#398

backend/app/controllers/preview_controller.rb

@@ -9,8 +9,6 @@ class PreviewController < ApplicationController
     render_bad_request(e.message)
   rescue Preview::HttpFetcher::FetchTimeout => e
     render_preview_error(e.message, :gateway_timeout)
-  rescue Preview::HttpFetcher::ResponseTooLarge => e
-    render_preview_error(e.message, :payload_too_large)
   rescue Preview::HttpFetcher::FetchFailed => e
     render_preview_error(e.message, :bad_gateway)
   end
@@ -30,8 +28,6 @@ class PreviewController < ApplicationController
     render_bad_request(e.message)
   rescue Preview::HttpFetcher::FetchTimeout => e
     render_preview_error(e.message, :gateway_timeout)
-  rescue Preview::HttpFetcher::ResponseTooLarge => e
-    render_preview_error(e.message, :payload_too_large)
   rescue Preview::HttpFetcher::FetchFailed => e
     render_preview_error(e.message, :bad_gateway)
   rescue Preview::ThumbnailFetcher::GenerationFailed, MiniMagick::Error => e

backend/app/services/preview/http_fetcher.rb

@@ -1,5 +1,4 @@
 require 'net/http'
-require 'json'
 
 module Preview
   class HttpFetcher
@@ -17,57 +16,24 @@ module Preview
       response = request(uri, addresses.first, max_bytes)
 
       if response.is_a?(Net::HTTPRedirection)
+        raise FetchFailed, 'redirect が多すぎます．' if redirects.zero?
+
         location = response['location']
-        if redirects.zero?
-          log_failure(:redirect_limit,
-                      url: uri.to_s,
-                      redirects:,
-                      location:,
-                      content_type: response['content-type'],
-                      content_length: response['content-length'])
-          raise FetchFailed, 'redirect が多すぎます．'
-        end
+        raise FetchFailed, 'redirect 先が不正です．' if location.blank?
 
-        if location.blank?
-          log_failure(:blank_redirect_location,
-                      url: uri.to_s,
-                      redirects:,
-                      content_type: response['content-type'],
-                      content_length: response['content-length'])
-          raise FetchFailed, 'redirect 先が不正です．'
-        end
-
-        redirect_url =
-            begin
-              URI.join(uri, location).to_s
-            rescue URI::InvalidURIError => e
-              log_failure(:invalid_redirect_location,
-                          url: uri.to_s,
-                          redirects:,
-                          location:,
-                          error: e.class.name,
-                          message: e.message)
-              raise FetchFailed, 'redirect 先が不正です．'
-            end
-
-        return fetch(redirect_url, max_bytes:, redirects: redirects - 1)
+        return fetch(URI.join(uri, location).to_s,
+                     max_bytes:,
+                     redirects: redirects - 1)
       end
 
       unless response.is_a?(Net::HTTPSuccess)
-        log_failure(:http_status,
-                    url: uri.to_s,
-                    code: response.code,
-                    content_type: response['content-type'],
-                    content_length: response['content-length'])
         raise FetchFailed, "外部サーバーが HTTP #{ response.code } を返しました．"
       end
 
       Response.new(response.body, response['content-type'].to_s, uri.to_s)
     rescue Net::OpenTimeout, Net::ReadTimeout, Timeout::Error => e
-      log_failure(:timeout, url: uri&.to_s || raw_url, error: e.class.name, message: e.message)
       raise FetchTimeout, e.message
     rescue SocketError, SystemCallError, OpenSSL::SSL::SSLError, EOFError => e
-      log_failure(:network_error, url: uri&.to_s || raw_url, error: e.class.name, message: e.message)
       raise FetchFailed, e.message
     end
 
