python-feedgen/feedgen/ext/dc.py

# -*- coding: utf-8 -*-
'''
    feedgen.ext.dc
    ~~~~~~~~~~~~~~~~~~~

    Extends the FeedGenerator to add Dubline Core Elements to the feeds.

    Descriptions partly taken from
    http://dublincore.org/documents/dcmi-terms/#elements-coverage

    :copyright: 2013-2016, Lars Kiesow <lkiesow@uos.de>

    :license: FreeBSD and LGPL, see license.* for more details.
'''

from lxml import etree
from feedgen.ext.base import BaseExtension


class DcBaseExtension(BaseExtension):
    '''Dublin Core Elements extension for podcasts.
    '''

    def __init__(self):
        # http://dublincore.org/documents/usageguide/elements.shtml
        # http://dublincore.org/documents/dces/
        # http://dublincore.org/documents/dcmi-terms/
        self._dcelem_contributor = None
        self._dcelem_coverage = None
        self._dcelem_creator = None
        self._dcelem_date = None
        self._dcelem_description = None
        self._dcelem_format = None
        self._dcelem_identifier = None
        self._dcelem_language = None
        self._dcelem_publisher = None
        self._dcelem_relation = None
        self._dcelem_rights = None
        self._dcelem_source = None
        self._dcelem_subject = None
        self._dcelem_title = None
        self._dcelem_type = None

    def extend_ns(self):
        return {'dc': 'http://purl.org/dc/elements/1.1/'}

    def _extend_xml(self, xml_elem):
        '''Extend xml_elem with set DC fields.

        :param xml_elem: etree element
        '''
        DCELEMENTS_NS = 'http://purl.org/dc/elements/1.1/'

        for elem in ['contributor', 'coverage', 'creator', 'date',
                     'description', 'language', 'publisher', 'relation',
                     'rights', 'source', 'subject', 'title', 'type', 'format',
                     'identifier']:
            if hasattr(self, '_dcelem_%s' % elem):
                for val in getattr(self, '_dcelem_%s' % elem) or []:
                    node = etree.SubElement(xml_elem,
                                            '{%s}%s' % (DCELEMENTS_NS, elem))
                    node.text = val

    def extend_atom(self, atom_feed):
        '''Extend an Atom feed with the set DC fields.

        :param atom_feed: The feed root element
        :returns: The feed root element
        '''

        self._extend_xml(atom_feed)

        return atom_feed

    def extend_rss(self, rss_feed):
        '''Extend a RSS feed with the set DC fields.

        :param rss_feed: The feed root element
        :returns: The feed root element.
        '''
        channel = rss_feed[0]
        self._extend_xml(channel)

        return rss_feed

    def dc_contributor(self, contributor=None, replace=False):
        '''Get or set the dc:contributor which is an entity responsible for
        making contributions to the resource.

        For more information see:
        http://dublincore.org/documents/dcmi-terms/#elements-contributor

        :param contributor: Contributor or list of contributors.
        :param replace: Replace alredy set contributors (deault: False).
        :returns: List of contributors.
        '''
        if contributor is not None:
            if not isinstance(contributor, list):
                contributor = [contributor]
            if replace or not self._dcelem_contributor:
                self._dcelem_contributor = []
            self._dcelem_contributor += contributor
        return self._dcelem_contributor

    def dc_coverage(self, coverage=None, replace=True):
        '''Get or set the dc:coverage which indicated the spatial or temporal
        topic of the resource, the spatial applicability of the resource, or
        the jurisdiction under which the resource is relevant.

        Spatial topic and spatial applicability may be a named place or a
        location specified by its geographic coordinates. Temporal topic may be
        a named period, date, or date range. A jurisdiction may be a named
        administrative entity or a geographic place to which the resource
        applies. Recommended best practice is to use a controlled vocabulary
        such as the Thesaurus of Geographic Names [TGN]. Where appropriate,
        named places or time periods can be used in preference to numeric
        identifiers such as sets of coordinates or date ranges.

