about summary refs log tree commit diff
path: root/app/lib/formatter.rb
blob: 1aeedac8afeb1264f3b613dd2fa4dc17d34f900b (plain) (blame)
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
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
# frozen_string_literal: true

require 'singleton'
require_relative './sanitize_config'

class HTMLRenderer < Redcarpet::Render::HTML
  def block_code(code, language)
    "<pre><code>#{encode(code).gsub("\n", "<br/>")}</code></pre>"
  end

  def autolink(link, link_type)
    return link if link_type == :email
    Formatter.instance.link_url(link)
  rescue Addressable::URI::InvalidURIError, IDN::Idna::IdnaError
    encode(link)
  end

  private

  def html_entities
    @html_entities ||= HTMLEntities.new
  end

  def encode(html)
    html_entities.encode(html)
  end
end

class Formatter
  include Singleton
  include RoutingHelper

  include ActionView::Helpers::TextHelper

  def format(status, **options)
    if status.reblog?
      prepend_reblog = status.reblog.account.acct
      status         = status.proper
    else
      prepend_reblog = false
    end

    raw_content = status.text

    if options[:inline_poll_options] && status.preloadable_poll
      raw_content = raw_content + "\n\n" + status.preloadable_poll.options.map { |title| "[ ] #{title}" }.join("\n")
    end

    return '' if raw_content.blank?

    unless status.local?
      html = reformat(raw_content)
      html = encode_custom_emojis(html, status.emojis, options[:autoplay]) if options[:custom_emojify]
      return html.html_safe # rubocop:disable Rails/OutputSafety
    end

    linkable_accounts = status.active_mentions.map(&:account)
    linkable_accounts << status.account

    html = raw_content
    html = "RT @#{prepend_reblog} #{html}" if prepend_reblog
    html = format_markdown(html) if status.content_type == 'text/markdown'
    html = encode_and_link_urls(html, linkable_accounts, keep_html: %w(text/markdown text/html).include?(status.content_type))
    html = reformat(html, true) if %w(text/markdown text/html).include?(status.content_type)
    html = encode_custom_emojis(html, status.emojis, options[:autoplay]) if options[:custom_emojify]

    unless %w(text/markdown text/html).include?(status.content_type)
      html = simple_format(html, {}, sanitize: false)
      html = html.delete("\n")
    end

    html.html_safe # rubocop:disable Rails/OutputSafety
  end

  def format_markdown(html)
    html = markdown_formatter.render(html)
    html.delete("\r").delete("\n")
  end

  def reformat(html, outgoing = false)
    sanitize(html, Sanitize::Config::MASTODON_STRICT.merge(outgoing: outgoing))
  rescue ArgumentError
    ''
  end

  def plaintext(status)
    return status.text if status.local?

    text = status.text.gsub(/(<br \/>|<br>|<\/p>)+/) { |match| "#{match}\n" }
    strip_tags(text)
  end

  def simplified_format(account, **options)
    html = account.local? ? linkify(account.note) : reformat(account.note)
    html = encode_custom_emojis(html, account.emojis, options[:autoplay]) if options[:custom_emojify]
    html.html_safe # rubocop:disable Rails/OutputSafety
  end

  def sanitize(html, config)
    Sanitize.fragment(html, config)
  end

  def format_spoiler(status, **options)
    html = encode(status.spoiler_text)
    html = encode_custom_emojis(html, status.emojis, options[:autoplay])
    html.html_safe # rubocop:disable Rails/OutputSafety
  end

  def format_poll_option(status, option, **options)
    html = encode(option.title)
    html = encode_custom_emojis(html, status.emojis, options[:autoplay])
    html.html_safe # rubocop:disable Rails/OutputSafety
  end

  def format_display_name(account, **options)
    html = encode(account.display_name.presence || account.username)
    html = encode_custom_emojis(html, account.emojis, options[:autoplay]) if options[:custom_emojify]
    html.html_safe # rubocop:disable Rails/OutputSafety
  end

  def format_field(account, str, **options)
    html = account.local? ? encode_and_link_urls(str, me: true) : reformat(str)
    html = encode_custom_emojis(html, account.emojis, options[:autoplay]) if options[:custom_emojify]
    html.html_safe # rubocop:disable Rails/OutputSafety
  end

  def linkify(text)
    html = encode_and_link_urls(text)
    html = simple_format(html, {}, sanitize: false)
    html = html.delete("\n")

