Interact with a file_field inside span - Watir/Selenium-Webdriver - ruby

Question

How do I interact with a file_field thats hidden by its parent?
<span class="btn button-large fileinput-button">
Select files...
<input accept="image/png, image/gif, image/jpeg" id="gallery_files" multiple="multiple" name="gallery_files" type="file">
</span>
The button overlays the input, therefore it's not visible.
Edit
For the record, here's my code:
data[:photos].each do |photo|
$browser.file_field.set photo
end
and the error: Watir::Wait::TimeoutError: timed out after 20 seconds, waiting for {:tag_name=>"input", :type=>"file"} to become present
Workable example in a Gist

Answer 1

I was a bit suprised, but I was able to set the file field in the sample HTML without any issue using:
browser.file_field.set('path/to/file.txt')
From the code, it looks like setting the file field only requires the input to exist. It does not require it to be visible (or present).
Given that you are getting a Watir::Wait::TimeoutError exception, I would guess that your code is actually failing before the file_field.set. As it looks like the page has the input in a dialog, I am guessing your code actually looks more like:
$browser.file_field.wait_until_present
data[:photos].each do |photo|
$browser.file_field.set photo
end
It would be the wait_until_present method that is actually throwing the exception.
Solution 1
Assuming that an explicit wait method is being called for the file field, you should be able to just remove the wait.
If you have the wait because the dialog is being loaded by Ajax, you could try waiting for a different element instead - eg the parent span.
Solution 2
If for some reason you need the file field to be present, you will need to change its CSS. In this case, the opacity:
p $browser.file_field.present?
#=> false
$browser.execute_script('arguments[0].style.opacity = "1.0";', browser.file_field)
p $browser.file_field.present?
#=> true

Answer 2

For my situation, this worked:
$browser.execute_script("jQuery(function($) {
$('.fileinput-button').css('visibility', 'hidden')
$('#gallery_files').css('visibility', 'visible').css('opacity', '1').css('width', '100').css('height', '50')
})")
I had to hide the parent span, then show, resize, and change the opacity of the input