http_winhttp.cpp

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/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <https://www.gnu.org/licenses/old-licenses/gpl-2.0>.
 */

 
#include "../../stdafx.h"
#include "../../debug.h"
#include "../../rev.h"
#include "../network_internal.h"
 
#include "http.h"
#include "http_shared.h"
 
#include <mutex>
#include <winhttp.h>
 
#include "../../safeguards.h"
 
static HINTERNET _winhttp_session = nullptr; 

class NetworkHTTPRequest {
private:
  const std::wstring uri; 
  HTTPThreadSafeCallback callback; 
  const std::string data; 
 
  HINTERNET connection = nullptr;      
  HINTERNET request = nullptr;         
  std::atomic<bool> finished = false;  
  int depth = 0;                       
 
public:
  NetworkHTTPRequest(std::wstring &&uri, HTTPCallback *callback, std::string &&data);
 
  ~NetworkHTTPRequest();
 
  void Connect();
  bool Receive();
  void WinHttpCallback(DWORD code, void *info, DWORD length);
};
 
static std::vector<NetworkHTTPRequest *> _http_requests; 
static std::vector<NetworkHTTPRequest *> _new_http_requests; 
static std::mutex _new_http_requests_mutex; 
 
static std::vector<HTTPThreadSafeCallback *> _http_callbacks; 
static std::vector<HTTPThreadSafeCallback *> _new_http_callbacks; 
static std::mutex _http_callback_mutex; 
static std::mutex _new_http_callback_mutex; 

NetworkHTTPRequest::NetworkHTTPRequest(std::wstring &&uri, HTTPCallback *callback, std::string &&data) :
  uri(std::move(uri)),
  callback(callback),
  data(std::move(data))
{
  std::lock_guard<std::mutex> lock(_new_http_callback_mutex);
  _new_http_callbacks.push_back(&this->callback);
}

static std::string GetLastErrorAsString()
{
  wchar_t buffer[512];
 
  DWORD error_code = GetLastError();
 
  if (FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_FROM_HMODULE | FORMAT_MESSAGE_IGNORE_INSERTS, GetModuleHandle(L"winhttp.dll"), error_code,
    MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), buffer, static_cast<DWORD>(std::size(buffer)), nullptr) == 0) {
    return fmt::format("unknown error {}", error_code);
  }
 
  return FS2OTTD(buffer);
}

void NetworkHTTPRequest::WinHttpCallback(DWORD code, void *info, DWORD length)
{
  if (this->finished) return;
 
  switch (code) {
    case WINHTTP_CALLBACK_STATUS_RESOLVING_NAME:
    case WINHTTP_CALLBACK_STATUS_NAME_RESOLVED:
    case WINHTTP_CALLBACK_STATUS_CONNECTING_TO_SERVER:
    case WINHTTP_CALLBACK_STATUS_CONNECTED_TO_SERVER:
    case WINHTTP_CALLBACK_STATUS_SENDING_REQUEST:
    case WINHTTP_CALLBACK_STATUS_REQUEST_SENT:
    case WINHTTP_CALLBACK_STATUS_RECEIVING_RESPONSE:
    case WINHTTP_CALLBACK_STATUS_RESPONSE_RECEIVED:
    case WINHTTP_CALLBACK_STATUS_CLOSING_CONNECTION:
    case WINHTTP_CALLBACK_STATUS_CONNECTION_CLOSED:
    case WINHTTP_CALLBACK_STATUS_HANDLE_CREATED:
    case WINHTTP_CALLBACK_STATUS_HANDLE_CLOSING:
      /* We don't care about these events, and explicitly ignore them. */
      break;
 
    case WINHTTP_CALLBACK_STATUS_REDIRECT:
      /* Make sure we are not in a redirect loop. */
      if (this->depth++ > 5) {
        Debug(net, 0, "HTTP request failed: too many redirects");
        this->callback.OnFailure();
        this->finished = true;
        return;
      }
      break;
 
    case WINHTTP_CALLBACK_STATUS_SENDREQUEST_COMPLETE:
      /* Next step: read response. */
      WinHttpReceiveResponse(this->request, nullptr);
      break;
 
    case WINHTTP_CALLBACK_STATUS_HEADERS_AVAILABLE:
    {
      /* Retrieve the status code. */
      DWORD status_code = 0;
      DWORD status_code_size = sizeof(status_code);
      WinHttpQueryHeaders(this->request, WINHTTP_QUERY_STATUS_CODE | WINHTTP_QUERY_FLAG_NUMBER, WINHTTP_HEADER_NAME_BY_INDEX, &status_code, &status_code_size, WINHTTP_NO_HEADER_INDEX);
      Debug(net, 3, "HTTP request status code: {}", status_code);
 
