fix encoding error on *too* random bytes

This should fix things like:

def __init__(self, val):
    self.val = val.decode("string_escape")
ValueError: Trailing \ in string
pathod/language/base.py:108: ValueError

test/pathod/test_language_websocket.py:83: in fr
    return netlib.websockets.Frame.from_bytes(tutils.render(wf, settings))
test/pathod/tutils.py:123: in render
    r = r.resolve(settings)
pathod/language/websockets.py:179: in resolve
    Key(base.TokValueLiteral(os.urandom(4)))

1 files changed, 5 insertions, 1 deletions

diff --git a/pathod/language/websockets.py b/pathod/language/websockets.py
index ea7c870e..09443a95 100644
--- a/pathod/language/websockets.py
+++ b/pathod/language/websockets.py
@@ -1,4 +1,6 @@
 import os
+import random
+import string
 import netlib.websockets
 import pyparsing as pp
 from . import base, generators, actions, message
@@ -175,8 +177,10 @@ class WebsocketFrame(message.Message):
                 Mask(True)
             )
         if not self.knone and self.mask and self.mask.value and not self.key:
+            allowed_chars = string.ascii_letters + string.digits
+            k = ''.join([allowed_chars[random.randrange(0, len(allowed_chars))] for i in range(4)])
             tokens.append(
-                Key(base.TokValueLiteral(os.urandom(4)))
+                Key(base.TokValueLiteral(k))
             )
         return self.__class__(
             [i.resolve(settings, self) for i in tokens]