tests/test_cache.py

import email.utils
import httplib2
import pytest
import re
import tests
import time


dummy_url = 'http://127.0.0.1:1'


def test_get_only_if_cached_cache_hit():
    # Test that can do a GET with cache and 'only-if-cached'
    http = httplib2.Http(cache=tests.get_cache_path())
    with tests.server_const_http(add_etag=True) as uri:
        http.request(uri, 'GET')
        response, content = http.request(uri, 'GET', headers={'cache-control': 'only-if-cached'})
    assert response.fromcache
    assert response.status == 200


def test_get_only_if_cached_cache_miss():
    # Test that can do a GET with no cache with 'only-if-cached'
    http = httplib2.Http(cache=tests.get_cache_path())
    with tests.server_const_http(request_count=0) as uri:
        response, content = http.request(uri, 'GET', headers={'cache-control': 'only-if-cached'})
    assert not response.fromcache
    assert response.status == 504


def test_get_only_if_cached_no_cache_at_all():
    # Test that can do a GET with no cache with 'only-if-cached'
    # Of course, there might be an intermediary beyond us
    # that responds to the 'only-if-cached', so this
    # test can't really be guaranteed to pass.
    http = httplib2.Http()
    with tests.server_const_http(request_count=0) as uri:
        response, content = http.request(uri, 'GET', headers={'cache-control': 'only-if-cached'})
    assert not response.fromcache
    assert response.status == 504


@pytest.mark.skip(reason='was commented in legacy code')
def test_TODO_vary_no():
    pass
    # when there is no vary, a different Accept header (e.g.) should not
    # impact if the cache is used
    # test that the vary header is not sent
    # uri = urllib.parse.urljoin(base, "vary/no-vary.asis")
    # response, content = http.request(uri, 'GET', headers={'Accept': 'text/plain'})
    # assert response.status == 200
    # assert 'vary' not in response
    #
    # response, content = http.request(uri, 'GET', headers={'Accept': 'text/plain'})
    # assert response.status == 200
    # assert response.fromcache, "Should be from cache"
    #
    # response, content = http.request(uri, 'GET', headers={'Accept': 'text/html'})
    # assert response.status == 200
    # assert response.fromcache, "Should be from cache"


def test_vary_header_simple():
    """
    RFC 2616 13.6
    When the cache receives a subsequent request whose Request-URI
    specifies one or more cache entries including a Vary header field,
    the cache MUST NOT use such a cache entry to construct a response
    to the new request unless all of the selecting request-headers
    present in the new request match the corresponding stored
    request-headers in the original request.
    """
    # test that the vary header is sent
    http = httplib2.Http(cache=tests.get_cache_path())
    response = tests.http_response_bytes(
        headers={'vary': 'Accept', 'cache-control': 'max-age=300'},
        add_date=True,
    )
    with tests.server_const_bytes(response, request_count=3) as uri:
        response, content = http.request(uri, 'GET', headers={'accept': 'text/plain'})
        assert response.status == 200
        assert 'vary' in response

        # get the resource again, from the cache since accept header in this
        # request is the same as the request
        response, content = http.request(uri, 'GET', headers={'Accept': 'text/plain'})
        assert response.status == 200
        assert response.fromcache, "Should be from cache"

        # get the resource again, not from cache since Accept headers does not match
        response, content = http.request(uri, 'GET', headers={'Accept': 'text/html'})
        assert response.status == 200
        assert not response.fromcache, "Should not be from cache"

        # get the resource again, without any Accept header, so again no match
        response, content = http.request(uri, 'GET')
        assert response.status == 200
        assert not response.fromcache, "Should not be from cache"


def test_vary_header_double():
    http = httplib2.Http(cache=tests.get_cache_path())
    response = tests.http_response_bytes(
        headers={'vary': 'Accept, Accept-Language', 'cache-control': 'max-age=300'},
        add_date=True,
    )
    with tests.server_const_bytes(response, request_count=3) as uri:
        response, content = http.request(uri, 'GET', headers={
            'Accept': 'text/plain',
            'Accept-Language': 'da, en-gb;q=0.8, en;q=0.7',
        })
        assert response.status == 200
        assert 'vary' in response

