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Class: ActiveStorage::Previewer

Relationships & Source Files
Namespace Children
Classes:
MuPDFPreviewer, PopplerPDFPreviewer, VideoPreviewer
Extension / Inclusion / Inheritance Descendants
Subclasses:
MuPDFPreviewer, PopplerPDFPreviewer, VideoPreviewer
Inherits: Object
Defined in: activestorage/lib/active_storage/previewer.rb

Overview

This is an abstract base class for previewers, which generate images from blobs. See MuPDFPreviewer and VideoPreviewer for examples of concrete subclasses.

Class Method Summary

Instance Attribute Summary

Instance Method Summary

Constructor Details

.new(blob) ⇒ Previewer

[ GitHub ] 

  


# File 'activestorage/lib/active_storage/previewer.rb', line 18



def initialize(blob)
  @blob = blob
end


  







Class Method Details



  

    .accept?(blob)  ⇒ Boolean 
  



  

    

Implement this method in a concrete subclass. Have it return true when given a blob from which the previewer can generate an image.


  





  


  [ GitHub ]


  

  


# File 'activestorage/lib/active_storage/previewer.rb', line 14



def self.accept?(blob)
  false
end


  







Instance Attribute Details



  

    #blob   (readonly)
  

  [ GitHub ]


  

  


# File 'activestorage/lib/active_storage/previewer.rb', line 10



attr_reader :blob


  







Instance Method Details



  

    #preview(**options)  
  



  

    

Override this method in a concrete subclass. Have it yield an attachable preview image (i.e. anything accepted by Attached::One#attach). Pass the additional options to the underlying blob that is created.


  





  
Raises:


    
  
  • 
    (NotImplementedError)
  
    • 





  [ GitHub ]


  

  


# File 'activestorage/lib/active_storage/previewer.rb', line 25



def preview(**options)
  raise NotImplementedError
end