Stop using uuid for choose_boundary() (#1380)

Stop using uuid for choose_boundary()

2 files changed, 8 insertions, 11 deletions

diff --git a/CHANGES.rst b/CHANGES.rst
index 4b6ca7cb..3c909e1c 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -20,7 +20,7 @@ dev (master)
 
 * Add the port to the connectionpool connect print (Pull #1251)
 
-* Lazily load `uuid` to boost performance on imports (Pull #1270)
+* Don't use the ``uuid`` module to create multipart data boundaries. (Pull #1380)
 
 * ``read_chunked()`` on a closed response returns no chunks. (Issue #1088)
 
diff --git a/urllib3/filepost.py b/urllib3/filepost.py
index 5af4fb31..78f1e19b 100644
--- a/urllib3/filepost.py
+++ b/urllib3/filepost.py
@@ -1,5 +1,7 @@
 from __future__ import absolute_import
+import binascii
 import codecs
+import os
 
 from io import BytesIO
 
@@ -13,16 +15,11 @@ writer = codecs.lookup('utf-8')[3]
 def choose_boundary():
     """
     Our embarrassingly-simple replacement for mimetools.choose_boundary.
-
-    We are lazily loading uuid here, because we don't want its issues
-
-    https://bugs.python.org/issue5885
-    https://bugs.python.org/issue11063
-
-    to affect our entire library.
     """
-    from uuid import uuid4
-    return uuid4().hex
+    boundary = binascii.hexlify(os.urandom(16))
+    if six.PY3:
+        boundary = boundary.decode('ascii')
+    return boundary
 
 
 def iter_field_objects(fields):
@@ -72,7 +69,7 @@ def encode_multipart_formdata(fields, boundary=None):
 
     :param boundary:
         If not specified, then a random boundary will be generated using
-        :func:`mimetools.choose_boundary`.
+        :func:`urllib3.filepost.choose_boundary`.
     """
     body = BytesIO()
     if boundary is None: