Opened 10 years ago

Closed 10 years ago

#938 closed defect (fixed)

lowercasify username on login request

Reported by: ayleph Owned by:
Priority: minor Milestone:
Component: programming Keywords: login, username
Cc: Parent Tickets:


When a user registers, the chosen username is lowercased before being stored to the database. When a user attempts to log in, the supplied username is passed through as it was typed, which may contain uppercase letters. A user who registered his or her name using uppercase letters may not realize that the username was lowercased internally and may continue trying to log in with uppercase letters.

After a failed login attempt with uppercase letters, the login form helpfully displays the username lowercased. However, it still may not be clear to the end user that he or she needs to log in with that lowercased username.

Change History (12)

comment:1 by ayleph, 10 years ago

Status: newreview

I branched off current GMG master and pushed a fix.

Summary: modify mediagoblin/auth/ to send the post-validated (ie, lowercasified) username to check_login_simple, rather than the pre-validated username.

comment:2 by Matt Molyneaux, 10 years ago

This could do with a a unit test to prevent regressions.

Also, the commit you've linked to doesn't seem to do anything other than refactor a few lines - am I missing something? (the parent commit is from the main GMG master branch)

comment:3 by ShawnRisk, 10 years ago

Keywords: test added

comment:4 by ayleph, 10 years ago

Yes, the commit does something :) I added a lengthy comment to the commit. I don't know how to write tests, and the docs don't really give much help there. I'll try to re-explain here.

In the original code, username = is called to store the username before login_form.validate() is run. This is bad because login_form.validate() can change the value of

If a user types in capital letters when he registers his account, the capital letters are lowercased before being stored in the database. If the user tries to log in with a username that contains capital letters, the username is lowercased when login_form.validate() is run. So a username stored before login_form.validate() is run may still contain capital letters and will fail to match the username in the database.

Steps to reproduce:

  1. Register an account with username 'TestUser'
  2. Try to log in with 'TestUser' and be denied
  3. See [] User u'TestUser' not found in log file, while login form now displays username as 'testuser' because the username was modified during validation
  4. Try to log in with 'testuser' and be granted access
  5. See [] Logging u'testuser' in in log file

The solution is to wait until after login_form.validate() to store the username. I ran into this exact problem on my instance, and this fixed it.

You could simply move line that stores username after login_form.validate() like this:

    if request.method == 'POST':

        if login_form.validate():
		username =
		user = check_login_simple(username,

But username isn't used elsewhere in this function, so why bother storing it to its own variable? So I just mimicked the way password was handled and wrote it like this:

    if request.method == 'POST':

        if login_form.validate():
		user = check_login_simple(

comment:5 by Matt Molyneaux, 10 years ago

OK, didn't realise login_form.validate() changed object data as well as returning a value (I'll grumble about that elsewhere :P )

As for unit tests, take a look at the tests already in Mediagoblin - your test only needs to POST some data and read the response. Something like this should give you a few hints.

Feel free to ping me in IRC if you need a bit more help with unit tests!

comment:6 by ayleph, 10 years ago

Keywords: login username added; test removed

Alright, I don't know if this is what you had in mind, but I modified to add three tests to check whether a username gets properly lowercased when the user attempts to log in with an uppercased username.

New tests:

  • Verify that username is no longer uppercased
  • Verify that username is properly lowercased
  • Verify that username which was converted from uppercase to lowercase returns a proper login

If you run this test on the codebase without the change from the commit linked in this ticket, the new tests will fail. If you modify the code with the changes in the linked commit, the new tests will pass.

@@ -229,6 +229,21 @@ def test_register_views(test_app):
     assert urlparse.urlsplit(response.location)[2] == '/'
     assert 'mediagoblin/root.html' in template.TEMPLATE_TEST_CONTEXT
+    ## Verify that username is lowercased on login attempt
+    template.clear_test_template_context()
+    response =
+        '/auth/login/', {
+            'username': u'ANGRYGIRL',
+            'password': 'iamveryveryangry'})
+    # Username should no longer be uppercased; it should be lowercased
+    assert not == u'ANGRYGIRL'
+    assert == u'angrygirl'
+    # User should be redirected
+    response.follow()
+    assert urlparse.urlsplit(response.location)[2] == '/'
+    assert 'mediagoblin/root.html' in template.TEMPLATE_TEST_CONTEXT
 def test_authentication_views(test_app):

The code change and the unit test updates are included in the branch linked below.

comment:7 by Matt Molyneaux, 10 years ago

Looks good to me! Passed unit tests locally. Didn't test rebasing/merging back to master.

comment:8 by Matt Molyneaux, 10 years ago

Status: reviewaccepted

Ah, I spoke too soon!

form is not the form from the last response.

You can verify this by changing the username to "ANGRYGIRL1", will still be angrygirl rather than angrygirl1

In order to avoid contamination with other parts of that unit test, I would recommend you split this bit of code into it's own test.

comment:9 by Matt Molyneaux, 10 years ago

In fact, it should probably be added to test_authentication_views (which is just below) - you can see examples there for getting the fresh form instance from each request too.

comment:10 by ayleph, 10 years ago

Okay, I think I got the unit test fixed. Let me know if there are still issues.

comment:11 by Matt Molyneaux, 10 years ago

Status: acceptedreview

OK, unit tests are fine now.

comment:12 by Christopher Allan Webber, 10 years ago

Resolution: fixed
Status: reviewclosed

Merged and pushed! Thank you!

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