aws & file checker

I have had open file from url function working under test conditions. The function accesses the url link, validates if it's a file from the internet & raises an exception if it's not. It downloads the file locally, and weblogo can open it from there. I added a file checking procedure to the the open URL function. I researched all the file extensions of formats that WebLogo accepts such as PIR, NEXUS, PHYLIP etc in addition to .txt files. It parses the path of the locally saved file to isolate the file extension and compares the file extension to the acceptable file types, and raises an exception if it the file type isn't valid. I'm reviewing the aws tutorials on how to launch web apps, and will change the dropbox chooser to a download URL checkbox, and the sequence box will accept a URL string instead of sequence data.