1 files changed, 125 insertions, 0 deletions
diff --git a/day4/task4/server.py b/day4/task4/server.py
new file mode 100644
index 0000000..d013b35
--- /dev/null
+++ b/day4/task4/server.py
@@ -0,0 +1,125 @@
+import socket
+import struct
+import json
+
+
+HOST, PORT = ADDR = '0.0.0.0', 6000
+CHUNK_SIZE = 4096000
+DATATYPE_SIZE = 4  # int
+
+
+def pack_str(data: str):
+    encoded = data.encode()
+    return struct.pack('I', len(encoded)) + encoded
+
+
+def pack_bytes(data: bytes):
+    return struct.pack('I', len(data)) + data
+
+
+def handle_request(data, connection):
+    request = json.loads(data)
+
+    # Хотя метод только один, но все равно лучше
+    # сразу написать расширяемое приложение
+    if request['method'] == 'get':
+        path = request['path']
+
+        try:
+            with open(path, 'rb') as f:
+                file_data = f.read()
+
+        except FileNotFoundError:
+            header = json.dumps({'status': 1, 'reason': 'Файл не найден'})
+            connection.sendall(pack_str(header))
+
+        except PermissionError:
+            header = json.dumps({'status': 1, 'reason': 'Файл не доступен для чтения'})
+            connection.sendall(pack_str(header))
+
+        # Я знаю, что это плохо, но сервер не должен падать,
+        # а других ошибок я не смог вспомнить
+        except Exception as e:
+            header = json.dumps({'status': 2, 'reason': f'{type(e)}: {e}'})
+            connection.sendall(pack_str(header))
+
+        else:
+            length = len(file_data)
+            header = json.dumps({'status': 0, 'size': length, 'path': request['path']})
+            connection.sendall(pack_str(header))
+            print(f'Started sending file of size {length} bytes...')
+            i = 0
+            while i < length:
+                packet = pack_bytes(file_data[i: i + CHUNK_SIZE])
+                connection.sendall(packet)
+                i += CHUNK_SIZE
+                print(i / length * 100, '%')
+            print(f'Transmission ended')
+
+
+def get_data(connection):
+    buffer = b''
+    # Считываем размер пакета
+    while len(buffer) < DATATYPE_SIZE:
+        data = connection.recv(DATATYPE_SIZE - len(buffer))
+        if not data:
+            raise ConnectionError('Connection was closed')
+
+        buffer += data
+
+    size_packed, buffer = buffer[:DATATYPE_SIZE], buffer[DATATYPE_SIZE:]
+    if not size_packed:
+        raise ConnectionError('Connection was closed')
+
+    (size,) = struct.unpack('I', size_packed)
+    data = connection.recv(size - len(buffer))
+    return buffer + data
+
+
+def handle_connection(connection, address):
+    while True:
+        try:
+            data = get_data(connection)
+
+        except ConnectionResetError:
+            print(f'Connection with {address[0]} was unexpectedly closed')
+            break
+
+        except ConnectionError:
+            print(f'Connection with {address[0]} was ended')
+            break
+
+        except KeyboardInterrupt:
+            raise KeyboardInterrupt()
+
+        else:
+            if not data:
+                print(f'Connection with {address[0]} was ended')
+                break
+            handle_request(data.decode(), connection)
+
+
+def main():
+    sock = socket.socket()
+    sock.bind(ADDR)
+    sock.listen(5)
+
+    while True:
+        print('Listening for new connections...')
+        try:
+            connection, address = sock.accept()
+            print(f'Got a connection from {address[0]}')
+            handle_connection(connection, address)
+
+        except ConnectionResetError:
+            print(f'Connection with {address[0]} was unexpectedly closed')
+
+        except KeyboardInterrupt:
+            print('Stopping server...')
+            sock.close()
+            print('Server stopped')
+            break
+
+
+if __name__ == '__main__':
+    main()