Add base api type classes w/ encoders in kafka.protocol.types

kafka/protocol/types.py

@@ -0,0 +1,55 @@
+from struct import pack
+
+
+class AbstractField(object):
+    def __init__(self, name):
+        self.name = name
+
+
+class Int8(AbstractField):
+    @classmethod
+    def encode(cls, value):
+        return pack('>b', value)
+
+
+class Int16(AbstractField):
+    @classmethod
+    def encode(cls, value):
+        return pack('>h', value)
+
+
+class Int32(AbstractField):
+    @classmethod
+    def encode(cls, value):
+        return pack('>i', value)
+
+
+class Int64(AbstractField):
+    @classmethod
+    def encode(cls, value):
+        return pack('>q', value)
+
+
+class String(AbstractField):
+    @classmethod
+    def encode(cls, value):
+        if value is None:
+            return Int16.encode(-1)
+        else:
+            return Int16.encode(len(value)) + value
+
+
+class Bytes(AbstractField):
+    @classmethod
+    def encode(cls, value):
+        if value is None:
+            return Int32.encode(-1)
+        else:
+            return Int32.encode(len(value)) + value
+
+
+class Array(object):
+    @classmethod
+    def encode(cls, values):
+        # Assume that values are already encoded
+        return Int32.encode(len(values)) + b''.join(values)