diff --git a/mitmproxy/contrib/py2/__init__.py b/mitmproxy/contrib/py2/__init__.py
deleted file mode 100644
index e69de29bb..000000000
diff --git a/mitmproxy/contrib/py2/tnetstring.py b/mitmproxy/contrib/py2/tnetstring.py
deleted file mode 100644
index 9bf20b09d..000000000
--- a/mitmproxy/contrib/py2/tnetstring.py
+++ /dev/null
@@ -1,375 +0,0 @@
-# imported from the tnetstring project: https://github.com/rfk/tnetstring
-#
-# Copyright (c) 2011 Ryan Kelly
-#
-# Permission is hereby granted, free of charge, to any person obtaining a copy
-# of this software and associated documentation files (the "Software"), to deal
-# in the Software without restriction, including without limitation the rights
-# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-# copies of the Software, and to permit persons to whom the Software is
-# furnished to do so, subject to the following conditions:
-#
-# The above copyright notice and this permission notice shall be included in
-# all copies or substantial portions of the Software.
-#
-# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-# THE SOFTWARE.
-"""
-tnetstring:  data serialization using typed netstrings
-======================================================
-
-
-This is a data serialization library. It's a lot like JSON but it uses a
-new syntax called "typed netstrings" that Zed has proposed for use in the
-Mongrel2 webserver.  It's designed to be simpler and easier to implement
-than JSON, with a happy consequence of also being faster in many cases.
-
-An ordinary netstring is a blob of data prefixed with its length and postfixed
-with a sanity-checking comma.  The string "hello world" encodes like this::
-
-    11:hello world,
-
-Typed netstrings add other datatypes by replacing the comma with a type tag.
-Here's the integer 12345 encoded as a tnetstring::
-
-    5:12345#
-
-And here's the list [12345,True,0] which mixes integers and bools::
-
-    19:5:12345#4:true!1:0#]
-
-Simple enough?  This module gives you the following functions:
-
-    :dump:    dump an object as a tnetstring to a file
-    :dumps:   dump an object as a tnetstring to a string
-    :load:    load a tnetstring-encoded object from a file
-    :loads:   load a tnetstring-encoded object from a string
-    :pop:     pop a tnetstring-encoded object from the front of a string
-
-Note that since parsing a tnetstring requires reading all the data into memory
-at once, there's no efficiency gain from using the file-based versions of these
-functions.  They're only here so you can use load() to read precisely one
-item from a file or socket without consuming any extra data.
-
-By default tnetstrings work only with byte strings, not unicode.  If you want
-unicode strings then pass an optional encoding to the various functions,
-like so::
-
-    >>> print(repr(tnetstring.loads("2:\\xce\\xb1,")))
-    '\\xce\\xb1'
-    >>>
-    >>> print(repr(tnetstring.loads("2:\\xce\\xb1,","utf8")))
-    u'\u03b1'
-
-"""
-from collections import deque
-
-import six
-
-__ver_major__ = 0
-__ver_minor__ = 2
-__ver_patch__ = 0
-__ver_sub__ = ""
-__version__ = "%d.%d.%d%s" % (
-    __ver_major__, __ver_minor__, __ver_patch__, __ver_sub__)
-
-
-def dumps(value):
-    """
-    This function dumps a python object as a tnetstring.
-    """
-    #  This uses a deque to collect output fragments in reverse order,
-    #  then joins them together at the end.  It's measurably faster
-    #  than creating all the intermediate strings.
-    #  If you're reading this to get a handle on the tnetstring format,
-    #  consider the _gdumps() function instead; it's a standard top-down
-    #  generator that's simpler to understand but much less efficient.
-    q = deque()
-    _rdumpq(q, 0, value)
-    return b''.join(q)
-
-
-def dump(value, file_handle):
-    """
-    This function dumps a python object as a tnetstring and
-    writes it to the given file.
-    """
-    file_handle.write(dumps(value))
-
-
-def _rdumpq(q, size, value):
-    """
-    Dump value as a tnetstring, to a deque instance, last chunks first.
-
-    This function generates the tnetstring representation of the given value,
-    pushing chunks of the output onto the given deque instance.  It pushes
-    the last chunk first, then recursively generates more chunks.
-
-    When passed in the current size of the string in the queue, it will return
-    the new size of the string in the queue.
-
-    Operating last-chunk-first makes it easy to calculate the size written
-    for recursive structures without having to build their representation as
-    a string.  This is measurably faster than generating the intermediate
-    strings, especially on deeply nested structures.