@@ -85,27 +51,12 @@ module Preview
 
       http.request(request) do |response|
         length = response['content-length'].to_i
-        if length > max_bytes
-          log_failure(:response_too_large,
-                      url: uri.to_s,
-                      content_type: response['content-type'],
-                      content_length: response['content-length'],
-                      max_bytes:)
-          raise ResponseTooLarge, '外部データが大きすぎます．'
-        end
+        raise ResponseTooLarge, '外部データが大きすぎます．' if length > max_bytes
 
         body = +''
         response.read_body do |chunk|
           body << chunk
-          next unless body.bytesize > max_bytes
-
-          log_failure(:response_too_large,
-                      url: uri.to_s,
-                      content_type: response['content-type'],
-                      content_length: response['content-length'],
-                      bytes_read: body.bytesize,
-                      max_bytes:)
-          raise ResponseTooLarge, '外部データが大きすぎます．'
+          raise ResponseTooLarge, '外部データが大きすぎます．' if body.bytesize > max_bytes
         end
         response.instance_variable_set(:@body, body)
         response.instance_variable_set(:@read, true)
@@ -113,10 +64,6 @@ module Preview
       end
     end
 
-    def self.log_failure(reason, **payload)
-      Rails.logger.warn("preview_http_fetcher_failure #{ { reason:, **payload }.to_json }")
-    end
-
-    private_class_method :request, :log_failure
+    private_class_method :request
   end
 end

backend/app/services/preview/known_site_extractor.rb

@@ -1,16 +1,7 @@
 module Preview
   class KnownSiteExtractor
     def self.thumbnail_url(uri)
-      youtube_thumbnail(uri)
-    end
-
-    def self.niconico_video_id(uri)
-      case uri.host&.downcase
-      when 'www.nicovideo.jp', 'nicovideo.jp'
-        uri.path[%r{\A/watch/(sm\d+)\z}, 1]
-      when 'nico.ms'
-        uri.path[%r{\A/(sm\d+)\z}, 1]
-      end
+      youtube_thumbnail(uri) || niconico_thumbnail(uri)
     end
 
     def self.youtube_thumbnail(uri)
@@ -26,6 +17,16 @@ module Preview
       "https://i.ytimg.com/vi/#{ id }/hqdefault.jpg"
     end
 
-    private_class_method :youtube_thumbnail
+    def self.niconico_thumbnail(uri)
+      return unless ['www.nicovideo.jp', 'nicovideo.jp', 'nico.ms'].include?(uri.host&.downcase)
+
+      id = uri.path[%r{/(?:watch/)?(sm\d+)\z}, 1]
+      return unless id
+
+      numeric_id = id.delete_prefix('sm')
+      "https://nicovideo.cdn.nimg.jp/thumbnails/#{ numeric_id }/#{ numeric_id }.L"
+    end
+
+    private_class_method :youtube_thumbnail, :niconico_thumbnail
   end
 end

backend/app/services/preview/thumbnail_fetcher.rb

@@ -1,95 +1,38 @@
 module Preview
   class ThumbnailFetcher
     class GenerationFailed < StandardError; end
-    ALLOWED_IMAGE_CONTENT_TYPES = [
-      'image/jpeg', 'image/png', 'image/gif', 'image/webp'
-    ].freeze
-    HTML_MAX_BYTES = 1.megabyte
-    NICONICO_XML_MAX_BYTES = 256.kilobytes
 
     def self.fetch(raw_url)
       uri, = UrlSafety.validate(raw_url)
 
       known_url = KnownSiteExtractor.thumbnail_url(uri)
-      image = fetch_image_or_nil(known_url) if known_url
-      return image if image
+      return fetch_image(known_url) if known_url
 
-      niconico_url = niconico_thumbnail_url(uri)
-      image = fetch_image_or_nil(niconico_url) if niconico_url
-      return image if image
-
-      page = HttpFetcher.fetch(uri.to_s, max_bytes: HTML_MAX_BYTES)
+      page = HttpFetcher.fetch(uri.to_s)
       metadata = HtmlMetadataExtractor.extract(page)
       raise GenerationFailed, 'サムネール画像が見つかりませんでした．' if metadata[:image_url].blank?
 
