Add step 3 get and set into Redis Server

pyredis/commands.py

@@ -18,19 +18,45 @@ def _handle_ping(command):
         return Error(data="ERR wrong number of arguments for 'ping' command")
 
 
-def _handle_unrecognised_command(command):
+def _handle_set(command, datastore):
+    if len(command) >= 3:
+        key = command[1].data.decode()
+        value = command[2].data.decode()
+        datastore[key] = value
+        return SimpleString("OK")
+    return Error("ERR wrong number of arguments for 'set' command")
+
+
+def _handle_get(command, datastore):
+    if len(command) == 2:
+        key = command[1].data.decode()
+        try:
+            value = datastore[key]
+        except KeyError:
+            return BulkString(None)
+        return BulkString(value)
+    return Error("ERR wrong numer of arguments for 'get' command")
+
+
+def _handle_unrecognised_command(command, *args):
     args = " ".join((f"'{c.data.decode()}'" for c in command[1:]))
     return Error(
         f"ERR unknown command '{command[0].data.decode()}', with args beginning with: {args}"
     )
 
 
-def handle_command(command):
+def handle_command(command, datastore):
     match command[0].data.decode().upper():
         case "ECHO":
             return _handle_echo(command)
 
         case "PING":
             return _handle_ping(command)
 
+        case "SET":
+            return _handle_set(command, datastore)
+
+        case "GET":
+            return _handle_get(command, datastore)
+
     return _handle_unrecognised_command(command)

pyredis/datastore.py

@@ -0,0 +1,10 @@
+class DataStore:
+    def __init__(self):
+        self._data = dict()
+
+    def __getitem__(self, key):
+        item = self._data[key]
+        return item
+
+    def __setitem__(self, key, value):
+        self._data[key] = value

pyredis/server.py

@@ -3,36 +3,17 @@
 
 from pyredis.protocol import extract_frame_from_buffer, encode_message
 from pyredis.commands import handle_command
+from pyredis.datastore import DataStore
 
 RECV_SIZE = 2048
 log = logging.getLogger("pyredis")
 
 
-def handle_client_connection(client_socket):
-    buffer = bytearray()
-    try:
-        while True:
-            data = client_socket.recv(RECV_SIZE)
-            log.info("Received data from client")
-            if not data:
-                break
-            buffer.extend(data)
-            frame, frame_size = extract_frame_from_buffer(buffer)
-            log.info("Extracted one frame from received data")
-            if frame:
-                buffer = buffer[frame_size:]
-                log.info("Processing one frame")
-                result = handle_command(frame)
-                client_socket.send(encode_message(result))
-
-    finally:
-        client_socket.close()
-
-
 class Server:
     def __init__(self, port) -> None:
         self.port = port
         self._running = False
+        self._datastore = DataStore()
 
     def run(self):
         self._running = True
@@ -47,7 +28,27 @@ def run(self):
             while self._running:
                 client_socket, _ = server_socket.accept()
                 log.info("Accepted one client")
-                handle_client_connection(client_socket)
+                self.handle_client_connection(client_socket, self._datastore)
+
+    def handle_client_connection(self, client_socket, datastore):
+        buffer = bytearray()
+        try:
+            while True:
+                data = client_socket.recv(RECV_SIZE)
+                log.info("Received data from client")
+                if not data:
+                    break
+                buffer.extend(data)
+                frame, frame_size = extract_frame_from_buffer(buffer)
+                log.info("Extracted one frame from received data")
+                if frame:
+                    buffer = buffer[frame_size:]
+                    log.info("Processing one frame")
+                    result = handle_command(frame, datastore)
+                    client_socket.send(encode_message(result))
+
+        finally:
+            client_socket.close()
 
     def stop(self):
         self._running = False

tests/test_commands.py

@@ -1,9 +1,17 @@
 import pytest
 
 from pyredis.commands import handle_command
+from pyredis.datastore import DataStore
 from pyredis.types import Array, BulkString, Error, Integer, SimpleString
 
 
+@pytest.fixture(scope="module")
+def datastore():
+    datastore = DataStore()
+    datastore["always_exist_key"] = "default"
+    return datastore
+
+
 @pytest.mark.parametrize(
     "command, expected",
     [
@@ -19,9 +27,26 @@
         ),
         # Ping Tests
         (Array([BulkString(b"ping")]), SimpleString("PONG")),
+        # Set Tests
         (Array([BulkString(b"ping"), BulkString(b"Hello")]), BulkString("Hello")),
+        (
+            Array([BulkString(b"set")]),
+            Error("ERR wrong number of arguments for 'set' command"),
+        ),
+        (
+            Array([BulkString(b"set"), SimpleString(b"key")]),
+            Error("ERR wrong number of arguments for 'set' command"),
+        ),
+        (
+            Array([BulkString(b"set"), SimpleString(b"key"), SimpleString(b"value")]),
+            SimpleString("OK"),
+        ),
+        (
+            Array([BulkString(b"get"), SimpleString(b"always_exist_key")]),
+            BulkString("default"),
+        ),
     ],
 )
-def test_handle_command(command, expected):
-    result = handle_command(command)
+def test_handle_command(command, expected, datastore):
+    result = handle_command(command, datastore)
     assert result == expected

tests/test_protocol.py

@@ -83,3 +83,9 @@ def test_read_frame(buffer, expected):
 def test_encode_message(message, expected):
     encoded_message = encode_message(message)
     assert encoded_message == expected
+
+
+def test_set_and_get_item():
+    ds = DataStore()
+    ds["key"] = 1
+    assert ds["key"] == 1