Explicitly perform bytes -> str decoding on Python 3

src/zope/server/http/httprequestparser.py

@@ -17,6 +17,7 @@
 processing but threads to do work.
 """
 import re
+import sys
 from io import BytesIO
 
 from six.moves.urllib.parse import unquote, urlsplit
@@ -27,6 +28,8 @@
 from zope.server.interfaces import IStreamConsumer
 from zope.interface import implementer
 
+PY3 = sys.version_info >= (3, )
+
 
 @implementer(IStreamConsumer)
 class HTTPRequestParser(object):
@@ -108,14 +111,15 @@ def parse_header(self, header_plus):
         else:
             first_line = header_plus.rstrip()
             header = b''
+        if PY3:
+            first_line = first_line.decode('latin1')
+            header = header.decode('latin1')
         self.first_line = first_line
         self.header = header
 
         lines = self.get_header_lines()
         headers = self.headers
         for line in lines:
-            if not isinstance(line, str):
-                line = line.decode('latin1')
             index = line.find(':')
             if index > 0:
                 key = line[:index]
@@ -159,9 +163,9 @@ def get_header_lines(self):
         Splits the header into lines, putting multi-line headers together.
         """
         r = []
-        lines = self.header.split(b'\n')
+        lines = self.header.split('\n')
         for line in lines:
-            if line and line[0] in b' \t':
+            if line and line[0] in ' \t':
                 r[-1] = r[-1] + line[1:]
             else:
                 r.append(line)
@@ -173,8 +177,6 @@ def get_header_lines(self):
 
     def crack_first_line(self):
         r = self.first_line
-        if not isinstance(r, str):
-            r = r.decode('latin1')
         m = self.first_line_re.match(r)
         if m is not None and m.end() == len(r):
             if m.group(3):

src/zope/server/linereceiver/linecommandparser.py

@@ -13,9 +13,14 @@
 ##############################################################################
 """Line Command Parser
 """
+
+import sys
+
 from zope.server.interfaces import IStreamConsumer
 from zope.interface import implementer
 
+PY3 = sys.version_info >= (3, )
+
 
 @implementer(IStreamConsumer)
 class LineCommandParser(object):
@@ -30,14 +35,12 @@ class LineCommandParser(object):
 
     max_line_length = 1024  # Not a hard limit
 
-
     def __init__(self, adj):
         """
         adj is an Adjustments object.
         """
         self.adj = adj
 
-
     def received(self, data):
         'See IStreamConsumer'
         if self.completed:
@@ -56,12 +59,12 @@ def received(self, data):
             self.inbuf = self.inbuf + s
             self.completed = 1
             line = self.inbuf.strip()
+            if PY3:
+                line = line.decode('utf-8')
             self.parseLine(line)
             return len(s)
 
     def parseLine(self, line):
-        if not isinstance(line, str):
-            line = line.decode('utf-8')
         parts = line.split(' ', 1)
         if len(parts) == 2:
             self.cmd, self.args = parts