[SRU] Cannot open a browser link from a snap that provides a link

[Sergio Schvezov]

[Impact]

Links in snaps cannot be opened on the host.

[Test Case]

Steps to reproduce:

- Run `sudo snap install telegram-sergiusens`
- Launch telegram-sergiusens.sergiusens (or from the dash)
- Receive a link
- Try an open the link.

The reason for it not working is that there is no browser in ubuntu-core and there is no handler that knows how to redirect this to the classic Ubuntu instance.

[Regression Potential]

 * The fix is a new package to be pulled in by snapd, so there is little risk of regression

[Other Info]

 * snapd-xdg-open is just one piece of two that are needed to fix this bug. The other piece is a fake xdg-open script that is available in the OS snap, which simply makes a D-Bus method invocation to the service in snapd-xdg-open

[Michael Vogt (mvo)]

Here is a strawman proposal:
- we add a small url-helper to ubuntu-core that contains "dbus-send --session snappy-url-helper $url"
- the snap needs to call "url-helper" (we could also call it xdg-open) when opening a url
- as part of the snapd deb (or as a dependency) we have a small dbus service on the host fs that listens to these dbus-send events and that proxies the url open requests (directly or via a window popup)

[Gustavo Niemeyer (niemeyer)]

Calling it xdg-open with similar semantics of xdg-open sounds nice. It already has an error code to report whether a tool was not found for it, so the application can give it a try and react appropriately if unavailable.

We need to do some basic validation on the value to make sure it looks sane and safe. xdg-open itself calls a huge number of openers and browsers, and we cannot trust that to be all safe.

[Gustavo Niemeyer (niemeyer)]

Can we prioritize this one to be handled sooner rather than later? Sounds like a very common problem desktop applications will face.

[William Hua (attente)]

Here's a proof of concept for the url helper:

https://github.com/ubuntu-core/snap-desktop-links

We just need to add the fake xdg-open script to the core image, and add the snappy-url-helper to xdg-utils along with a service file to D-Bus activate it on the host.

[Adam Conrad (adconrad)]

Hello Sergio, or anyone else affected,

Accepted snapd-xdg-open into xenial-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/snapd-xdg-open/0.0.0~16.04 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, and change the tag from verification-needed to verification-done. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Lucy Llewellyn (lucyllewy)]

I've run across a similar problem with corebird snapped using github.com/diddledan/corebird-snap. dholbach suggested that it might be this bug.

corebird cannot open browser windows with the message in the terminal:

Error org.freedesktop.DBus.Error.ServiceUnknown: The name com.canonical.SafeLauncher was not provided by any .service files

Using snapd 2.15.2 from xenial-proposed does not fix the problem in my instance. My problem _might_ be a separate issue though, so I'm NOT marking that verification has failed.

[Lucy Llewellyn (lucyllewy)]

Ok, marking verification-done. I obviously misread the instructions and had installed snapd from proposed when I should have been testing snapd-xdg-open.

snapd-xdg-open-0.0.0~16.04 fixes corebird's opening of browser windows (corebird is currently in devmode on my system).

[Martin Pitt (pitti)]

Releasing this is blocked by fixing this bug in yakkety.

[Robie Basak (racb)]

I diffed 0.0.0 from Yakkety with 0.0.0~16.04 in Xenial, and I see:

--- snapd-xdg-open-0.0.0/data/com.canonical.SafeLauncher.service 1970-01-01 00:00:00.000000000 +0000
+++ snapd-xdg-open-0.0.0~16.04/data/com.canonical.SafeLauncher.service 2016-07-07 16:39:57.000000000 +0000
@@ -0,0 +1,3 @@
+[D-BUS Service]
+Name=com.canonical.SafeLauncher
+Exec=/usr/lib/x86_64-linux-gnu/snapd-xdg-open

It seems that data/com.canonical.SafeLauncher.service has been added in the Xenial backport, but this is not mentioned in the changelog. Was this intentional? Could this mean that the version in Yakkety doesn't work?

[Martin Pitt (pitti)]

> Releasing this is blocked by fixing this bug in yakkety.

Ping? Yakkety releases tomorrow and it's too late to land this in yakkety proper, but it should at least be a yakkety SRU. Releasing this to xenial-updates is still blocked by fixing it in the devel series.

[Sebastien Bacher (seb128)]

The .service is generated at build time by the Makefile

"com.canonical.SafeLauncher.service: Makefile
 $(AM_V_GEN) (echo '[D-BUS Service]'; \
              echo 'Name=com.canonical.SafeLauncher'; \"

the static version included in the xenial upload shouldn't be there but it doesn't create issue since it's replaced a buildtime (you can look at the i386 the libexecdir is correct and not the x86 one from the static version)

[Launchpad Janitor (janitor)]

This bug was fixed in the package snapd-xdg-open - 0.0.0~16.04

---------------
snapd-xdg-open (0.0.0~16.04) xenial; urgency=medium

  * Backport to xenial (LP: #1580740)

 -- Ubuntu Desktop Team <email address hidden> Fri, 07 Jul 2016 12:45:00 -0400

[Brian Murray (brian-murray)]

The verification of the Stable Release Update for snapd-xdg-open has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

[Lucy Llewellyn (lucyllewy)]

did this get SRUd for yakkety, too? if not, then that needs to happen!

[Ville Ranki (ville-ranki)]

Nope, still can't open links from snaps in Yakkety.

[Oliver Grawert (ogra)]

there was another issue found in snap-confine that is just being fixed see bug 1661023
this should soon land in xenial (not sure when it will make its way into yakkety though)