PyGithub/github/PaginatedList.py

# -*- coding: utf-8 -*-

############################ Copyrights and license ############################
#                                                                              #
# Copyright 2012 Vincent Jacques <vincent@vincent-jacques.net>                 #
# Copyright 2012 Zearin <zearin@gonk.net>                                      #
# Copyright 2013 Bill Mill <bill.mill@gmail.com>                               #
# Copyright 2013 Vincent Jacques <vincent@vincent-jacques.net>                 #
# Copyright 2013 davidbrai <davidbrai@gmail.com>                               #
#                                                                              #
# This file is part of PyGithub. http://jacquev6.github.com/PyGithub/          #
#                                                                              #
# PyGithub is free software: you can redistribute it and/or modify it under    #
# the terms of the GNU Lesser General Public License as published by the Free  #
# Software Foundation, either version 3 of the License, or (at your option)    #
# any later version.                                                           #
#                                                                              #
# PyGithub is distributed in the hope that it will be useful, but WITHOUT ANY  #
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS    #
# FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more #
# details.                                                                     #
#                                                                              #
# You should have received a copy of the GNU Lesser General Public License     #
# along with PyGithub. If not, see <http://www.gnu.org/licenses/>.             #
#                                                                              #
################################################################################

import github.GithubObject
import inspect

class PaginatedListBase:
    def __init__(self):
        self.__elements = list()

    def __getitem__(self, index):
        assert isinstance(index, (int, slice))
        if isinstance(index, (int, long)):
            self.__fetchToIndex(index)
            return self.__elements[index]
        else:
            return self._Slice(self, index)

    def __iter__(self):
        for element in self.__elements:
            yield element
        while self._couldGrow():
            newElements = self.__grow()
            for element in newElements:
                yield element

    def _isBiggerThan(self, index):
        return len(self.__elements) > index or self._couldGrow()

    def __fetchToIndex(self, index):
        while len(self.__elements) <= index and self._couldGrow():
            self.__grow()

    def __grow(self):
        newElements = self._fetchNextPage()
        self.__elements += newElements
        return newElements

    class _Slice:
        def __init__(self, theList, theSlice):
            self.__list = theList
            self.__start = theSlice.start or 0
            self.__stop = theSlice.stop
            self.__step = theSlice.step or 1

        def __iter__(self):
            index = self.__start
            while not self.__finished(index):
                if self.__list._isBiggerThan(index):
                    yield self.__list[index]
                    index += self.__step
                else:
                    return

        def __finished(self, index):
            return self.__stop is not None and index >= self.__stop


class PaginatedList(PaginatedListBase):
    """
    This class abstracts the `pagination of the API <http://developer.github.com/v3/#pagination>`_.

    You can simply enumerate through instances of this class::

        for repo in user.get_repos():
            print repo.name

    You can also index them or take slices::

        second_repo = user.get_repos()[1]
        first_repos = user.get_repos()[:10]

    And if you really need it, you can explicitely access a specific page::

        some_repos = user.get_repos().get_page(0)
        some_other_repos = user.get_repos().get_page(3)
    """

    def __init__(self, contentClass, requester, firstUrl, firstParams):
        PaginatedListBase.__init__(self)
        self.__requester = requester
        self.__contentClass = contentClass
        self.__firstUrl = firstUrl
        self.__firstParams = firstParams or ()
        self.__nextUrl = firstUrl
        self.__nextParams = firstParams or {}
        if self.__requester.per_page != 30:
            self.__nextParams["per_page"] = self.__requester.per_page

    def _couldGrow(self):
        return self.__nextUrl is not None
        
    def makePage(self, headers, data):
        '''
        Adapte for diffrent __init__ signature in refactoring, remove when done
        '''

        try: # Try use old __init__ signature
            return [
                self.__contentClass(self.__requester, element, completed=False)
                for element in data]
        except TypeError: # must be new
            return [
                self.__contentClass(self.__requester, headers, element, completed=False)
                for element in data]




    def _fetchNextPage(self):
        headers, data = self.__requester.requestJsonAndCheck("GET", self.__nextUrl, self.__nextParams, None)

        links = self.__parseLinkHeader(headers)
        if len(data) > 0 and "next" in links:
            self.__nextUrl = links["next"]
        else:
            self.__nextUrl = None
        self.__nextParams = None

        return self.makePage(headers, data)

    def __parseLinkHeader(self, headers):
        links = {}
        if "link" in headers:
            linkHeaders = headers["link"].split(",")
            for linkHeader in linkHeaders:
                (url, rel) = linkHeader.split("; ")
                url = url[1:-1]
                rel = rel[5:-1]
                links[rel] = url
        return links

    def get_page(self, page):
        params = dict(self.__firstParams)
        if page != 0:
            params["page"] = page + 1
        if self.__requester.per_page != 30:
            params["per_page"] = self.__requester.per_page
        headers, data = self.__requester.requestJsonAndCheck("GET", self.__firstUrl, params, None)

        return self.makePage(headers, data)