我在c ++中的http服务器没有正确发送所有文件

Question

我正在使用c ++编写HTTP服务器,现在它适用于文本文件的请求,但是当尝试获取jpeg或其他内容时,只会发送部分文件.这个问题似乎是,当我用fgets(缓冲,2000年,returned_file)似乎增加比它实际上最终将进入缓冲得多的文件位置指示器.为什么会这样？我把我的所有代码放在下面.问题出现在响应代码为200时发生的while(true)循环中.感谢任何回复的人.

// Interpret the command line arguments
unsigned short port = 8080;

if ( (argc != 1) && (argc != 3) && (argc != 5) ) {
  cerr << "Usage: " << argv[0];
  cerr << " -p <port number> -d <base directory>" << endl;
  return 1;
}
else {
  for (int i = 1; i < argc; ++i) {
    if (strcmp(argv[i], "-p") == 0)
      port = (unsigned short) atoi(argv[++i]);
    else if (strcmp(argv[i], "-d") == 0)
      base_directory = argv[++i];
  }
}
// if base_directory was not given, set it to current working directory
if ( !base_directory ) {
  base_directory = getcwd(base_directory, 100);
}

// Create TCP socket
int tcp_sock = socket(AF_INET, SOCK_STREAM, 0);
if (tcp_sock < 0) {
  cerr << "Unable to create TCP socket." << endl;
  return 2;
}

// Create server socket
sockaddr_in server;
server.sin_family = AF_INET;
server.sin_port = htons( port );
server.sin_addr.s_addr = INADDR_ANY;

// Bind the socket
if (bind(tcp_sock, (sockaddr*)&server, sizeof(server)) < 0) {
  cerr << "Unable to bind TCP socket." << endl;
  return 3;
}

// Listen for a connection request on TCP port
listen(tcp_sock, 5);

// Create HTTP_Request object and start a while loop of accepting connections
char buffer[2000];
int bytes_recv = 0;
int recv_len = 0;
string error_reply;

HTTP_Response* response;

while (true) {
  int acc_tcp_sock = accept(tcp_sock, NULL, NULL);
  if (acc_tcp_sock == -1) {
    cerr << "Unable to open TCP connection with client." << endl;
  }
  do {
    // may want to do just one recv
    recv_len = recv( acc_tcp_sock, buffer + bytes_recv,
      2000 - bytes_recv, 0 );
    bytes_recv += recv_len;
  } while (false);
  bytes_recv = 0;
  // may want to see if this causes a memory leak
  HTTP_Request* request = HTTP_Request::Parse(buffer, 2000);

  response = handle_request(request); // function to handle the request

  // Put response header into buffer
  response->Print( buffer, 2000 );

  // if 200 and GET then send header with file
  if ( response->Get_code() == 200 ) {
    // send response header
    if ( send( acc_tcp_sock, buffer, strlen(buffer), 0 ) < 0 ) {
      cerr << "Unable to send response header to client." << endl;
    }
    if ( method == "GET" ) {
      // send file
      while ( true ) {
        fgets( buffer, 2000, returned_file );
        if ( feof( returned_file ) ) break;
        if ( send( acc_tcp_sock, buffer, strlen(buffer), 0 ) < 0 ) {
          cerr << "Unable to send file in response to client." << endl;
        }
      }
    }
    fclose( returned_file ); // close file
  }
  else {
    if ( method == "GET" ) {
      error_reply = buffer + error_page;
      if ( send( acc_tcp_sock, error_reply.c_str(), error_reply.length(), 0 ) < 0 ) {
        cerr << "Unable to send response to client." << endl;
      }
    }
    else {
      if ( send( acc_tcp_sock, buffer, strlen(buffer), 0 ) < 0 ) {
        cerr << "Unable to send respone header to client." << endl;
      }
    }
  }

  close( acc_tcp_sock ); // close the connection
}

return 0;

Answer 1

不要fgets()用于读取需要逐位存活的二进制数据.您不希望记录分隔符转换,并且如果您以这种方式读取它,某些系统可能会假定它是文本.就此而言,换行和记录分隔符完全没有意义,因此fgets()扫描它们的功能充其量只是令人困惑的低效率,最糟糕的是根本不具备二进制功能.

使用fread(3)或者更好的是,使用原始系统调用(无论如何,在非Unix上使用Posix API)read(2).这将读取一定数量的逐位数据并告诉您它读取了多少.(关于使用哪种具有二进制功能的API:通常,我们建议缓冲数据,因为我们通常以线条等小单位处理它.但是,当将整个文件从一个地方移动到另一个地方时,缓冲会减慢你的速度.在这种情况下使用起来更简单,更快捷read().)

你也不能strlen()二进制数据.您必须使用API​​调用中的字节数.

Answer 2

不会在二进制文件上使用strlen break吗？

send( acc_tcp_sock, buffer, strlen(buffer), 0 )