        References:
        [TGN] http://www.getty.edu/research/tools/vocabulary/tgn/index.html

        :param coverage: Coverage of the feed.
        :param replace: Replace already set coverage (default: True).
        :returns: Coverage of the feed.
        '''
        if coverage is not None:
            if not isinstance(coverage, list):
                coverage = [coverage]
            if replace or not self._dcelem_coverage:
                self._dcelem_coverage = []
            self._dcelem_coverage = coverage
        return self._dcelem_coverage

    def dc_creator(self, creator=None, replace=False):
        '''Get or set the dc:creator which is an entity primarily responsible
        for making the resource.

        For more information see:
        http://dublincore.org/documents/dcmi-terms/#elements-creator

        :param creator: Creator or list of creators.
        :param replace: Replace alredy set creators (deault: False).
        :returns: List of creators.
        '''
        if creator is not None:
            if not isinstance(creator, list):
                creator = [creator]
            if replace or not self._dcelem_creator:
                self._dcelem_creator = []
            self._dcelem_creator += creator
        return self._dcelem_creator

    def dc_date(self, date=None, replace=True):
        '''Get or set the dc:date which describes a point or period of time
        associated with an event in the lifecycle of the resource.

        For more information see:
        http://dublincore.org/documents/dcmi-terms/#elements-date

        :param date: Date or list of dates.
        :param replace: Replace alredy set dates (deault: True).
        :returns: List of dates.
        '''
        if date is not None:
            if not isinstance(date, list):
                date = [date]
            if replace or not self._dcelem_date:
                self._dcelem_date = []
            self._dcelem_date += date
        return self._dcelem_date

    def dc_description(self, description=None, replace=True):
        '''Get or set the dc:description which is an account of the resource.

        For more information see:
        http://dublincore.org/documents/dcmi-terms/#elements-description

        :param description: Description or list of descriptions.
        :param replace: Replace alredy set descriptions (deault: True).
        :returns: List of descriptions.
        '''
        if description is not None:
            if not isinstance(description, list):
                description = [description]
            if replace or not self._dcelem_description:
                self._dcelem_description = []
            self._dcelem_description += description
        return self._dcelem_description

    def dc_format(self, format=None, replace=True):
        '''Get or set the dc:format which describes the file format, physical
        medium, or dimensions of the resource.

        For more information see:
        http://dublincore.org/documents/dcmi-terms/#elements-format

        :param format: Format of the resource or list of formats.
        :param replace: Replace alredy set format (deault: True).
        :returns: Format of the resource.
        '''
        if format is not None:
            if not isinstance(format, list):
                format = [format]
            if replace or not self._dcelem_format:
                self._dcelem_format = []
            self._dcelem_format += format
        return self._dcelem_format

    def dc_identifier(self, identifier=None, replace=True):
        '''Get or set the dc:identifier which should be an unambiguous
        reference to the resource within a given context.

        For more inidentifierion see:
        http://dublincore.org/documents/dcmi-terms/#elements-identifier

        :param identifier: Identifier of the resource or list of identifiers.
        :param replace: Replace alredy set identifier (deault: True).
        :returns: Identifiers of the resource.
        '''
        if identifier is not None:
            if not isinstance(identifier, list):
                identifier = [identifier]
            if replace or not self._dcelem_identifier:
                self._dcelem_identifier = []
            self._dcelem_identifier += identifier

    def dc_language(self, language=None, replace=True):
        '''Get or set the dc:language which describes a language of the
        resource.

        For more information see:
        http://dublincore.org/documents/dcmi-terms/#elements-language

        :param language: Language or list of languages.
        :param replace: Replace alredy set languages (deault: True).
        :returns: List of languages.
        '''
        if language is not None:
            if not isinstance(language, list):
                language = [language]
            if replace or not self._dcelem_language:
                self._dcelem_language = []
            self._dcelem_language += language
        return self._dcelem_language

    def dc_publisher(self, publisher=None, replace=False):
        '''Get or set the dc:publisher which is an entity responsible for
        making the resource available.

        For more information see:
        http://dublincore.org/documents/dcmi-terms/#elements-publisher

        :param publisher: Publisher or list of publishers.
        :param replace: Replace alredy set publishers (deault: False).
        :returns: List of publishers.
        '''
        if publisher is not None:
            if not isinstance(publisher, list):
                publisher = [publisher]
            if replace or not self._dcelem_publisher:
                self._dcelem_publisher = []
            self._dcelem_publisher += publisher
        return self._dcelem_publisher

    def dc_relation(self, relation=None, replace=False):
        '''Get or set the dc:relation which describes a related ressource.

