Make it easy to monkey-patch length of frames repr.

Fix #1451.

Author: aaugustin

src/websockets/frames.py

@@ -146,6 +146,9 @@ class Frame:
     rsv2: bool = False
     rsv3: bool = False
 
+    # Monkey-patch if you want to see more in logs. Should be a multiple of 3.
+    MAX_LOG = 75
+
     def __str__(self) -> str:
         """
         Return a human-readable representation of a frame.
@@ -163,8 +166,9 @@ def __str__(self) -> str:
             # We'll show at most the first 16 bytes and the last 8 bytes.
             # Encode just what we need, plus two dummy bytes to elide later.
             binary = self.data
-            if len(binary) > 25:
-                binary = b"".join([binary[:16], b"\x00\x00", binary[-8:]])
+            if len(binary) > self.MAX_LOG // 3:
+                cut = (self.MAX_LOG // 3 - 1) // 3  # by default cut = 8
+                binary = b"".join([binary[: 2 * cut], b"\x00\x00", binary[-cut:]])
             data = " ".join(f"{byte:02x}" for byte in binary)
         elif self.opcode is OP_CLOSE:
             data = str(Close.parse(self.data))
@@ -179,15 +183,17 @@ def __str__(self) -> str:
                 coding = "text"
             except (UnicodeDecodeError, AttributeError):
                 binary = self.data
-                if len(binary) > 25:
-                    binary = b"".join([binary[:16], b"\x00\x00", binary[-8:]])
+                if len(binary) > self.MAX_LOG // 3:
+                    cut = (self.MAX_LOG // 3 - 1) // 3  # by default cut = 8
+                    binary = b"".join([binary[: 2 * cut], b"\x00\x00", binary[-cut:]])
                 data = " ".join(f"{byte:02x}" for byte in binary)
                 coding = "binary"
         else:
             data = "''"
 
-        if len(data) > 75:
-            data = data[:48] + "..." + data[-24:]
+        if len(data) > self.MAX_LOG:
+            cut = self.MAX_LOG // 3 - 1  # by default cut = 24
+            data = data[: 2 * cut] + "..." + data[-cut:]
 
         metadata = ", ".join(filter(None, [coding, length, non_final]))