Merge branch 'master' into custom-discarded-job-handling

20 files changed, 509 insertions, 66 deletions

diff --git a/activestorage/lib/active_storage/analyzer.rb b/activestorage/lib/active_storage/analyzer.rb
new file mode 100644
index 0000000000..837785a12b
--- /dev/null
+++ b/activestorage/lib/active_storage/analyzer.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+require "active_storage/downloading"
+
+module ActiveStorage
+  # This is an abstract base class for analyzers, which extract metadata from blobs. See
+  # ActiveStorage::Analyzer::ImageAnalyzer for an example of a concrete subclass.
+  class Analyzer
+    include Downloading
+
+    attr_reader :blob
+
+    # Implement this method in a concrete subclass. Have it return true when given a blob from which
+    # the analyzer can extract metadata.
+    def self.accept?(blob)
+      false
+    end
+
+    def initialize(blob)
+      @blob = blob
+    end
+
+    # Override this method in a concrete subclass. Have it return a Hash of metadata.
+    def metadata
+      raise NotImplementedError
+    end
+
+    private
+      def logger
+        ActiveStorage.logger
+      end
+  end
+end
diff --git a/activestorage/lib/active_storage/analyzer/image_analyzer.rb b/activestorage/lib/active_storage/analyzer/image_analyzer.rb
new file mode 100644
index 0000000000..25e0251e6e
--- /dev/null
+++ b/activestorage/lib/active_storage/analyzer/image_analyzer.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+module ActiveStorage
+  # Extracts width and height in pixels from an image blob.
+  #
+  # Example:
+  #
+  #   ActiveStorage::Analyzer::ImageAnalyzer.new(blob).metadata
+  #   # => { width: 4104, height: 2736 }
+  #
+  # This analyzer relies on the third-party {MiniMagick}[https://github.com/minimagick/minimagick] gem. MiniMagick requires
+  # the {ImageMagick}[http://www.imagemagick.org] system library. These libraries are not provided by Rails; you must
+  # install them yourself to use this analyzer.
+  class Analyzer::ImageAnalyzer < Analyzer
+    def self.accept?(blob)
+      blob.image?
+    end
+
+    def metadata
+      read_image do |image|
+        { width: image.width, height: image.height }
+      end
+    rescue LoadError
+      logger.info "Skipping image analysis because the mini_magick gem isn't installed"
+      {}
+    end
+
+    private
+      def read_image
+        download_blob_to_tempfile do |file|
+          require "mini_magick"
+          yield MiniMagick::Image.new(file.path)
+        end
+      end
+  end
+end
diff --git a/activestorage/lib/active_storage/analyzer/null_analyzer.rb b/activestorage/lib/active_storage/analyzer/null_analyzer.rb
new file mode 100644
index 0000000000..8ff7ce48e5
--- /dev/null
+++ b/activestorage/lib/active_storage/analyzer/null_analyzer.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+module ActiveStorage
+  class Analyzer::NullAnalyzer < Analyzer # :nodoc:
+    def self.accept?(blob)
+      true
+    end
+
+    def metadata
+      {}
+    end
+  end
+end
diff --git a/activestorage/lib/active_storage/analyzer/video_analyzer.rb b/activestorage/lib/active_storage/analyzer/video_analyzer.rb
new file mode 100644
index 0000000000..1c144baa37
--- /dev/null
+++ b/activestorage/lib/active_storage/analyzer/video_analyzer.rb
@@ -0,0 +1,93 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/hash/compact"
+
+module ActiveStorage
+  # Extracts the following from a video blob:
+  #
+  # * Width (pixels)
+  # * Height (pixels)
+  # * Duration (seconds)
+  # * Angle (degrees)
+  # * Aspect ratio
+  #
+  # Example:
+  #
+  #   ActiveStorage::VideoAnalyzer.new(blob).metadata
+  #   # => { width: 640, height: 480, duration: 5.0, angle: 0, aspect_ratio: [4, 3] }
+  #
+  # This analyzer requires the {ffmpeg}[https://www.ffmpeg.org] system library, which is not provided by Rails. You must
+  # install ffmpeg yourself to use this analyzer.
+  class Analyzer::VideoAnalyzer < Analyzer
+    class_attribute :ffprobe_path, default: "ffprobe"
+
+    def self.accept?(blob)
+      blob.video?
+    end
+
+    def metadata
+      { width: width, height: height, duration: duration, angle: angle, aspect_ratio: aspect_ratio }.compact
+    end
+
+    private
+      def width
+        rotated? ? raw_height : raw_width
+      end
+
+      def height
+        rotated? ? raw_width : raw_height
+      end
+
+      def raw_width
+        Integer(video_stream["width"]) if video_stream["width"]
+      end
+
+      def raw_height
+        Integer(video_stream["height"]) if video_stream["height"]
+      end
+
+      def duration
+        Float(video_stream["duration"]) if video_stream["duration"]
+      end
+
+      def angle
+        Integer(tags["rotate"]) if tags["rotate"]
+      end
+
+      def aspect_ratio
+        if descriptor = video_stream["display_aspect_ratio"]
+          descriptor.split(":", 2).collect(&:to_i)
+        end
+      end
+
+      def rotated?
+        angle == 90 || angle == 270
+      end
+
+
+      def tags
+        @tags ||= video_stream["tags"] || {}
+      end
+
+      def video_stream
+        @video_stream ||= streams.detect { |stream| stream["codec_type"] == "video" } || {}
+      end
+
+      def streams
+        probe["streams"] || []
+      end
+
+      def probe
+        download_blob_to_tempfile { |file| probe_from(file) }
+      end
+
+      def probe_from(file)
+        IO.popen([ ffprobe_path, "-print_format", "json", "-show_streams", "-v", "error", file.path ]) do |output|
+          JSON.parse(output.read)
+        end
+      rescue Errno::ENOENT
+        logger.info "Skipping video analysis because ffmpeg isn't installed"
+        {}
+      end
+  end
+end
diff --git a/activestorage/lib/active_storage/attached/macros.rb b/activestorage/lib/active_storage/attached/macros.rb
index 35a081adc4..2b38a9b887 100644
--- a/activestorage/lib/active_storage/attached/macros.rb
+++ b/activestorage/lib/active_storage/attached/macros.rb
@@ -12,6 +12,10 @@ module ActiveStorage
     # There is no column defined on the model side, Active Storage takes
     # care of the mapping between your records and the attachment.
     #
+    # To avoid N+1 queries, you can include the attached blobs in your query like so:
+    #
+    #   User.with_attached_avatar
+    #
     # Under the covers, this relationship is implemented as a +has_one+ association to a
     # ActiveStorage::Attachment record and a +has_one-through+ association to a
     # ActiveStorage::Blob record. These associations are available as +avatar_attachment+
@@ -28,11 +32,17 @@ module ActiveStorage
         def #{name}
           @active_storage_attached_#{name} ||= ActiveStorage::Attached::One.new("#{name}", self, dependent: #{dependent == :purge_later ? ":purge_later" : "false"})
         end
+
+        def #{name}=(attachable)
+          #{name}.attach(attachable)
+        end
       CODE
 