    html.html_safe # rubocop:disable Rails/OutputSafety
  end

  def link_url(url)
    "<a href=\"#{encode(url)}\" target=\"blank\" rel=\"nofollow noopener noreferrer\">#{link_html(url)}</a>"
  end

  private

  def markdown_formatter
    extensions = {
      autolink: true,
      no_intra_emphasis: true,
      fenced_code_blocks: true,
      disable_indented_code_blocks: true,
      strikethrough: true,
      lax_spacing: true,
      space_after_headers: true,
      superscript: true,
      underline: true,
      highlight: true,
      footnotes: false,
    }

    renderer = HTMLRenderer.new({
      filter_html: false,
      escape_html: false,
      no_images: true,
      no_styles: true,
      safe_links_only: true,
      hard_wrap: true,
      link_attributes: { target: '_blank', rel: 'nofollow noopener' },
    })

    Redcarpet::Markdown.new(renderer, extensions)
  end

  def html_entities
    @html_entities ||= HTMLEntities.new
  end

  def encode(html)
    html_entities.encode(html)
  end

  def encode_and_link_urls(html, accounts = nil, options = {})
    if accounts.is_a?(Hash)
      options  = accounts
      accounts = nil
    end

    entities = options[:keep_html] ? html_friendly_extractor(html) : utf8_friendly_extractor(html, extract_url_without_protocol: false)

    rewrite(html.dup, entities, options[:keep_html]) do |entity|
      if entity[:url]
        link_to_url(entity, options)
      elsif entity[:hashtag]
        link_to_hashtag(entity)
      elsif entity[:screen_name]
        link_to_mention(entity, accounts)
      end
    end
  end

  def count_tag_nesting(tag)
    if tag[1] == '/' then -1
    elsif tag[-2] == '/' then 0
    else 1
    end
  end

  # rubocop:disable Metrics/BlockNesting
  def encode_custom_emojis(html, emojis, animate = false)
    return html if emojis.empty?

    emoji_map = emojis.each_with_object({}) { |e, h| h[e.shortcode] = [full_asset_url(e.image.url), full_asset_url(e.image.url(:static))] }

    i                     = -1
    tag_open_index        = nil
    inside_shortname      = false
    shortname_start_index = -1
    invisible_depth       = 0

    while i + 1 < html.size
      i += 1

      if invisible_depth.zero? && inside_shortname && html[i] == ':'
        shortcode = html[shortname_start_index + 1..i - 1]
        emoji     = emoji_map[shortcode]

        if emoji
          original_url, static_url = emoji
          replacement = begin
            if animate
              "<img draggable=\"false\" class=\"emojione\" alt=\":#{encode(shortcode)}:\" title=\":#{encode(shortcode)}:\" src=\"#{encode(original_url)}\" />"
            else
              "<img draggable=\"false\" class=\"emojione custom-emoji\" alt=\":#{encode(shortcode)}:\" title=\":#{encode(shortcode)}:\" src=\"#{encode(static_url)}\" data-original=\"#{original_url}\" data-static=\"#{static_url}\" />"
            end
          end
          before_html = shortname_start_index.positive? ? html[0..shortname_start_index - 1] : ''
          html        = before_html + replacement + html[i + 1..-1]
          i          += replacement.size - (shortcode.size + 2) - 1
        else
          i -= 1
        end

        inside_shortname = false
      elsif tag_open_index && html[i] == '>'
        tag = html[tag_open_index..i]
        tag_open_index = nil
        if invisible_depth.positive?
          invisible_depth += count_tag_nesting(tag)
        elsif tag == '<span class="invisible">'
          invisible_depth = 1
        end
      elsif html[i] == '<'
        tag_open_index   = i
        inside_shortname = false
      elsif !tag_open_index && html[i] == ':'
        inside_shortname      = true
        shortname_start_index = i
      end
    end

    html
  end
  # rubocop:enable Metrics/BlockNesting

  def rewrite(text, entities, keep_html = false)
    text = text.to_s

    # Sort by start index
    entities = entities.sort_by do |entity|
      indices = entity.respond_to?(:indices) ? entity.indices : entity[:indices]
      indices.first
    end

    result = []

    last_index = entities.reduce(0) do |index, entity|
      indices = entity.respond_to?(:indices) ? entity.indices : entity[:indices]
      result << (keep_html ? text[index...indices.first] : encode(text[index...indices.first]))
      result << yield(entity)
      indices.last
    end

