switch to different guac implementation, shuffle some stuff around

cvmlib/__init__.py

@@ -1,68 +1,9 @@
-from typing import List, Optional
 from enum import IntEnum
 
-def guac_decode(string: str) -> Optional[List[str]]:
-    """Implementation of guacamole decoder
-    Example: guac_decode(\"4.chat,5.hello\") -> [\"chat\", \"hello\"]"""
-
-    if not string:
-        return []
-
-    idx: int = 0
-    distance: int
-    result: List[str] = []
-    chars: List[str] = list(string)
-
-    while True:
-        dist_str: str = ""
-
-        while chars[idx].isdecimal():
-            dist_str += chars[idx]
-            idx = idx + 1
-
-        if idx >= 1:
-            idx -= 1
-
-        if not dist_str.isdigit():
-            return None
-
-        distance = int(dist_str)
-        idx += 1
-
-        if chars[idx] != ".":
-            return None
-
-        idx += 1
-
-        addition: str = ""
-        for num in range(idx, idx + distance):
-            addition += chars[num]
-
-        result.append(addition)
-
-        idx += distance
-        if idx >= len(chars):
-            return None
-
-        if chars[idx] == ",":
-            pass
-        elif chars[idx] == ";":
-            break
-        else:
-            return None
-
-        idx += 1
-
-    return result
-
-def guac_encode(*args: str) -> str:
-    """Implementation of guacamole encoder
-    Example: guac_encode(\"chat\", \"hello\") -> \"4.chat,5.hello;\" """
-
-    return f"{','.join(f'{len(arg)}.{arg}' for arg in args)};"
-
+# ENUMS
 class CollabVMState(IntEnum):
     """Represents client connection states."""
+    
     WS_DISCONNECTED = -1
     """WebSocket is disconnected."""
     WS_CONNECTED = 0
@@ -74,6 +15,7 @@ class CollabVMState(IntEnum):
 
 class CollabVMRank(IntEnum):
     """Represents user ranks."""
+    
     Unregistered = 0
     """Represents an unregistered user."""
     Registered = 1
@@ -85,6 +27,7 @@ class CollabVMRank(IntEnum):
 
 class CollabVMClientRenameStatus(IntEnum):
     """Represents the status of a client rename attempt."""
+    
     SUCCEEDED = 0
     """The rename attempt was successful."""
     FAILED_TAKEN = 1
@@ -92,4 +35,51 @@ class CollabVMClientRenameStatus(IntEnum):
     FAILED_INVALID = 2
     """The desired name is invalid."""
     FAILED_REJECTED = 3
-    """The rename attempt was authoritatively rejected."""
+    """The rename attempt was authoritatively rejected."""
+
+# GUACAMOLE
+def guac_encode(elements: list) -> str:
+    return ','.join([f'{len(element)}.{element}' for element in elements]) + ';'
+
+def guac_decode(instruction: str) -> list:
+    elements = []
+    position = 0
+
+    # Loop and collect elements
+    continueScanning = True
+    while continueScanning:
+        # Ensure current position is not out of bounds
+        if position >= len(instruction):
+            raise ValueError(f"Unexpected EOL in guacamole instruction at character {position}")
+        # Get position of separator
+        separatorPosition = instruction.index('.', position)
+        # Read and validate element length
+        try:
+            elementLength = int(instruction[position:separatorPosition])
+        except ValueError:
+            raise ValueError(f"Malformed element length in guacamole exception at character {position}")
+        if elementLength < 0 or elementLength > len(instruction) - separatorPosition - 1:
+            raise ValueError(f"Invalid element length in guacamole exception at character {position}")
+        position = separatorPosition + 1
+
+        # Collect element
+        element = instruction[position:position+elementLength]
+        
+        position = position + elementLength
+
+        elements.append(element)
+
+        # Check separator
+        if position >= len(instruction):
+            raise ValueError(f"Unexpected EOL in guacamole instruction at character {position}")
+        
+        # Check terminator
+        match instruction[position]:
+            case ',':
+                position = position + 1
+            case ';':
+                continueScanning = False
+            case _:
+                raise ValueError(f"Unexpected '{instruction[position]}' in guacamole instruction at character {position}")
+    
+    return elements

cvmsentry.py

@@ -1,4 +1,4 @@
-from typing import List, Optional
+from typing import List
 from cvmlib import guac_decode, guac_encode, CollabVMRank, CollabVMState, CollabVMClientRenameStatus
 import config
 import os, random, websockets, asyncio
@@ -39,10 +39,10 @@ def get_origin_from_ws_url(ws_url: str) -> str:
 
 async def send_chat_message(websocket, message: str):
     log.debug(f"Sending chat message: {message}")
-    await websocket.send(guac_encode("chat", message))
+    await websocket.send(guac_encode(["chat", message]))
 
 async def send_guac(websocket, *args: str):
-    await websocket.send(guac_encode(*args))
+    await websocket.send(guac_encode(list(args)))
 
 async def connect(vm_name: str):
     global STATE
@@ -72,7 +72,7 @@ async def connect(vm_name: str):
             vm_botuser[vm_name] = ""
         # response = await websocket.recv()
         async for message in websocket:
-            decoded: Optional[List[str]] = guac_decode(str(message))
+            decoded: List[str] = guac_decode(str(message))
             match decoded:
                 case ["nop"]:
                     await send_guac(websocket, "nop")