       has_one :"#{name}_attachment", -> { where(name: name) }, class_name: "ActiveStorage::Attachment", as: :record
       has_one :"#{name}_blob", through: :"#{name}_attachment", class_name: "ActiveStorage::Blob", source: :blob
 
+      scope :"with_attached_#{name}", -> { includes("#{name}_attachment": :blob) }
+
       if dependent == :purge_later
         before_destroy { public_send(name).purge_later }
       end
@@ -67,6 +77,10 @@ module ActiveStorage
         def #{name}
           @active_storage_attached_#{name} ||= ActiveStorage::Attached::Many.new("#{name}", self, dependent: #{dependent == :purge_later ? ":purge_later" : "false"})
         end
+
+        def #{name}=(attachables)
+          #{name}.attach(attachables)
+        end
       CODE
 
       has_many :"#{name}_attachments", -> { where(name: name) }, as: :record, class_name: "ActiveStorage::Attachment"
diff --git a/activestorage/lib/active_storage/attached/many.rb b/activestorage/lib/active_storage/attached/many.rb
index 59b7d7d559..6eace65b79 100644
--- a/activestorage/lib/active_storage/attached/many.rb
+++ b/activestorage/lib/active_storage/attached/many.rb
@@ -13,15 +13,18 @@ module ActiveStorage
     end
 
     # Associates one or several attachments with the current record, saving them to the database.
-    # Examples:
     #
     #   document.images.attach(params[:images]) # Array of ActionDispatch::Http::UploadedFile objects
     #   document.images.attach(params[:signed_blob_id]) # Signed reference to blob from direct upload
-    #   document.images.attach(io: File.open("~/racecar.jpg"), filename: "racecar.jpg", content_type: "image/jpg")
+    #   document.images.attach(io: File.open("/path/to/racecar.jpg"), filename: "racecar.jpg", content_type: "image/jpg")
     #   document.images.attach([ first_blob, second_blob ])
     def attach(*attachables)
       attachables.flatten.collect do |attachable|
-        attachments.create!(name: name, blob: create_blob_from(attachable))
+        if record.new_record?
+          attachments.build(record: record, blob: create_blob_from(attachable))
+        else
+          attachments.create!(record: record, blob: create_blob_from(attachable))
+        end
       end
     end
 