      /* If there is any error, we simply abort the request. */
      if (status_code >= 400) {
        /* No need to be verbose about rate limiting. */
        Debug(net, status_code == HTTP_429_TOO_MANY_REQUESTS ? 1 : 0, "HTTP request failed: status-code {}", status_code);
        this->callback.OnFailure();
        this->finished = true;
        return;
      }
 
      /* Next step: query for any data. */
      WinHttpQueryDataAvailable(this->request, nullptr);
    } break;
 
    case WINHTTP_CALLBACK_STATUS_DATA_AVAILABLE:
    {
      /* Retrieve the amount of data available to process. */
      DWORD size = *(DWORD *)info;
 
      /* Next step: read the data in a temporary allocated buffer.
       * The buffer will be freed by OnReceiveData() in the next step. */
      char *buffer = size == 0 ? nullptr : new char[size];
      WinHttpReadData(this->request, buffer, size, 0);
    } break;
 
    case WINHTTP_CALLBACK_STATUS_READ_COMPLETE:
      Debug(net, 6, "HTTP callback: {} bytes", length);
 
      this->callback.OnReceiveData(std::unique_ptr<char[]>(static_cast<char *>(info)), length);
 
      if (length == 0) {
        /* Next step: no more data available: request is finished. */
        this->finished = true;
        Debug(net, 1, "HTTP request succeeded");
      } else {
        /* Next step: query for more data. */
        WinHttpQueryDataAvailable(this->request, nullptr);
      }
 
      break;
 
    case WINHTTP_CALLBACK_STATUS_SECURE_FAILURE:
    case WINHTTP_CALLBACK_STATUS_REQUEST_ERROR:
      Debug(net, 0, "HTTP request failed: {}", GetLastErrorAsString());
      this->callback.OnFailure();
      this->finished = true;
      break;
 
    default:
      Debug(net, 0, "HTTP request failed: unexpected callback code 0x{:x}", code);
      this->callback.OnFailure();
      this->finished = true;
      return;
  }
}

static void CALLBACK StaticWinHttpCallback(HINTERNET, DWORD_PTR context, DWORD code, void *info, DWORD length)
{
  if (context == 0) return;
 
  NetworkHTTPRequest *request = (NetworkHTTPRequest *)context;
  request->WinHttpCallback(code, info, length);
}

void NetworkHTTPRequest::Connect()
{
  Debug(net, 1, "HTTP request to {}", std::string(uri.begin(), uri.end()));
 
  URL_COMPONENTS url_components = {};
  wchar_t scheme[32];
  wchar_t hostname[128];
  wchar_t url_path[4096];
 
  /* Convert the URL to its components. */
  url_components.dwStructSize = sizeof(url_components);
  url_components.lpszScheme = scheme;
  url_components.dwSchemeLength = static_cast<DWORD>(std::size(scheme));
  url_components.lpszHostName = hostname;
  url_components.dwHostNameLength = static_cast<DWORD>(std::size(hostname));
  url_components.lpszUrlPath = url_path;
  url_components.dwUrlPathLength = static_cast<DWORD>(std::size(url_path));
  WinHttpCrackUrl(this->uri.c_str(), 0, 0, &url_components);
 
  /* Create the HTTP connection. */
  this->connection = WinHttpConnect(_winhttp_session, url_components.lpszHostName, url_components.nPort, 0);
  if (this->connection == nullptr) {
    Debug(net, 0, "HTTP request failed: {}", GetLastErrorAsString());
    this->callback.OnFailure();
    this->finished = true;
    return;
  }
 
  this->request = WinHttpOpenRequest(connection, data.empty() ? L"GET" : L"POST", url_components.lpszUrlPath, nullptr, WINHTTP_NO_REFERER, WINHTTP_DEFAULT_ACCEPT_TYPES, url_components.nScheme == INTERNET_SCHEME_HTTPS ? WINHTTP_FLAG_SECURE : 0);
  if (this->request == nullptr) {
    WinHttpCloseHandle(this->connection);
 
    Debug(net, 0, "HTTP request failed: {}", GetLastErrorAsString());
    this->callback.OnFailure();
    this->finished = true;
    return;
  }
 
