mia-accounting-django/mia_core/utils.py

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# The core application of the Mia project.
# by imacat <imacat@mail.imacat.idv.tw>, 2020/7/1
# Copyright (c) 2020 imacat.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""The views of the mia core application.
"""
import urllib.parse
from django.utils.translation import pgettext
class UrlBuilder:
"""The URL builder.
Attributes:
base_path (str): the base path
params (list[Param]): The query parameters
"""
base_path = None
params = []
def __init__(self, start_url):
"""Constructs a new URL builder.
Args:
start_url (str): The URL to start with
"""
pos = start_url.find("?")
if pos == -1:
self.base_path = start_url
return
self.base_path = start_url[:pos]
self.params = []
for piece in start_url[pos+1:].split("&"):
pos = piece.find("=")
name = urllib.parse.unquote(piece[:pos])
value = urllib.parse.unquote(piece[pos+1:])
self.params.append(self.Param(name, value))
def add_param(self, name, value):
"""Adds a query parameter.
Args:
name (str): The parameter name
value (str): The parameter value
Returns:
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UrlBuilder: The URL builder itself, with the parameter
modified.
"""
self.params.append(self.Param(name, value))
return self
def del_param(self, name):
"""Removes a query parameter.
Args:
name (str): The parameter name
Returns:
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UrlBuilder: The URL builder itself, with the parameter
modified.
"""
self.params = [x for x in self.params if x.name != name]
return self
def set_param(self, name, value):
"""Sets a query parameter. The current parameters with the
same name will be replaced.
Args:
name (str): The parameter name
value (str): The parameter value
Returns:
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UrlBuilder: The URL builder itself, with the parameter
modified.
"""
return self.del_param(name).add_param(name, value)
def clone(self):
"""Returns a copy of this URL builder.
Returns:
UrlBuilder: A copy of this URL builder.
"""
another = UrlBuilder(self.base_path)
another.params = [
self.Param(x.name, x.value) for x in self.params]
return another
def __str__(self):
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if len(self.params) == 0:
return self.base_path
return self.base_path + "?" + "&".join([
str(x) for x in self.params])
class Param:
"""A query parameter.
Attributes:
name (str): The parameter name
value (str): The parameter value
"""
name = None
value = None
def __init__(self, name, value):
"""Constructs a new query parameter
Args:
name (str): The parameter name
value (str): The parameter value
"""
self.name = name
self.value = value
def __str__(self):
"""Returns the string representation of this query
parameter.
Returns:
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str: The string representation of this query
parameter
"""
return "%s=%s" % (
urllib.parse.quote(self.name),
urllib.parse.quote(self.value))
class Pagination:
"""The pagination.
Args:
request (HttpRequest): The request
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records (list[Model]): All the records
page_no (int): The specified page number
page_size (int): The specified number of records per page
is_reversed (bool): Whether we should display the last
page first
Raises:
PageNoOutOfRangeError: if the specified page number is out
of range or is redundant.
Attributes:
current_url (bool): The current request URL
is_reversed (bool): Whether we should display the last
page first
page_size (int): The page size.
total_pages (int): The total number of pages available.
is_paged (bool): Whether there are more than one page.
page_no (int): The current page number.
records (list[Model]): The records in the current page.
links (list[Link]): The navigation links in the pagination
bar.
"""
current_url = None
is_reversed = False
page_size = None
total_pages = None
is_paged = None
page_no = None
records = None
DEFAULT_PAGE_SIZE = 10
def __init__(self, current_url, records, page_no,
page_size, is_reversed=False):
self.current_url = current_url
self.is_reversed = is_reversed
self.page_size = page_size \
if page_size is not None \
else self.DEFAULT_PAGE_SIZE
self.total_pages = int(
(len(records) - 1) / self.page_size) + 1
self.is_paged = self.total_pages > 1
if not self.is_paged:
self.page_no = 1
self.records = records
self._links = []
return
default_page = 1 if not is_reversed else self.total_pages
if page_no == default_page:
raise PageNoOutOfRangeException()
self.page_no = page_no \
if page_no is not None \
else default_page
if self.page_no > self.total_pages:
raise PageNoOutOfRangeException()
start_no = self.page_size * (self.page_no - 1)
self.records = records[start_no:start_no + self.page_size]
_links = None
@property
def links(self):
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"""Returns the navigation links of the pagination bar."""
if self._links is None:
base_url = UrlBuilder(self.current_url).del_param("page")
self._links = []
# The previous page
link = self.Link()
link.title = pgettext("Pagination|", "Previous")
if self.page_no > 1:
if self.page_no - 1 == 1:
if not self.is_reversed:
link.url = str(base_url)
else:
link.url = str(base_url.clone().add_param(
"page", "1"))
else:
link.url = str(base_url.clone().add_param(
"page", str(self.page_no - 1)))
link.is_small_screen = True
self._links.append(link)
# The first page
link = self.Link()
link.title = "1"
if not self.is_reversed:
link.url = str(base_url)
else:
link.url = str(base_url.clone().add_param("page", "1"))
if self.page_no == 1:
link.is_active = True
self._links.append(link)
# The previous ellipsis
if self.page_no > 4:
link = self.Link()
if self.page_no > 5:
link.title = pgettext("Pagination|", "...")
else:
link.title = "2"
link.url = str(base_url.clone().add_param(
"page", "2"))
self._links.append(link)
# The nearby pages
for no in range(self.page_no - 2, self.page_no + 3):
if no <= 1 or no >= self.total_pages:
continue
link = self.Link()
link.title = str(no)
link.url = str(base_url.clone().add_param(
"page", str(no)))
if no == self.page_no:
link.is_active = True
self._links.append(link)
# The next ellipsis
if self.page_no + 3 < self.total_pages:
link = self.Link()
if self.page_no + 4 < self.total_pages:
link.title = pgettext("Pagination|", "...")
else:
link.title = str(self.total_pages - 1)
link.url = str(base_url.clone().add_param(
"page", str(self.total_pages - 1)))
self._links.append(link)
# The last page
link = self.Link()
link.title = str(self.total_pages)
if self.is_reversed:
link.url = str(base_url)
else:
link.url = str(base_url.clone().add_param(
"page", str(self.total_pages)))
if self.page_no == self.total_pages:
link.is_active = True
self._links.append(link)
# The next page
link = self.Link()
link.title = pgettext("Pagination|", "Next")
if self.page_no < self.total_pages:
if self.page_no + 1 == self.total_pages:
if self.is_reversed:
link.url = str(base_url)
else:
link.url = str(base_url.clone().add_param(
"page", str(self.total_pages)))
else:
link.url = str(base_url.clone().add_param(
"page", str(self.page_no + 1)))
link.is_small_screen = True
self._links.append(link)
return self._links
class Link:
"""A navigation link in the pagination bar.
Attributes:
url (str): The link URL, or for a non-link slot.
title (str): The title of the link.
is_active (bool): Whether this link is currently active.
is_small_screen (bool): Whether this link is for small
screens
"""
url = None
title = None
is_active = False
is_small_screen = False
class PageNoOutOfRangeException(Exception):
"""The error thrown when the specified page number is out of
range.
"""
pass