Shell: Add file system browser to retrieve arbitrary files

app/controllers/execution_environments_controller.rb

@@ -2,9 +2,10 @@
 
 class ExecutionEnvironmentsController < ApplicationController
   include CommonBehavior
+  include FileConversion
 
   before_action :set_docker_images, only: %i[create edit new update]
-  before_action :set_execution_environment, only: MEMBER_ACTIONS + %i[execute_command shell statistics sync_to_runner_management]
+  before_action :set_execution_environment, only: MEMBER_ACTIONS + %i[execute_command shell list_files statistics sync_to_runner_management]
   before_action :set_testing_framework_adapters, only: %i[create edit new update]
 
   def authorize!
@@ -30,11 +31,24 @@ class ExecutionEnvironmentsController < ApplicationController
 
   def execute_command
     runner = Runner.for(current_user, @execution_environment)
-    sudo = ActiveModel::Type::Boolean.new.cast(params[:sudo])
-    output = runner.execute_command(params[:command], privileged_execution: sudo, raise_exception: false)
+    @privileged_execution = ActiveModel::Type::Boolean.new.cast(params[:sudo]) || @execution_environment.privileged_execution
+    output = runner.execute_command(params[:command], privileged_execution: @privileged_execution, raise_exception: false)
     render json: output.except(:messages)
   end
 
+  def list_files
+    runner = Runner.for(current_user, @execution_environment)
+    @privileged_execution = ActiveModel::Type::Boolean.new.cast(params[:sudo]) || @execution_environment.privileged_execution
+    begin
+      files = runner.retrieve_files(path: params[:path], recursive: false, privileged_execution: @privileged_execution)
+      downloadable_files, additional_directories = convert_files_json_to_files files
+      js_tree = FileTree.new(downloadable_files, additional_directories, force_closed: true).to_js_tree
+      render json: js_tree[:core][:data]
+    rescue Runner::Error::WorkspaceError
+      render json: []
+    end
+  end
+
   def working_time_query
     "
       SELECT exercise_id, avg(working_time) as average_time, stddev_samp(extract('epoch' from working_time)) * interval '1 second' as stddev_time
@@ -225,4 +239,14 @@ class ExecutionEnvironmentsController < ApplicationController
       redirect_to ExecutionEnvironment, alert: t('execution_environments.index.synchronize_all.failure')
     end
   end
+
+  def augment_files_for_download(files)
+    files.map do |file|
+      # Downloadable files get an indicator whether we performed a privileged execution.
+      # The download path is added dynamically in the frontend.
+      file.privileged_execution = @privileged_execution
+      file
+    end
+  end
+  private :augment_files_for_download
 end

app/controllers/live_streams_controller.rb

@@ -21,12 +21,21 @@ class LiveStreamsController < ApplicationController
     send_runner_file(runner, desired_file, fallback_location)
   end
 
+  def download_arbitrary_file
+    @execution_environment = authorize ExecutionEnvironment.find(params[:id])
+    desired_file = params[:filename].to_s
+    runner = Runner.for(current_user, @execution_environment)
+    fallback_location = shell_execution_environment_path(@execution_environment)
+    privileged = params[:sudo] || @execution_environment.privileged_execution?
+    send_runner_file(runner, desired_file, fallback_location, privileged: privileged)
+  end
+
   private
 
-  def send_runner_file(runner, desired_file, redirect_fallback = root_path)
+  def send_runner_file(runner, desired_file, redirect_fallback = root_path, privileged: false)
     filename = File.basename(desired_file)
     send_stream(filename: filename, disposition: 'attachment') do |stream|
-      runner.download_file desired_file do |chunk, overall_size, content_type|
+      runner.download_file desired_file, privileged_execution: privileged do |chunk, overall_size, content_type|
         unless response.committed?
           # Disable Rack::ETag, which would otherwise cause the response to be cached
           # See https://github.com/rack/rack/issues/1619#issuecomment-848460528