fix: improve compressed download progress bars

when downloading a large and extremely compressed file, user feedback would stop after we had received an uncompressed amount of data equal to the compressed size of the data.

Downloading the spansh galaxy data, for example, only transfers 1.5GB of data after compression, but the file itself expands to over 9GB, resulting in the progress bar sticking at 1.5GB and looking as though it has failed/hung.

tradedangerous/transfers.py

@@ -149,6 +149,14 @@ def download(
             raise TradeException(
                 "Remote server gave an empty response. Please try again later."
             )
+
+    # if the file is being compressed by the server, the headers tell us the
+    # length of the compressed data, but in our loop below we will be receiving
+    # the uncompressed data, which should be larger, which will cause our
+    # download indicators to sit at 100% for a really long time if the file is
+    # heavily compressed and large (e.g spansh 1.5gb compressed vs 9GB uncompressed)
+    if encoding == "gzip" and length:
+        length *= 4
 
     if tdenv.detail > 1:
         if length: