re-organize windows named pipe code

web3/providers/ipc.py

@@ -25,43 +25,19 @@ from .base import JSONBaseProvider
 
 @contextlib.contextmanager
 def get_ipc_socket(ipc_path, timeout=0.1):
-
-    # On Windows named pipe is used. Simulate socket with it.
     if sys.platform == 'win32':
-        import win32file
-        import pywintypes
-
-        class NamedPipe(object):
-            def __init__(self, ipc_path):
-                try:
-                    self.handle = win32file.CreateFile(
-                        ipc_path, win32file.GENERIC_READ | win32file.GENERIC_WRITE,
-                        0, None, win32file.OPEN_EXISTING, 0, None)
-                except pywintypes.error as err:
-                    raise IOError(err)
-
-            def recv(self, max_length):
-                (err, data) = win32file.ReadFile(self.handle, max_length)
-                if err:
-                    raise IOError(err)
-                return data
-
-            def sendall(self, data):
-                return win32file.WriteFile(self.handle, data)
-
-            def close(self):
-                self.handle.close()
+        # On Windows named pipe is used. Simulate socket with it.
+        from web3.utils.windows import NamedPipe
 
         pipe = NamedPipe(ipc_path)
-        yield pipe
-        pipe.close()
-
+        with contextlib.closing(pipe):
+            yield pipe
     else:
         sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
         sock.connect(ipc_path)
         sock.settimeout(timeout)
-        yield sock
-        sock.close()
+        with contextlib.closing(sock):
+            yield sock
 
 
 def get_default_ipc_path(testnet=False):

web3/utils/windows.py

@@ -0,0 +1,31 @@
+import sys
+
+
+if sys.platform != 'win32':
+    raise ImportError("This module should not be imported on non `win32` platforms")
+
+
+import win32file  # noqa: E402
+import pywintypes  # noqa: E402
+
+
+class NamedPipe(object):
+    def __init__(self, ipc_path):
+        try:
+            self.handle = win32file.CreateFile(
+                ipc_path, win32file.GENERIC_READ | win32file.GENERIC_WRITE,
+                0, None, win32file.OPEN_EXISTING, 0, None)
+        except pywintypes.error as err:
+            raise IOError(err)
+
+    def recv(self, max_length):
+        (err, data) = win32file.ReadFile(self.handle, max_length)
+        if err:
+            raise IOError(err)
+        return data
+
+    def sendall(self, data):
+        return win32file.WriteFile(self.handle, data)
+
+    def close(self):
+        self.handle.close()