  /* Send the request (possibly with a payload). */
  if (data.empty()) {
    WinHttpSendRequest(this->request, WINHTTP_NO_ADDITIONAL_HEADERS, 0, WINHTTP_NO_REQUEST_DATA, 0, 0, reinterpret_cast<DWORD_PTR>(this));
  } else {
    /* When the payload starts with a '{', it is a JSON payload. */
    LPCWSTR content_type = data.starts_with("{") ? L"Content-Type: application/json\r\n" : L"Content-Type: application/x-www-form-urlencoded\r\n";
    WinHttpSendRequest(this->request, content_type, -1, const_cast<char *>(data.data()), static_cast<DWORD>(data.size()), static_cast<DWORD>(data.size()), reinterpret_cast<DWORD_PTR>(this));
  }
}

bool NetworkHTTPRequest::Receive()
{
  if (this->callback.cancelled && !this->finished) {
    Debug(net, 1, "HTTP request failed: cancelled by user");
    this->callback.OnFailure();
    this->finished = true;
    /* Fall-through, as we are waiting for IsQueueEmpty() to happen. */
  }
 
  return this->finished && this->callback.IsQueueEmpty();
}

NetworkHTTPRequest::~NetworkHTTPRequest()
{
  if (this->request) {
    WinHttpCloseHandle(this->request);
    WinHttpCloseHandle(this->connection);
  }
 
  std::lock_guard<std::mutex> lock(_http_callback_mutex);
  _http_callbacks.erase(std::remove(_http_callbacks.begin(), _http_callbacks.end(), &this->callback), _http_callbacks.end());
}
 
/* static */ void NetworkHTTPSocketHandler::Connect(std::string_view uri, HTTPCallback *callback, std::string &&data)
{
  auto request = new NetworkHTTPRequest(std::wstring(uri.begin(), uri.end()), callback, std::move(data));
  request->Connect();
 
  std::lock_guard<std::mutex> lock(_new_http_requests_mutex);
  _new_http_requests.push_back(request);
}
 
/* static */ void NetworkHTTPSocketHandler::HTTPReceive()
{
  /* Process all callbacks. */
  {
    std::lock_guard<std::mutex> lock(_http_callback_mutex);
 
    {
      std::lock_guard<std::mutex> lock(_new_http_callback_mutex);
      if (!_new_http_callbacks.empty()) {
        /* We delay adding new callbacks, as HandleQueue() below might add a new callback. */
        _http_callbacks.insert(_http_callbacks.end(), _new_http_callbacks.begin(), _new_http_callbacks.end());
        _new_http_callbacks.clear();
      }
    }
 
    for (auto &callback : _http_callbacks) {
      callback->HandleQueue();
    }
  }
 
  /* Process all requests. */
  {
    std::lock_guard<std::mutex> lock(_new_http_requests_mutex);
    if (!_new_http_requests.empty()) {
      /* We delay adding new requests, as Receive() below can cause a callback which adds a new requests. */
      _http_requests.insert(_http_requests.end(), _new_http_requests.begin(), _new_http_requests.end());
      _new_http_requests.clear();
    }
  }
 
  if (_http_requests.empty()) return;
 
  for (auto it = _http_requests.begin(); it != _http_requests.end(); /* nothing */) {
    NetworkHTTPRequest *cur = *it;
 
    if (cur->Receive()) {
      it = _http_requests.erase(it);
      delete cur;
      continue;
    }
 
    ++it;
  }
}
 
void NetworkHTTPInitialize()
{
  /* We create a single session, from which we build up every other request. */
  std::string user_agent = fmt::format("OpenTTD/{}", GetNetworkRevisionString());
  _winhttp_session = WinHttpOpen(std::wstring(user_agent.begin(), user_agent.end()).c_str(), WINHTTP_ACCESS_TYPE_DEFAULT_PROXY, WINHTTP_NO_PROXY_NAME, WINHTTP_NO_PROXY_BYPASS, WINHTTP_FLAG_ASYNC);
 
  /* Set the callback function for all requests. The "context" maps it back into the actual request instance. */
  WinHttpSetStatusCallback(_winhttp_session, StaticWinHttpCallback, WINHTTP_CALLBACK_FLAG_ALL_NOTIFICATIONS, 0);
 
  /* 10 seconds timeout for requests. */
  WinHttpSetTimeouts(_winhttp_session, 10000, 10000, 10000, 10000);
}
 
void NetworkHTTPUninitialize()
{
  WinHttpCloseHandle(_winhttp_session);
}