39 行
1.1 KiB
Ruby
39 行
1.1 KiB
Ruby
module Preview
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class ThumbnailFetcher
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class GenerationFailed < StandardError; end
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def self.fetch(raw_url)
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uri, = UrlSafety.validate(raw_url)
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known_url = KnownSiteExtractor.thumbnail_url(uri)
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return fetch_image(known_url) if known_url
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page = HttpFetcher.fetch(uri.to_s)
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metadata = HtmlMetadataExtractor.extract(page)
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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?
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fetch_image(metadata[:image_url])
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end
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def self.title(raw_url)
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uri, = UrlSafety.validate(raw_url)
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HtmlMetadataExtractor.extract(HttpFetcher.fetch(uri.to_s))[:title]
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end
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def self.fetch_image(url)
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response = HttpFetcher.fetch(url)
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unless response.content_type.downcase.start_with?('image/')
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raise GenerationFailed, 'サムネール画像が見つかりませんでした．'
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end
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response.body
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rescue HttpFetcher::FetchTimeout
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raise
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rescue HttpFetcher::FetchFailed
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raise GenerationFailed, 'サムネール画像を取得できませんでした．'
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end
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private_class_method :fetch_image
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end
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end
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