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view test/test_redis_session.py @ 7853:03c1b7ae3a68
issue2551328/issue2551264 unneeded next link and total_count incorrect
Fix: issue2551328 - REST results show next link if number of
results is a multiple of page size. (Found by members of
team 3 in the UMass-Boston CS682 Spring 2024 class.)
issue2551264 - REST X-Total-Count header and @total_size
count incorrect when paginated
These issues arose because we retrieved the exact number of rows
from the database as requested by the user using the @page_size
parameter. With this changeset, we retrieve up to 10 million + 1
rows from the database. If the total number of rows exceeds 10
million, we set the total_count indicators to -1 as an invalid
size. (The max number of requested rows (default 10 million +1)
can be modified by the admin through interfaces.py.)
By retrieving more data than necessary, we can calculate the
total count by adding @page_index*@page_size to the number of
rows returned by the query.
Furthermore, since we return more than @page_size rows, we can
determine the existence of a row at @page_size+1 and use that
information to determine if a next link should be
provided. Previously, a next link was returned if @page_size rows
were retrieved.
This change does not guarantee that the user will get @page_size
rows returned. Access policy filtering occurs after the rows are
returned, and discards rows inaccessible by the user.
Using the current @page_index/@page_size it would be difficult to
have the roundup code refetch data and make sure that a full
@page_size set of rows is returned. E.G. @page_size=100 and 5 of
them are dropped due to access restrictions. We then fetch 10
items and add items 1-4 and 6 (5 is inaccessible). There is no
way to calculate the new database offset at:
@page_index*@page_size + 6 from the URL. We would need to add an
@page_offset=6 or something.
This could work since the client isn't adding 1 to @page_index to
get the next page. Thanks to HATEOAS, the client just uses the
'next' url. But I am not going to cross that bridge without a
concrete use case.
This can also be handled client side by merging a short response
with the next response and re-paginating client side.
Also added extra index markers to the docs to highlight use of
interfaces.py.
| author | John Rouillard <rouilj@ieee.org> |
|---|---|
| date | Mon, 01 Apr 2024 09:57:16 -0400 |
| parents | 1b7162938988 |
| children | a4923cec0afa |
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# # Copyright (c) 2001 Bizar Software Pty Ltd (http://www.bizarsoftware.com.au/) # This module is free software, and you may redistribute it and/or modify # under the same terms as Python, so long as this copyright message and # disclaimer are retained in their original form. # # IN NO EVENT SHALL BIZAR SOFTWARE PTY LTD BE LIABLE TO ANY PARTY FOR # DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING # OUT OF THE USE OF THIS CODE, EVEN IF THE AUTHOR HAS BEEN ADVISED OF THE # POSSIBILITY OF SUCH DAMAGE. # # BIZAR SOFTWARE PTY LTD SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, # BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS # FOR A PARTICULAR PURPOSE. THE CODE PROVIDED HEREUNDER IS ON AN "AS IS" # BASIS, AND THERE IS NO OBLIGATION WHATSOEVER TO PROVIDE MAINTENANCE, # SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. import unittest, os, shutil, time from roundup.anypy import strings import pytest try: from roundup.backends.sessions_redis import Sessions, OneTimeKeys skip_redis = lambda func, *args, **kwargs: func from redis import AuthenticationError, ConnectionError except ImportError as e: from .pytest_patcher import mark_class skip_redis = mark_class(pytest.mark.skip( reason='Skipping redis tests: redis module not available')) from .test_sqlite import sqliteOpener from .test_anydbm import anydbmOpener from .session_common import SessionTest class RedisSessionTest(SessionTest): def setUp(self): '''This must not be called if redis can not be loaded. It will cause an error since the ConnectionError and AuthenticationError exceptions aren't defined. ''' SessionTest.setUp(self) import os if 'pytest_redis_pw' in os.environ and os.environ['pytest_redis_pw']: pw = os.environ['pytest_redis_pw'] if ':' in pw: # pw is user:password pw = "%s@" % pw else: # pw is just password pw = ":%s@" % pw else: pw = "" # redefine the session db's as redis. self.db.config.SESSIONDB_BACKEND = "redis" self.db.config.SESSIONDB_REDIS_URL = \ 'redis://%slocalhost:6379/15?health_check_interval=2' % pw self.db.Session = None self.db.Otk = None self.sessions = self.db.getSessionManager() self.otks = self.db.getOTKManager() try: self.sessions.redis.keys() except (AuthenticationError, ConnectionError) as e: self.skipTest('Redis server unavailable: "%s".' % e) # database should be empty. Verify so we don't clobber # somebody's working database. self.assertEqual(self.sessions.redis.keys(), [], "Tests will not run on a db with keys. " "Run flushdb in 'redis-cli -n 15 -p 6379 -h localhost' " "to empty db first") self.assertEqual(self.otks.redis.keys(), [], "Tests will not run on a db with keys. " "Run flushdb in 'redis-cli -n 15 -p 6379 -h localhost' " "to empty db first") def tearDown(self): self.sessions.clear() self.otks.clear() SessionTest.tearDown(self) # reset to default session backend self.db.config.SESSIONDB_BACKEND = "" self.db.Session = None self.db.Otk = None self.sessions = None self.otks = None def get_ts(self, key="random_session"): db_tstamp = self.db.Session.redis.ttl( self.db.Session.makekey(key)) + \ time.time() print(db_tstamp) return (db_tstamp,) @skip_redis class redis_sqliteSessionTest(sqliteOpener, RedisSessionTest, unittest.TestCase): s2b = lambda x,y : y def testLifetime(self): ts = self.sessions.lifetime(300) print(ts) now = time.time() print(now) self.assertGreater(now + 302, ts) self.assertLess(now + 298, ts) def testDbType(self): self.assertIn("roundlite", repr(self.db)) self.assertIn("roundup.backends.sessions_redis.Sessions", repr(self.db.Session)) @skip_redis class redis_anydbmSessionTest(anydbmOpener, RedisSessionTest, unittest.TestCase): s2b = lambda x,y: strings.s2b(y) def testLifetime(self): ts = self.sessions.lifetime(300) print(ts) now = time.time() print(now) self.assertGreater(now + 302, ts) self.assertLess(now + 298, ts) def testDbType(self): self.assertIn("back_anydbm", repr(self.db)) self.assertIn("roundup.backends.sessions_redis.Sessions", repr(self.db.Session))
