Implemented some of the datatypes and some tests for them.

minecraft/networking/datatypes.py

@@ -0,0 +1,310 @@
+"""
+Contains the datatypes used by the networking part of `pyminecraft`.
+The types are described at http://wiki.vg/Protocol#Data_types
+
+These datatypes are used by the packet definitions.
+"""
+
+__all__ = ["ENDIANNESS",
+           "Datatype",
+           "Boolean",
+           "Byte", "UnsignedByte",
+           "Short", "UnsignedShort",
+           "Integer", "UnsignedInteger",
+           "Long", "UnsignedLong",
+           "LongLong", "UnsignedLongLong",
+           "Float",
+           "Double",
+           "VarInt", "VarLong",
+           "String"]
+
+from minecraft.exceptions import DeserializationError, SerializationError
+from io import BytesIO
+import struct
+import collections
+
+ENDIANNESS = "!"  # Network, big-endian
+
+
+class Datatype(object):
+    """
+    Base object for all `pyminecraft` networking datatypes.
+
+
+    .. note::
+        If ``ALLOWED_SERIALIZATION_TYPES`` is not empty, only the types found
+        in ``ALLOWED_SERIALIZATION_TYPES`` are allowed as serialization
+        ``data``. This does somewhat go against the Duck-typing principle.
+
+        The same applies for ``ALLOWED_DESERIALIZATION_TYPES``.
+    """
+    FORMAT = ""
+    SIZE = 0
+
+    ALLOWED_SERIALIZATION_TYPES = tuple()
+    ALLOWED_DESERIALIZATION_TYPES = tuple()
+
+    @classmethod
+    def read(cls, fileobject):
+        bin_data = fileobject.read(cls.SIZE)
+        return cls.deserialize(bin_data)
+
+    @classmethod
+    def deserialize(cls, data):
+        cls.raise_deserialization_data(data)
+
+        deserialized_data = struct.unpack(ENDIANNESS + cls.FORMAT, data)[0]
+        return deserialized_data
+
+    @classmethod
+    def write(cls, fileobject, data):
+        return fileobject.write(cls.serialize(data))
+
+    @classmethod
+    def serialize(cls, data):
+        cls.raise_serialization_data(data)
+
+        serialized_data = struct.pack(ENDIANNESS + cls.FORMAT, data)
+        return serialized_data
+
+    @classmethod
+    def raise_serialization_data(cls, data):
+        """
+        Raises an appropriate ``Exception`` if ``data`` is not valid.
+
+        :return: ``None``
+        :rtype: ``None``
+        :raises: ``TypeError``, ``ValueError``
+        """
+        if (cls.ALLOWED_SERIALIZATION_TYPES and
+            not any([isinstance(data, type_) for type_
+                    in cls.ALLOWED_SERIALIZATION_TYPES])):
+
+            e = "'data's type ('{}') is not an allowed type."
+            e = e.format(type(data).__name__)
+
+            raise TypeError(e)
+
+        cls._raise_serialization_value_error_data(data)
+
+        return None
+
+    @staticmethod
+    def _raise_serialization_value_error_data(data):
+        """
+        Raises a ValueError if ``data`` is not valid.
+
+        :return: ``None``
+        :rtype: ``None``
+        :raises: ``ValueError``
+        """
+        return None
+
+    @classmethod
+    def raise_deserialization_data(cls, data):
+        """
+        Raises an appropriate ``Exception`` if ``data`` is not valid.
+
+        :return: ``None``
+        :rtype: ``None``
+        :raises: ``TypeError``, ``ValueError``
+        """
+        if (cls.ALLOWED_DESERIALIZATION_TYPES and
+            not any([isinstance(data, type_) for type_
+                    in cls.ALLOWED_DESERIALIZATION_TYPES])):
+
+            err = "'data's type ('{}') is not an allowed type."
+            err = err.format(type(data).__name__)
+
+            raise TypeError(err)
+
+        if cls.SIZE != len(data):
+            err = "'data' must have a length of {}, not {}"
+            err = err.format(str(cls.SIZE), len(data))
+
+            raise TypeError(err)
+
+        return None
+
+
+class Boolean(Datatype):
+    FORMAT = "?"
+    SIZE = 1
+
+    ALLOWED_SERIALIZATION_TYPES = (bool,)
+    ALLOWED_DESERIALIZATION_TYPES = (collections.Sequence,)
+
+
+class Byte(Datatype):
+    FORMAT = "b"
+    SIZE = 1
+
+    @staticmethod
+    def _raise_serialization_value_error_data(data):
+        if not -128 <= data <= 127:
+            e = "'data' must be an integer with value between -128 and 127."