@@ -36,6 +39,11 @@ module ActiveStorage
       attachments.any?
     end
 
+    # Deletes associated attachments without purging them, leaving their respective blobs in place.
+    def detach
+      attachments.destroy_all if attached?
+    end
+
     # Directly purges each associated attachment (i.e. destroys the blobs and
     # attachments and deletes the files on the service).
     def purge
diff --git a/activestorage/lib/active_storage/attached/one.rb b/activestorage/lib/active_storage/attached/one.rb
index ac90f32d95..0244232b2c 100644
--- a/activestorage/lib/active_storage/attached/one.rb
+++ b/activestorage/lib/active_storage/attached/one.rb
@@ -14,17 +14,16 @@ module ActiveStorage
     end
 
     # Associates a given attachment with the current record, saving it to the database.
-    # Examples:
     #
     #   person.avatar.attach(params[:avatar]) # ActionDispatch::Http::UploadedFile object
     #   person.avatar.attach(params[:signed_blob_id]) # Signed reference to blob from direct upload
-    #   person.avatar.attach(io: File.open("~/face.jpg"), filename: "face.jpg", content_type: "image/jpg")
+    #   person.avatar.attach(io: File.open("/path/to/face.jpg"), filename: "face.jpg", content_type: "image/jpg")
     #   person.avatar.attach(avatar_blob) # ActiveStorage::Blob object
     def attach(attachable)
       if attached? && dependent == :purge_later
         replace attachable
       else
-        write_attachment create_attachment_from(attachable)
+        write_attachment build_attachment_from(attachable)
       end
     end
 
@@ -39,6 +38,14 @@ module ActiveStorage
       attachment.present?
     end
 
+    # Deletes the attachment without purging it, leaving its blob in place.
+    def detach
+      if attached?
+        attachment.destroy
+        write_attachment nil
+      end
+    end
+
     # Directly purges the attachment (i.e. destroys the blob and
     # attachment and deletes the file on the service).
     def purge
@@ -59,14 +66,14 @@ module ActiveStorage
       def replace(attachable)
         blob.tap do
           transaction do
-            destroy
-            write_attachment create_attachment_from(attachable)
+            detach
+            write_attachment build_attachment_from(attachable)
           end
         end.purge_later
       end
 
-      def create_attachment_from(attachable)
-        ActiveStorage::Attachment.create!(record: record, name: name, blob: create_blob_from(attachable))
+      def build_attachment_from(attachable)
+        ActiveStorage::Attachment.new(record: record, name: name, blob: create_blob_from(attachable))
       end
 
       def write_attachment(attachment)
diff --git a/activestorage/lib/active_storage/downloading.rb b/activestorage/lib/active_storage/downloading.rb
new file mode 100644
index 0000000000..3dac6b116a
--- /dev/null
+++ b/activestorage/lib/active_storage/downloading.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+module ActiveStorage
+  module Downloading
+    private
+      # Opens a new tempfile in #tempdir and copies blob data into it. Yields the tempfile.
+      def download_blob_to_tempfile # :doc:
+        Tempfile.open("ActiveStorage", tempdir) do |file|
+          download_blob_to file
+          yield file
+        end
+      end
+
+      # Efficiently downloads blob data into the given file.
+      def download_blob_to(file) # :doc:
+        file.binmode
+        blob.download { |chunk| file.write(chunk) }
+        file.rewind
+      end
+
+      # Returns the directory in which tempfiles should be opened. Defaults to +Dir.tmpdir+.
+      def tempdir # :doc:
+        Dir.tmpdir
+      end
+  end
+end
diff --git a/activestorage/lib/active_storage/engine.rb b/activestorage/lib/active_storage/engine.rb
index 590a36a30a..b870e6d4d6 100644
--- a/activestorage/lib/active_storage/engine.rb
+++ b/activestorage/lib/active_storage/engine.rb
@@ -3,19 +3,29 @@
 require "rails"
 require "active_storage"
 
+require "active_storage/previewer/pdf_previewer"
+require "active_storage/previewer/video_previewer"
+
+require "active_storage/analyzer/image_analyzer"
+require "active_storage/analyzer/video_analyzer"
+
 module ActiveStorage
   class Engine < Rails::Engine # :nodoc:
     isolate_namespace ActiveStorage
 
     config.active_storage = ActiveSupport::OrderedOptions.new
+    config.active_storage.previewers = [ ActiveStorage::Previewer::PDFPreviewer, ActiveStorage::Previewer::VideoPreviewer ]
+    config.active_storage.analyzers = [ ActiveStorage::Analyzer::ImageAnalyzer, ActiveStorage::Analyzer::VideoAnalyzer ]
+    config.active_storage.paths = ActiveSupport::OrderedOptions.new
 
     config.eager_load_namespaces << ActiveStorage
 
-    initializer "active_storage.logger" do
-      require "active_storage/service"
-
+    initializer "active_storage.configs" do
       config.after_initialize do |app|
-        ActiveStorage::Service.logger = app.config.active_storage.logger || Rails.logger
+        ActiveStorage.logger     = app.config.active_storage.logger || Rails.logger
+        ActiveStorage.queue      = app.config.active_storage.queue
+        ActiveStorage.previewers = app.config.active_storage.previewers || []
+        ActiveStorage.analyzers  = app.config.active_storage.analyzers || []
       end
     end
 
