		options:          m.options,
+	}
+	clone.options.AdminRequired = false
+	return clone
+}
+
+// WithSuccessOptional allows the middleware to continue with the request even if authentication fails
+func (m *AuthMiddleware) WithSuccessOptional() *AuthMiddleware {
+	// Create a new instance to avoid modifying the original
+	clone := &AuthMiddleware{
+		apiKeyMiddleware: m.apiKeyMiddleware,
+		jwtMiddleware:    m.jwtMiddleware,
+		options:          m.options,
+	}
+	clone.options.SuccessOptional = true
+	return clone
+}
+
+func (m *AuthMiddleware) Add() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		// First try JWT auth
+		userID, isAdmin, err := m.jwtMiddleware.Verify(c, m.options.AdminRequired)
+		if err == nil {
+			// JWT auth succeeded, continue with the request
+			c.Set("userID", userID)
+			c.Set("userIsAdmin", isAdmin)
+			c.Next()
+			return
+		}
+
+		// JWT auth failed, try API key auth
+		userID, isAdmin, err = m.apiKeyMiddleware.Verify(c, m.options.AdminRequired)
+		if err == nil {
+			// API key auth succeeded, continue with the request
+			c.Set("userID", userID)
+			c.Set("userIsAdmin", isAdmin)
+			c.Next()
+			return
+		}
+
+		if m.options.SuccessOptional {
+			c.Next()
+			return
+		}
+
+		// Both JWT and API key auth failed
+		c.Abort()
+		c.Error(err)
+	}
+}