Downloads::File: fix following 302 redirects during download.

Fixes downloading yande.re preview images for iqdb. Yande.re previews
return a 302 redirect to the actual file. Before the html in the body of
the 302 response would get prepended to the image file.

https://files.yande.re/data/preview/12/8f/128fb480d8589be26d1dce7e1d841bcb.jpg
=> https://assets.yande.re/data/preview/12/8f/128fb480d8589be26d1dce7e1d841bcb.jpg

app/logical/downloads/file.rb

@@ -26,9 +26,9 @@ module Downloads
       end
     end
 
-    def download!(tries: 3, **options)
+    def download!(url: uncached_url, tries: 3, **options)
       Retriable.retriable(on: RETRIABLE_ERRORS, tries: tries, base_interval: 0) do
-        file = http_get_streaming(uncached_url, headers: strategy.headers, **options)
+        file = http_get_streaming(url, headers: strategy.headers, **options)
         return [file, strategy]
       end
     end
@@ -43,6 +43,8 @@ module Downloads
       size = 0
 
       res = HTTParty.get(url, httparty_options) do |chunk|
+        next if chunk.code == 302
+
         size += chunk.size
         raise Error.new("File is too large (max size: #{max_size})") if size > max_size && max_size > 0
 
@@ -66,6 +68,10 @@ module Downloads
       url
     end
 
+    def preview_url
+      @preview_url ||= Addressable::URI.parse(strategy.preview_url)
+    end
+
     def file_url
       @file_url ||= Addressable::URI.parse(strategy.image_url)
     end