@@ -59,5 +69,21 @@ module ActiveStorage
         end
       end
     end
+
+    initializer "active_storage.paths" do
+      config.after_initialize do |app|
+        if ffprobe_path = app.config.active_storage.paths.ffprobe
+          ActiveStorage::Analyzer::VideoAnalyzer.ffprobe_path = ffprobe_path
+        end
+
+        if ffmpeg_path = app.config.active_storage.paths.ffmpeg
+          ActiveStorage::Previewer::VideoPreviewer.ffmpeg_path = ffmpeg_path
+        end
+
+        if mutool_path = app.config.active_storage.paths.mutool
+          ActiveStorage::Previewer::PDFPreviewer.mutool_path = mutool_path
+        end
+      end
+    end
   end
 end
diff --git a/activestorage/lib/active_storage/gem_version.rb b/activestorage/lib/active_storage/gem_version.rb
index e1d7b3493a..f048bb0b77 100644
--- a/activestorage/lib/active_storage/gem_version.rb
+++ b/activestorage/lib/active_storage/gem_version.rb
@@ -10,7 +10,7 @@ module ActiveStorage
     MAJOR = 5
     MINOR = 2
     TINY  = 0
-    PRE   = "alpha"
+    PRE   = "beta2"
 
     STRING = [MAJOR, MINOR, TINY, PRE].compact.join(".")
   end
diff --git a/activestorage/lib/active_storage/log_subscriber.rb b/activestorage/lib/active_storage/log_subscriber.rb
index 0d00a75c0e..a4e148c1a5 100644
--- a/activestorage/lib/active_storage/log_subscriber.rb
+++ b/activestorage/lib/active_storage/log_subscriber.rb
@@ -18,6 +18,10 @@ module ActiveStorage
       info event, color("Deleted file from key: #{key_in(event)}", RED)
     end
 
+    def service_delete_prefixed(event)
+      info event, color("Deleted files by key prefix: #{event.payload[:prefix]}", RED)
+    end
+
     def service_exist(event)
       debug event, color("Checked if file exists at key: #{key_in(event)} (#{event.payload[:exist] ? "yes" : "no"})", BLUE)
     end
@@ -27,7 +31,7 @@ module ActiveStorage
     end
 
     def logger
-      ActiveStorage::Service.logger
+      ActiveStorage.logger
     end
 
