441 lines
14 KiB
Python
441 lines
14 KiB
Python
# The core application of the Mia project.
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# by imacat <imacat@mail.imacat.idv.tw>, 2020/7/1
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# Copyright (c) 2020 imacat.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""The utilities of the Mia core application.
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"""
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import random
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import urllib.parse
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from typing import Dict, List, Any, Type
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from django.conf import settings
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from django.db.models import Model, Q
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from django.http import HttpRequest
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from django.utils.translation import pgettext, get_language
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def new_pk(cls: Type[Model]) -> int:
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"""Finds a random ID that does not conflict with the existing data records.
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Args:
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cls: The Django model class.
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Returns:
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The new random ID.
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"""
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while True:
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pk = random.randint(100000000, 999999999)
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try:
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cls.objects.get(pk=pk)
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except cls.DoesNotExist:
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return pk
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def strip_post(post: Dict[str, str]) -> None:
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"""Strips the values of the POSTed data. Empty strings are removed.
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Args:
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post (dict[str]): The POSTed data.
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"""
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for key in list(post.keys()):
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post[key] = post[key].strip()
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if post[key] == "":
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del post[key]
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class Language:
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"""A language.
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Args:
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language: The Django language code.
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Attributes:
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id (str): The language ID
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db (str): The database column suffix of this language.
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locale (str); The locale name of this language.
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is_default (bool): Whether this is the default language.
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"""
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def __init__(self, language: str):
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self.id = language
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self.db = "_" + language.lower().replace("-", "_")
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if language == "zh-hant":
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self.locale = "zh-TW"
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elif language == "zh-hans":
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self.locale = "zh-CN"
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else:
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self.locale = language
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self.is_default = (language == settings.LANGUAGE_CODE)
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@staticmethod
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def default():
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return Language(settings.LANGUAGE_CODE)
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@staticmethod
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def current():
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return Language(get_language())
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class UrlBuilder:
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"""The URL builder.
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Attributes:
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path (str): the base path
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params (list[Param]): The query parameters
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"""
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def __init__(self, start_url: str):
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"""Constructs a new URL builder.
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Args:
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start_url (str): The URL to start with
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"""
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pos = start_url.find("?")
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if pos == -1:
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self.path = start_url
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self.params = []
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return
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self.path = start_url[:pos]
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self.params = []
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for piece in start_url[pos + 1:].split("&"):
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pos = piece.find("=")
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name = urllib.parse.unquote(piece[:pos])
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value = urllib.parse.unquote(piece[pos + 1:])
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self.params.append(self.Param(name, value))
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def add(self, name, value):
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"""Adds a query parameter.
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Args:
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name (str): The parameter name
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value (str): The parameter value
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Returns:
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UrlBuilder: The URL builder itself, with the parameter
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modified.
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"""
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if value is not None:
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self.params.append(self.Param(name, value))
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return self
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def remove(self, name):
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"""Removes a query parameter.
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Args:
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name (str): The parameter name
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Returns:
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UrlBuilder: The URL builder itself, with the parameter
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modified.
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"""
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self.params = [x for x in self.params if x.name != name]
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return self
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def query(self, **kwargs):
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"""A keyword-styled query parameter setter. The existing values are
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always replaced. Multiple-values are added when the value is a list or
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tuple. The existing values are dropped when the value is None.
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"""
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for key in kwargs:
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self.remove(key)
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if isinstance(kwargs[key], list) or isinstance(kwargs[key], tuple):
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for value in kwargs[key]:
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self.add(key, value)
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elif kwargs[key] is None:
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pass
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else:
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self.add(key, kwargs[key])
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return self
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def clone(self):
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"""Returns a copy of this URL builder.
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Returns:
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UrlBuilder: A copy of this URL builder.
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"""
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another = UrlBuilder(self.path)
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another.params = [
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self.Param(x.name, x.value) for x in self.params]
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return another
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def __str__(self) -> str:
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if len(self.params) == 0:
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return self.path
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return self.path + "?" + "&".join([
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str(x) for x in self.params])
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class Param:
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"""A query parameter.
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Attributes:
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name: The parameter name
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value: The parameter value
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"""
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def __init__(self, name: str, value: str):
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"""Constructs a new query parameter
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Args:
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name (str): The parameter name
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value (str): The parameter value
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"""
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self.name = name
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self.value = value
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def __str__(self) -> str:
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"""Returns the string representation of this query
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parameter.
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Returns:
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str: The string representation of this query
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parameter
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"""
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return "%s=%s" % (
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urllib.parse.quote(self.name),
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urllib.parse.quote(self.value))
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class Pagination:
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"""The pagination.
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Args:
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request: The request.
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items: All the items.
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is_reversed: Whether we should display the last page first.
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Raises:
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PaginationException: With invalid pagination parameters
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Attributes:
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current_url (UrlBuilder): The current request URL.
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is_reversed (bool): Whether we should display the last page first.
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page_size (int): The page size.
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total_pages (int): The total number of pages available.
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is_paged (bool): Whether there are more than one page.
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page_no (int): The current page number.
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items (list[Model]): The items in the current page.