-    """
-    write = q.appendleft
-    if value is None:
-        write(b'0:~')
-        return size + 3
-    elif value is True:
-        write(b'4:true!')
-        return size + 7
-    elif value is False:
-        write(b'5:false!')
-        return size + 8
-    elif isinstance(value, six.integer_types):
-        data = str(value).encode()
-        ldata = len(data)
-        span = str(ldata).encode()
-        write(b'#')
-        write(data)
-        write(b':')
-        write(span)
-        return size + 2 + len(span) + ldata
-    elif isinstance(value, float):
-        #  Use repr() for float rather than str().
-        #  It round-trips more accurately.
-        #  Probably unnecessary in later python versions that
-        #  use David Gay's ftoa routines.
-        data = repr(value).encode()
-        ldata = len(data)
-        span = str(ldata).encode()
-        write(b'^')
-        write(data)
-        write(b':')
-        write(span)
-        return size + 2 + len(span) + ldata
-    elif isinstance(value, bytes):
-        lvalue = len(value)
-        span = str(lvalue).encode()
-        write(b',')
-        write(value)
-        write(b':')
-        write(span)
-        return size + 2 + len(span) + lvalue
-    elif isinstance(value, (list, tuple)):
-        write(b']')
-        init_size = size = size + 1
-        for item in reversed(value):
-            size = _rdumpq(q, size, item)
-        span = str(size - init_size).encode()
-        write(b':')
-        write(span)
-        return size + 1 + len(span)
-    elif isinstance(value, dict):
-        write(b'}')
-        init_size = size = size + 1
-        for (k, v) in value.items():
-            size = _rdumpq(q, size, v)
-            size = _rdumpq(q, size, k)
-        span = str(size - init_size).encode()
-        write(b':')
-        write(span)
-        return size + 1 + len(span)
-    else:
-        raise ValueError("unserializable object: {} ({})".format(value, type(value)))
-
-
-def _gdumps(value):
-    """
-    Generate fragments of value dumped as a tnetstring.
-
-    This is the naive dumping algorithm, implemented as a generator so that
-    it's easy to pass to "".join() without building a new list.
-
-    This is mainly here for comparison purposes; the _rdumpq version is
-    measurably faster as it doesn't have to build intermediate strins.
-    """
-    if value is None:
-        yield b'0:~'
-    elif value is True:
-        yield b'4:true!'
-    elif value is False:
-        yield b'5:false!'
-    elif isinstance(value, six.integer_types):
-        data = str(value).encode()
-        yield str(len(data)).encode()
-        yield b':'
-        yield data
-        yield b'#'
-    elif isinstance(value, float):
-        data = repr(value).encode()
-        yield str(len(data)).encode()
-        yield b':'
-        yield data
-        yield b'^'
-    elif isinstance(value, bytes):
-        yield str(len(value)).encode()
-        yield b':'
-        yield value
-        yield b','
-    elif isinstance(value, (list, tuple)):
-        sub = []
-        for item in value:
-            sub.extend(_gdumps(item))
-        sub = b''.join(sub)
-        yield str(len(sub)).encode()
-        yield b':'
-        yield sub
-        yield b']'
-    elif isinstance(value, (dict,)):
-        sub = []
-        for (k, v) in value.items():
-            sub.extend(_gdumps(k))
-            sub.extend(_gdumps(v))
-        sub = b''.join(sub)
-        yield str(len(sub)).encode()
-        yield b':'
-        yield sub
-        yield b'}'
-    else:
-        raise ValueError("unserializable object")
-
-
-def loads(string):
-    """
-    This function parses a tnetstring into a python object.
-    """
-    #  No point duplicating effort here.  In the C-extension version,
-    #  loads() is measurably faster then pop() since it can avoid
-    #  the overhead of building a second string.
-    return pop(string)[0]
-
-
-def load(file_handle):
-    """load(file) -> object
-
-    This function reads a tnetstring from a file and parses it into a
-    python object.  The file must support the read() method, and this
-    function promises not to read more data than necessary.
-    """
-    #  Read the length prefix one char at a time.
-    #  Note that the netstring spec explicitly forbids padding zeros.
-    c = file_handle.read(1)
-    if not c.isdigit():
-        raise ValueError("not a tnetstring: missing or invalid length prefix")
-    datalen = ord(c) - ord('0')
-    c = file_handle.read(1)
-    if datalen != 0:
-        while c.isdigit():
-            datalen = (10 * datalen) + (ord(c) - ord('0'))
-            if datalen > 999999999:
-                errmsg = "not a tnetstring: absurdly large length prefix"
-                raise ValueError(errmsg)
-            c = file_handle.read(1)
-    if c != b':':
-        raise ValueError("not a tnetstring: missing or invalid length prefix")
-    #  Now we can read and parse the payload.
