nexarch/workflow/internal/backchannelapi/backchannelapi.go

// Package backchannelapi ist die HTTP-Bindung der Rueckkanal-API
// (VOR-04). Nutzeridentitaet kommt uebergangsweise aus X-User-Id, wie
// bereits bei caseapi (VOR-01) und approvalapi (APR-01) etabliert.
// X-Tenant-Slug traegt den Tenant-Kontext des urspruenglich anfragenden
// Nutzers (VOR-06) -- unabhaengig vom Geltungsbereich des Service-
// Credentials, mit dem DMS/Mail selbst gegenueber Workflow authentifiziert
// sind.
package backchannelapi

import (
	"encoding/json"
	"errors"
	"net/http"

	"gitea.perlbach24.de/scripte/nexarch/workflow/internal/backchannel"
)

type Server struct {
	svc *backchannel.Service
}

func NewServer(svc *backchannel.Service) *Server {
	return &Server{svc: svc}
}

// RegisterRoutes bindet GET /objects/{module}/{type}/{id}/context.
func (s *Server) RegisterRoutes(mux *http.ServeMux) {
	mux.HandleFunc("GET /objects/{module}/{objectType}/{id}/context", s.handleContext)
}

func (s *Server) handleContext(w http.ResponseWriter, r *http.Request) {
	userID := r.Header.Get("X-User-Id")
	if userID == "" {
		writeError(w, http.StatusUnauthorized, "X-User-Id fehlt")
		return
	}
	tenantSlug := r.Header.Get("X-Tenant-Slug")
	if tenantSlug == "" {
		writeError(w, http.StatusUnauthorized, "X-Tenant-Slug fehlt")
		return
	}

	moduleName := r.PathValue("module")
	objectType := r.PathValue("objectType")
	id := r.PathValue("id")

	ctxResult, err := s.svc.ForObject(r.Context(), moduleName, objectType, id, userID, tenantSlug)
	switch {
	case err == nil:
		writeJSON(w, http.StatusOK, ctxResult)
	case errors.Is(err, backchannel.ErrForbidden):
		writeError(w, http.StatusForbidden, "nicht berechtigt")
	default:
		writeError(w, http.StatusInternalServerError, "kontext konnte nicht gelesen werden")
	}
}

func writeJSON(w http.ResponseWriter, status int, v any) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	_ = json.NewEncoder(w).Encode(v)
}

func writeError(w http.ResponseWriter, status int, message string) {
	writeJSON(w, status, map[string]string{"error": message})
}