User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:35.0) Gecko/20100101 Firefox/35.0 Build ID: 20150125222008 Steps to reproduce: User agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:35.0) Gecko/20100101 Firefox/35.0 - Log in a moodle platform - click on a pdf file to open it NOTE: This issue is (in my opinion) unrelated to the default behaviour of the pdf-viewer but rather to the innability of firefox (also happens in Google Chrome) to realize that it should open the pdf-viewer instead of asking what to do. Firefox correctly opens a pdf file as long as the URL states it (example pdf-file: http://www.ripe.net/ripe/meetings/ripe-52/presentations/ripe52-plenary-kroot-anycast.pdf), nevertheless these condition doesn't happen for the moodle files, which (I think) are under a javascript function for getting them. Actual results: - Firefox ask what to do with the pdf file (open it with OS default viewer, save it) Expected results: Open the pdf file in the pdf built-in viewer.

We need either an example public url or you can post the http headers from the server for a request. >but rather to the innability of firefox (also happens in Google Chrome) to realize that it should open the pdf-viewer instead of asking what to do. I guess you don't know that there is a "content-disposition: attachment" http header that always forces a save as window. That is mandatory based on the http RFCs.

firefox http headers for biased pdf viewer

Hey Mathias Yes you are right, I don't know the content of the http RFCs. I am just a user that wanted to see a pdf in firefox but couldn't. Therefore I thought that it might be a bug. I just hoped that it can make firefox even better :) Now you can see http headers that you requested me. I hope it helps. In that case I loaded the headers while forcing firefox to open the pdf on itself i.e. selecting the firefox binary as the option in the "open with" drop down menu.

from the log: Content-Disposition: attachment; filename="NGI4-MultimediaTransport_ZusatzWS1415.pdf" This http header forces a download....