-    #  This repeats the dispatch logic of pop() so we can avoid
-    #  re-constructing the outermost tnetstring.
-    data = file_handle.read(datalen)
-    if len(data) != datalen:
-        raise ValueError("not a tnetstring: length prefix too big")
-    tns_type = file_handle.read(1)
-    if tns_type == b',':
-        return data
-    if tns_type == b'#':
-        try:
-            return int(data)
-        except ValueError:
-            raise ValueError("not a tnetstring: invalid integer literal")
-    if tns_type == b'^':
-        try:
-            return float(data)
-        except ValueError:
-            raise ValueError("not a tnetstring: invalid float literal")
-    if tns_type == b'!':
-        if data == b'true':
-            return True
-        elif data == b'false':
-            return False
-        else:
-            raise ValueError("not a tnetstring: invalid boolean literal")
-    if tns_type == b'~':
-        if data:
-            raise ValueError("not a tnetstring: invalid null literal")
-        return None
-    if tns_type == b']':
-        l = []
-        while data:
-            item, data = pop(data)
-            l.append(item)
-        return l
-    if tns_type == b'}':
-        d = {}
-        while data:
-            key, data = pop(data)
-            val, data = pop(data)
-            d[key] = val
-        return d
-    raise ValueError("unknown type tag")
-
-
-def pop(string):
-    """pop(string,encoding='utf_8') -> (object, remain)
-
-    This function parses a tnetstring into a python object.
-    It returns a tuple giving the parsed object and a string
-    containing any unparsed data from the end of the string.
-    """
-    #  Parse out data length, type and remaining string.
-    try:
-        dlen, rest = string.split(b':', 1)
-        dlen = int(dlen)
-    except ValueError:
-        raise ValueError("not a tnetstring: missing or invalid length prefix: {}".format(string))
-    try:
-        data, tns_type, remain = rest[:dlen], rest[dlen:dlen + 1], rest[dlen + 1:]
-    except IndexError:
-        #  This fires if len(rest) < dlen, meaning we don't need
-        #  to further validate that data is the right length.
-        raise ValueError("not a tnetstring: invalid length prefix: {}".format(dlen))
-    #  Parse the data based on the type tag.
-    if tns_type == b',':
-        return data, remain
-    if tns_type == b'#':
-        try:
-            return int(data), remain
-        except ValueError:
-            raise ValueError("not a tnetstring: invalid integer literal: {}".format(data))
-    if tns_type == b'^':
-        try:
-            return float(data), remain
-        except ValueError:
-            raise ValueError("not a tnetstring: invalid float literal: {}".format(data))
-    if tns_type == b'!':
-        if data == b'true':
-            return True, remain
-        elif data == b'false':
-            return False, remain
-        else:
-            raise ValueError("not a tnetstring: invalid boolean literal: {}".format(data))
-    if tns_type == b'~':
-        if data:
-            raise ValueError("not a tnetstring: invalid null literal")
-        return None, remain
-    if tns_type == b']':
-        l = []
-        while data:
-            item, data = pop(data)
-            l.append(item)
-        return (l, remain)
-    if tns_type == b'}':
-        d = {}
-        while data:
-            key, data = pop(data)
-            val, data = pop(data)
-            d[key] = val
-        return d, remain
-    raise ValueError("unknown type tag: {}".format(tns_type))
diff --git a/mitmproxy/contrib/py3/__init__.py b/mitmproxy/contrib/py3/__init__.py
deleted file mode 100644
index e69de29bb..000000000
diff --git a/mitmproxy/contrib/py3/tnetstring.py b/mitmproxy/contrib/py3/tnetstring.py
deleted file mode 100644
index 6998fc820..000000000
--- a/mitmproxy/contrib/py3/tnetstring.py
+++ /dev/null
@@ -1,237 +0,0 @@
-"""
-tnetstring:  data serialization using typed netstrings
-======================================================
-
-This is a custom Python 3 implementation of tnetstrings.
-Compared to other implementations, the main difference
-is the conversion of dictionary keys to str.
