API - CRUD for peers, interfaces and users (#340)

Public REST API implementation to handle peers, interfaces and users. It also includes some simple provisioning endpoints.

The Swagger API documentation is available under /api/v1/doc.html

internal/app/api/v1/handlers/base.go

@@ -0,0 +1,81 @@
+package handlers
+
+import (
+	"errors"
+	"net/http"
+
+	"github.com/gin-contrib/cors"
+	"github.com/gin-gonic/gin"
+	"github.com/h44z/wg-portal/internal/app/api/core"
+	"github.com/h44z/wg-portal/internal/app/api/v1/models"
+	"github.com/h44z/wg-portal/internal/domain"
+)
+
+type Handler interface {
+	GetName() string
+	RegisterRoutes(g *gin.RouterGroup, authenticator *authenticationHandler)
+}
+
+// To compile the API documentation use the
+// api_build_tool
+// command that can be found in the $PROJECT_ROOT/cmd/api_build_tool directory.
+
+// @title WireGuard Portal Public API
+// @version 1.0
+// @description The WireGuard Portal REST API enables efficient management of WireGuard VPN configurations through a set of JSON-based endpoints.
+// @description It supports creating and editing peers, interfaces, and user profiles, while also providing role-based access control and auditing.
+// @description This API allows seamless integration with external tools or scripts for automated network configuration and administration.
+
+// @license.name MIT
+// @license.url https://github.com/h44z/wg-portal/blob/master/LICENSE.txt
+
+// @contact.name WireGuard Portal Project
+// @contact.url https://github.com/h44z/wg-portal
+
+// @securityDefinitions.basic BasicAuth
+
+// @BasePath /api/v1
+// @query.collection.format multi
+
+func NewRestApi(userSource UserSource, handlers ...Handler) core.ApiEndpointSetupFunc {
+	authenticator := &authenticationHandler{
+		userSource: userSource,
+	}
+
+	return func() (core.ApiVersion, core.GroupSetupFn) {
+		return "v1", func(group *gin.RouterGroup) {
+			group.Use(cors.Default())
+
+			// Handler functions
+			for _, h := range handlers {
+				h.RegisterRoutes(group, authenticator)
+			}
+		}
+	}
+}
+
+func ParseServiceError(err error) (int, models.Error) {
+	if err == nil {
+		return 500, models.Error{
+			Code:    500,
+			Message: "unknown server error",
+		}
+	}
+
+	code := http.StatusInternalServerError
+	switch {
+	case errors.Is(err, domain.ErrNotFound):
+		code = http.StatusNotFound
+	case errors.Is(err, domain.ErrNoPermission):
+		code = http.StatusForbidden
+	case errors.Is(err, domain.ErrDuplicateEntry):
+		code = http.StatusConflict
+	case errors.Is(err, domain.ErrInvalidData):
+		code = http.StatusBadRequest
+	}
+
+	return code, models.Error{
+		Code:    code,
+		Message: err.Error(),
+	}
+}