tooltip for pdf size (automatically found)

I have tables listing various pdf documents in my wiki. I use [[Image:Pdficon.png|16px|link={{filepath:MyFileName.pdf}}]] in the wiki table to display a small icon (Pdficon.png) that when clicked opens the pdf file.

I want to get a popup showing the size of the pdf file when I mouse over the icon. I know I can do it "manually" with the RegularTooltips extension like this: {{#inline-tooltip: | 350 kB}}.

However, I would like to have some wiki code that finds the filesize (e.g. 350 kB) and populates that popup for me automatically.

Is there anything remotely close to this already available?

If you have Scribunto installed, you can use the file attribute of the mw.title object by defining Module:File data:

-- Convert a property to custom unit of measurement:
local bit32 = require 'bit32'
local conversions = {
    size = function (bytes, unit)
        local shifts = { b = 0, kb = 10, mb = 20, gb = 30 }
        return bit32.rshift (bytes, shifts [(unit or 'b'):lower()] or 0)
    end
}

-- Function that returns a function returning certain file attribute:
local function attribute_function (attr)
    return function (frame)
        local text = frame.args [1]
        local title = mw.title.new (text, 6) -- 6 is File:.
        local attrs = title.file
        if not attrs.exists then
            return nil
        end
        -- Take multi-page files into account (| page = n):
        if frame.args.page and attrs.pages then
            attrs = attrs.pages[tonumber (frame.args.page) or 1]
        end
        local value = attrs [attr]
        -- Process optional parameters if defined for this property:
        if conversions [attr] then
            -- Normal table methods do not work on frame.args:
            local optional = {}
            for key, arg in ipairs (frame.args) do
                if key ~= 1 then
                    optional [key - 1] = arg
                end
            end
            value = conversions [attr] (value, unpack (optional))
        end
        return value
    end
end

local module = {}

for _, property in ipairs {
    'width',
    'height',
    'size',
    'mimeType',
    'length'
} do
    module [property] = attribute_function (property)
end

return module

Get the file size by adding to wikitext:

• {{#invoke:File data|size|MyFileName.pdf}} or
• {{#invoke:File data|size|MyFileName.pdf|KB}}