        # we are from cache
        response, content = http.request(uri, 'GET', headers={
            'Accept': 'text/plain', 'Accept-Language': 'da, en-gb;q=0.8, en;q=0.7'})
        assert response.fromcache, "Should be from cache"

        response, content = http.request(uri, 'GET', headers={'Accept': 'text/plain'})
        assert response.status == 200
        assert not response.fromcache

        # get the resource again, not from cache, varied headers don't match exact
        response, content = http.request(uri, 'GET', headers={'Accept-Language': 'da'})
        assert response.status == 200
        assert not response.fromcache, "Should not be from cache"


def test_vary_unused_header():
    http = httplib2.Http(cache=tests.get_cache_path())
    response = tests.http_response_bytes(
        headers={'vary': 'X-No-Such-Header', 'cache-control': 'max-age=300'},
        add_date=True,
    )
    with tests.server_const_bytes(response, request_count=1) as uri:
        # A header's value is not considered to vary if it's not used at all.
        response, content = http.request(uri, 'GET', headers={'Accept': 'text/plain'})
        assert response.status == 200
        assert 'vary' in response

        # we are from cache
        response, content = http.request(uri, 'GET', headers={'Accept': 'text/plain'})
        assert response.fromcache, "Should be from cache"


def test_get_cache_control_no_cache():
    # Test Cache-Control: no-cache on requests
    http = httplib2.Http(cache=tests.get_cache_path())
    with tests.server_const_http(
            add_date=True, add_etag=True,
            headers={'cache-control': 'max-age=300'}, request_count=2) as uri:
        response, _ = http.request(uri, 'GET', headers={'accept-encoding': 'identity'})
        assert response.status == 200
        assert response['etag'] != ''
        assert not response.fromcache
        response, _ = http.request(uri, 'GET', headers={'accept-encoding': 'identity'})
        assert response.status == 200
        assert response.fromcache
        response, _ = http.request(uri, 'GET', headers={'accept-encoding': 'identity', 'Cache-Control': 'no-cache'})
        assert response.status == 200
        assert not response.fromcache


def test_get_cache_control_pragma_no_cache():
    # Test Pragma: no-cache on requests
    http = httplib2.Http(cache=tests.get_cache_path())
    with tests.server_const_http(
            add_date=True, add_etag=True,
            headers={'cache-control': 'max-age=300'}, request_count=2) as uri:
        response, _ = http.request(uri, 'GET', headers={'accept-encoding': 'identity'})
        assert response['etag'] != ''
        response, _ = http.request(uri, 'GET', headers={'accept-encoding': 'identity'})
        assert response.status == 200
        assert response.fromcache
        response, _ = http.request(uri, 'GET', headers={'accept-encoding': 'identity', 'Pragma': 'no-cache'})
        assert response.status == 200
        assert not response.fromcache


def test_get_cache_control_no_store_request():
    # A no-store request means that the response should not be stored.
    http = httplib2.Http(cache=tests.get_cache_path())
    with tests.server_const_http(
            add_date=True, add_etag=True,
            headers={'cache-control': 'max-age=300'}, request_count=2) as uri:
        response, _ = http.request(uri, 'GET', headers={'Cache-Control': 'no-store'})
        assert response.status == 200
        assert not response.fromcache
        response, _ = http.request(uri, 'GET', headers={'Cache-Control': 'no-store'})
        assert response.status == 200
        assert not response.fromcache


def test_get_cache_control_no_store_response():
    # A no-store response means that the response should not be stored.
    http = httplib2.Http(cache=tests.get_cache_path())
    with tests.server_const_http(
            add_date=True, add_etag=True,
            headers={'cache-control': 'max-age=300, no-store'}, request_count=2) as uri:
        response, _ = http.request(uri, 'GET')
        assert response.status == 200
        assert not response.fromcache
        response, _ = http.request(uri, 'GET')
        assert response.status == 200
        assert not response.fromcache