-      fetch_image!(metadata[:image_url])
+      fetch_image(metadata[:image_url])
     end
 
     def self.title(raw_url)
       uri, = UrlSafety.validate(raw_url)
-      HtmlMetadataExtractor.extract(
-          HttpFetcher.fetch(uri.to_s, max_bytes: HTML_MAX_BYTES))[:title]
+      HtmlMetadataExtractor.extract(HttpFetcher.fetch(uri.to_s))[:title]
     end
 
-    def self.fetch_image_or_nil(url)
-      return nil if url.blank?
-
+    def self.fetch_image(url)
       response = HttpFetcher.fetch(url)
-      return nil unless allowed_image_content_type?(response.content_type)
-
-      response.body
-    rescue HttpFetcher::FetchTimeout
-      raise
-    rescue HttpFetcher::FetchFailed
-      nil
-    end
-
-    def self.fetch_image!(url)
-      response = HttpFetcher.fetch(url)
-      unless allowed_image_content_type?(response.content_type)
+      unless response.content_type.downcase.start_with?('image/')
         raise GenerationFailed, 'サムネール画像が見つかりませんでした．'
       end
 
       response.body
     rescue HttpFetcher::FetchTimeout
       raise
-    rescue HttpFetcher::ResponseTooLarge
-      raise
     rescue HttpFetcher::FetchFailed
       raise GenerationFailed, 'サムネール画像を取得できませんでした．'
     end
 
-    def self.niconico_thumbnail_url(uri)
-      video_id = KnownSiteExtractor.niconico_video_id(uri)
-      return nil if video_id.blank?
-
-      response = HttpFetcher.fetch("https://ext.nicovideo.jp/api/getthumbinfo/#{ video_id }",
-                                   max_bytes: NICONICO_XML_MAX_BYTES)
-      xml = Nokogiri::XML(response.body)
-      return nil unless xml.at_xpath('/nicovideo_thumb_response/@status')&.value == 'ok'
-
-      xml.at_xpath('//thumbnail_url')&.text&.strip.presence
-    rescue HttpFetcher::FetchFailed, HttpFetcher::FetchTimeout => e
-      Rails.logger.info("preview_niconico_getthumbinfo_fallback #{ { url: uri.to_s,
-                                                                     video_id:,
-                                                                     error: e.class.name,
-                                                                     message: e.message }.to_json }")
-      nil
-    rescue Nokogiri::XML::SyntaxError => e
-      Rails.logger.info("preview_niconico_getthumbinfo_fallback #{ { url: uri.to_s,
-                                                                     video_id:,
-                                                                     error: e.class.name,
-                                                                     message: e.message }.to_json }")
-      nil
-    end
-
-    def self.allowed_image_content_type?(content_type)
-      mime_type = content_type.to_s.split(';', 2).first.downcase.strip
-      ALLOWED_IMAGE_CONTENT_TYPES.include?(mime_type)
-    end
-
-    private_class_method :fetch_image_or_nil, :fetch_image!,
-                         :niconico_thumbnail_url,
-                         :allowed_image_content_type?
+    private_class_method :fetch_image
   end
 end

backend/app/services/preview/url_safety.rb

@@ -40,8 +40,6 @@ module Preview
       end
 
       [uri, parsed_addresses.map(&:to_s)]
-    rescue Resolv::ResolvError
-      raise UnsafeUrl, 'URL のホストを解決できません．'
     rescue URI::InvalidURIError, IPAddr::InvalidAddressError
       raise UnsafeUrl, 'URL が不正です．'
     end

backend/spec/requests/preview_spec.rb

@@ -1,46 +1,28 @@
-require 'rails_helper'
+require "rails_helper"
 
 
-RSpec.describe 'Preview', type: :request do
-  describe 'GET /preview/title' do
-    it '401 unless logged in' do
+RSpec.describe "Preview", type: :request do
+  describe "GET /preview/title" do
+    it "401 unless logged in" do
       sign_out
-      get '/preview/title', params: { url: 'example.com' }
+      get "/preview/title", params: { url: "example.com" }
       expect(response).to have_http_status(:unauthorized)
     end
 
