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Diffstat (limited to 'activestorage/app/models/active_storage/blob')
3 files changed, 174 insertions, 0 deletions
diff --git a/activestorage/app/models/active_storage/blob/analyzable.rb b/activestorage/app/models/active_storage/blob/analyzable.rb new file mode 100644 index 0000000000..5bda6e6d73 --- /dev/null +++ b/activestorage/app/models/active_storage/blob/analyzable.rb @@ -0,0 +1,57 @@ +# frozen_string_literal: true + +require "active_storage/analyzer/null_analyzer" + +module ActiveStorage::Blob::Analyzable + # Extracts and stores metadata from the file associated with this blob using a relevant analyzer. Active Storage comes + # with built-in analyzers for images and videos. See ActiveStorage::Analyzer::ImageAnalyzer and + # ActiveStorage::Analyzer::VideoAnalyzer for information about the specific attributes they extract and the third-party + # libraries they require. + # + # To choose the analyzer for a blob, Active Storage calls +accept?+ on each registered analyzer in order. It uses the + # first analyzer for which +accept?+ returns true when given the blob. If no registered analyzer accepts the blob, no + # metadata is extracted from it. + # + # In a Rails application, add or remove analyzers by manipulating +Rails.application.config.active_storage.analyzers+ + # in an initializer: + # + # # Add a custom analyzer for Microsoft Office documents: + # Rails.application.config.active_storage.analyzers.append DOCXAnalyzer + # + # # Remove the built-in video analyzer: + # Rails.application.config.active_storage.analyzers.delete ActiveStorage::Analyzer::VideoAnalyzer + # + # Outside of a Rails application, manipulate +ActiveStorage.analyzers+ instead. + # + # You won't ordinarily need to call this method from a Rails application. New blobs are automatically and asynchronously + # analyzed via #analyze_later when they're attached for the first time. + def analyze + update! metadata: metadata.merge(extract_metadata_via_analyzer) + end + + # Enqueues an ActiveStorage::AnalyzeJob which calls #analyze. + # + # This method is automatically called for a blob when it's attached for the first time. You can call it to analyze a blob + # again (e.g. if you add a new analyzer or modify an existing one). + def analyze_later + ActiveStorage::AnalyzeJob.perform_later(self) + end + + # Returns true if the blob has been analyzed. + def analyzed? + analyzed + end + + private + def extract_metadata_via_analyzer + analyzer.metadata.merge(analyzed: true) + end + + def analyzer + analyzer_class.new(self) + end + + def analyzer_class + ActiveStorage.analyzers.detect { |klass| klass.accept?(self) } || ActiveStorage::Analyzer::NullAnalyzer + end +end diff --git a/activestorage/app/models/active_storage/blob/identifiable.rb b/activestorage/app/models/active_storage/blob/identifiable.rb new file mode 100644 index 0000000000..2c17ddc25f --- /dev/null +++ b/activestorage/app/models/active_storage/blob/identifiable.rb @@ -0,0 +1,24 @@ +# frozen_string_literal: true + +module ActiveStorage::Blob::Identifiable + def identify + update! content_type: identify_content_type, identified: true unless identified? + end + + def identified? + identified + end + + private + def identify_content_type + Marcel::MimeType.for download_identifiable_chunk, name: filename.to_s, declared_type: content_type + end + + def download_identifiable_chunk + if byte_size.positive? + service.download_chunk key, 0...4.kilobytes + else + "" + end + end +end diff --git a/activestorage/app/models/active_storage/blob/representable.rb b/activestorage/app/models/active_storage/blob/representable.rb new file mode 100644 index 0000000000..03d5511481 --- /dev/null +++ b/activestorage/app/models/active_storage/blob/representable.rb @@ -0,0 +1,93 @@ +# frozen_string_literal: true + +module ActiveStorage::Blob::Representable + extend ActiveSupport::Concern + + included do + has_one_attached :preview_image + end + + # Returns an ActiveStorage::Variant instance with the set of +transformations+ provided. This is only relevant for image + # files, and it allows any image to be transformed for size, colors, and the like. Example: + # + # avatar.variant(resize_to_fit: [100, 100]).processed.service_url + # + # This will create and process a variant of the avatar blob that's constrained to a height and width of 100px. + # Then it'll upload said variant to the service according to a derivative key of the blob and the transformations. + # + # Frequently, though, you don't actually want to transform the variant right away. But rather simply refer to a + # specific variant that can be created by a controller on-demand. Like so: + # + # <%= image_tag Current.user.avatar.variant(resize_to_fit: [100, 100]) %> + # + # This will create a URL for that specific blob with that specific variant, which the ActiveStorage::RepresentationsController + # can then produce on-demand. + # + # Raises ActiveStorage::InvariableError if ImageMagick cannot transform the blob. To determine whether a blob is + # variable, call ActiveStorage::Blob#variable?. + def variant(transformations) + if variable? + ActiveStorage::Variant.new(self, transformations) + else + raise ActiveStorage::InvariableError + end + end + + # Returns true if ImageMagick can transform the blob (its content type is in +ActiveStorage.variable_content_types+). + def variable? + ActiveStorage.variable_content_types.include?(content_type) + end + + + # Returns an ActiveStorage::Preview instance with the set of +transformations+ provided. A preview is an image generated + # from a non-image blob. Active Storage comes with built-in previewers for videos and PDF documents. The video previewer + # extracts the first frame from a video and the PDF previewer extracts the first page from a PDF document. + # + # blob.preview(resize_to_fit: [100, 100]).processed.service_url + # + # Avoid processing previews synchronously in views. Instead, link to a controller action that processes them on demand. + # Active Storage provides one, but you may want to create your own (for example, if you need authentication). Here’s + # how to use the built-in version: + # + # <%= image_tag video.preview(resize_to_fit: [100, 100]) %> + # + # This method raises ActiveStorage::UnpreviewableError if no previewer accepts the receiving blob. To determine + # whether a blob is accepted by any previewer, call ActiveStorage::Blob#previewable?. + def preview(transformations) + if previewable? + ActiveStorage::Preview.new(self, transformations) + else + raise ActiveStorage::UnpreviewableError + end + end + + # Returns true if any registered previewer accepts the blob. By default, this will return true for videos and PDF documents. + def previewable? + ActiveStorage.previewers.any? { |klass| klass.accept?(self) } + end + + + # Returns an ActiveStorage::Preview for a previewable blob or an ActiveStorage::Variant for a variable image blob. + # + # blob.representation(resize_to_fit: [100, 100]).processed.service_url + # + # Raises ActiveStorage::UnrepresentableError if the receiving blob is neither variable nor previewable. Call + # ActiveStorage::Blob#representable? to determine whether a blob is representable. + # + # See ActiveStorage::Blob#preview and ActiveStorage::Blob#variant for more information. + def representation(transformations) + case + when previewable? + preview transformations + when variable? + variant transformations + else + raise ActiveStorage::UnrepresentableError + end + end + + # Returns true if the blob is variable or previewable. + def representable? + variable? || previewable? + end +end |