does not work with ftp files (1.8.557 latest version for Chrome)

[yashamon]

Link to PDF file (or attach file here): ftp://ftp.fernuni-hagen.de/pub/pdf/urz-broschueren/broschueren/a0279510.pdf
Configuration:

• Web browser and its version: Chrome 61.0.3163.91
• Operating system and its version: OSX 10.12.6
• PDF.js version: 1.8.557
• Is an extension: yes

Steps to reproduce the problem:

1. Go to ftp pdf like ftp://ftp.fernuni-hagen.de/pub/pdf/urz-broschueren/broschueren/a0279510.pdf2.
   Get unexpected server error.

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension):

[yashamon]

So I am guessing chrome users are kind of second class citizens in this case :(

[Snuffleupagus]

According to https://bugs.chromium.org/p/chromium/issues/detail?id=435547#c46, this is an upstream issue in Google Chrome itself rather than in the PDF.js extension.

[Rob--W]

I'm going to disable ftp support for Chrome 59+ because of the upstream Chrome issue.

I can think of a work-around to enable FTP display anyway, but I am not sure if that is worth the effort. @yashamon Would it be an acceptable solution for you to be able to open ftp PDFs in Chrome (either with the built-in viewer, if any, or as a download + drag file to Chrome)?

The work-around that I am thinking of relies on the fact that Chrome only allows ftp:-requests from ftp:-URLs:

1. Find any tab with the ftp: scheme.
2. If not found, open a temporary (inactive) tab with a ftp: URL.
3. Let the extension run a content script in the tab (from 1 or 2), and let that script fetch the ftp:-resource.
4. Send back the response to the original tab and show the PDF.

Now, if there is an existing tab with a ftp:-URL, then this work-around would barely have any noticeable difference when compared with the pre-Chrome 59 method. But if there is not such a tab (which I fully expect), then opening a tab can be confusing. But that confusion might be worth it, if the alternative is to not have an easy way to display PDF files.

[timvandermeij]

Closing since #9595 is merged.

[Rob--W]

FYI: Upstream bug report to request access to ftp URLs: https://bugs.chromium.org/p/chromium/issues/detail?id=904455