Python cache.generic_bulk_cached_fetch函数代码示例

def bulk_get_streams(realm, stream_names):
    if isinstance(realm, Realm):
        realm_id = realm.id
    else:
        realm_id = realm

    def fetch_streams_by_name(stream_names):
        # This should be just
        #
        # Stream.objects.select_related("realm").filter(name__iexact__in=stream_names,
        #                                               realm_id=realm_id)
        #
        # But chaining __in and __iexact doesn't work with Django's
        # ORM, so we have the following hack to construct the relevant where clause
        if len(stream_names) == 0:
            return []
        upper_list = ", ".join(["UPPER(%s)"] * len(stream_names))
        where_clause = "UPPER(zerver_stream.name::text) IN (%s)" % (upper_list,)
        return get_active_streams(realm_id).select_related("realm").extra(
            where=[where_clause],
            params=stream_names)

    return generic_bulk_cached_fetch(lambda stream_name: get_stream_cache_key(stream_name, realm),
                                     fetch_streams_by_name,
                                     [stream_name.lower() for stream_name in stream_names],
                                     id_fetcher=lambda stream: stream.name.lower())

def user_ids_to_users(user_ids: List[int], realm: Realm) -> List[UserProfile]:
    # TODO: Consider adding a flag to control whether deactivated
    # users should be included.

    def fetch_users_by_id(user_ids: List[int]) -> List[UserProfile]:
        if len(user_ids) == 0:
            return []

        return list(UserProfile.objects.filter(id__in=user_ids).select_related())

    user_profiles_by_id = generic_bulk_cached_fetch(
        cache_key_function=user_profile_by_id_cache_key,
        query_function=fetch_users_by_id,
        object_ids=user_ids
    )  # type: Dict[int, UserProfile]

    found_user_ids = user_profiles_by_id.keys()
    missed_user_ids = [user_id for user_id in user_ids if user_id not in found_user_ids]
    if missed_user_ids:
        raise JsonableError(_("Invalid user ID: %s" % (missed_user_ids[0])))

    user_profiles = list(user_profiles_by_id.values())
    for user_profile in user_profiles:
        if user_profile.realm != realm:
            raise JsonableError(_("Invalid user ID: %s" % (user_profile.id,)))
    return user_profiles

def messages_for_ids(message_ids: List[int],
                     user_message_flags: Dict[int, List[str]],
                     search_fields: Dict[int, Dict[str, str]],
                     apply_markdown: bool,
                     client_gravatar: bool,
                     allow_edit_history: bool) -> List[Dict[str, Any]]:

    cache_transformer = MessageDict.build_dict_from_raw_db_row
    id_fetcher = lambda row: row['id']

    message_dicts = generic_bulk_cached_fetch(to_dict_cache_key_id,
                                              MessageDict.get_raw_db_rows,
                                              message_ids,
                                              id_fetcher=id_fetcher,
                                              cache_transformer=cache_transformer,
                                              extractor=extract_message_dict,
                                              setter=stringify_message_dict)

    message_list = []  # type: List[Dict[str, Any]]

    for message_id in message_ids:
        msg_dict = message_dicts[message_id]
        msg_dict.update({"flags": user_message_flags[message_id]})
        if message_id in search_fields:
            msg_dict.update(search_fields[message_id])
        # Make sure that we never send message edit history to clients
        # in realms with allow_edit_history disabled.
        if "edit_history" in msg_dict and not allow_edit_history:
            del msg_dict["edit_history"]
        message_list.append(msg_dict)

    MessageDict.post_process_dicts(message_list, apply_markdown, client_gravatar)

    return message_list

def bulk_get_recipients(type, type_ids):
    def cache_key_function(type_id):
        return get_recipient_cache_key(type, type_id)
    def query_function(type_ids):
        return Recipient.objects.filter(type=type, type_id__in=type_ids)

    return generic_bulk_cached_fetch(cache_key_function, query_function, type_ids,
                                     id_fetcher=lambda recipient: recipient.type_id)

def bulk_get_users(emails: List[str], realm: Optional[Realm],
                   base_query: 'QuerySet[UserProfile]'=None) -> Dict[str, UserProfile]:
    if base_query is None:
        assert realm is not None
        query = UserProfile.objects.filter(realm=realm, is_active=True)
        realm_id = realm.id
    else:
        # WARNING: Currently, this code path only really supports one
        # version of `base_query` being used (because otherwise,
        # they'll share the cache, which can screw up the filtering).
        # If you're using this flow, you'll need to re-do any filters
        # in base_query in the code itself; base_query is just a perf
        # optimization.
        query = base_query
        realm_id = 0

