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/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