    result << (keep_html ? text[last_index..-1] : encode(text[last_index..-1]))

    result.flatten.join
  end

  UNICODE_ESCAPE_BLACKLIST_RE = /\p{Z}|\p{P}/

  def utf8_friendly_extractor(text, options = {})
    old_to_new_index = [0]

    escaped = text.chars.map do |c|
      output = begin
        if c.ord.to_s(16).length > 2 && !UNICODE_ESCAPE_BLACKLIST_RE.match?(c)
          CGI.escape(c)
        else
          c
        end
      end

      old_to_new_index << old_to_new_index.last + output.length

      output
    end.join

    # Note: I couldn't obtain list_slug with @user/list-name format
    # for mention so this requires additional check
    special = Extractor.extract_urls_with_indices(escaped, options).map do |extract|
      new_indices = [
        old_to_new_index.find_index(extract[:indices].first),
        old_to_new_index.find_index(extract[:indices].last),
      ]

      next extract.merge(
        indices: new_indices,
        url: text[new_indices.first..new_indices.last - 1]
      )
    end

    standard = Extractor.extract_entities_with_indices(text, options)
    extra = Extractor.extract_extra_uris_with_indices(text, options)

    Extractor.remove_overlapping_entities(special + standard + extra)
  end

  def html_friendly_extractor(html, options = {})
    gaps = []
    total_offset = 0

    escaped = html.gsub(/<[^>]*>|&#[0-9]+;/) do |match|
      total_offset += match.length - 1
      end_offset = Regexp.last_match.end(0)
      gaps << [end_offset - total_offset, total_offset]
      "\u200b"
    end

    entities = Extractor.extract_hashtags_with_indices(escaped, :check_url_overlap => false) +
               Extractor.extract_mentions_or_lists_with_indices(escaped)
    Extractor.remove_overlapping_entities(entities).map do |extract|
      pos = extract[:indices].first
      offset_idx = gaps.rindex { |gap| gap.first <= pos }
      offset = offset_idx.nil? ? 0 : gaps[offset_idx].last
      next extract.merge(
        :indices => [extract[:indices].first + offset, extract[:indices].last + offset]
      )
    end
  end

  def link_to_url(entity, options = {})
    url        = Addressable::URI.parse(entity[:url])
    html_attrs = { target: '_blank', rel: 'nofollow noopener noreferrer' }

    html_attrs[:rel] = "me #{html_attrs[:rel]}" if options[:me]

    Twitter::Autolink.send(:link_to_text, entity, link_html(entity[:url]), url, html_attrs)
  rescue Addressable::URI::InvalidURIError, IDN::Idna::IdnaError
    encode(entity[:url])
  end

  def link_to_mention(entity, linkable_accounts)
    acct = entity[:screen_name]

    return link_to_account(acct) unless linkable_accounts

    account = linkable_accounts.find { |item| TagManager.instance.same_acct?(item.acct, acct) }
    account ? mention_html(account) : "@#{encode(acct)}"
  end

  def link_to_account(acct)
    username, domain = acct.split('@')

    domain  = nil if TagManager.instance.local_domain?(domain)
    account = EntityCache.instance.mention(username, domain)

    account ? mention_html(account) : "@#{encode(acct)}"
  end

  def link_to_hashtag(entity)
    hashtag_html(entity[:hashtag])
  end

  def link_html(url)
    url    = Addressable::URI.parse(url).to_s
    prefix = url.match(/\A(https?:\/\/(www\.)?|xmpp:)/).to_s
    text   = url[prefix.length, 30]
    suffix = url[prefix.length + 30..-1]
    cutoff = url[prefix.length..-1].length > 30

    "<span class=\"invisible\">#{encode(prefix)}</span><span class=\"#{cutoff ? 'ellipsis' : ''}\">#{encode(text)}</span><span class=\"invisible\">#{encode(suffix)}</span>"
  end

  def hashtag_html(tag)
    "<a href=\"#{encode(tag_url(tag))}\" class=\"mention hashtag\" rel=\"tag\">#<span>#{encode(tag)}</span></a>"
  end

  def mention_html(account)
    "<span class=\"h-card\"><a href=\"#{encode(ActivityPub::TagManager.instance.url_for(account))}\" class=\"u-url mention\">@<span>#{encode(account.username)}</span></a></span>"
  end
end