+            raise ValueError(e)
+
+
+class UnsignedByte(Datatype):
+    FORMAT = "B"
+    SIZE = 1
+
+
+class Short(Datatype):
+    FORMAT = "h"
+    SIZE = 2
+
+
+class UnsignedShort(Datatype):
+    FORMAT = "H"
+    SIZE = 2
+
+
+class Integer(Datatype):
+    FORMAT = "i"
+    SIZE = 4
+
+
+class UnsignedInteger(Datatype):
+    FORMAT = "I"
+    SIZE = 4
+
+
+class Long(Datatype):
+    FORMAT = "l"
+    SIZE = 4
+
+
+class UnsignedLong(Datatype):
+    FORMAT = "L"
+    SIZE = 4
+
+
+class LongLong(Datatype):
+    FORMAT = "q"
+    SIZE = 8
+
+
+class UnsignedLongLong(Datatype):
+    FORMAT = "Q"
+    SIZE = 8
+
+
+class Float(Datatype):
+    FORMAT = "f"
+    SIZE = 4
+
+
+class Double(Datatype):
+    FORMAT = "d"
+    SIZE = 8
+
+
+class VarInt(Datatype):
+    # See: https://developers.google.com/protocol-buffers/docs/encoding#varints
+    # See: https://github.com/ammaraskar/pyCraft/blob/7e8df473520d57ca22fb57888681f51705128cdc/network/types.py#l123  # noqa
+    # See: https://github.com/google/protobuf/blob/0c59f2e6fc0a2cb8e8e3b4c7327f650e8586880a/python/google/protobuf/internal/decoder.py#l107  # noqa
+    # According to http://wiki.vg/Protocol#Data_types,
+    # MineCraftian VarInts can be at most 5 bytes.
+
+    # Maximum integer value: size of serialized VarInt in bytes
+    SIZE_TABLE = {
+        2**7: 1,
+        2**14: 2,
+        2**21: 3,
+        2**28: 4,
+        2**35: 5,
+    }
+
+    # Largest element in SIZE_TABLE, assuming largest element is last.
+    MAX_SIZE = list(SIZE_TABLE.items())[-1][-1]
+
+    @classmethod
+    def read(cls, fileobject):
+        number = 0  # The decoded number
+
+        i = 0  # Incrementor
+        while True:
+            if i > cls.MAX_SIZE:  # Check if we have exceeded max-size
+                name_of_self = str(type(cls))
+                e = "Data too large to be a {}".format(name_of_self)
+                raise DeserializationError(e)
+
+            try:
+                byte = ord(fileobject.read(1))  # Read a byte as integer
+            except TypeError:
+                e = "Fileobject ran out of data. Socket closed?"
+                raise DeserializationError(e)
+
+            number |= ((byte & 0x7f) << (i * 7))
+            if not (byte & 0x80):
+                break
+
+            i += 1
+        return number
+
+    @classmethod
+    def deserialize(cls, data):
+        data_fileobject = BytesIO(bytes(data))
+        return cls.read(data_fileobject)
+
+    @classmethod
+    def serialize(cls, data):
+        if data > cls.SIZE_TABLE[-1][0]:
+            name_of_self = str(type(cls))
+            e = "Number too big to serialize as {}".format(name_of_self)
+            raise SerializationError(e)
+
+        result = bytes()  # Where we store the serialized number
+
+        while True:
+            byte = data & 0x7f
+            data >>= 7
+
+            result += UnsignedByte.serialize(byte | (0x80 if data > 0 else 0))
+
+            if not data:
+                break
+
+        return result
+
+
+class VarLong(VarInt):
+    # According to http://wiki.vg/Protocol#Data_types,
+    # MineCraftian VarInts can be at most 10 bytes.
+    SIZE_TABLE = VarInt.SIZE_TABLE
+    SIZE_TABLE.update(
+        {
+            2**42: 6,
+            2**49: 7,
+            2**56: 8,
+            2**63: 9,
+            2**70: 10,
+        }
+    )
+
+    MAX_SIZE = list(SIZE_TABLE.items())[-1][-1]
+
+
+class String(Datatype):
+    FORMAT = "utf-8"
+
+    @classmethod
+    def read(cls, fileobject):
+        str_size = VarInt.read(fileobject)
+        string = fileobject.read(str_size).decode(cls.FORMAT)
+
+        return string
+
+    @classmethod
+    def deserialize(cls, data):
+        data_fileobject = BytesIO(bytes(data))
+        return cls.read(data_fileobject)
+
+    @classmethod
+    def serialize(cls, data):
+        data = data.encode(cls.FORMAT)
+        len_data = VarInt.serialize(len(data))
+
+        return len_data + data

tests/test_datatypes.py

@@ -0,0 +1,147 @@
+from minecraft.networking.datatypes import *
+from minecraft.exceptions import DeserializationError
+
+import unittest
+
+
+# # Note, we use the actual classes as keys.