-
-An ordinary tnetstring is a blob of data prefixed with its length and postfixed
-with its type. Here are some examples:
-
-    >>> tnetstring.dumps("hello world")
-    11:hello world,
-    >>> tnetstring.dumps(12345)
-    5:12345#
-    >>> tnetstring.dumps([12345, True, 0])
-    19:5:12345#4:true!1:0#]
-
-This module gives you the following functions:
-
-    :dump:    dump an object as a tnetstring to a file
-    :dumps:   dump an object as a tnetstring to a string
-    :load:    load a tnetstring-encoded object from a file
-    :loads:   load a tnetstring-encoded object from a string
-
-Note that since parsing a tnetstring requires reading all the data into memory
-at once, there's no efficiency gain from using the file-based versions of these
-functions.  They're only here so you can use load() to read precisely one
-item from a file or socket without consuming any extra data.
-
-The tnetstrings specification explicitly states that strings are binary blobs
-and forbids the use of unicode at the protocol level.
-**This implementation decodes dictionary keys as surrogate-escaped ASCII**,
-all other strings are returned as plain bytes.
-
-:Copyright: (c) 2012-2013 by Ryan Kelly <ryan@rfk.id.au>.
-:Copyright: (c) 2014 by Carlo Pires <carlopires@gmail.com>.
-:Copyright: (c) 2016 by Maximilian Hils <tnetstring3@maximilianhils.com>.
-
-:License: MIT
-"""
-
-import collections
-from typing import io, Union, Tuple
-
-TSerializable = Union[None, bool, int, float, bytes, list, tuple, dict]
-
-
-def dumps(value: TSerializable) -> bytes:
-    """
-    This function dumps a python object as a tnetstring.
-    """
-    #  This uses a deque to collect output fragments in reverse order,
-    #  then joins them together at the end.  It's measurably faster
-    #  than creating all the intermediate strings.
-    q = collections.deque()
-    _rdumpq(q, 0, value)
-    return b''.join(q)
-
-
-def dump(value: TSerializable, file_handle: io.BinaryIO) -> None:
-    """
-    This function dumps a python object as a tnetstring and
-    writes it to the given file.
-    """
-    file_handle.write(dumps(value))
-
-
-def _rdumpq(q: collections.deque, size: int, value: TSerializable) -> int:
-    """
-    Dump value as a tnetstring, to a deque instance, last chunks first.
-
-    This function generates the tnetstring representation of the given value,
-    pushing chunks of the output onto the given deque instance.  It pushes
-    the last chunk first, then recursively generates more chunks.
-
-    When passed in the current size of the string in the queue, it will return
-    the new size of the string in the queue.
-
-    Operating last-chunk-first makes it easy to calculate the size written
-    for recursive structures without having to build their representation as
-    a string.  This is measurably faster than generating the intermediate
-    strings, especially on deeply nested structures.
-    """
-    write = q.appendleft
-    if value is None:
-        write(b'0:~')
-        return size + 3
-    elif value is True:
-        write(b'4:true!')
-        return size + 7
-    elif value is False:
-        write(b'5:false!')
-        return size + 8
-    elif isinstance(value, int):
-        data = str(value).encode()
-        ldata = len(data)
-        span = str(ldata).encode()
-        write(b'%s:%s#' % (span, data))
-        return size + 2 + len(span) + ldata
-    elif isinstance(value, float):
-        #  Use repr() for float rather than str().
-        #  It round-trips more accurately.
-        #  Probably unnecessary in later python versions that
-        #  use David Gay's ftoa routines.
-        data = repr(value).encode()
-        ldata = len(data)
-        span = str(ldata).encode()
-        write(b'%s:%s^' % (span, data))
-        return size + 2 + len(span) + ldata
-    elif isinstance(value, bytes):
-        lvalue = len(value)
-        span = str(lvalue).encode()
-        write(b'%s:%s,' % (span, value))
-        return size + 2 + len(span) + lvalue
-    elif isinstance(value, (list, tuple)):
-        write(b']')
-        init_size = size = size + 1
-        for item in reversed(value):
-            size = _rdumpq(q, size, item)
-        span = str(size - init_size).encode()
-        write(b':')
-        write(span)
-        return size + 1 + len(span)
-    elif isinstance(value, dict):
-        write(b'}')
-        init_size = size = size + 1
-        for (k, v) in value.items():
-            if isinstance(k, str):
-                k = k.encode("ascii", "strict")
-            size = _rdumpq(q, size, v)
-            size = _rdumpq(q, size, k)
-        span = str(size - init_size).encode()
-        write(b':')
-        write(span)
-        return size + 1 + len(span)
-    else:
-        raise ValueError("unserializable object: {} ({})".format(value, type(value)))
-
-
-def loads(string: bytes) -> TSerializable:
-    """
-    This function parses a tnetstring into a python object.
