From 2506c0b9a96d48f14624acfa552fc88e38a542ae Mon Sep 17 00:00:00 2001
From: Armin Ronacher <armin.ronacher@active-4.com>
Date: Sat, 8 Feb 2014 17:45:09 +0000
Subject: [PATCH] Fixed sending etags for file streams with a name.  This fixes
 #930.

---
 CHANGES                    |  1 +
 flask/helpers.py           | 21 +++++++++++++--------
 flask/testsuite/helpers.py | 11 +++++++++++
 3 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/CHANGES b/CHANGES
index 0737c590..8b76c5fc 100644
--- a/CHANGES
+++ b/CHANGES
@@ -17,6 +17,7 @@ Version 0.10.2
 - Fixed an issue with query parameters getting removed from requests in
   the test client when absolute URLs were requested.
 - Made `@before_first_request` into a decorator as intended.
+- Fixed an etags bug when sending a file without a name.
 
 Version 0.10.1
 --------------
diff --git a/flask/helpers.py b/flask/helpers.py
index c71da85b..7b69b63c 100644
--- a/flask/helpers.py
+++ b/flask/helpers.py
@@ -538,14 +538,19 @@ def send_file(filename_or_fp, mimetype=None, as_attachment=False,
         rv.expires = int(time() + cache_timeout)
 
     if add_etags and filename is not None:
-        rv.set_etag('flask-%s-%s-%s' % (
-            os.path.getmtime(filename),
-            os.path.getsize(filename),
-            adler32(
-                filename.encode('utf-8') if isinstance(filename, text_type)
-                else filename
-            ) & 0xffffffff
-        ))
+        try:
+            rv.set_etag('flask-%s-%s-%s' % (
+                os.path.getmtime(filename),
+                os.path.getsize(filename),
+                adler32(
+                    filename.encode('utf-8') if isinstance(filename, text_type)
+                    else filename
+                ) & 0xffffffff
+            ))
+        except OSError:
+            warn('Access %s failed, maybe it does not exist, so ignore etags in '
+                 'headers' % filename, stacklevel=2)
+
         if conditional:
             rv = rv.make_conditional(request)
             # make sure we don't send x-sendfile for servers that
diff --git a/flask/testsuite/helpers.py b/flask/testsuite/helpers.py
index 518d9384..c645dc14 100644
--- a/flask/testsuite/helpers.py
+++ b/flask/testsuite/helpers.py
@@ -264,6 +264,17 @@ class SendfileTestCase(FlaskTestCase):
                 rv.close()
             # etags
             self.assert_equal(len(captured), 1)
+            with catch_warnings() as captured:
+                from StringIO import StringIO as PYStringIO
+                f = PYStringIO('Test')
+                f.name = 'test.txt'
+                rv = flask.send_file(f)
+                rv.direct_passthrough = False
+                self.assert_equal(rv.data, b'Test')
+                self.assert_equal(rv.mimetype, 'text/plain')
+                rv.close()
+            # attachment_filename and etags
+            self.assert_equal(len(captured), 3)
             with catch_warnings() as captured:
                 f = StringIO('Test')
                 rv = flask.send_file(f, mimetype='text/plain')