-    it '403 when logged in as guest' do
-      sign_in_as(create(:user, :guest))
-      get '/preview/title', params: { url: 'example.com' }
-      expect(response).to have_http_status(:forbidden)
-    end
-
-    it '400 when url blank' do
-      sign_in_as(create(:user, :member))
-      get '/preview/title', params: { url: '' }
+    it "400 when url blank" do
+      sign_in_as(create(:user))
+      get "/preview/title", params: { url: "" }
       expect(response).to have_http_status(:bad_request)
     end
 
-    it 'returns parsed title' do
-      sign_in_as(create(:user, :member))
-      allow(Preview::ThumbnailFetcher)
-          .to receive(:title)
-          .with('example.com')
-          .and_return('Hello')
+    it "returns parsed title (stubbing URI.open)" do
+      sign_in_as(create(:user))
+      fake_html = "<html><head><title>  Hello  </title></head></html>"
+      allow(URI).to receive(:open).and_return(StringIO.new(fake_html))
 
-      get '/preview/title', params: { url: 'example.com' }
+      get "/preview/title", params: { url: "example.com" }
       expect(response).to have_http_status(:ok)
-      expect(json['title']).to eq('Hello')
-    end
-
-    it '413 when fetched response is too large' do
-      sign_in_as(create(:user, :member))
-      allow(Preview::ThumbnailFetcher)
-          .to receive(:title)
-          .and_raise(Preview::HttpFetcher::ResponseTooLarge, '外部データが大きすぎます．')
-
-      get '/preview/title', params: { url: 'example.com' }
-      expect(response).to have_http_status(:payload_too_large)
+      expect(json["title"]).to eq("Hello")
     end
   end
 end

backend/spec/services/preview/http_fetcher_spec.rb

@@ -1,23 +0,0 @@
-require 'rails_helper'
-
-RSpec.describe Preview::HttpFetcher do
-  describe '.fetch' do
-    it 'raises FetchFailed when redirect location is invalid' do
-      redirect = Net::HTTPFound.new('1.1', '302', 'Found')
-      redirect['location'] = 'http://[invalid'
-
-      allow(Preview::UrlSafety).to receive(:validate)
-          .with('https://example.com/page')
-          .and_return([URI.parse('https://example.com/page'), ['203.0.113.10']])
-      allow(described_class).to receive(:request)
-          .and_return(redirect)
-      allow(Rails.logger).to receive(:warn)
-
-      expect {
-        described_class.fetch('https://example.com/page')
-      }.to raise_error(Preview::HttpFetcher::FetchFailed)
-      expect(Rails.logger).to have_received(:warn)
-          .with(/invalid_redirect_location/)
-    end
-  end
-end