def test_get_cache_control_no_cache_no_store_request():
    # Test that a no-store, no-cache clears the entry from the cache
    # even if it was cached previously.
    http = httplib2.Http(cache=tests.get_cache_path())
    with tests.server_const_http(
            add_date=True, add_etag=True,
            headers={'cache-control': 'max-age=300'}, request_count=3) as uri:
        response, _ = http.request(uri, 'GET')
        response, _ = http.request(uri, 'GET')
        assert response.fromcache
        response, _ = http.request(uri, 'GET', headers={'Cache-Control': 'no-store, no-cache'})
        assert response.status == 200
        assert not response.fromcache
        response, _ = http.request(uri, 'GET', headers={'Cache-Control': 'no-store, no-cache'})
        assert response.status == 200
        assert not response.fromcache


def test_update_invalidates_cache():
    # Test that calling PUT or DELETE on a
    # URI that is cache invalidates that cache.
    http = httplib2.Http(cache=tests.get_cache_path())

    def handler(request):
        if request.method in ('PUT', 'PATCH', 'DELETE'):
            return tests.http_response_bytes(status=405)
        return tests.http_response_bytes(
            add_date=True, add_etag=True, headers={'cache-control': 'max-age=300'})

    with tests.server_request(handler, request_count=3) as uri:
        response, _ = http.request(uri, 'GET')
        response, _ = http.request(uri, 'GET')
        assert response.fromcache
        response, _ = http.request(uri, 'DELETE')
        assert response.status == 405
        assert not response.fromcache
        response, _ = http.request(uri, 'GET')
        assert not response.fromcache


def handler_conditional_update(request):
    respond = tests.http_response_bytes
    if request.method == 'GET':
        if request.headers.get('if-none-match', '') == '12345':
            return respond(status=304)
        return respond(add_date=True, headers={'etag': '12345', 'cache-control': 'max-age=300'})
    elif request.method in ('PUT', 'PATCH', 'DELETE'):
        if request.headers.get('if-match', '') == '12345':
            return respond(status=200)
        return respond(status=412)
    return respond(status=405)


@pytest.mark.parametrize('method', ('PUT', 'PATCH'))
def test_update_uses_cached_etag(method):
    # Test that we natively support http://www.w3.org/1999/04/Editing/
    http = httplib2.Http(cache=tests.get_cache_path())
    with tests.server_request(handler_conditional_update, request_count=3) as uri:
        response, _ = http.request(uri, 'GET')
        assert response.status == 200
        assert not response.fromcache
        response, _ = http.request(uri, 'GET')
        assert response.status == 200
        assert response.fromcache
        response, _ = http.request(uri, method, body=b'foo')
        assert response.status == 200
        response, _ = http.request(uri, method, body=b'foo')
        assert response.status == 412


def test_update_uses_cached_etag_and_oc_method():
    # Test that we natively support http://www.w3.org/1999/04/Editing/
    http = httplib2.Http(cache=tests.get_cache_path())
    with tests.server_request(handler_conditional_update, request_count=2) as uri:
        response, _ = http.request(uri, 'GET')
        assert response.status == 200
        assert not response.fromcache
        response, _ = http.request(uri, 'GET')
        assert response.status == 200
        assert response.fromcache
        http.optimistic_concurrency_methods.append('DELETE')
        response, _ = http.request(uri, 'DELETE')
        assert response.status == 200


def test_update_uses_cached_etag_overridden():
    # Test that we natively support http://www.w3.org/1999/04/Editing/
    http = httplib2.Http(cache=tests.get_cache_path())
    with tests.server_request(handler_conditional_update, request_count=2) as uri:
        response, content = http.request(uri, 'GET')
        assert response.status == 200
        assert not response.fromcache
        response, content = http.request(uri, 'GET')
        assert response.status == 200
        assert response.fromcache
        response, content = http.request(uri, 'PUT', body=b'foo', headers={'if-match': 'fred'})
        assert response.status == 412


