Submit datafile

[alephreish]

Not sure what the root of the problem is, but it's impossible to submit any file on https://site.shinyserver.dck.gmw.rug.nl/ggplotgui/: file upload goes smoothly, but upon hitting the "Submit datafile" button the server disconnects and no data is loaded. Local version works fine.

For the sake of context, my request header looks as follows:

GET /ggplotgui/ HTTP/1.1
Host: site.shinyserver.dck.gmw.rug.nl
User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:57.0) Gecko/20100101 Firefox/57.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate, br
Connection: keep-alive
Upgrade-Insecure-Requests: 1

[alephreish]

OK, this particular issue affects only xls files and is likely due to the package readxl not being included. CSV parsing is a separate issue #7