-    """
-    return pop(string)[0]
-
-
-def load(file_handle: io.BinaryIO) -> TSerializable:
-    """load(file) -> object
-
-    This function reads a tnetstring from a file and parses it into a
-    python object.  The file must support the read() method, and this
-    function promises not to read more data than necessary.
-    """
-    #  Read the length prefix one char at a time.
-    #  Note that the netstring spec explicitly forbids padding zeros.
-    c = file_handle.read(1)
-    data_length = b""
-    while c.isdigit():
-        data_length += c
-        if len(data_length) > 9:
-            raise ValueError("not a tnetstring: absurdly large length prefix")
-        c = file_handle.read(1)
-    if c != b":":
-        raise ValueError("not a tnetstring: missing or invalid length prefix")
-
-    data = file_handle.read(int(data_length))
-    data_type = file_handle.read(1)[0]
-
-    return parse(data_type, data)
-
-
-def parse(data_type: int, data: bytes) -> TSerializable:
-    if data_type == ord(b','):
-        return data
-    if data_type == ord(b'#'):
-        try:
-            return int(data)
-        except ValueError:
-            raise ValueError("not a tnetstring: invalid integer literal: {}".format(data))
-    if data_type == ord(b'^'):
-        try:
-            return float(data)
-        except ValueError:
-            raise ValueError("not a tnetstring: invalid float literal: {}".format(data))
-    if data_type == ord(b'!'):
-        if data == b'true':
-            return True
-        elif data == b'false':
-            return False
-        else:
-            raise ValueError("not a tnetstring: invalid boolean literal: {}".format(data))
-    if data_type == ord(b'~'):
-        if data:
-            raise ValueError("not a tnetstring: invalid null literal")
-        return None
-    if data_type == ord(b']'):
-        l = []
-        while data:
-            item, data = pop(data)
-            l.append(item)
-        return l
-    if data_type == ord(b'}'):
-        d = {}
-        while data:
-            key, data = pop(data)
-            if isinstance(key, bytes):
-                key = key.decode("ascii", "strict")
-            val, data = pop(data)
-            d[key] = val
-        return d
-    raise ValueError("unknown type tag: {}".format(data_type))
-
-
-def pop(data: bytes) -> Tuple[TSerializable, bytes]:
-    """
-    This function parses a tnetstring into a python object.
-    It returns a tuple giving the parsed object and a string
-    containing any unparsed data from the end of the string.
-    """
-    #  Parse out data length, type and remaining string.
-    try:
-        length, data = data.split(b':', 1)
-        length = int(length)
-    except ValueError:
-        raise ValueError("not a tnetstring: missing or invalid length prefix: {}".format(data))
-    try:
-        data, data_type, remain = data[:length], data[length], data[length + 1:]
-    except IndexError:
-        #  This fires if len(data) < dlen, meaning we don't need
-        #  to further validate that data is the right length.
-        raise ValueError("not a tnetstring: invalid length prefix: {}".format(length))
-    # Parse the data based on the type tag.
-    return parse(data_type, data), remain
-
-
-__all__ = ["dump", "dumps", "load", "loads", "pop"]
diff --git a/mitmproxy/contrib/py3/tnetstring_tests.py b/mitmproxy/contrib/py3/tnetstring_tests.py
deleted file mode 100644
index 4ee184d5c..000000000
--- a/mitmproxy/contrib/py3/tnetstring_tests.py
+++ /dev/null
@@ -1,133 +0,0 @@
-import unittest
-import random
-import math
-import io
-from . import tnetstring
-import struct
-
-MAXINT = 2 ** (struct.Struct('i').size * 8 - 1) - 1
-
-FORMAT_EXAMPLES = {
-    b'0:}': {},
-    b'0:]': [],
-    b'51:5:hello,39:11:12345678901#4:this,4:true!0:~4:\x00\x00\x00\x00,]}':
-            {'hello': [12345678901, b'this', True, None, b'\x00\x00\x00\x00']},
-    b'5:12345#': 12345,
-    b'12:this is cool,': b'this is cool',
-    b'0:,': b'',
-    b'0:~': None,
-    b'4:true!': True,
-    b'5:false!': False,
-    b'10:\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00,': b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00',
-    b'24:5:12345#5:67890#5:xxxxx,]': [12345, 67890, b'xxxxx'],
-    b'18:3:0.1^3:0.2^3:0.3^]': [0.1, 0.2, 0.3],
-    b'243:238:233:228:223:218:213:208:203:198:193:188:183:178:173:168:163:158:153:148:143:138:133:128:123:118:113:108:103:99:95:91:87:83:79:75:71:67:63:59:55:51:47:43:39:35:31:27:23:19:15:11:hello-there,]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]': [[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[b'hello-there']]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]
-}
-
-def get_random_object(random=random, depth=0):
-    """Generate a random serializable object."""
