118 lines
3.9 KiB
D
118 lines
3.9 KiB
D
module server_protocol;
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import std.socket;
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import std.algorithm;
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import std.conv;
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import std.stdio;
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import streams;
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const int SEGMENT_BITS = 0x7F;
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const int CONTINUE_BIT = 0x80;
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struct ServerStatus {
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bool online;
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int playersOnline;
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int maxPlayers;
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string[] playerNames;
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}
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ServerStatus fetchStatus(string ipAndPort) {
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ptrdiff_t portIdx = countUntil(ipAndPort, ":");
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if (portIdx == -1) throw new Exception("Invalid IP address. Port is required.");
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string ip = ipAndPort[0..portIdx];
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ushort port = ipAndPort[portIdx + 1 .. $].to!ushort;
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Address address = new InternetAddress(ip, port);
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writeln(address);
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Socket socket = new TcpSocket(address);
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auto sIn = SocketInputStream(socket);
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auto sOut = SocketOutputStream(socket);
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auto bufferedOut = bufferedOutputStreamFor(sOut);
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auto arrayOut = byteArrayOutputStream();
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writeVarInt(&arrayOut, 0x00);
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writeVarInt(&arrayOut, 763);
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writeString(&arrayOut, ip);
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auto dOut = dataOutputStreamFor(&arrayOut, Endianness.BigEndian);
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dOut.writeToStream(port);
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writeVarInt(&arrayOut, 1);
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ubyte[] handshakePacket = arrayOut.toArray();
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writeln(handshakePacket);
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writeVarInt(&bufferedOut, cast(int) handshakePacket.length);
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bufferedOut.writeToStream(handshakePacket);
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bufferedOut.flushStream();
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writeln("Sent handshake packet.");
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auto arrayOut2 = byteArrayOutputStream();
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writeVarInt(arrayOut2, 0x00);
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ubyte[] statusRequestPacket = arrayOut2.toArray();
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writeVarInt(bufferedOut, cast(int) statusRequestPacket.length);
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bufferedOut.writeToStream(statusRequestPacket);
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bufferedOut.flushStream();
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writeln("Sent status request packet.");
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int responsePacketSize = readVarInt(sIn);
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writefln!"Got response of %d bytes"(responsePacketSize);
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ubyte[] packetIdAndData = new ubyte[responsePacketSize];
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StreamResult result = sIn.readFromStream(packetIdAndData);
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if (result.hasError || result.count != responsePacketSize) throw new Exception("Failed to read response packet.");
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auto packetIn = arrayInputStreamFor(packetIdAndData);
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int packetId = readVarInt(packetIn);
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if (packetId != 0x00) throw new Exception("Received invalid packetId when receiving status response.");
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string jsonStr = readString(packetIn);
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writeln(jsonStr);
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ServerStatus status;
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return status;
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}
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int readVarInt(S)(S s) if (isByteInputStream!S) {
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int value = 0;
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int position = 0;
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ubyte[1] buf;
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while (true) {
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writeln("Attempting to read from stream...");
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StreamResult result = s.readFromStream(buf);
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writeln(result);
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if (result.hasError) throw new Exception(cast(string) result.error.message);
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ubyte currentByte = buf[0];
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value |= (currentByte & SEGMENT_BITS) << position;
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if ((currentByte & CONTINUE_BIT) == 0) break;
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position += 7;
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if (position >= 32) throw new Exception("VarInt is too big.");
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}
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return value;
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}
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void writeVarInt(S)(S s, int value) if (isByteOutputStream!S) {
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while (true) {
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if ((value & ~SEGMENT_BITS) == 0) {
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StreamResult r = s.writeToStream([cast(ubyte) value]);
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if (r.hasError || r.count != 1) throw new Exception("Failed to write byte to stream");
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return;
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}
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StreamResult r = s.writeToStream([(value & SEGMENT_BITS) | CONTINUE_BIT]);
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if (r.hasError || r.count != 1) throw new Exception("Failed to write byte to stream");
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value >>>= 7;
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}
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}
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string readString(S)(S s) if (isByteInputStream!S) {
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int length = readVarInt(s);
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ubyte[] data = new ubyte[length];
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StreamResult result = s.readFromStream(data);
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if (result.hasError || result.count != length) throw new Exception("Couldn't read string.");
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return cast(string) data.idup;
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}
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void writeString(S)(S s, string str) if (isByteOutputStream!S) {
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ubyte[] bytes = cast(ubyte[]) str;
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writeVarInt(s, cast(int) bytes.length);
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s.writeToStream(bytes);
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}
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