     private
diff --git a/activestorage/lib/active_storage/previewer.rb b/activestorage/lib/active_storage/previewer.rb
new file mode 100644
index 0000000000..3d485988e9
--- /dev/null
+++ b/activestorage/lib/active_storage/previewer.rb
@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+require "active_storage/downloading"
+
+module ActiveStorage
+  # This is an abstract base class for previewers, which generate images from blobs. See
+  # ActiveStorage::Previewer::PDFPreviewer and ActiveStorage::Previewer::VideoPreviewer for examples of
+  # concrete subclasses.
+  class Previewer
+    include Downloading
+
+    attr_reader :blob
+
+    # Implement this method in a concrete subclass. Have it return true when given a blob from which
+    # the previewer can generate an image.
+    def self.accept?(blob)
+      false
+    end
+
+    def initialize(blob)
+      @blob = blob
+    end
+
+    # Override this method in a concrete subclass. Have it yield an attachable preview image (i.e.
+    # anything accepted by ActiveStorage::Attached::One#attach).
+    def preview
+      raise NotImplementedError
+    end
+
+    private
+      # Executes a system command, capturing its binary output in a tempfile. Yields the tempfile.
+      #
+      # Use this method to shell out to a system library (e.g. mupdf or ffmpeg) for preview image
+      # generation. The resulting tempfile can be used as the +:io+ value in an attachable Hash:
+      #
+      #   def preview
+      #     download_blob_to_tempfile do |input|
+      #       draw "my-drawing-command", input.path, "--format", "png", "-" do |output|
+      #         yield io: output, filename: "#{blob.filename.base}.png", content_type: "image/png"
+      #       end
+      #     end
+      #   end
+      #
+      # The output tempfile is opened in the directory returned by ActiveStorage::Downloading#tempdir.
+      def draw(*argv) # :doc:
+        Tempfile.open("ActiveStorage", tempdir) do |file|
+          capture(*argv, to: file)
+          yield file
+        end
+      end
+
+      def capture(*argv, to:)
+        to.binmode
+        IO.popen(argv) { |out| IO.copy_stream(out, to) }
+        to.rewind
+      end
+
+      def logger
+        ActiveStorage.logger
+      end
+  end
+end
diff --git a/activestorage/lib/active_storage/previewer/pdf_previewer.rb b/activestorage/lib/active_storage/previewer/pdf_previewer.rb
new file mode 100644
index 0000000000..b84aefcc9c
--- /dev/null
+++ b/activestorage/lib/active_storage/previewer/pdf_previewer.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+module ActiveStorage
+  class Previewer::PDFPreviewer < Previewer
+    class_attribute :mutool_path, default: "mutool"
+
+    def self.accept?(blob)
+      blob.content_type == "application/pdf"
+    end
+
+    def preview
+      download_blob_to_tempfile do |input|
+        draw_first_page_from input do |output|
+          yield io: output, filename: "#{blob.filename.base}.png", content_type: "image/png"
+        end
+      end
+    end
+
+    private
+      def draw_first_page_from(file, &block)
+        draw mutool_path, "draw", "-F", "png", "-o", "-", file.path, "1", &block
+      end
+  end
+end
diff --git a/activestorage/lib/active_storage/previewer/video_previewer.rb b/activestorage/lib/active_storage/previewer/video_previewer.rb
new file mode 100644
index 0000000000..5d06e33f44
--- /dev/null
+++ b/activestorage/lib/active_storage/previewer/video_previewer.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+module ActiveStorage
+  class Previewer::VideoPreviewer < Previewer
+    class_attribute :ffmpeg_path, default: "ffmpeg"
+
+    def self.accept?(blob)
+      blob.video?
+    end
+
+    def preview
+      download_blob_to_tempfile do |input|
+        draw_relevant_frame_from input do |output|
+          yield io: output, filename: "#{blob.filename.base}.png", content_type: "image/png"
+        end
+      end
+    end
+
+    private
+      def draw_relevant_frame_from(file, &block)
+        draw ffmpeg_path, "-i", file.path, "-y", "-vcodec", "png",
+          "-vf", "thumbnail", "-vframes", "1", "-f", "image2", "-", &block
+      end
+  end
+end
diff --git a/activestorage/lib/active_storage/service.rb b/activestorage/lib/active_storage/service.rb
index b80fdea1ab..c8f675db86 100644
--- a/activestorage/lib/active_storage/service.rb
+++ b/activestorage/lib/active_storage/service.rb
@@ -4,6 +4,7 @@ require "active_storage/log_subscriber"
 
 module ActiveStorage
   class IntegrityError < StandardError; end
+
   # Abstract class serving as an interface for concrete services.
   #
   # The available services are:
@@ -40,7 +41,7 @@ module ActiveStorage
     extend ActiveSupport::Autoload
     autoload :Configurator
 
-    class_attribute :logger
+    class_attribute :url_expires_in, default: 5.minutes
 
     class << self
       # Configure an Active Storage service by name from a set of configurations,
@@ -77,6 +78,11 @@ module ActiveStorage
       raise NotImplementedError
     end
 
+    # Delete files at keys starting with the +prefix+.
+    def delete_prefixed(prefix)
+      raise NotImplementedError
+    end
+
     # Return +true+ if a file exists at the +key+.
     def exist?(key)
       raise NotImplementedError
@@ -103,15 +109,19 @@ module ActiveStorage
     end
 
     private
-      def instrument(operation, key, payload = {}, &block)
+      def instrument(operation, payload = {}, &block)
         ActiveSupport::Notifications.instrument(
           "service_#{operation}.active_storage",
-          payload.merge(key: key, service: service_name), &block)
+          payload.merge(service: service_name), &block)
       end
 
       def service_name
         # ActiveStorage::Service::DiskService => Disk
         self.class.name.split("::").third.remove("Service")
       end
+
+      def content_disposition_with(type: "inline", filename:)
+        (type.to_s.presence_in(%w( attachment inline )) || "inline") + "; #{filename.parameters}"
+      end
   end
 end
diff --git a/activestorage/lib/active_storage/service/azure_storage_service.rb b/activestorage/lib/active_storage/service/azure_storage_service.rb
index 895cc9c2f1..19b09991b3 100644
--- a/activestorage/lib/active_storage/service/azure_storage_service.rb
+++ b/activestorage/lib/active_storage/service/azure_storage_service.rb
@@ -19,7 +19,7 @@ module ActiveStorage
     end
 
     def upload(key, io, checksum: nil)
-      instrument :upload, key, checksum: checksum do
+      instrument :upload, key: key, checksum: checksum do
         begin
           blobs.create_block_blob(container, key, io, content_md5: checksum)
         rescue Azure::Core::Http::HTTPError
@@ -28,13 +28,13 @@ module ActiveStorage
       end
     end
 
