scgi.asynchronous: move {en,de}coding to internal module

2 files changed, 17 insertions, 8 deletions

diff --git a/wsgitools/internal.py b/wsgitools/internal.py
new file mode 100644
index 0000000..c392b6a
--- /dev/null
+++ b/wsgitools/internal.py
@@ -0,0 +1,14 @@
+if bytes is str:
+    def bytes2str(bstr):
+        assert isinstance(bstr, bytes)
+        return bstr
+    def str2bytes(sstr):
+        assert isinstance(sstr, str)
+        return sstr
+else:
+    def bytes2str(bstr):
+        assert isinstance(bstr, bytes)
+        return bstr.decode("iso-8859-1") # always successful
+    def str2bytes(sstr):
+        assert isinstance(sstr, str)
+        return sstr.encode("iso-8859-1") # might fail, but spec says it doesn't
diff --git a/wsgitools/scgi/asynchronous.py b/wsgitools/scgi/asynchronous.py
index 2c97f42..3009593 100644
--- a/wsgitools/scgi/asynchronous.py
+++ b/wsgitools/scgi/asynchronous.py
@@ -6,6 +6,7 @@ import socket
 import sys
 import errno
 
+from wsgitools.internal import bytes2str, str2bytes
 from wsgitools.scgi import _convert_environ, FileWrapper
 
 if sys.version_info[0] >= 3:
@@ -51,9 +52,7 @@ class SCGIConnection(asyncore.dispatcher):
             status, headers = self.outheaders
             headdata = "".join(map("%s: %s\r\n".__mod__, headers))
             headdata = "Status: %s\r\n%s\r\n" % (status, headdata)
-            if not isinstance(headdata, bytes):
-                headdata = headdata.encode("iso-8859-1")
-            self.outbuff = headdata
+            self.outbuff = str2bytes(headdata)
             self.outheaders = True
 
     def _wsgi_write(self, data):
@@ -98,10 +97,7 @@ class SCGIConnection(asyncore.dispatcher):
 
             while buff.count(b'\0') >= 2:
                 key, value, buff = buff.split(b'\0', 2)
-                if not isinstance(key, str):
-                    key = key.decode("iso-8859-1")
-                    value = value.decode("iso-8859-1")
-                self.environ[key] = value
+                self.environ[bytes2str(key)] = bytes2str(value)
                 self.reqlen -= len(key) + len(value) + 2
 
             self.inbuff = buff + remainder
@@ -276,4 +272,3 @@ class SCGIServer(asyncore.dispatcher):
         """Runs the server. It will not return and you can invoke
         C{asyncore.loop()} instead achieving the same effect."""
         asyncore.loop()
-