-    #  The probability of generating a scalar value increases as the depth increase.
-    #  This ensures that we bottom out eventually.
-    if random.randint(depth,10) <= 4:
-        what = random.randint(0,1)
-        if what == 0:
-            n = random.randint(0,10)
-            l = []
-            for _ in range(n):
-                l.append(get_random_object(random,depth+1))
-            return l
-        if what == 1:
-            n = random.randint(0,10)
-            d = {}
-            for _ in range(n):
-                n = random.randint(0,100)
-                k = str([random.randint(32,126) for _ in range(n)])
-                d[k] = get_random_object(random,depth+1)
-            return d
-    else:
-        what = random.randint(0,4)
-        if what == 0:
-            return None
-        if what == 1:
-            return True
-        if what == 2:
-            return False
-        if what == 3:
-            if random.randint(0,1) == 0:
-                return random.randint(0,MAXINT)
-            else:
-                return -1 * random.randint(0,MAXINT)
-        n = random.randint(0,100)
-        return bytes([random.randint(32,126) for _ in range(n)])
-
-class Test_Format(unittest.TestCase):
-    def test_roundtrip_format_examples(self):
-        for data, expect in FORMAT_EXAMPLES.items():
-            self.assertEqual(expect,tnetstring.loads(data))
-            self.assertEqual(expect,tnetstring.loads(tnetstring.dumps(expect)))
-            self.assertEqual((expect,b''),tnetstring.pop(data))
-
-    def test_roundtrip_format_random(self):
-        for _ in range(500):
-            v = get_random_object()
-            self.assertEqual(v,tnetstring.loads(tnetstring.dumps(v)))
-            self.assertEqual((v,b""),tnetstring.pop(tnetstring.dumps(v)))
-
-    def test_unicode_handling(self):
-        with self.assertRaises(ValueError):
-            tnetstring.dumps("hello")
-        self.assertEqual(tnetstring.dumps("hello".encode()),b"5:hello,")
-        self.assertEqual(type(tnetstring.loads(b"5:hello,")),bytes)
-
-    def test_roundtrip_format_unicode(self):
-        for _ in range(500):
-            v = get_random_object()
-            self.assertEqual(v,tnetstring.loads(tnetstring.dumps(v)))
-            self.assertEqual((v,b''),tnetstring.pop(tnetstring.dumps(v)))
-
-    def test_roundtrip_big_integer(self):
-        i1 = math.factorial(30000)
-        s = tnetstring.dumps(i1)
-        i2 = tnetstring.loads(s)
-        self.assertEqual(i1, i2)
-
-class Test_FileLoading(unittest.TestCase):
-    def test_roundtrip_file_examples(self):
-        for data, expect in FORMAT_EXAMPLES.items():
-            s = io.BytesIO()
-            s.write(data)
-            s.write(b'OK')
-            s.seek(0)
-            self.assertEqual(expect,tnetstring.load(s))
-            self.assertEqual(b'OK',s.read())
-            s = io.BytesIO()
-            tnetstring.dump(expect,s)
-            s.write(b'OK')
-            s.seek(0)
-            self.assertEqual(expect,tnetstring.load(s))
-            self.assertEqual(b'OK',s.read())
-
-    def test_roundtrip_file_random(self):
-        for _ in range(500):
-            v = get_random_object()
-            s = io.BytesIO()
-            tnetstring.dump(v,s)
-            s.write(b'OK')
-            s.seek(0)
-            self.assertEqual(v,tnetstring.load(s))
-            self.assertEqual(b'OK',s.read())
-
-    def test_error_on_absurd_lengths(self):
-        s = io.BytesIO()
-        s.write(b'1000000000:pwned!,')
-        s.seek(0)
-        with self.assertRaises(ValueError):
-            tnetstring.load(s)
-        self.assertEqual(s.read(1),b':')
-
-def suite():
-    loader = unittest.TestLoader()
-    suite = unittest.TestSuite()
-    suite.addTest(loader.loadTestsFromTestCase(Test_Format))
-    suite.addTest(loader.loadTestsFromTestCase(Test_FileLoading))
-    return suite
\ No newline at end of file
diff --git a/mitmproxy/contrib/tnetstring.py b/mitmproxy/contrib/tnetstring.py
index 1ebaba215..5fc26b450 100644
--- a/mitmproxy/contrib/tnetstring.py
+++ b/mitmproxy/contrib/tnetstring.py
@@ -1,8 +1,254 @@
+"""
+tnetstring:  data serialization using typed netstrings
+======================================================
+
+This is a custom Python 3 implementation of tnetstrings.