    def fetch_users_by_email(emails: List[str]) -> List[UserProfile]:
        # This should be just
        #
        # UserProfile.objects.select_related("realm").filter(email__iexact__in=emails,
        #                                                    realm=realm)
        #
        # But chaining __in and __iexact doesn't work with Django's
        # ORM, so we have the following hack to construct the relevant where clause
        if len(emails) == 0:
            return []

        upper_list = ", ".join(["UPPER(%s)"] * len(emails))
        where_clause = "UPPER(zerver_userprofile.email::text) IN (%s)" % (upper_list,)
        return query.select_related("realm").extra(
            where=[where_clause],
            params=emails)

    return generic_bulk_cached_fetch(
        # Use a separate cache key to protect us from conflicts with
        # the get_user cache.
        lambda email: 'bulk_get_users:' + user_profile_cache_key_id(email, realm_id),
        fetch_users_by_email,
        [email.lower() for email in emails],
        id_fetcher=lambda user_profile: user_profile.email.lower()
    )

#.........这里部分代码省略.........
        if len(first_unread_result) > 0:
            anchor = first_unread_result[0][0]
        else:
            anchor = LARGER_THAN_MAX_MESSAGE_ID

    before_query = None
    after_query = None
    if num_before != 0:
        before_anchor = anchor
        if num_after != 0:
            # Don't include the anchor in both the before query and the after query
            before_anchor = anchor - 1
        before_query = query.where(inner_msg_id_col <= before_anchor) \
                            .order_by(inner_msg_id_col.desc()).limit(num_before)
    if num_after != 0:
        after_query = query.where(inner_msg_id_col >= anchor) \
                           .order_by(inner_msg_id_col.asc()).limit(num_after)

    if anchor == LARGER_THAN_MAX_MESSAGE_ID:
        # There's no need for an after_query if we're targeting just the target message.
        after_query = None

    if before_query is not None:
        if after_query is not None:
            query = union_all(before_query.self_group(), after_query.self_group())
        else:
            query = before_query
    elif after_query is not None:
        query = after_query
    else:
        # This can happen when a narrow is specified.
        query = query.where(inner_msg_id_col == anchor)

    main_query = alias(query)
    query = select(main_query.c, None, main_query).order_by(column("message_id").asc())
    # This is a hack to tag the query we use for testing
    query = query.prefix_with("/* get_old_messages */")
    query_result = list(sa_conn.execute(query).fetchall())

    # The following is a little messy, but ensures that the code paths
    # are similar regardless of the value of include_history.  The
    # 'user_messages' dictionary maps each message to the user's
    # UserMessage object for that message, which we will attach to the
    # rendered message dict before returning it.  We attempt to
    # bulk-fetch rendered message dicts from remote cache using the
    # 'messages' list.
    search_fields = dict() # type: Dict[int, Dict[str, Text]]
    message_ids = [] # type: List[int]
    user_message_flags = {} # type: Dict[int, List[str]]
    if include_history:
        message_ids = [row[0] for row in query_result]

        # TODO: This could be done with an outer join instead of two queries
        user_message_flags = dict((user_message.message_id, user_message.flags_list()) for user_message in
                                  UserMessage.objects.filter(user_profile=user_profile,
                                                             message__id__in=message_ids))
        for row in query_result:
            message_id = row[0]
            if user_message_flags.get(message_id) is None:
                user_message_flags[message_id] = ["read", "historical"]
            if is_search:
                (_, subject, rendered_content, content_matches, subject_matches) = row
                search_fields[message_id] = get_search_fields(rendered_content, subject,
                                                              content_matches, subject_matches)
    else:
        for row in query_result:
            message_id = row[0]
            flags = row[1]
            user_message_flags[message_id] = parse_usermessage_flags(flags)

            message_ids.append(message_id)

            if is_search:
                (_, _, subject, rendered_content, content_matches, subject_matches) = row
                search_fields[message_id] = get_search_fields(rendered_content, subject,
                                                              content_matches, subject_matches)

    cache_transformer = lambda row: MessageDict.build_dict_from_raw_db_row(row, apply_markdown)
    id_fetcher = lambda row: row['id']

    message_dicts = generic_bulk_cached_fetch(lambda message_id: to_dict_cache_key_id(message_id, apply_markdown),
                                              Message.get_raw_db_rows,
                                              message_ids,
                                              id_fetcher=id_fetcher,
                                              cache_transformer=cache_transformer,
                                              extractor=extract_message_dict,
                                              setter=stringify_message_dict)

    message_list = []
    for message_id in message_ids:
        msg_dict = message_dicts[message_id]
        msg_dict.update({"flags": user_message_flags[message_id]})
        msg_dict.update(search_fields.get(message_id, {}))
        message_list.append(msg_dict)

    statsd.incr('loaded_old_messages', len(message_list))
    ret = {'messages': message_list,
           "result": "success",
           "msg": ""}
    return json_success(ret)