Move shared constants, exceptions & helpers.py into /shared/

shared/helpers.py

@@ -0,0 +1,76 @@
+import html
+import json
+import time
+from typing import List, Tuple, Any
+
+from shared import constants
+
+HEADER_LENGTH = 10
+
+
+def prepare(message: str, encoding='utf-8') -> bytes:
+    """Prepares a message for sending through a socket by adding a proper header and encoding it."""
+    header = f'{len(message):<{HEADER_LENGTH}}'
+    return (header + message).encode(encoding)
+
+
+def prepare_json(obj: Any) -> bytes:
+    """
+    Prepares a object for sending as encoded JSON with a header.
+
+    :param obj: A JSON-encodable object
+    :return: Encoded JSON
+    """
+    return prepare(json.dumps(obj))
+
+
+def prepare_message(nickname: str, message: str, color: str, message_id: int, timestamp: int = None) -> bytes:
+    return prepare_json(
+        {
+            'type': constants.Types.MESSAGE,
+            'nickname': nickname,
+            'content': message,
+            'color': color,
+            'time': timestamp or int(time.time()),
+            'id': message_id,
+        }
+    )
+
+
+def prepare_message_history(messages: List[Tuple[int, str, str, str, int]]) -> bytes:
+    """Returns a encoded JSON message history object with the messages provided"""
+    return prepare_json(
+        {
+            'type': constants.Types.MESSAGE_HISTORY,
+            'messages': [
+                {
+                    'type': constants.Types.MESSAGE,
+                    'nickname': nickname,
+                    'content': message,
+                    'color': color,
+                    'time': timestamp,
+                    'id': message_id
+                } for message_id, nickname, color, message, timestamp in messages
+            ]
+        }
+    )
+
+
+def prepare_request(request: str) -> bytes:
+    """Helper function for creating a request message."""
+    return prepare_json({'type': constants.Types.REQUEST, 'request': request})
+
+
+def formatted_message(message: dict) -> str:
+    """Given a message dict object, return a color formatted and GUI ready string."""
+    nick_esc = html.escape(message["nickname"])
+    msg_esc = html.escape(message["message"])
+    return f'&lt;<span style="color: {message["color"]}">{nick_esc}</span>&gt; {msg_esc}'
+
+
+def sizeof_fmt(num, suffix='B'):
+    for unit in ['', 'Ki', 'Mi', 'Gi', 'Ti', 'Pi', 'Ei', 'Zi']:
+        if abs(num) < 1024.0:
+            return "%3.0f%s%s" % (num, unit, suffix)
+        num /= 1024.0
+    return "%.1f%s%s" % (num, 'Yi', suffix)