Extend Mypy checking to pathod

* mypy checking pathod

* initial commit , fixed errors

* tox: mypy checking to pathod

* Fixed mypy test failed

* issue was with args in custom_contentview.py

* tox: mypy checking to #2221

* follow-import=skip since we cant provide args to custom_contentview.py during mypy testing

* Lint , Typo Fixed

* code style: module import

13 files changed, 51 insertions, 39 deletions

diff --git a/examples/simple/custom_contentview.py b/examples/simple/custom_contentview.py
index 289e1efe..71f92575 100644
--- a/examples/simple/custom_contentview.py
+++ b/examples/simple/custom_contentview.py
@@ -3,7 +3,10 @@ This example shows how one can add a custom contentview to mitmproxy.
 The content view API is explained in the mitmproxy.contentviews module.
 """
 from mitmproxy import contentviews
-from typing import Tuple, Iterable, AnyStr, List
+import typing
+
+
+CVIEWSWAPCASE = typing.Tuple[str, typing.Iterable[typing.List[typing.Tuple[str, typing.AnyStr]]]]
 
 
 class ViewSwapCase(contentviews.View):
@@ -14,7 +17,7 @@ class ViewSwapCase(contentviews.View):
     prompt = ("swap case text", "z")
     content_types = ["text/plain"]
 
-    def __call__(self, data: bytes, **metadata) -> Tuple[str, Iterable[List[Tuple[str, AnyStr]]]]:
+    def __call__(self, data: typing.AnyStr, **metadata) -> CVIEWSWAPCASE:
         return "case-swapped text", contentviews.format_text(data.swapcase())
 
 
diff --git a/examples/simple/io_read_dumpfile.py b/examples/simple/io_read_dumpfile.py
index 87d37c0f..ea544cc4 100644
--- a/examples/simple/io_read_dumpfile.py
+++ b/examples/simple/io_read_dumpfile.py
@@ -1,8 +1,9 @@
 #!/usr/bin/env python
+
+# type: ignore
 #
 # Simple script showing how to read a mitmproxy dump file
 #
-
 from mitmproxy import io
 from mitmproxy.exceptions import FlowReadException
 import pprint
diff --git a/examples/simple/io_write_dumpfile.py b/examples/simple/io_write_dumpfile.py
index 7c4c6a7a..cf7c4f52 100644
--- a/examples/simple/io_write_dumpfile.py
+++ b/examples/simple/io_write_dumpfile.py
@@ -8,12 +8,13 @@ to multiple files in parallel.
 import random
 import sys
 from mitmproxy import io, http
+import typing  # noqa
 
 
 class Writer:
     def __init__(self, path: str) -> None:
         if path == "-":
-            f = sys.stdout  # type: io.TextIO
+            f = sys.stdout  # type: typing.IO[typing.Any]
         else:
             f = open(path, "wb")
         self.w = io.FlowWriter(f)
diff --git a/pathod/language/actions.py b/pathod/language/actions.py
index e85affac..fc57a18b 100644
--- a/pathod/language/actions.py
+++ b/pathod/language/actions.py
@@ -2,9 +2,7 @@ import abc
 import copy
 import random
 from functools import total_ordering
-
 import pyparsing as pp
-
 from . import base
 
 
@@ -52,7 +50,7 @@ class _Action(base.Token):
 
 
 class PauseAt(_Action):
-    unique_name = None
+    unique_name = None  # type: ignore
 
     def __init__(self, offset, seconds):
         _Action.__init__(self, offset)
@@ -103,7 +101,7 @@ class DisconnectAt(_Action):
 
 
 class InjectAt(_Action):
-    unique_name = None
+    unique_name = None  # type: ignore
 
     def __init__(self, offset, value):
         _Action.__init__(self, offset)
diff --git a/pathod/language/base.py b/pathod/language/base.py
index 3a810ef0..c8892748 100644
--- a/pathod/language/base.py
+++ b/pathod/language/base.py
@@ -3,10 +3,9 @@ import os
 import abc
 import functools
 import pyparsing as pp
-
 from mitmproxy.utils import strutils
 from mitmproxy.utils import human
-
+import typing  # noqa
 from . import generators, exceptions
 
