nexarch/connect/internal/dms2importapi/dms2importapi.go

// Package dms2importapi is the HTTP binding for DMS2-02's import
// assistant: upload a third-party export, get a field-mapping preview
// back, adjust it, then execute the import and see the result. Identity
// comes from X-User-Id/X-Tenant-Slug, the same transitional pattern
// connect/internal/statusapi already uses.
package dms2importapi

import (
	"encoding/json"
	"io"
	"net/http"
	"strings"

	"gitea.perlbach24.de/scripte/nexarch/connect/internal/dms2import"
	"gitea.perlbach24.de/scripte/nexarch/connect/internal/fieldmapping"
)

// connectorName/instance identify the field mapping saved for this
// assistant in fieldmapping.Store — one mapping per tenant, since a
// tenant realistically migrates from one third-party system at a time.
const (
	connectorName        = "dms2_import"
	connectorInstanceID  = "paperless_ngx"
	maxUploadBytes  int64 = 200 << 20 // 200 MiB: generous for a test/migration export, not unbounded
)

type Server struct {
	mappings *fieldmapping.Store
	runs     *dms2import.Store
}

func NewServer(mappings *fieldmapping.Store, runs *dms2import.Store) *Server {
	return &Server{mappings: mappings, runs: runs}
}

func (s *Server) RegisterRoutes(mux *http.ServeMux) {
	mux.HandleFunc("POST /dms2/import/preview", s.requireIdentity(s.handlePreview))
	mux.HandleFunc("POST /dms2/import/execute", s.requireIdentity(s.handleExecute))
	mux.HandleFunc("GET /dms2/import/runs/{id}", s.requireIdentity(s.handleGetRun))
}

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

type previewResponse struct {
	DocumentCount    int                    `json:"document_count"`
	AvailableFields  []string               `json:"available_fields"`
	SuggestedMapping []fieldmapping.Entry   `json:"suggested_mapping"`
	Schema           []fieldmapping.FieldDef `json:"schema"`
}

func (s *Server) handlePreview(w http.ResponseWriter, r *http.Request, _ string) {
	data, ok := readUploadedZip(w, r)
	if !ok {
		return
	}
	docs, err := dms2import.ParsePaperlessExport(data)
	if err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}
	fields := dms2import.DetectFields(docs)
	writeJSON(w, http.StatusOK, previewResponse{
		DocumentCount:    len(docs),
		AvailableFields:  fields,
		SuggestedMapping: dms2import.SuggestMapping(fields),
		Schema:           dms2import.Schema(),
	})
}

type executeResponse struct {
	RunID         string   `json:"run_id"`
	DocumentCount int      `json:"document_count"`
	SuccessCount  int      `json:"success_count"`
	ErrorCount    int      `json:"error_count"`
	Errors        []string `json:"errors"`
}

func (s *Server) handleExecute(w http.ResponseWriter, r *http.Request, tenantSlug string) {
	data, ok := readUploadedZip(w, r)
	if !ok {
		return
	}
	var entries []fieldmapping.Entry
	if err := json.Unmarshal([]byte(r.FormValue("mapping")), &entries); err != nil {
		writeError(w, http.StatusBadRequest, "mapping ist kein gueltiges JSON-Feld-Array")
		return
	}

	schema := dms2import.Schema()
	saved, err := s.mappings.Save(r.Context(), fieldmapping.Ref{
		TenantSlug: tenantSlug, ConnectorName: connectorName, ConnectorInstanceID: connectorInstanceID,
	}, entries, schema)
	if err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}
	if err := fieldmapping.ValidateForExecution(saved, schema); err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}

	docs, err := dms2import.ParsePaperlessExport(data)
	if err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}
	bundles, buildErrs := dms2import.BuildBundles(docs, saved)

	run, err := s.runs.RecordRun(r.Context(), tenantSlug, dms2import.FormatPaperlessNGX, len(docs), len(bundles), buildErrs, saved.Version)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "import-lauf konnte nicht gespeichert werden")
		return
	}
	writeJSON(w, http.StatusOK, executeResponse{
		RunID:         run.ID,
		DocumentCount: run.DocumentCount,
		SuccessCount:  run.SuccessCount,
		ErrorCount:    run.ErrorCount,
		Errors:        run.Errors,
	})
}

func (s *Server) handleGetRun(w http.ResponseWriter, r *http.Request, tenantSlug string) {
	id := r.PathValue("id")
	run, err := s.runs.GetRun(r.Context(), tenantSlug, id)
	if err != nil {
		if err == dms2import.ErrRunNotFound {
			writeError(w, http.StatusNotFound, "import-lauf nicht gefunden")
			return
		}
		writeError(w, http.StatusInternalServerError, "import-lauf konnte nicht gelesen werden")
		return
	}
	writeJSON(w, http.StatusOK, executeResponse{
		RunID:         run.ID,
		DocumentCount: run.DocumentCount,
		SuccessCount:  run.SuccessCount,
		ErrorCount:    run.ErrorCount,
		Errors:        run.Errors,
	})
}

func readUploadedZip(w http.ResponseWriter, r *http.Request) ([]byte, bool) {
	r.Body = http.MaxBytesReader(w, r.Body, maxUploadBytes)
	if err := r.ParseMultipartForm(32 << 20); err != nil {
		writeError(w, http.StatusBadRequest, "multipart-anfrage konnte nicht gelesen werden (evtl. zu gross)")
		return nil, false
	}
	file, header, err := r.FormFile("file")
	if err != nil {
		writeError(w, http.StatusBadRequest, "feld 'file' fehlt")
		return nil, false
	}
	defer file.Close()
	if !strings.HasSuffix(strings.ToLower(header.Filename), ".zip") {
		writeError(w, http.StatusBadRequest, "nur .zip-Exporte werden unterstuetzt")
		return nil, false
	}
	data, err := io.ReadAll(file)
	if err != nil {
		writeError(w, http.StatusBadRequest, "datei konnte nicht gelesen werden")
		return nil, false
	}
	return data, true
}

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, msg string) {
	writeJSON(w, status, map[string]string{"error": msg})
}