nexarch/dms/internal/savedsearchapi/handler.go

package savedsearchapi

import (
	"encoding/json"
	"errors"
	"net/http"
	"net/http/httptest"
	"net/url"
	"strings"

	"github.com/jackc/pgx/v5/pgxpool"

	"gitea.perlbach24.de/scripte/nexarch/dms/internal/savedsearch"
)

type Server struct {
	pool   *pgxpool.Pool
	search http.Handler
}

// search ist der Handler von GET /search; Aufrufe laufen mit der Identitaet
// der aufrufenden Person, nie der des Besitzers.
func NewServer(pool *pgxpool.Pool, search http.Handler) *Server {
	return &Server{pool: pool, search: search}
}

func (s *Server) RegisterRoutes(mux *http.ServeMux) {
	mux.HandleFunc("GET /saved-searches", s.handleList)
	mux.HandleFunc("POST /saved-searches", s.handleCreate)
	mux.HandleFunc("PUT /saved-searches/{id}", s.handleUpdate)
	mux.HandleFunc("DELETE /saved-searches/{id}", s.handleDelete)
	mux.HandleFunc("GET /saved-searches/{id}/results", s.handleResults)
}

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, err error) {
	status := http.StatusInternalServerError
	switch {
	case errors.Is(err, savedsearch.ErrInvalid):
		status = http.StatusBadRequest
	case errors.Is(err, savedsearch.ErrNotFound):
		status = http.StatusNotFound
	case errors.Is(err, savedsearch.ErrConflict):
		status = http.StatusConflict
	}
	writeJSON(w, status, map[string]string{"error": err.Error()})
}

func caller(w http.ResponseWriter, r *http.Request) (string, bool) {
	c := strings.TrimSpace(r.URL.Query().Get("caller"))
	if c == "" {
		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "fehlender pflicht-parameter \"caller\""})
	}
	return c, c != ""
}

type input struct {
	Name   string `json:"name"`
	Query  string `json:"query"`
	Shared bool   `json:"shared"`
}

func decode(w http.ResponseWriter, r *http.Request) (input, bool) {
	var in input
	if err := json.NewDecoder(http.MaxBytesReader(w, r.Body, 16<<10)).Decode(&in); err != nil {
		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "ungueltiger request-body"})
		return in, false
	}
	return in, true
}

func (s *Server) handleList(w http.ResponseWriter, r *http.Request) {
	c, ok := caller(w, r)
	if !ok {
		return
	}
	out, err := savedsearch.List(r.Context(), s.pool, c)
	if err != nil {
		writeError(w, err)
		return
	}
	writeJSON(w, http.StatusOK, out)
}

func (s *Server) handleCreate(w http.ResponseWriter, r *http.Request) {
	c, ok := caller(w, r)
	if !ok {
		return
	}
	in, ok := decode(w, r)
	if !ok {
		return
	}
	out, err := savedsearch.Create(r.Context(), s.pool, c, in.Name, in.Query, in.Shared)
	if err != nil {
		writeError(w, err)
		return
	}
	writeJSON(w, http.StatusCreated, out)
}

func (s *Server) handleUpdate(w http.ResponseWriter, r *http.Request) {
	c, ok := caller(w, r)
	if !ok {
		return
	}
	in, ok := decode(w, r)
	if !ok {
		return
	}
	out, err := savedsearch.Update(r.Context(), s.pool, c, r.PathValue("id"), in.Name, in.Query, in.Shared)
	if err != nil {
		writeError(w, err)
		return
	}
	writeJSON(w, http.StatusOK, out)
}

func (s *Server) handleDelete(w http.ResponseWriter, r *http.Request) {
	c, ok := caller(w, r)
	if !ok {
		return
	}
	if err := savedsearch.Delete(r.Context(), s.pool, c, r.PathValue("id")); err != nil {
		writeError(w, err)
		return
	}
	w.WriteHeader(http.StatusNoContent)
}

func (s *Server) handleResults(w http.ResponseWriter, r *http.Request) {
	c, ok := caller(w, r)
	if !ok {
		return
	}
	saved, err := savedsearch.Get(r.Context(), s.pool, c, r.PathValue("id"))
	if err != nil {
		writeError(w, err)
		return
	}
	values, err := url.ParseQuery(saved.Query)
	if err != nil {
		writeError(w, savedsearch.ErrInvalid)
		return
	}
	values.Set("caller", c)
	for _, p := range []string{"limit", "offset"} {
		if v := r.URL.Query().Get(p); v != "" {
			values.Set(p, v)
		}
	}
	req := httptest.NewRequest(http.MethodGet, "/search?"+values.Encode(), nil).WithContext(r.Context())
	rec := httptest.NewRecorder()
	s.search.ServeHTTP(rec, req)
	for k, v := range rec.Header() {
		w.Header()[k] = v
	}
	w.WriteHeader(rec.Code)
	_, _ = w.Write(rec.Body.Bytes())
}