+# # Format: DATATYPE_OBJ = (LIST_OF_VALID_VALUES, LIST_OF_INVALID_VALUES)
+# TEST_DATA = {
+#     Boolean: [True, False],
+#     Byte: [-127, -25, 0, 125],
+#     UnsignedByte: [0, 125],
+#     Byte: [-22, 22],
+#     Short: [-340, 22, 350],
+#     UnsignedShort: [0, 400],
+#     Integer: [-1000, 1000],
+#     VarInt: [1, 250, 50000, 10000000],
+#     Long: [50000000],
+#     Float: [21.000301],
+#     Double: [36.004002],
+#     ShortPrefixedByteArray: [bytes(245)],
+#     VarIntPrefixedByteArray: [bytes(1234)],
+#     StringType: ["hello world"]
+# }
+
+
+class BaseDatatypeTester(unittest.TestCase):
+    DATATYPE_CLS = Datatype  # We use Datatype as a an example here.
+
+    # TEST_DATA_VALID_VALUES should have the following format:
+    # [(DESERIALIZED_VALUE, SERIALIZED_VALUE), ...]
+    #
+    # So that DESERIALIZED_VALUE is SERIALIZED_VALUE when serialized
+    # and vice versa.
+
+    TEST_DATA_VALID_VALUES = []
+
+    # TEST_DATA_INVALID_SERIALIZATION_VALUES should be a list of tuples
+    # containing the value and the expected exception.
+    TEST_DATA_INVALID_SERIALIZATION_VALUES = []
+
+    # TEST_DATA_INVALID_DESERIALIZATION_VALUES should be a list of tuples
+    # containing the value and the expected exception.
+    TEST_DATA_INVALID_DESERIALIZATION_VALUES = []
+
+    def test_init(self):
+        d = self.DATATYPE_CLS()  # noqa
+
+    def test_init_with_arg(self):
+        # We shouldn't accept any parameters.
+        with self.assertRaises(TypeError):
+            d = self.DATATYPE_CLS("This is a positional argument...")  # noqa
+
+    def test_valid_data_serialization_values(self):
+        for deserialized_val, serialized_val in self.TEST_DATA_VALID_VALUES:
+            self.assertEqual(self.DATATYPE_CLS.serialize(deserialized_val),
+                             serialized_val)
+
+    def test_valid_data_deserialization_values(self):
+        for deserialized_val, serialized_val in self.TEST_DATA_VALID_VALUES:
+            self.assertEqual(self.DATATYPE_CLS.deserialize(serialized_val),
+                             deserialized_val)
+
+    def test_invalid_data_serialization_values(self):
+        for value, exception in self.TEST_DATA_INVALID_SERIALIZATION_VALUES:
+            with self.assertRaises(exception):
+                self.DATATYPE_CLS.serialize(value)
+
+    def test_invalid_data_deserialization_values(self):
+        for value, exception in self.TEST_DATA_INVALID_DESERIALIZATION_VALUES:
+            with self.assertRaises(exception):
+                self.DATATYPE_CLS.deserialize(value)
+
+
+class DatatypeTest(BaseDatatypeTester):
+    DATATYPE_CLS = Datatype
+
+
+class BooleanTest(BaseDatatypeTester):
+    DATATYPE_CLS = Boolean
+
+    TEST_DATA_VALID_VALUES = [
+        (True, b"\x01"),
+        (False, b"\x00")
+    ]
+
+    TEST_DATA_INVALID_SERIALIZATION_VALUES = [
+        ("\x00", TypeError),
+        ("\x01", TypeError),
+        ("\x02", TypeError),
+        (-1, TypeError),
+        (0, TypeError),
+        (1, TypeError),
+        ("", TypeError),
+        ("Test", TypeError)
+    ]
+
+    TEST_DATA_INVALID_DESERIALIZATION_VALUES = [
+        (-1, TypeError),
+        (0, TypeError),
+        (1, TypeError),
+        ("", TypeError),
+        ("Test", TypeError),
+        (True, TypeError),
+        (False, TypeError)
+    ]
+
+
+class ByteTest(BaseDatatypeTester):
+    DATATYPE_CLS = Byte
+
+    TEST_DATA_VALID_VALUES = [
+        (-128, b"\x80"),
+        (-22, b"\xea"),
+        (0, b"\x00"),
+        (22, b"\x16"),
+        (127, b"\x7f")
+    ]
+
+    TEST_DATA_INVALID_SERIALIZATION_VALUES = [
+        (-500, ValueError),
+        (128, ValueError),
+        (1024, ValueError),
+
+    ]
+
+# def _bin(binstr):
+#     """
+#     Accepts a pretty looking string of binary numbers and
+#     returns the binary number.
+
+#     Parameters:
+#         binstr - a string with this format: `'1010 0010 0100'`.
+
+#     Returns:
+#         Int
+#     """
+#     binstr = binstr.replace(" ", "")  # Remove all spaces.
+#     num = int("0b" + binstr, 2)
+
+#     return num
+
+
+# class VarIntTests(unittest.TestCase):
+#     def test1(self):
+#         self.assertEqual(VarInt.deserialize(_bin("0000 0001")), 1)
+#         self.assertEqual(VarInt.deserialize(_bin("1010 1100 0000 0010")), 300)