This commit includes a paydown on technical debt incurred two years ago,
when I didn't know that it was bad to make custom Read and Show instances
for types. As the routes need Read and Show for Transfer, which includes a
Key, and deriving my own Read instance of key was not practical,
I had to finally clean that up.
So the compact Key read and show functions are now file2key and key2file,
and Read and Show are now derived instances.
Changed all code that used the old instances, compiler checked.
(There were a few places, particularly in Command.Unused, and the test
suite where the Show instance continue to be used for legitimate
comparisons; ie show key_x == show key_y (though really in a bloom filter))
This should work on linux (xdg-open) and OSX (open). If the program
is not in $PATH, it falls back to opening a browser window/tab with file:///
The only tricky bit is the javascript code, that handles clicking on the
link. This is to avoid unnecessary page refreshes. Until I added the
return false at the end, the <a>'s normal click event also fired, so two
file browsers opened. I have not checked portability extensively.
This allows me to not build-depend on blaze-markup, which was causing
me some trouble when tring to build with cabal on debian. Seems debian
ships Text.Blaze.Renderer.String in two packages.
Now the javascript does an ajax call at the start to request the url
to use to poll, and the notification id is generated then, once we know
javascript is working.
Depending on how the webapp was started up and whether the user clicked on
any links in it, window.close() may be disallowed by browser security
policy. Also if that fails, display a modal dialog that nicely blackens out
the webapp.
TODO: avoid Escape closing it. Bootstrap's docs are unclear about how to do
that.