 
@@ -84,7 +83,7 @@ class Token:
         return None
 
     @property
-    def unique_name(self):
+    def unique_name(self) -> typing.Optional[str]:
         """
             Controls uniqueness constraints for tokens. No two tokens with the
             same name will be allowed. If no uniquness should be applied, this
@@ -334,7 +333,7 @@ class OptionsOrValue(_Component):
         Can be any of a specified set of options, or a value specifier.
     """
     preamble = ""
-    options = []
+    options = []  # type: typing.List[str]
 
     def __init__(self, value):
         # If it's a string, we were passed one of the options, so we lower-case
@@ -376,7 +375,7 @@ class OptionsOrValue(_Component):
 
 
 class Integer(_Component):
-    bounds = (None, None)
+    bounds = (None, None)  # type: typing.Tuple[typing.Union[int, None], typing.Union[int , None]]
     preamble = ""
 
     def __init__(self, value):
@@ -442,7 +441,7 @@ class FixedLengthValue(Value):
         A value component lead by an optional preamble.
     """
     preamble = ""
-    length = None
+    length = None  # type: typing.Optional[int]
 
     def __init__(self, value):
         Value.__init__(self, value)
@@ -511,7 +510,7 @@ class IntField(_Component):
     """
         An integer field, where values can optionally specified by name.
     """
-    names = {}
+    names = {}  # type: typing.Dict[str, int]
     max = 16
     preamble = ""
 
@@ -546,7 +545,7 @@ class NestedMessage(Token):
         A nested message, as an escaped string with a preamble.
     """
     preamble = ""
-    nest_type = None
+    nest_type = None  # type: ignore
 
     def __init__(self, value):
         Token.__init__(self)
diff --git a/pathod/language/http.py b/pathod/language/http.py
index 8fcf9edc..5cd717a9 100644
--- a/pathod/language/http.py
+++ b/pathod/language/http.py
@@ -54,7 +54,7 @@ class Method(base.OptionsOrValue):
 
 
 class _HeaderMixin:
-    unique_name = None
+    unique_name = None  # type: ignore
 
     def format_header(self, key, value):
         return [key, b": ", value, b"\r\n"]
@@ -143,7 +143,7 @@ class _HTTPMessage(message.Message):
 
 
 class Response(_HTTPMessage):
-    unique_name = None
+    unique_name = None  # type: ignore
     comps = (
         Header,
         ShortcutContentType,
diff --git a/pathod/language/http2.py b/pathod/language/http2.py
index 08c5f6d7..47d6e370 100644
--- a/pathod/language/http2.py
+++ b/pathod/language/http2.py
@@ -1,9 +1,9 @@
 import pyparsing as pp
-
 from mitmproxy.net import http
 from mitmproxy.net.http import user_agents, Headers
 from . import base, message
 
+
 """
     Normal HTTP requests:
         <method>:<path>:<header>:<body>
@@ -41,7 +41,7 @@ def get_header(val, headers):
 
 
 class _HeaderMixin:
-    unique_name = None
+    unique_name = None  # type: ignore
 
     def values(self, settings):
         return (
@@ -146,7 +146,7 @@ class Times(base.Integer):
 
 
 class Response(_HTTP2Message):
-    unique_name = None
+    unique_name = None  # type: ignore
     comps = (
         Header,
         Body,
diff --git a/pathod/language/message.py b/pathod/language/message.py
index 6cdaaa0b..6b4c5021 100644
--- a/pathod/language/message.py
+++ b/pathod/language/message.py
@@ -1,13 +1,14 @@
 import abc
 from . import actions, exceptions
 from mitmproxy.utils import strutils
+import typing  # noqa
 
 LOG_TRUNCATE = 1024
 
 
 class Message:
     __metaclass__ = abc.ABCMeta
-    logattrs = []
+    logattrs = []  # type: typing.List[str]
 
     def __init__(self, tokens):
         track = set([])
diff --git a/pathod/language/websockets.py b/pathod/language/websockets.py
index a237381c..b4faf59b 100644
--- a/pathod/language/websockets.py
+++ b/pathod/language/websockets.py
@@ -4,6 +4,7 @@ import mitmproxy.net.websockets
 from mitmproxy.utils import strutils
 import pyparsing as pp
 from . import base, generators, actions, message
+import typing  # noqa
 
 NESTED_LEADER = b"pathod!"
 