+Compared to other implementations, the main difference
+is that this implementation supports a custom unicode datatype.
+
+An ordinary tnetstring is a blob of data prefixed with its length and postfixed
+with its type. Here are some examples:
+
+    >>> tnetstring.dumps("hello world")
+    11:hello world,
+    >>> tnetstring.dumps(12345)
+    5:12345#
+    >>> tnetstring.dumps([12345, True, 0])
+    19:5:12345#4:true!1:0#]
+
+This module gives you the following functions:
+
+    :dump:    dump an object as a tnetstring to a file
+    :dumps:   dump an object as a tnetstring to a string
+    :load:    load a tnetstring-encoded object from a file
+    :loads:   load a tnetstring-encoded object from a string
+
+Note that since parsing a tnetstring requires reading all the data into memory
+at once, there's no efficiency gain from using the file-based versions of these
+functions.  They're only here so you can use load() to read precisely one
+item from a file or socket without consuming any extra data.
+
+The tnetstrings specification explicitly states that strings are binary blobs
+and forbids the use of unicode at the protocol level.
+**This implementation decodes dictionary keys as surrogate-escaped ASCII**,
+all other strings are returned as plain bytes.
+
+:Copyright: (c) 2012-2013 by Ryan Kelly <ryan@rfk.id.au>.
+:Copyright: (c) 2014 by Carlo Pires <carlopires@gmail.com>.
+:Copyright: (c) 2016 by Maximilian Hils <tnetstring3@maximilianhils.com>.
+
+:License: MIT
+"""
+
+import collections
 import six
+from typing import io, Union, Tuple  # noqa
 
-if six.PY2:
-    from .py2.tnetstring import load, loads, dump, dumps, pop
-else:
-    from .py3.tnetstring import load, loads, dump, dumps, pop
+TSerializable = Union[None, bool, int, float, bytes, list, tuple, dict]
 
-__all__ = ["load", "loads", "dump", "dumps", "pop"]
+
+def dumps(value):
+    # type: (TSerializable) -> bytes
+    """
+    This function dumps a python object as a tnetstring.
+    """
+    #  This uses a deque to collect output fragments in reverse order,
+    #  then joins them together at the end.  It's measurably faster
+    #  than creating all the intermediate strings.
+    q = collections.deque()
+    _rdumpq(q, 0, value)
+    return b''.join(q)
+
+
+def dump(value, file_handle):
+    # type: (TSerializable, io.BinaryIO) -> None
+    """
+    This function dumps a python object as a tnetstring and
+    writes it to the given file.
+    """
+    file_handle.write(dumps(value))
+
+
+def _rdumpq(q, size, value):
+    # type: (collections.deque, int, TSerializable) -> int
+    """
+    Dump value as a tnetstring, to a deque instance, last chunks first.
+
+    This function generates the tnetstring representation of the given value,
+    pushing chunks of the output onto the given deque instance.  It pushes
+    the last chunk first, then recursively generates more chunks.
+
+    When passed in the current size of the string in the queue, it will return
+    the new size of the string in the queue.
+
+    Operating last-chunk-first makes it easy to calculate the size written
+    for recursive structures without having to build their representation as
+    a string.  This is measurably faster than generating the intermediate
+    strings, especially on deeply nested structures.
+    """
+    write = q.appendleft
+    if value is None:
+        write(b'0:~')
+        return size + 3
+    elif value is True:
+        write(b'4:true!')
+        return size + 7
+    elif value is False:
+        write(b'5:false!')
+        return size + 8
+    elif isinstance(value, int):
+        data = str(value).encode()
+        ldata = len(data)
+        span = str(ldata).encode()
+        write(b'%s:%s#' % (span, data))
+        return size + 2 + len(span) + ldata
+    elif isinstance(value, float):
+        #  Use repr() for float rather than str().
+        #  It round-trips more accurately.
+        #  Probably unnecessary in later python versions that
+        #  use David Gay's ftoa routines.
