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#include "NetworkServerLookup.hpp"
#include <stdexcept>
#include <QHostInfo>
#include <QString>
std::tuple<QHostAddress, quint16>
network_server_lookup (QString query
, quint16 default_service_port
, QHostAddress default_host_address
, QAbstractSocket::NetworkLayerProtocol required_protocol)
{
query = query.trimmed ();
QHostAddress host_address {default_host_address};
quint16 service_port {default_service_port};
QString host_name;
if (!query.isEmpty ())
{
int port_colon_index {-1};
if ('[' == query[0])
{
// assume IPv6 combined address/port syntax [<address>]:<port>
auto close_bracket_index = query.lastIndexOf (']');
host_name = query.mid (1, close_bracket_index - 1);
port_colon_index = query.indexOf (':', close_bracket_index);
}
else
{
port_colon_index = query.lastIndexOf (':');
host_name = query.left (port_colon_index);
}
host_name = host_name.trimmed ();
if (port_colon_index >= 0)
{
bool ok;
service_port = query.mid (port_colon_index + 1).trimmed ().toUShort (&ok);
if (!ok)
{
throw std::runtime_error {"network server lookup error: invalid port"};
}
}
}
if (!host_name.isEmpty ())
{
auto host_info = QHostInfo::fromName (host_name);
if (host_info.addresses ().isEmpty ())
{
throw std::runtime_error {"network server lookup error: host name lookup failed"};
}
bool found {false};
for (int i {0}; i < host_info.addresses ().size () && !found; ++i)
{
host_address = host_info.addresses ().at (i);
switch (required_protocol)
{
case QAbstractSocket::IPv4Protocol:
case QAbstractSocket::IPv6Protocol:
if (required_protocol != host_address.protocol ())
{
break;
}
// fall through
case QAbstractSocket::AnyIPProtocol:
found = true;
break;
default:
throw std::runtime_error {"network server lookup error: invalid required protocol"};
}
}
if (!found)
{
throw std::runtime_error {"network server lookup error: no suitable host address found"};
}
}
return std::make_tuple (host_address, service_port);
}
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