広場投稿追加画面の刷新 (#399) (#413)

Reviewed-on: #413
Co-authored-by: miteruzo <miteruzo@naver.com>
Co-committed-by: miteruzo <miteruzo@naver.com>

backend/app/services/preview/http_fetcher.rb

@@ -67,7 +67,8 @@ module Preview
       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)
+      log_failure(:network_error, url: uri&.to_s || raw_url, error: e.class.name,
+                  message: e.message)
       raise FetchFailed, e.message
     end
 

backend/app/services/preview/known_site_extractor.rb

@@ -4,6 +4,15 @@ module Preview
       youtube_thumbnail(uri)
     end
 
+    def self.youtube_video_id(uri)
+      case uri.host&.downcase
+      when 'youtu.be'
+        uri.path.split('/').reject(&:blank?).first
+      when 'www.youtube.com', 'youtube.com', 'm.youtube.com'
+        uri.path == '/watch' ? URI.decode_www_form(uri.query.to_s).to_h['v'] : nil
+      end&.then { _1 if _1.match?(/\A[A-Za-z0-9_-]{6,20}\z/) }
+    end
+
     def self.niconico_video_id(uri)
       case uri.host&.downcase
       when 'www.nicovideo.jp', 'nicovideo.jp'
@@ -14,14 +23,8 @@ module Preview
     end
 
     def self.youtube_thumbnail(uri)
-      id =
-          case uri.host&.downcase
-          when 'youtu.be'
-            uri.path.split('/').reject(&:blank?).first
-          when 'www.youtube.com', 'youtube.com', 'm.youtube.com'
-            uri.path == '/watch' ? URI.decode_www_form(uri.query.to_s).to_h['v'] : nil
-          end
-      return unless id&.match?(/\A[A-Za-z0-9_-]{6,20}\z/)
+      id = youtube_video_id(uri)
+      return unless id
 
       "https://i.ytimg.com/vi/#{ id }/hqdefault.jpg"
     end

backend/app/services/preview/thumbnail_fetcher.rb

@@ -1,7 +1,7 @@
 module Preview
   class ThumbnailFetcher
     class GenerationFailed < StandardError; end
-    ALLOWED_IMAGE_CONTENT_TYPES = [
+    RASTER_IMAGE_CONTENT_TYPES = [
       'image/jpeg', 'image/png', 'image/gif', 'image/webp'
     ].freeze
     HTML_MAX_BYTES = 1.megabyte
@@ -25,6 +25,24 @@ module Preview
       fetch_image!(metadata[:image_url])
     end
 
+    def self.fetch_image_response(raw_url)
+      uri, = UrlSafety.validate(raw_url)
+      response = HttpFetcher.fetch(uri.to_s)
+      unless Post.remote_thumbnail_image_bytes?(
+                 response.body,
+                 content_type: response.content_type)
+        raise GenerationFailed, 'サムネール画像が見つかりませんでした．'
+      end
+
+      response
+    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.title(raw_url)
       uri, = UrlSafety.validate(raw_url)
       HtmlMetadataExtractor.extract(
@@ -35,7 +53,9 @@ module Preview
       return nil if url.blank?
 
       response = HttpFetcher.fetch(url)
-      return nil unless allowed_image_content_type?(response.content_type)
+      return nil unless Post.remote_thumbnail_image_bytes?(
+                            response.body,
+                            content_type: response.content_type)
 
       response.body
     rescue HttpFetcher::FetchTimeout
@@ -45,18 +65,7 @@ module Preview
     end
 
     def self.fetch_image!(url)
-      response = HttpFetcher.fetch(url)
-      unless allowed_image_content_type?(response.content_type)
-        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．'
+      fetch_image_response(url).body
     end
 
     def self.niconico_thumbnail_url(uri)
@@ -70,26 +79,24 @@ module Preview
 
       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 }")
+      payload = {
+          url: uri.to_s,
+          video_id:,
+          error: e.class.name,
+          message: e.message }
+      Rails.logger.info("preview_niconico_getthumbinfo_fallback #{ payload.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 }")
+      payload = {
+          url: uri.to_s,
+          video_id:,
+          error: e.class.name,
+          message: e.message }
+      Rails.logger.info("preview_niconico_getthumbinfo_fallback #{ payload.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?
+                         :niconico_thumbnail_url
   end
 end