backend/spec/services/preview/thumbnail_fetcher_spec.rb

@@ -1,51 +0,0 @@
-require 'rails_helper'
-
-RSpec.describe Preview::ThumbnailFetcher do
-  describe '.fetch' do
-    it 'rejects svg thumbnails' do
-      page = Preview::HttpFetcher::Response.new(
-          '<meta property="og:image" content="https://example.com/thumb.svg">',
-          'text/html',
-          'https://example.com/page')
-      svg = Preview::HttpFetcher::Response.new(
-          '<svg></svg>',
-          'image/svg+xml',
-          'https://example.com/thumb.svg')
-
-      allow(Preview::UrlSafety).to receive(:validate)
-          .and_return([URI.parse('https://example.com/page'), ['203.0.113.10']])
-      allow(Preview::HttpFetcher).to receive(:fetch)
-          .with('https://example.com/page', max_bytes: described_class::HTML_MAX_BYTES)
-          .and_return(page)
-      allow(Preview::HttpFetcher).to receive(:fetch)
-          .with('https://example.com/thumb.svg')
-          .and_return(svg)
-
-      expect {
-        described_class.fetch('https://example.com/page')
-      }.to raise_error(Preview::ThumbnailFetcher::GenerationFailed)
-    end
-
-    it 'accepts allowed image content type with parameters' do
-      page = Preview::HttpFetcher::Response.new(
-          '<meta property="og:image" content="https://example.com/thumb.jpg">',
-          'text/html',
-          'https://example.com/page')
-      image = Preview::HttpFetcher::Response.new(
-          'jpeg-bytes',
-          'image/jpeg; charset=binary',
-          'https://example.com/thumb.jpg')
-
-      allow(Preview::UrlSafety).to receive(:validate)
-          .and_return([URI.parse('https://example.com/page'), ['203.0.113.10']])
-      allow(Preview::HttpFetcher).to receive(:fetch)
-          .with('https://example.com/page', max_bytes: described_class::HTML_MAX_BYTES)
-          .and_return(page)
-      allow(Preview::HttpFetcher).to receive(:fetch)
-          .with('https://example.com/thumb.jpg')
-          .and_return(image)
-
-      expect(described_class.fetch('https://example.com/page')).to eq('jpeg-bytes')
-    end
-  end
-end

backend/spec/services/preview/url_safety_spec.rb

@@ -1,15 +0,0 @@
-require 'rails_helper'
-
-RSpec.describe Preview::UrlSafety do
-  describe '.validate' do
-    it 'raises UnsafeUrl when DNS resolution fails' do
-      allow(Resolv).to receive(:getaddresses)
-          .with('missing.example')
-          .and_raise(Resolv::ResolvError)
-
-      expect {
-        described_class.validate('https://missing.example')
-      }.to raise_error(Preview::UrlSafety::UnsafeUrl)
-    end
-  end
-end

frontend/src/index.css

@@ -239,11 +239,6 @@ body
   background: var(--top-nav-submenu-bg);
 }
 
-.top-nav-mobile-menu .top-nav-submenu
-{
-  background: var(--top-nav-mobile-active-bg);
-}
-
 .top-nav-mobile-menu
 {
   background: var(--top-nav-mobile-menu-bg);

frontend/src/index.test.ts

@@ -1,22 +0,0 @@
-import { readFileSync } from 'node:fs'
-import { resolve } from 'node:path'
-
-import { describe, expect, it } from 'vitest'
-
-
-const indexCss = readFileSync (
-    resolve (process.cwd (), 'src/index.css'),
-    'utf8')
-const compactIndexCss = indexCss.replace (/\s+/g, ' ')
-const mobileActiveRule = '.top-nav-mobile-active {'
-    + ' background: var(--top-nav-mobile-active-bg); }'
-const mobileSubmenuRule = '.top-nav-mobile-menu .top-nav-submenu {'
-    + ' background: var(--top-nav-mobile-active-bg); }'
-
-
-describe ('TopNav mobile menu colours', () => {
-  it ('uses one background variable for active rows and expanded submenus', () => {
-    expect (compactIndexCss).toContain (mobileActiveRule)
-    expect (compactIndexCss).toContain (mobileSubmenuRule)
-  })
-})

frontend/src/lib/settings.test.ts

@@ -89,12 +89,8 @@ describe ('settings', () => {
   })
 
   it ('derives TopNav colours without mixing mobile active backgrounds', () => {
-    const tokens = buildThemeTokens ('light', { })
-
-    expect (tokens.topNavMobileActiveBackground).toBe (
+    expect (buildThemeTokens ('light', { }).topNavMobileActiveBackground).toBe (
 	LIGHT_THEME_TOKENS.topNavRootBackgroundDesktop)
-    expect (tokens.topNavMobileActiveBackground).not.toBe (
-	tokens.topNavRootBackgroundMobile)
     expect (buildThemeTokens ('dark', { }).topNavMobileActiveBackground).toBe (
 	DARK_THEME_TOKENS.topNavActiveBackground)
   })