        For more information see:
        http://dublincore.org/documents/dcmi-terms/#elements-relation

        :param relation: Relation or list of relations.
        :param replace: Replace alredy set relations (deault: False).
        :returns: List of relations.
        '''
        if relation is not None:
            if not isinstance(relation, list):
                relation = [relation]
            if replace or not self._dcelem_relation:
                self._dcelem_relation = []
            self._dcelem_relation += relation
        return self._dcelem_relation

    def dc_rights(self, rights=None, replace=False):
        '''Get or set the dc:rights which may contain information about rights
        held in and over the resource.

        For more information see:
        http://dublincore.org/documents/dcmi-terms/#elements-rights

        :param rights: Rights information or list of rights information.
        :param replace: Replace alredy set rightss (deault: False).
        :returns: List of rights information.
        '''
        if rights is not None:
            if not isinstance(rights, list):
                rights = [rights]
            if replace or not self._dcelem_rights:
                self._dcelem_rights = []
            self._dcelem_rights += rights
        return self._dcelem_rights

    def dc_source(self, source=None, replace=False):
        '''Get or set the dc:source which is a related resource from which the
        described resource is derived.

        The described resource may be derived from the related resource in
        whole or in part. Recommended best practice is to identify the related
        resource by means of a string conforming to a formal identification
        system.

        For more information see:
        http://dublincore.org/documents/dcmi-terms/#elements-source

        :param source: Source or list of sources.
        :param replace: Replace alredy set sources (deault: False).
        :returns: List of sources.
        '''
        if source is not None:
            if not isinstance(source, list):
                source = [source]
            if replace or not self._dcelem_source:
                self._dcelem_source = []
            self._dcelem_source += source
        return self._dcelem_source

    def dc_subject(self, subject=None, replace=False):
        '''Get or set the dc:subject which describes the topic of the resource.

        For more information see:
        http://dublincore.org/documents/dcmi-terms/#elements-subject

        :param subject: Subject or list of subjects.
        :param replace: Replace alredy set subjects (deault: False).
        :returns: List of subjects.
        '''
        if subject is not None:
            if not isinstance(subject, list):
                subject = [subject]
            if replace or not self._dcelem_subject:
                self._dcelem_subject = []
            self._dcelem_subject += subject
        return self._dcelem_subject

    def dc_title(self, title=None, replace=True):
        '''Get or set the dc:title which is a name given to the resource.

        For more information see:
        http://dublincore.org/documents/dcmi-terms/#elements-title

        :param title: Title or list of titles.
        :param replace: Replace alredy set titles (deault: False).
        :returns: List of titles.
        '''
        if title is not None:
            if not isinstance(title, list):
                title = [title]
            if replace or not self._dcelem_title:
                self._dcelem_title = []
            self._dcelem_title += title
        return self._dcelem_title

    def dc_type(self, type=None, replace=False):
        '''Get or set the dc:type which describes the nature or genre of the
        resource.

        For more information see:
        http://dublincore.org/documents/dcmi-terms/#elements-type

        :param type: Type or list of types.
        :param replace: Replace alredy set types (deault: False).
        :returns: List of types.
        '''
        if type is not None:
            if not isinstance(type, list):
                type = [type]
            if replace or not self._dcelem_type:
                self._dcelem_type = []
            self._dcelem_type += type
        return self._dcelem_type


class DcExtension(DcBaseExtension):
    '''Dublin Core Elements extension for podcasts.
    '''


class DcEntryExtension(DcBaseExtension):
    '''Dublin Core Elements extension for podcasts.
    '''
    def extend_atom(self, entry):
        '''Add dc elements to an atom item. Alters the item itself.

        :param entry: An atom entry element.
        :returns: The entry element.
        '''
        self._extend_xml(entry)
        return entry

    def extend_rss(self, item):
        '''Add dc elements to a RSS item. Alters the item itself.

        :param item: A RSS item element.
        :returns: The item element.
        '''
        self._extend_xml(item)
        return item