Source code for meta.templatetags.meta

# -*- coding: utf-8 -*-
from __future__ import absolute_import, print_function, unicode_literals

from django import template
from django.apps import apps
from django.utils.html import escape
from django.utils.safestring import mark_safe
from django.utils.six import string_types

register = template.Library()

# Use sekizai if installed, otherwise define a templatetag stub
if apps.is_installed('sekizai'):
    from sekizai.templatetags.sekizai_tags import Addtoblock
    register.tag('addtoblock', Addtoblock)
else:
    from meta.compat import addtoblock
    register.tag('addtoblock', addtoblock)


@register.simple_tag
def meta(name, content):
    """
    Generates a meta tag according to the following markup:

    <meta name="{name}" content="{content}">

    :param name: meta name
    :param content: content value
    """
    return custom_meta('name', name, content)


@register.simple_tag
def custom_meta(attr, name, content):
    """
    Generates a custom meta tag:

    <meta {attr}="{name}" content="{content}">

    :param attr: meta attribute name
    :param name: meta name
    :param content: content value
    """
    return '<meta {attr}="{name}" content="{content}">'.format(
        attr=escape(attr), name=escape(name), content=escape(content)
    )


@register.simple_tag
def meta_list(name, lst):
    """
    Renders in a single meta a list of values (e.g.: keywords list)

    :param name: meta name
    :param lst: values
    """
    try:
        return custom_meta('name', name, ', '.join(lst))
    except Exception:
        return ''


@register.simple_tag
def meta_extras(extra_props):
    """
    Generates the markup for a list of meta tags

    Each key,value paur is passed to :py:func:meta to generate the markup

    :param extra_props: dictionary of additional meta tags
    """
    if not extra_props:
        return ''
    return ' '.join([meta(name, extra_props[name]) if extra_props[name] else ''
                     for name in extra_props])


@register.simple_tag
def custom_meta_extras(extra_custom_props):
    """
    Generates the markup for a list of custom meta tags

    Each tuple is passed to :py:func:custom_meta to generate the markup

    :param extra_custom_props: list of tuple of additional meta tags
    """
    if not extra_custom_props:
        return ''
    return ' '.join([custom_meta(name_key, name_value, content) if content else ''
                     for name_key, name_value, content in extra_custom_props])


@register.simple_tag
def title_prop(value):
    """
    Title tag

    :param value: title value
    """
    return '<title>%s</title>' % escape(value)


@register.simple_tag
def generic_prop(namespace, name, value):
    """
    Generic property setter that allows to create custom namespaced meta
    e.g.: fb:profile_id.
    """
    return custom_meta('property', '%s:%s' % (namespace, name), value)


@register.simple_tag
def og_prop(name, value):
    """
    Generic OpenGraph property

    :param name: property name (without 'og:' namespace)
    :param value: property value
    """
    return custom_meta('property', 'og:%s' % name, value)


@register.simple_tag
def facebook_prop(name, value):
    """
    Generic Facebook property

    :param name: property name (without 'fb:' namespace)
    :param value: property value
    """
    return custom_meta('property', 'fb:%s' % name, value)


@register.simple_tag
def twitter_prop(name, value):
    """
    Generic Twitter property

    :param name: property name (without 'twitter:' namespace)
    :param value: property value
    """
    return custom_meta('name', 'twitter:%s' % name, value)


@register.simple_tag
def googleplus_prop(name, value):
    """
    Generic Google+ property

    :param name: property name
    :param value: property value
    """
    return custom_meta('itemprop', name, value)


@register.simple_tag
def googleplus_html_scope(value):
    """
    This is meant to be used as attribute to html / body or other tags to
    define schema.org type

    :param value: declared scope
    """
    return ' itemscope itemtype="http://schema.org/%s" ' % escape(value)


@register.simple_tag
def googleplus_scope(value):
    """
    Alias for googleplus_html_scope

    :param value: declared scope
    """
    return googleplus_html_scope(value)


@register.simple_tag(takes_context=True)
def meta_namespaces(context):
    """
    Include OG namespaces. To be used in the <head> tag.
    """
    # do nothing if meta is not in context
    if not context.get('meta'):
        return ''

    meta = context['meta']
    namespaces = ['og: http://ogp.me/ns#']

    # add Facebook namespace
    if meta.use_facebook:
        namespaces.append('fb: http://ogp.me/ns/fb#')

    # add custom namespaces
    # needs to be after Facebook
    if meta.custom_namespace:
        custom_namespaces = meta.custom_namespace
        if isinstance(meta.custom_namespace, string_types):
            custom_namespaces = [meta.custom_namespace]
        for ns in custom_namespaces:
            custom_namespace = '{0}: http://ogp.me/ns/{0}#'.format(ns)
            namespaces.append(custom_namespace)

    return mark_safe(' prefix="{0}"'.format(' '.join(namespaces)))


@register.simple_tag(takes_context=True)
def meta_namespaces_gplus(context):
    """
    Include google+ attributes. To be used in the <html> or <body> tag.
    """
    # do nothing if meta is not in context or if G+ is not enabled
    if not context.get('meta') or not context['meta'].use_googleplus:
        return ''
    return mark_safe(
        ' itemscope itemtype="http://schema.org/{0}" '.format(context['meta'].gplus_type)
    )