-    def download(key)
+    def download(key, &block)
       if block_given?
-        instrument :streaming_download, key do
+        instrument :streaming_download, key: key do
           stream(key, &block)
         end
       else
-        instrument :download, key do
+        instrument :download, key: key do
           _, io = blobs.get_blob(container, key)
           io.force_encoding(Encoding::BINARY)
         end
@@ -42,7 +42,7 @@ module ActiveStorage
     end
 
     def delete(key)
-      instrument :delete, key do
+      instrument :delete, key: key do
         begin
           blobs.delete_blob(container, key)
         rescue Azure::Core::Http::HTTPError
@@ -51,8 +51,24 @@ module ActiveStorage
       end
     end
 
+    def delete_prefixed(prefix)
+      instrument :delete_prefixed, prefix: prefix do
+        marker = nil
+
+        loop do
+          results = blobs.list_blobs(container, prefix: prefix, marker: marker)
+
+          results.each do |blob|
+            blobs.delete_blob(container, blob.name)
+          end
+
+          break unless marker = results.continuation_token.presence
+        end
+      end
+    end
+
     def exist?(key)
-      instrument :exist, key do |payload|
+      instrument :exist, key: key do |payload|
         answer = blob_for(key).present?
         payload[:exist] = answer
         answer
@@ -60,13 +76,13 @@ module ActiveStorage
     end
 
     def url(key, expires_in:, filename:, disposition:, content_type:)
-      instrument :url, key do |payload|
+      instrument :url, key: key do |payload|
         base_url = url_for(key)
         generated_url = signer.signed_uri(
           URI(base_url), false,
           permissions: "r",
           expiry: format_expiry(expires_in),
-          content_disposition: disposition,
+          content_disposition: content_disposition_with(type: disposition, filename: filename),
           content_type: content_type
         ).to_s
 
@@ -77,7 +93,7 @@ module ActiveStorage
     end
 
     def url_for_direct_upload(key, expires_in:, content_type:, content_length:, checksum:)
-      instrument :url, key do |payload|
+      instrument :url, key: key do |payload|
         base_url = url_for(key)
         generated_url = signer.signed_uri(URI(base_url), false, permissions: "rw",
           expiry: format_expiry(expires_in)).to_s
@@ -108,15 +124,15 @@ module ActiveStorage
       end
 
       # Reads the object for the given key in chunks, yielding each to the block.
-      def stream(key, options = {}, &block)
+      def stream(key)
         blob = blob_for(key)
 
         chunk_size = 5.megabytes
         offset = 0
 
         while offset < blob.properties[:content_length]
-          _, io = blobs.get_blob(container, key, start_range: offset, end_range: offset + chunk_size - 1)
-          yield io
+          _, chunk = blobs.get_blob(container, key, start_range: offset, end_range: offset + chunk_size - 1)
+          yield chunk.force_encoding(Encoding::BINARY)
           offset += chunk_size
         end
       end
diff --git a/activestorage/lib/active_storage/service/disk_service.rb b/activestorage/lib/active_storage/service/disk_service.rb
index f600753a08..a8728c5bc3 100644
--- a/activestorage/lib/active_storage/service/disk_service.rb
+++ b/activestorage/lib/active_storage/service/disk_service.rb
@@ -16,7 +16,7 @@ module ActiveStorage
     end
 
     def upload(key, io, checksum: nil)
-      instrument :upload, key, checksum: checksum do
+      instrument :upload, key: key, checksum: checksum do
         IO.copy_stream(io, make_path_for(key))
         ensure_integrity_of(key, checksum) if checksum
       end
@@ -24,7 +24,7 @@ module ActiveStorage
 
     def download(key)
       if block_given?
-        instrument :streaming_download, key do
+        instrument :streaming_download, key: key do
           File.open(path_for(key), "rb") do |file|
             while data = file.read(64.kilobytes)
               yield data
@@ -32,14 +32,14 @@ module ActiveStorage
           end
         end
       else
-        instrument :download, key do
+        instrument :download, key: key do
           File.binread path_for(key)
         end
       end
     end
 
     def delete(key)
-      instrument :delete, key do
+      instrument :delete, key: key do
         begin
           File.delete path_for(key)
         rescue Errno::ENOENT
@@ -48,8 +48,16 @@ module ActiveStorage
       end
     end
 
