[ActiveStorage] Possible to override storage preview for custom service?

Rikki_Pitt · March 13, 2018, 10:38pm

Hi folks,

I’m testing out Rails 5.2.0.rc1 and decided to dive in by creating an activestorage service for Dropbox.

A project I’m working on requires the upload of files to the Dropbox platform which I’ve successfully achieved.

Dropbox provides it’s own preview images for a vast number of file types (e.g. PSD, PNG, JPG, Sketch etc).

I was wondering how I might go about extending/overriding the attachment previewer to use and return a URL from the Dropbox API if they have one?

Thanks for any advice you might have.

Best,

Rikki

Rikki_Pitt · March 14, 2018, 12:05am

Ah ha, this looks promising:

github.com

rails/rails/blob/main/activestorage/app/models/active_storage/preview.rb

# frozen_string_literal: true

# Some non-image blobs can be previewed: that is, they can be presented as images. A video blob can be previewed by
# extracting its first frame, and a PDF blob can be previewed by extracting its first page.
#
# A previewer extracts a preview image from a blob. Active Storage provides previewers for videos and PDFs.
# ActiveStorage::Previewer::VideoPreviewer is used for videos whereas ActiveStorage::Previewer::PopplerPDFPreviewer
# and ActiveStorage::Previewer::MuPDFPreviewer are used for PDFs. Build custom previewers by
# subclassing ActiveStorage::Previewer and implementing the requisite methods. Consult the ActiveStorage::Previewer
# documentation for more details on what's required of previewers.
#
# To choose the previewer for a blob, Active Storage calls +accept?+ on each registered previewer in order. It uses the
# first previewer for which +accept?+ returns true when given the blob. In a Rails application, add or remove previewers
# by manipulating +Rails.application.config.active_storage.previewers+ in an initializer:
#
#   Rails.application.config.active_storage.previewers
#   # => [ ActiveStorage::Previewer::PopplerPDFPreviewer, ActiveStorage::Previewer::MuPDFPreviewer, ActiveStorage::Previewer::VideoPreviewer ]
#
#   # Add a custom previewer for Microsoft Office documents:
#   Rails.application.config.active_storage.previewers << DOCXPreviewer

This file has been truncated. show original

Topic		Replies	Views
[Active Storage] Multiple Previews rubyonrails-core feature	0	320	July 26, 2019
Non-image file variants rubyonrails-core activestorage	5	622	June 10, 2023
[ActiveStorage][Feature Proposal] Adding Support of Dropbox rubyonrails-core	11	915	April 9, 2019
Accessing ActiveStorage image variants directly rubyonrails-talk	3	476	January 23, 2024
[ActiveStorage] Make a preview from a middle frame of the attached video rubyonrails-core feature	1	462	October 1, 2019

[ActiveStorage] Possible to override storage preview for custom service?

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