LimitedLengthFile: Handle io.UnsupportedOperation from socket.tell(). (#35)

On Python 3, socket.makefile() returns an object with a tell() method, but one that always raises io.UnsupportedOperation.

2 files changed, 27 insertions, 3 deletions

diff --git a/paste/httpserver.py b/paste/httpserver.py
index 063c180..7709c60 100755
--- a/paste/httpserver.py
+++ b/paste/httpserver.py
@@ -20,6 +20,7 @@ if pyOpenSSL is installed, it also provides SSL capabilities.
 from __future__ import print_function
 import atexit
 import traceback
+import io
 import socket, sys, threading
 import posixpath
 import six
@@ -523,9 +524,11 @@ class LimitedLengthFile(object):
 
     def tell(self):
         if hasattr(self.file, 'tell'):
-            return self.file.tell()
-        else:
-            return self._consumed
+            try:
+                return self.file.tell()
+            except io.UnsupportedOperation:
+                pass
+        return self._consumed
 
 class ThreadPool(object):
     """
diff --git a/tests/test_httpserver.py b/tests/test_httpserver.py
index 20a4320..512f06d 100644
--- a/tests/test_httpserver.py
+++ b/tests/test_httpserver.py
@@ -1,5 +1,8 @@
 import email
 import io
+import socket
+
+import six
 
 from paste.httpserver import LimitedLengthFile, WSGIHandler
 from six.moves import StringIO
@@ -49,5 +52,23 @@ def test_environ_with_multiple_values():
 def test_limited_length_file():
     backing = io.BytesIO(b'0123456789')
     f = LimitedLengthFile(backing, 9)
+    assert f.tell() == 0
     assert f.read() == b'012345678'
+    assert f.tell() == 9
     assert f.read() == b''
+
+def test_limited_length_file_tell_on_socket():
+    backing_read, backing_write = socket.socketpair()
+    if six.PY2:
+        # On Python 2, socketpair() returns an internal socket type rather than
+        # the public one.
+        backing_read = socket.socket(_sock=backing_read)
+    f = LimitedLengthFile(backing_read.makefile('rb'), 10)
+    backing_write.send(b'0123456789')
+    backing_write.close()
+    assert f.tell() == 0
+    assert f.read(1) == b'0'
+    assert f.tell() == 1
+    assert f.read() == b'123456789'
+    assert f.tell() == 10
+    backing_read.close()