+    def delete_prefixed(prefix)
+      instrument :delete_prefixed, prefix: prefix do
+        Dir.glob(path_for("#{prefix}*")).each do |path|
+          FileUtils.rm_rf(path)
+        end
+      end
+    end
+
     def exist?(key)
-      instrument :exist, key do |payload|
+      instrument :exist, key: key do |payload|
         answer = File.exist? path_for(key)
         payload[:exist] = answer
         answer
@@ -57,16 +65,17 @@ module ActiveStorage
     end
 
     def url(key, expires_in:, filename:, disposition:, content_type:)
-      instrument :url, key do |payload|
+      instrument :url, key: key do |payload|
         verified_key_with_expiration = ActiveStorage.verifier.generate(key, expires_in: expires_in, purpose: :blob_key)
 
         generated_url =
           if defined?(Rails.application)
             Rails.application.routes.url_helpers.rails_disk_service_path \
               verified_key_with_expiration,
-              filename: filename, disposition: disposition, content_type: content_type
+              filename: filename, disposition: content_disposition_with(type: disposition, filename: filename), content_type: content_type
           else
-            "/rails/active_storage/disk/#{verified_key_with_expiration}/#{filename}?content_type=#{content_type}&disposition=#{disposition}"
+            "/rails/active_storage/disk/#{verified_key_with_expiration}/#{filename}?content_type=#{content_type}" \
+              "&disposition=#{content_disposition_with(type: disposition, filename: filename)}"
           end
 
         payload[:url] = generated_url
@@ -76,7 +85,7 @@ module ActiveStorage
     end
 
     def url_for_direct_upload(key, expires_in:, content_type:, content_length:, checksum:)
-      instrument :url, key do |payload|
+      instrument :url, key: key do |payload|
         verified_token_with_expiration = ActiveStorage.verifier.generate(
           {
             key: key,
diff --git a/activestorage/lib/active_storage/service/gcs_service.rb b/activestorage/lib/active_storage/service/gcs_service.rb
index 685dd61a0a..6f6f4105fe 100644
--- a/activestorage/lib/active_storage/service/gcs_service.rb
+++ b/activestorage/lib/active_storage/service/gcs_service.rb
@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+gem "google-cloud-storage", "~> 1.8"
+
 require "google/cloud/storage"
 require "active_support/core_ext/object/to_query"
 
@@ -7,34 +9,42 @@ module ActiveStorage
   # Wraps the Google Cloud Storage as an Active Storage service. See ActiveStorage::Service for the generic API
   # documentation that applies to all services.
   class Service::GCSService < Service
-    attr_reader :client, :bucket
-
-    def initialize(project:, keyfile:, bucket:, **options)
-      @client = Google::Cloud::Storage.new(project: project, keyfile: keyfile, **options)
-      @bucket = @client.bucket(bucket)
+    def initialize(**config)
+      @config = config
     end
 
     def upload(key, io, checksum: nil)
-      instrument :upload, key, checksum: checksum do
+      instrument :upload, key: key, checksum: checksum do
         begin
-          bucket.create_file(io, key, md5: checksum)
+          # The official GCS client library doesn't allow us to create a file with no Content-Type metadata.
+          # We need the file we create to have no Content-Type so we can control it via the response-content-type
+          # param in signed URLs. Workaround: let the GCS client create the file with an inferred
+          # Content-Type (usually "application/octet-stream") then clear it.
+          bucket.create_file(io, key, md5: checksum).update do |file|
+            file.content_type = nil
+          end
         rescue Google::Cloud::InvalidArgumentError
           raise ActiveStorage::IntegrityError
         end
       end
     end
 
-    # FIXME: Add streaming when given a block
+    # FIXME: Download in chunks when given a block.
     def download(key)
-      instrument :download, key do
+      instrument :download, key: key do
         io = file_for(key).download
         io.rewind
-        io.read
+
+        if block_given?
+          yield io.read
+        else
+          io.read
+        end
       end
     end
 
     def delete(key)
-      instrument :delete, key do
+      instrument :delete, key: key do
         begin
           file_for(key).delete
         rescue Google::Cloud::NotFoundError
@@ -43,8 +53,14 @@ module ActiveStorage
       end
     end
 
+    def delete_prefixed(prefix)
+      instrument :delete_prefixed, prefix: prefix do
+        bucket.files(prefix: prefix).all(&:delete)
+      end
+    end
+
     def exist?(key)
-      instrument :exist, key do |payload|
+      instrument :exist, key: key do |payload|
         answer = file_for(key).exists?
         payload[:exist] = answer
         answer
@@ -52,9 +68,9 @@ module ActiveStorage
     end
 
     def url(key, expires_in:, filename:, content_type:, disposition:)
-      instrument :url, key do |payload|
+      instrument :url, key: key do |payload|
         generated_url = file_for(key).signed_url expires: expires_in, query: {
-          "response-content-disposition" => disposition,
+          "response-content-disposition" => content_disposition_with(type: disposition, filename: filename),
           "response-content-type" => content_type
         }
 
