pkg/common/support.go

// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

package common

import (
	"encoding/json"
	"errors"
	"log/slog"
	"net/http"
	"reflect"
	"strings"

	"github.com/apache/airavata-custos/pkg/service"
)

func DecodeJSON(r *http.Request, dst any) error {
	dec := json.NewDecoder(r.Body)
	dec.DisallowUnknownFields()
	return dec.Decode(dst)
}

func WriteJSON(w http.ResponseWriter, status int, body any) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	if body == nil {
		return
	}
	// A nil slice would encode as JSON null; list endpoints must return [].
	if v := reflect.ValueOf(body); v.Kind() == reflect.Slice && v.IsNil() {
		body = []any{}
	}
	_ = json.NewEncoder(w).Encode(body)
}

func WriteError(w http.ResponseWriter, status int, err error) {
	WriteJSON(w, status, map[string]string{"error": err.Error()})
}

func WriteServiceError(w http.ResponseWriter, err error) {
	switch {
	case errors.Is(err, service.ErrNotFound):
		WriteError(w, http.StatusNotFound, err)
	case errors.Is(err, service.ErrAlreadyExists):
		WriteError(w, http.StatusConflict, err)
	case errors.Is(err, service.ErrInvalidInput):
		WriteError(w, http.StatusBadRequest, err)
	default:
		// Avoid leaking driver messages to clients; log the full error.
		slog.Error("internal server error", "error", err.Error())
		WriteError(w, http.StatusInternalServerError, errors.New(strings.TrimSpace("internal server error")))
	}
}