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"""
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DEFAULT_PAGE_SIZE = 10
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def __init__(self, request: HttpRequest, items: List[Any],
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is_reversed: bool = False):
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self.current_url = UrlBuilder(request.get_full_path())
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self.is_reversed = is_reversed
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self.page_size = self.DEFAULT_PAGE_SIZE
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self.total_pages = None
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self.is_paged = None
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self.page_no = 1
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self.items = []
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# The page size
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try:
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self.page_size = int(request.GET["page-size"])
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if self.page_size == self.DEFAULT_PAGE_SIZE:
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raise PaginationException(self.current_url.remove("page-size"))
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if self.page_size < 1:
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raise PaginationException(self.current_url.remove("page-size"))
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except KeyError:
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self.page_size = self.DEFAULT_PAGE_SIZE
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except ValueError:
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raise PaginationException(self.current_url.remove("page-size"))
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self.total_pages = int(
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(len(items) - 1) / self.page_size) + 1
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default_page_no = 1 if not is_reversed else self.total_pages
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self.is_paged = self.total_pages > 1
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# The page number
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try:
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self.page_no = int(request.GET["page"])
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if not self.is_paged:
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raise PaginationException(self.current_url.remove("page"))
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if self.page_no == default_page_no:
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raise PaginationException(self.current_url.remove("page"))
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if self.page_no < 1:
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raise PaginationException(self.current_url.remove("page"))
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if self.page_no > self.total_pages:
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raise PaginationException(self.current_url.remove("page"))
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except KeyError:
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self.page_no = default_page_no
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except ValueError:
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raise PaginationException(self.current_url.remove("page"))
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if not self.is_paged:
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self.page_no = 1
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self.items = items
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return
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start_no = self.page_size * (self.page_no - 1)
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self.items = items[start_no:start_no + self.page_size]
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def links(self):
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"""Returns the navigation links of the pagination bar.
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Returns:
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List[Link]: The navigation links of the pagination bar.
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"""
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base_url = self.current_url.clone().remove("page").remove("s")
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links = []
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# The previous page
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link = self.Link()
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link.title = pgettext("Pagination|", "Previous")
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if self.page_no > 1:
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if self.page_no - 1 == 1:
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if not self.is_reversed:
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link.url = str(base_url)
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else:
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link.url = str(base_url.clone().add(
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"page", "1"))
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else:
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link.url = str(base_url.clone().add(
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"page", str(self.page_no - 1)))
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link.is_small_screen = True
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links.append(link)
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# The first page
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link = self.Link()
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link.title = "1"
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if not self.is_reversed:
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link.url = str(base_url)
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else:
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link.url = str(base_url.clone().add(
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"page", "1"))
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if self.page_no == 1:
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link.is_active = True
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links.append(link)
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# The previous ellipsis
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if self.page_no > 4:
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link = self.Link()
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if self.page_no > 5:
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link.title = pgettext("Pagination|", "...")
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else:
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link.title = "2"
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link.url = str(base_url.clone().add(
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"page", "2"))
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links.append(link)
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# The nearby pages
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for no in range(self.page_no - 2, self.page_no + 3):
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if no <= 1 or no >= self.total_pages:
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continue
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link = self.Link()
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link.title = str(no)
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link.url = str(base_url.clone().add(
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"page", str(no)))
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if no == self.page_no:
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link.is_active = True
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links.append(link)
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# The next ellipsis
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if self.page_no + 3 < self.total_pages:
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link = self.Link()
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if self.page_no + 4 < self.total_pages:
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link.title = pgettext("Pagination|", "...")
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else:
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link.title = str(self.total_pages - 1)
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link.url = str(base_url.clone().add(
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"page", str(self.total_pages - 1)))
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links.append(link)
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# The last page
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link = self.Link()
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link.title = str(self.total_pages)
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if self.is_reversed:
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link.url = str(base_url)
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else:
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link.url = str(base_url.clone().add(
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"page", str(self.total_pages)))
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if self.page_no == self.total_pages:
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link.is_active = True
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links.append(link)
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# The next page
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link = self.Link()
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link.title = pgettext("Pagination|", "Next")
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if self.page_no < self.total_pages:
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if self.page_no + 1 == self.total_pages:
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if self.is_reversed:
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link.url = str(base_url)
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else:
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link.url = str(base_url.clone().add(
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"page", str(self.total_pages)))
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else:
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link.url = str(base_url.clone().add(
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"page", str(self.page_no + 1)))
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link.is_small_screen = True
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links.append(link)
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return links
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class Link:
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"""A navigation link in the pagination bar.
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Attributes:
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url (str): The link URL, or for a non-link slot.
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title (str): The title of the link.
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is_active (bool): Whether this link is currently active.
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is_small_screen (bool): Whether this link is for small
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screens
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"""
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def __int__(self):
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self.url = None
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self.title = None
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self.is_active = False
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self.is_small_screen = False
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def page_size_options(self):
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"""Returns the page size options.
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Returns:
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List[PageSizeOption]: The page size options.
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"""
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base_url = self.current_url.remove("page").remove("page-size")
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return [self.PageSizeOption(x, self._page_size_url(base_url, x))
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for x in [10, 100, 200]]
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@staticmethod
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def _page_size_url(base_url: UrlBuilder, size: int) -> str:
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"""Returns the URL for a new page size.
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Args:
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base_url (UrlBuilder): The base URL builder.
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size (int): The new page size.
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Returns:
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str: The URL for the new page size.
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"""
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if size == Pagination.DEFAULT_PAGE_SIZE:
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return str(base_url)
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return str(base_url.clone().add("page-size", str(size)))
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class PageSizeOption:
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"""A page size option.
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Args:
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size: The page size.
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url: The URL of this page size.
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Attributes:
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size (int): The page size.
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url (str): The URL for this page size.
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"""
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def __init__(self, size: int, url: str):
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self.size = size
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self.url = url
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class PaginationException(Exception):
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"""The exception thrown with invalid pagination parameters.
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Args:
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url_builder: The canonical URL to redirect to.
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Attributes:
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url (str): The canonical URL to redirect to.
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"""
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def __init__(self, url_builder: UrlBuilder):
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self.url = str(url_builder)
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