@@ -65,7 +81,7 @@ module ActiveStorage
     end
 
     def url_for_direct_upload(key, expires_in:, content_type:, content_length:, checksum:)
-      instrument :url, key do |payload|
+      instrument :url, key: key do |payload|
         generated_url = bucket.signed_url key, method: "PUT", expires: expires_in,
           content_type: content_type, content_md5: checksum
 
@@ -80,8 +96,18 @@ module ActiveStorage
     end
 
     private
+      attr_reader :config
+
       def file_for(key)
         bucket.file(key, skip_lookup: true)
       end
+
+      def bucket
+        @bucket ||= client.bucket(config.fetch(:bucket))
+      end
+
+      def client
+        @client ||= Google::Cloud::Storage.new(config.except(:bucket))
+      end
   end
 end
diff --git a/activestorage/lib/active_storage/service/mirror_service.rb b/activestorage/lib/active_storage/service/mirror_service.rb
index 39e922f7ab..7eca8ce7f4 100644
--- a/activestorage/lib/active_storage/service/mirror_service.rb
+++ b/activestorage/lib/active_storage/service/mirror_service.rb
@@ -35,6 +35,11 @@ module ActiveStorage
       perform_across_services :delete, key
     end
 
+    # Delete files at keys starting with the +prefix+ on all services.
+    def delete_prefixed(prefix)
+      perform_across_services :delete_prefixed, prefix
+    end
+
     private
       def each_service(&block)
         [ primary, *mirrors ].each(&block)
diff --git a/activestorage/lib/active_storage/service/s3_service.rb b/activestorage/lib/active_storage/service/s3_service.rb
index e074269353..c95672f338 100644
--- a/activestorage/lib/active_storage/service/s3_service.rb
+++ b/activestorage/lib/active_storage/service/s3_service.rb
@@ -17,7 +17,7 @@ module ActiveStorage
     end
 
     def upload(key, io, checksum: nil)
-      instrument :upload, key, checksum: checksum do
+      instrument :upload, key: key, checksum: checksum do
         begin
           object_for(key).put(upload_options.merge(body: io, content_md5: checksum))
         rescue Aws::S3::Errors::BadDigest
@@ -26,26 +26,32 @@ module ActiveStorage
       end
     end
 
-    def download(key)
+    def download(key, &block)
       if block_given?
-        instrument :streaming_download, key do
+        instrument :streaming_download, key: key do
           stream(key, &block)
         end
       else
-        instrument :download, key do
+        instrument :download, key: key do
           object_for(key).get.body.read.force_encoding(Encoding::BINARY)
         end
       end
     end
 
     def delete(key)
-      instrument :delete, key do
+      instrument :delete, key: key do
         object_for(key).delete
       end
     end
 
+    def delete_prefixed(prefix)
+      instrument :delete_prefixed, prefix: prefix do
+        bucket.objects(prefix: prefix).batch_delete!
+      end
+    end
+
     def exist?(key)
-      instrument :exist, key do |payload|
+      instrument :exist, key: key do |payload|
         answer = object_for(key).exists?
         payload[:exist] = answer
         answer
@@ -53,9 +59,9 @@ module ActiveStorage
     end
 
     def url(key, expires_in:, filename:, disposition:, content_type:)
-      instrument :url, key do |payload|
+      instrument :url, key: key do |payload|
         generated_url = object_for(key).presigned_url :get, expires_in: expires_in.to_i,
-          response_content_disposition: disposition,
+          response_content_disposition: content_disposition_with(type: disposition, filename: filename),
           response_content_type: content_type
 
         payload[:url] = generated_url
@@ -65,7 +71,7 @@ module ActiveStorage
     end
 
     def url_for_direct_upload(key, expires_in:, content_type:, content_length:, checksum:)
-      instrument :url, key do |payload|
+      instrument :url, key: key do |payload|
         generated_url = object_for(key).presigned_url :put, expires_in: expires_in.to_i,
           content_type: content_type, content_length: content_length, content_md5: checksum
 
@@ -85,14 +91,14 @@ module ActiveStorage
       end
 
       # Reads the object for the given key in chunks, yielding each to the block.
-      def stream(key, options = {}, &block)
+      def stream(key)
         object = object_for(key)
 
         chunk_size = 5.megabytes
         offset = 0
 
         while offset < object.content_length
-          yield object.read(options.merge(range: "bytes=#{offset}-#{offset + chunk_size - 1}"))
+          yield object.get(range: "bytes=#{offset}-#{offset + chunk_size - 1}").body.read.force_encoding(Encoding::BINARY)
           offset += chunk_size
         end
       end