html5 users should be allowed to upload/download

[ERIC GRAMMATICO]

Upload/download any type of file from html5 interface is not possible for the time being.

At this time of writing only pdf printing is possible.

[Antoine Martin]

Added download support in r15360 + r15361 + r15363 + r15364, including options on the connect dialog page, we now fallback to downloading the PDF if the print popup is blocked.
I can trigger a download using:

xpra control :10 send-file "/home/antoine/Downloads/changeset_15139.diff"

Also added the ability to save print jobs on the server using XPRA_SAVE_PRINT_JOBS=/some/path/ in r15362. (useful for comparing)

Still TODO: add a GUI toolbar we can click on, this can be used for an upload button, we could also show a download button if the user wants to make the download a manual process, same for clipboard (#1461) which could use an indicator and run fully synchronously (without necessarily needing to sync with the PRIMARY selection). Same for printing: we can show the document to print using a button in that toolbar.

Noticed that the HTML5 code never got updated for chunked transfers (#1026), would be nice to add.

Upload links:

• ​get filename
• ​Convert file input to Blob
• ​File APIs: we may want to support uploading multiple files at once, drag and drop would be cool (no need for toolbar!)
• we can get the mimetype from blob.type

[Antoine Martin]

Support for uploading files added in r15370.
The toolbar functionality has been moved to a new ticket: #1471.

To test:

• start a server:

  xpra start --bind-tcp=0.0.0.0: --no-daemon --open-files=yes
  

(with older versions, "open-files" can only be set through the /etc/xpra/conf.d/15_file_transfers.conf - not setting this option will allow the file to be uploaded, but it will not be opened)

• open the html5 client in a browser, ie:

  xdg-open http://localhost:14500/
  

Then you can just open a file manager and drop any file onto the html5 client, and it will magically appear there. (after the upload, it will be opened using the default application, which is "xdg-open" on Linux)

@ERIC GRAMMATICO: to test, you need the latest html5 client code, which you can download from svn here: http://xpra.org/svn/Xpra/trunk/src/html5/, this should work with any recent version of the xpra server.
(for testing downloads, see comment:2)

[ERIC GRAMMATICO]

Works ! Thanks !