@pytest.mark.parametrize(
    'data', (
        ({}, {}),
        ({'cache-control': ' no-cache'},
         {'no-cache': 1}),
        ({'cache-control': ' no-store, max-age = 7200'},
         {'no-store': 1, 'max-age': '7200'}),
        ({'cache-control': ' , '}, {'': 1}),  # FIXME
        ({'cache-control': 'Max-age=3600;post-check=1800,pre-check=3600'},
         {'max-age': '3600;post-check=1800', 'pre-check': '3600'}),
    ), ids=lambda data: str(data[0]))
def test_parse_cache_control(data):
    header, expected = data
    assert httplib2._parse_cache_control(header) == expected


def test_normalize_headers():
    # Test that we normalize headers to lowercase
    h = httplib2._normalize_headers({'Cache-Control': 'no-cache', 'Other': 'Stuff'})
    assert 'cache-control' in h
    assert 'other' in h
    assert h['other'] == 'Stuff'


@pytest.mark.parametrize(
    'data', (
        ({'cache-control': 'no-cache'}, {'cache-control': 'max-age=7200'}, 'TRANSPARENT'),
        ({}, {'cache-control': 'max-age=fred, min-fresh=barney'}, 'STALE'),
        ({}, {'date': '{now}', 'expires': '{now+3}'}, 'FRESH'),
        ({}, {'date': '{now}', 'expires': '{now+3}', 'cache-control': 'no-cache'}, 'STALE'),
        ({'cache-control': 'must-revalidate'}, {}, 'STALE'),
        ({}, {'cache-control': 'must-revalidate'}, 'STALE'),
        ({}, {'date': '{now}', 'cache-control': 'max-age=0'}, 'STALE'),
        ({'cache-control': 'only-if-cached'}, {}, 'FRESH'),
        ({}, {'date': '{now}', 'expires': '0'}, 'STALE'),
        ({}, {'data': '{now+3}'}, 'STALE'),
        ({'cache-control': 'max-age=0'}, {'date': '{now}', 'cache-control': 'max-age=2'}, 'STALE'),
        ({'cache-control': 'min-fresh=2'}, {'date': '{now}', 'expires': '{now+2}'}, 'STALE'),
        ({'cache-control': 'min-fresh=2'}, {'date': '{now}', 'expires': '{now+4}'}, 'FRESH'),
    ), ids=lambda data: str(data))
def test_entry_disposition(data):
    now = time.time()
    nowre = re.compile(r'{now([\+\-]\d+)?}')

    def render(s):
        m = nowre.match(s)
        if m:
            offset = int(m.expand(r'\1')) if m.group(1) else 0
            s = email.utils.formatdate(now + offset, usegmt=True)
        return s

    request, response, expected = data
    request = {k: render(v) for k, v in request.items()}
    response = {k: render(v) for k, v in response.items()}
    assert httplib2._entry_disposition(response, request) == expected


def test_expiration_model_fresh():
    response_headers = {
        'date': email.utils.formatdate(usegmt=True),
        'cache-control': 'max-age=2'
    }
    assert httplib2._entry_disposition(response_headers, {}) == 'FRESH'
    # TODO: add current time as _entry_disposition argument to avoid sleep in tests
    time.sleep(3)
    assert httplib2._entry_disposition(response_headers, {}) == 'STALE'


def test_expiration_model_date_and_expires():
    now = time.time()
    response_headers = {
        'date': email.utils.formatdate(now, usegmt=True),
        'expires': email.utils.formatdate(now + 2, usegmt=True),
    }
    assert httplib2._entry_disposition(response_headers, {}) == 'FRESH'
    time.sleep(3)
    assert httplib2._entry_disposition(response_headers, {}) == 'STALE'


# TODO: Repeat all cache tests with memcache. pytest.mark.parametrize
# cache = memcache.Client(['127.0.0.1:11211'], debug=0)
# #cache = memcache.Client(['10.0.0.4:11211'], debug=1)
# http = httplib2.Http(cache)