1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
|
# frozen_string_literal: true
# Copyright (C) 2019-2020 Miquel Sabaté Solà <mikisabate@gmail.com>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
require_relative 'render_helper'
module Jekyll
# Render the OG image meta HTML tag for the currently rendered page.
class RenderOGImageTag < Liquid::Tag
include ::Jekyll::RenderHelper
# The path to be used when the current page does not have a specific image.
DEFAULT_PATH = '/images/default.png'
def render(context)
img = "#{normalize(context['raw_title'])}.png"
path = image_exists?(img) ? "/images/posts/#{img}" : DEFAULT_PATH
render_meta('og:image', "http://jo.mssola.com#{path}") +
render_meta('og:image:width', 630) +
render_meta('og:image:height', 315) +
render_meta('twitter:image', "http://jo.mssola.com#{path}", name: true)
end
protected
# Returns true if the given image exists inside of /images/posts.
def image_exists?(image)
return false if image == '.png'
path = File.expand_path(File.join(File.dirname(__FILE__), '..', 'images', 'posts', image))
File.file?(path)
end
# Downcases the given string and replaces space characters with "-"
def normalize(str)
str.gsub(/\s/, '-').downcase
end
end
end
Liquid::Template.register_tag('render_og_image', Jekyll::RenderOGImageTag)
|
