Monkeypatch zeroconf to remove the 15 character service name limit.

src/calibre/devices/smart_device_app/driver.py

@@ -384,6 +384,10 @@ class SMART_DEVICE_APP(DeviceConfig, DevicePlugin):
         self.debug_start_time = time.time()
         self.debug_time = time.time()
         self.is_connected = False
+        # Hack to work around the newly-enforced 15 character service name limit.
+        # "monkeypatch" zeroconf with a function without the check
+        import zeroconf
+        zeroconf.service_type_name = service_type_name
 
     # Don't call this method from the GUI unless you are sure that there is no
     # network traffic in progress. Otherwise the gui might hang waiting for the
@@ -2032,3 +2036,111 @@ class SMART_DEVICE_APP(DeviceConfig, DevicePlugin):
 
     def is_running(self):
         return getattr(self, 'listen_socket', None) is not None
+
+# Function to monkeypatch zeroconf to remove the 15 character name length restriction.
+# Copied from https://github.com/jstasiak/python-zeroconf version 0.28.1
+
+from zeroconf import (BadTypeInNameException, _HAS_A_TO_Z,
+                      _HAS_ONLY_A_TO_Z_NUM_HYPHEN_UNDERSCORE,
+                      _HAS_ASCII_CONTROL_CHARS,
+                      _HAS_ONLY_A_TO_Z_NUM_HYPHEN)
+
+def service_type_name(type_: str, *, allow_underscores: bool = False) -> str:
+    """
+    Validate a fully qualified service name, instance or subtype. [rfc6763]
+
+    Returns fully qualified service name.
+
+    Domain names used by mDNS-SD take the following forms:
+
+                   <sn> . <_tcp|_udp> . local.
+      <Instance> . <sn> . <_tcp|_udp> . local.
+      <sub>._sub . <sn> . <_tcp|_udp> . local.
+
+    1) must end with 'local.'
+
+      This is true because we are implementing mDNS and since the 'm' means
+      multi-cast, the 'local.' domain is mandatory.
+
+    2) local is preceded with either '_udp.' or '_tcp.'
+
+    3) service name <sn> precedes <_tcp|_udp>
+
+      The rules for Service Names [RFC6335] state that they may be no more
+      than fifteen characters long (not counting the mandatory underscore),
+      consisting of only letters, digits, and hyphens, must begin and end
+      with a letter or digit, must not contain consecutive hyphens, and
+      must contain at least one letter.
+
+    The instance name <Instance> and sub type <sub> may be up to 63 bytes.
+
+    The portion of the Service Instance Name is a user-
+    friendly name consisting of arbitrary Net-Unicode text [RFC5198]. It
+    MUST NOT contain ASCII control characters (byte values 0x00-0x1F and
+    0x7F) [RFC20] but otherwise is allowed to contain any characters,
+    without restriction, including spaces, uppercase, lowercase,
+    punctuation -- including dots -- accented characters, non-Roman text,
+    and anything else that may be represented using Net-Unicode.
+
+    :param type_: Type, SubType or service name to validate
+    :return: fully qualified service name (eg: _http._tcp.local.)
+    """
+    if not (type_.endswith('._tcp.local.') or type_.endswith('._udp.local.')):
+        raise BadTypeInNameException("Type '%s' must end with '._tcp.local.' or '._udp.local.'" % type_)
+
+    remaining = type_[: -len('._tcp.local.')].split('.')
+    name = remaining.pop()
+    if not name:
+        raise BadTypeInNameException("No Service name found")
+
+    if len(remaining) == 1 and len(remaining[0]) == 0:
+        raise BadTypeInNameException("Type '%s' must not start with '.'" % type_)
+
+    if name[0] != '_':
+        raise BadTypeInNameException("Service name (%s) must start with '_'" % name)
+
+    # remove leading underscore
+    name = name[1:]
+
+#     if len(name) > 15:
+#         raise BadTypeInNameException("Service name (%s) must be <= 15 bytes" % name)
+
+    if '--' in name:
+        raise BadTypeInNameException("Service name (%s) must not contain '--'" % name)
+
+    if '-' in (name[0], name[-1]):
+        raise BadTypeInNameException("Service name (%s) may not start or end with '-'" % name)
+
+    if not _HAS_A_TO_Z.search(name):
+        raise BadTypeInNameException("Service name (%s) must contain at least one letter (eg: 'A-Z')" % name)
+
+    allowed_characters_re = (
+        _HAS_ONLY_A_TO_Z_NUM_HYPHEN_UNDERSCORE if allow_underscores else _HAS_ONLY_A_TO_Z_NUM_HYPHEN
+    )
+
+    if not allowed_characters_re.search(name):
+        raise BadTypeInNameException(
+            "Service name (%s) must contain only these characters: "
+            "A-Z, a-z, 0-9, hyphen ('-')%s" % (name, ", underscore ('_')" if allow_underscores else "")
+        )
+
+    if remaining and remaining[-1] == '_sub':
+        remaining.pop()
+        if len(remaining) == 0 or len(remaining[0]) == 0:
+            raise BadTypeInNameException("_sub requires a subtype name")
+
+    if len(remaining) > 1:
+        remaining = ['.'.join(remaining)]
+
+    if remaining:
+        length = len(remaining[0].encode('utf-8'))
+        if length > 63:
+            raise BadTypeInNameException("Too long: '%s'" % remaining[0])
+
+        if _HAS_ASCII_CONTROL_CHARS.search(remaining[0]):
+            raise BadTypeInNameException(
+                "Ascii control character 0x00-0x1F and 0x7F illegal in '%s'" % remaining[0]
+            )
+
+    return '_' + name + type_[-len('._tcp.local.') :]
+