From 6e25228b2e8bd9556b879c629ee20876271bf7da Mon Sep 17 00:00:00 2001 From: "Miss Islington (bot)" <31488909+miss-islington@users.noreply.github.com> Date: Sun, 23 Apr 2023 05:20:34 -0700 Subject: [3.11] gh-81403: Fix for CacheFTPHandler in urllib (GH-13951) (#103705) * gh-81403: Fix for CacheFTPHandler in urllib (GH-13951) bpo-37222: Fix for CacheFTPHandler in urllib A call to FTP.ntransfercmd must be followed by FTP.voidresp to clear the "end transfer" message. Without this, the client and server get out of sync, which will result in an error if the FTP instance is reused to open a second URL. This scenario occurs for even the most basic usage of CacheFTPHandler. Reverts the patch merged as a resolution to bpo-16270 and adds a test case for the CacheFTPHandler in test_urllib2net.py. (cherry picked from commit e38bebb9ee805df6848f42845e71c8da8a821ad3) Co-authored-by: Dan Hemberger <846186+hemberger@users.noreply.github.com> Co-authored-by: Senthil Kumaran * Added NEWS entry. --------- Co-authored-by: Dan Hemberger <846186+hemberger@users.noreply.github.com> Co-authored-by: Senthil Kumaran --- Lib/test/test_urllib2net.py | 2 ++ Lib/urllib/request.py | 6 ++++++ .../next/Library/2023-04-22-22-14-09.gh-issue-81403.zVz9Td.rst | 3 +++ 3 files changed, 11 insertions(+) create mode 100644 Misc/NEWS.d/next/Library/2023-04-22-22-14-09.gh-issue-81403.zVz9Td.rst diff --git a/Lib/test/test_urllib2net.py b/Lib/test/test_urllib2net.py index 5da41c3..d8d882b 100644 --- a/Lib/test/test_urllib2net.py +++ b/Lib/test/test_urllib2net.py @@ -134,8 +134,10 @@ class OtherNetworkTests(unittest.TestCase): # They do sometimes catch some major disasters, though. def test_ftp(self): + # Testing the same URL twice exercises the caching in CacheFTPHandler urls = [ 'ftp://www.pythontest.net/README', + 'ftp://www.pythontest.net/README', ('ftp://www.pythontest.net/non-existent-file', None, urllib.error.URLError), ] diff --git a/Lib/urllib/request.py b/Lib/urllib/request.py index 73ad012..24911bb 100644 --- a/Lib/urllib/request.py +++ b/Lib/urllib/request.py @@ -2469,7 +2469,13 @@ class ftpwrapper: return (ftpobj, retrlen) def endtransfer(self): + if not self.busy: + return self.busy = 0 + try: + self.ftp.voidresp() + except ftperrors(): + pass def close(self): self.keepalive = False diff --git a/Misc/NEWS.d/next/Library/2023-04-22-22-14-09.gh-issue-81403.zVz9Td.rst b/Misc/NEWS.d/next/Library/2023-04-22-22-14-09.gh-issue-81403.zVz9Td.rst new file mode 100644 index 0000000..6adb71f --- /dev/null +++ b/Misc/NEWS.d/next/Library/2023-04-22-22-14-09.gh-issue-81403.zVz9Td.rst @@ -0,0 +1,3 @@ +:class:`urllib.request.CacheFTPHandler` no longer raises :class:`URLError` +if a cached FTP instance is reused. ftplib's endtransfer method calls +voidresp to drain the connection to handle FTP instance reuse properly. -- cgit v0.12