PDF only embeds first 19 external images, then blanks. No error present

[jathayde]

PDF only embeds first 19 external images, then blanks. No error present

[unixmonkey]

I suspect your issue is that the image has to load from a remote source multiple times, which is longer than the timeout to get assets, so wkhtmltopdf gives up.

You can try adjusting the timeout, or using the window_status setting. Though, if the images are the same repeated, I'd suggest caching them so they don't have to re-download every time.

Maybe something like this (untested, but I'm sure you'll see where I'm going):

def embed_remote_image(url, content_type)
  # Setup data store to memoize assets already downloaded.
  @assets ||= @assets.presence || {}
    
  # Return early from cache if already cached.
  return @assets[url] if @assets[url].present?

  asset = URI.open(url, "r:UTF-8", &:read)
  base64 = Base64.encode64(asset.to_s).gsub(/\s+/, "")
  result = "data:#{content_type};base64,#{Rack::Utils.escape(base64)}"

  # Cache { url: result } to @assets hash for later requests to the same URL.
  @assets[url] = result

  result
rescue OpenURI::HTTPError => e
  if e.message == '404 Not Found'
    Rails.logger.debug "Missing file"
  elsif e.message == '403 Forbidden'
    Rails.logger.debug "Forbidden file"
  else
    Rails.logger.debug { "HTTP Error: #{e.message}" }
  end
end

[dmitry]

Have you tried to render the same image more than 18 times (have you tried to debug URI.read return?)?
I've tried to render base64 images and it can render 500 easily.

[jathayde]

Interesting follow up - I've been trying to work on this intermittently. A real-time render on a similar PDF on the site will do hundreds of images no problem. Only when it kicks to a background task does this happen. So somewhere in either the controller or the task, this is failing silently. There's nothing glaring in console (but it also runs by a mile a minute pulling everything in). I'm guessing something is breaking in the background task, and not with the image fetching itself.