+        data = repr(value).encode()
+        ldata = len(data)
+        span = str(ldata).encode()
+        write(b'%s:%s^' % (span, data))
+        return size + 2 + len(span) + ldata
+    elif isinstance(value, bytes):
+        data = value
+        ldata = len(data)
+        span = str(ldata).encode()
+        write(b'%s:%s,' % (span, data))
+        return size + 2 + len(span) + ldata
+    elif isinstance(value, six.text_type):
+        data = value.encode()
+        ldata = len(data)
+        span = str(ldata).encode()
+        write(b'%s:%s;' % (span, data))
+        return size + 2 + len(span) + ldata
+    elif isinstance(value, (list, tuple)):
+        write(b']')
+        init_size = size = size + 1
+        for item in reversed(value):
+            size = _rdumpq(q, size, item)
+        span = str(size - init_size).encode()
+        write(b':')
+        write(span)
+        return size + 1 + len(span)
+    elif isinstance(value, dict):
+        write(b'}')
+        init_size = size = size + 1
+        for (k, v) in value.items():
+            if isinstance(k, str):
+                k = k.encode("ascii", "strict")
+            size = _rdumpq(q, size, v)
+            size = _rdumpq(q, size, k)
+        span = str(size - init_size).encode()
+        write(b':')
+        write(span)
+        return size + 1 + len(span)
+    else:
+        raise ValueError("unserializable object: {} ({})".format(value, type(value)))
+
+
+def loads(string):
+    # type: (bytes) -> TSerializable
+    """
+    This function parses a tnetstring into a python object.
+    """
+    return pop(string)[0]
+
+
+def load(file_handle):
+    # type: (io.BinaryIO) -> TSerializable
+    """load(file) -> object
+
+    This function reads a tnetstring from a file and parses it into a
+    python object.  The file must support the read() method, and this
+    function promises not to read more data than necessary.
+    """
+    #  Read the length prefix one char at a time.
+    #  Note that the netstring spec explicitly forbids padding zeros.
+    c = file_handle.read(1)
+    data_length = b""
+    while c.isdigit():
+        data_length += c
+        if len(data_length) > 9:
+            raise ValueError("not a tnetstring: absurdly large length prefix")
+        c = file_handle.read(1)
+    if c != b":":
+        raise ValueError("not a tnetstring: missing or invalid length prefix")
+
+    data = file_handle.read(int(data_length))
+    data_type = file_handle.read(1)[0]
+
+    return parse(data_type, data)
+
+
+def parse(data_type, data):
+    # type: (int, bytes) -> TSerializable
+    if data_type == ord(b','):
+        return data
+    if data_type == ord(b';'):
+        return data.decode()
+    if data_type == ord(b'#'):
+        try:
+            return int(data)
+        except ValueError:
+            raise ValueError("not a tnetstring: invalid integer literal: {}".format(data))
+    if data_type == ord(b'^'):
+        try:
+            return float(data)
+        except ValueError:
+            raise ValueError("not a tnetstring: invalid float literal: {}".format(data))
+    if data_type == ord(b'!'):
+        if data == b'true':
+            return True
+        elif data == b'false':
+            return False
+        else:
+            raise ValueError("not a tnetstring: invalid boolean literal: {}".format(data))
+    if data_type == ord(b'~'):
+        if data:
+            raise ValueError("not a tnetstring: invalid null literal")
+        return None
+    if data_type == ord(b']'):
+        l = []
+        while data:
+            item, data = pop(data)
+            l.append(item)
+        return l
+    if data_type == ord(b'}'):
+        d = {}
+        while data:
+            key, data = pop(data)
+            if isinstance(key, bytes):
+                key = key.decode("ascii", "strict")
+            val, data = pop(data)
+            d[key] = val
+        return d
+    raise ValueError("unknown type tag: {}".format(data_type))
+
+
+def pop(data):
+    # type: (bytes) -> Tuple[TSerializable, bytes]
+    """
+    This function parses a tnetstring into a python object.
+    It returns a tuple giving the parsed object and a string
+    containing any unparsed data from the end of the string.
+    """
+    #  Parse out data length, type and remaining string.
+    try:
+        length, data = data.split(b':', 1)
+        length = int(length)
+    except ValueError:
+        raise ValueError("not a tnetstring: missing or invalid length prefix: {}".format(data))
+    try:
+        data, data_type, remain = data[:length], data[length], data[length + 1:]
+    except IndexError:
+        #  This fires if len(data) < dlen, meaning we don't need
+        #  to further validate that data is the right length.
+        raise ValueError("not a tnetstring: invalid length prefix: {}".format(length))
+    # Parse the data based on the type tag.
+    return parse(data_type, data), remain
+
+
+__all__ = ["dump", "dumps", "load", "loads", "pop"]