@@ -20,7 +21,7 @@ class OpCode(base.IntField):
         "close": mitmproxy.net.websockets.OPCODE.CLOSE,
         "ping": mitmproxy.net.websockets.OPCODE.PING,
         "pong": mitmproxy.net.websockets.OPCODE.PONG,
-    }
+    }  # type: typing.Dict[str, int]
     max = 15
     preamble = "c"
 
@@ -239,7 +240,14 @@ class NestedFrame(base.NestedMessage):
     nest_type = WebsocketFrame
 
 
+COMP = typing.Tuple[
+    typing.Type[OpCode], typing.Type[Length], typing.Type[Fin], typing.Type[RSV1], typing.Type[RSV2], typing.Type[RSV3], typing.Type[Mask],
+    typing.Type[actions.PauseAt], typing.Type[actions.DisconnectAt], typing.Type[actions.InjectAt], typing.Type[KeyNone], typing.Type[Key],
+    typing.Type[Times], typing.Type[Body], typing.Type[RawBody]
+]
+
+
 class WebsocketClientFrame(WebsocketFrame):
-    components = COMPONENTS + (
+    components = typing.cast(COMP, COMPONENTS + (
         NestedFrame,
-    )
+    ))
diff --git a/pathod/pathod.py b/pathod/pathod.py
index 7416d325..7c773c3b 100644
--- a/pathod/pathod.py
+++ b/pathod/pathod.py
@@ -3,19 +3,17 @@ import logging
 import os
 import sys
 import threading
-
 from mitmproxy.net import tcp
 from mitmproxy import certs as mcerts
 from mitmproxy.net import websockets
 from mitmproxy import version
-
 import urllib
 from mitmproxy import exceptions
-
 from pathod import language
 from pathod import utils
 from pathod import log
 from pathod import protocols
+import typing  # noqa
 
 
 DEFAULT_CERT_DOMAIN = b"pathod.net"
@@ -71,7 +69,7 @@ class SSLOptions:
 
 class PathodHandler(tcp.BaseHandler):
     wbufsize = 0
-    sni = None
+    sni = None  # type: typing.Union[str, None, bool]
 
     def __init__(
         self,
diff --git a/pathod/test.py b/pathod/test.py
index 81f5805f..52f3ba02 100644
--- a/pathod/test.py
+++ b/pathod/test.py
@@ -1,16 +1,16 @@
 import io
 import time
 import queue
-
 from . import pathod
 from mitmproxy.types import basethread
+import typing  # noqa
 
 
 class Daemon:
     IFACE = "127.0.0.1"
 
-    def __init__(self, ssl=None, **daemonargs):
-        self.q = queue.Queue()
+    def __init__(self, ssl=None, **daemonargs) -> None:
+        self.q = queue.Queue()  # type: queue.Queue
         self.logfp = io.StringIO()
         daemonargs["logfp"] = self.logfp
         self.thread = _PaThread(self.IFACE, self.q, ssl, daemonargs)
@@ -25,18 +25,18 @@ class Daemon:
     def __enter__(self):
         return self
 
-    def __exit__(self, type, value, traceback):
+    def __exit__(self, type, value, traceback) -> bool:
         self.logfp.truncate(0)
         self.shutdown()
         return False
 
-    def p(self, spec):
+    def p(self, spec: str) -> str:
         """
             Return a URL that will render the response in spec.
         """
         return "%s/p/%s" % (self.urlbase, spec)
 
-    def text_log(self):
+    def text_log(self) -> str:
         return self.logfp.getvalue()
 
     def wait_for_silence(self, timeout=5):
@@ -62,7 +62,7 @@ class Daemon:
             return None
         return l[-1]
 
-    def log(self):
+    def log(self) -> typing.List[typing.Dict]:
         """
             Return the log buffer as a list of dictionaries.
         """
diff --git a/pathod/utils.py b/pathod/utils.py
index 44ad1f87..11b1dccd 100644
--- a/pathod/utils.py
+++ b/pathod/utils.py
@@ -1,6 +1,7 @@
 import os
 import sys
 from mitmproxy.utils import data as mdata
+import typing  # noqa
 
 
 class MemBool:
@@ -9,10 +10,10 @@ class MemBool:
         Truth-checking with a memory, for use in chained if statements.
     """
 
-    def __init__(self):
-        self.v = None
+    def __init__(self) -> None:
+        self.v = None  # type: typing.Optional[bool]
 
-    def __call__(self, v):
+    def __call__(self, v: bool) -> bool:
         self.v = v
         return bool(v)
 
diff --git a/tox.ini b/tox.ini
index fafb455e..3f3240ae 100644
--- a/tox.ini
+++ b/tox.ini
@@ -28,6 +28,8 @@ commands =
   python3 test/filename_matching.py
   rstcheck README.rst
   mypy --ignore-missing-imports ./mitmproxy
+  mypy --ignore-missing-imports ./pathod
+  mypy --ignore-missing-imports --follow-imports=skip  ./examples/simple/
 
 [testenv:individual_coverage]
 deps =