http_client.h

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//
// Copyright (C) 2019 The Android Open Source Project
//
// 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.
 
#pragma once
 
#include <functional>
#include <optional>
#include <string>
#include <string_view>
#include <type_traits>
#include <vector>
 
#include "fmt/format.h"
 
#include "cuttlefish/result/result.h"
 
namespace cuttlefish {
 
struct HttpVoidResponse {};
 
struct HttpHeader {
  std::string name;
  std::string value;
};
 
template <typename T>
struct HttpResponse {
  bool HttpInfo() const { return http_code >= 100 && http_code <= 199; }
  bool HttpSuccess() const { return http_code >= 200 && http_code <= 299; }
  bool HttpRedirect() const { return http_code >= 300 && http_code <= 399; }
  bool HttpClientError() const { return http_code >= 400 && http_code <= 499; }
  bool HttpServerError() const { return http_code >= 500 && http_code <= 599; }
 
  std::string StatusDescription() const {
    switch (http_code) {
      case 200:
        return "OK";
      case 201:
        return "Created";
      case 204:
        return "No Content";
      case 400:
        return "Bad Request";
      case 401:
        return "Unauthorized";
      case 403:
        return "Forbidden";
      case 404:
        return "File Not Found";
      case 500:
        return "Internal Server Error";
      case 502:
        return "Bad Gateway";
      case 503:
        return "Service Unavailable";
      default:
        return fmt::format("Status Code: {}", http_code);
    }
  }
 
  typename std::conditional<std::is_void_v<T>, HttpVoidResponse, T>::type data;
  long http_code;
  std::vector<HttpHeader> headers;
};
 
std::optional<std::string_view> HeaderValue(
    const std::vector<HttpHeader>& headers, std::string_view header_name);
 
enum class HttpMethod {
  kGet,
  kPost,
  kDelete,
  kHead,
};
 
struct HttpRequest {
  HttpMethod method;
  std::string url;
  std::vector<std::string> headers;
  std::string data_to_write;
};
 
class HttpClient {
 public:
  typedef std::function<bool(char*, size_t)> DataCallback;
 
  virtual ~HttpClient();
 
  // Returns response's status code.
  virtual Result<HttpResponse<void>> DownloadToCallback(
      HttpRequest, DataCallback callback) = 0;
};
 
}  // namespace cuttlefish