resource_handler.hpp

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/*
 * Copyright 2020 Robert Bosch GmbH
 *
 * Licensed 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.
 *
 * SPDX-License-Identifier: Apache-2.0
 */
#pragma once
 
#include <fstream>
#include <string>  // for string
 
#include <cloe/handler.hpp>           // for Request, Response
#include <cloe/utility/resource.hpp>  // for ResourceHandler
 
#ifndef NDEBUG
#include <cloe/core.hpp>  // for Logger
#endif
 
#define RESOURCE_HANDLER(resource, ct) ::cloe::utility::ResourceHandler(RESOURCE(resource), ct)
#define RESOURCE_LOADER(resource) ::cloe::utility::ResourceLoader(RESOURCE(resource))
 
namespace cloe {
namespace utility {
 
class ResourceLoader {
 public:
  explicit ResourceLoader(Resource r) : res_(r) {}
 
  std::string to_string() const {
#ifndef NDEBUG
    // Check if the file given in path exists, and if so, load it.
    std::ifstream ifs{res_.filepath()};
    std::string data;
    if (ifs.is_open()) {
      data = static_cast<std::stringstream const&>(std::stringstream() << ifs.rdbuf()).str();
    } else {
      logger::get("cloe")->warn("File does not exist: {}", res_.filepath());
      data = res_.to_string();
    }
    return data;
#else
    return res_.to_string();
#endif
  }
 
  friend void to_json(cloe::Json& j, const ResourceLoader& c);
 
 private:
  Resource res_;
};
 
class ResourceHandler {
 public:
  ResourceHandler(Resource r, ContentType t) : resl_(r), type_(t) {}
  void operator()(const Request&, Response& r) { r.set_body(resl_.to_string(), type_); }
 
 private:
  ResourceLoader resl_;
  ContentType type_;
};
 
void to_json(cloe::Json& j, const ResourceLoader& c) {
  try {
    j = fable::parse_json(c.to_string());
  } catch (cloe::Json::type_error& e) {
    j = {c.res_.filepath(), c.to_string()};
  }
}
 
}  // namespace utility
}  // namespace cloe