"No screenshot available" handling / non-ubuntu branding

We shall have to speak to the screenshots.debian.net guys to work this one out.

To retrieve a screenshot thumbnail, we simple have an image pointing to screenshot.debian.net/thumbnail/PACKAGENAME

When there is no screenshot, the site simply returns that placeholder image instead, there is no current way of telling us that there is infact no screenshot

@Kiwinote
If you want to chase this up with the screenshot.debian.net guys, you are most welcome :-)

Is the placeholder image at least returned with a 404 response code?

@mpt:
no, the placeholder image doesn't come with a 404 response code.

A not so clean workaround would be to check the filesize and the last
modified date of the image. If you looked at both of them you could be
reasonably sure if the image returned is or isn't the placeholder image. The
only problems with that would be that once in however many thousand times
you may block an image which you shouldn't and that you would need to roll
out a new update of software-store if the screenshots.debian.org people
modify the image.

screenshots.debian.net that should be..

On Tue, Sep 8, 2009 at 4:48 PM, Kiwinote <email address hidden> wrote:

> @mpt:
> no, the placeholder image doesn't come with a 404 response code.
>
> A not so clean workaround would be to check the filesize and the last
> modified date of the image. If you looked at both of them you could be
> reasonably sure if the image returned is or isn't the placeholder image. The
> only problems with that would be that once in however many thousand times
> you may block an image which you shouldn't and that you would need to roll
> out a new update of software-store if the screenshots.debian.org people
> modify the image.
>

Hi, I'm the creator and admin of screenshots.debian.net. I've already worked with Michael Vogt to get screenshot support running in Synaptic which I think is a great feature.

I'll be happy to help you brand screenshots.debian.net to make it more ubuntu-ish. Let me know which way you prefer.

(1) Should a missing screenshot return a dummy image? Or no image but just a 404 response? The dummy image has the big advantage to trivially integrate into any website by just using an IMG-SRC tag and always getting a valid image back.
(2) I could offer some kind of machine-readable information per package. Like a JSON response that would help you figure out if a certain screenshot is available and what its URLs are.
(3) Could you provide me with a dummy placeholder sized 160x120 (for the small thumbnail) and 800x600 (for the actual large screenshot)?
(4) As you can see on http://screenshots.debian.net/ ("Using our screenshots") there are a few URLs that can be used to retrieve screenshots and thumbnails. Any special preference on how the URLs for Ubuntu could look? I could imagine

 http://screenshots.debian.net/thumbnail/PACKAGENAME/ubuntu
 or
 http://screenshots.debian.net/thumbnail-ubuntu/PACKAGENAME
 instead of
 http://screenshots.debian.net/thumbnail/PACKAGENAME

and

 http://screenshots.debian.net/screenshot/PACKAGENAME/ubuntu
 or
  http://screenshots.debian.net/screenshot-ubuntu/PACKAGENAME
 instead of
 http://screenshots.debian.net/screenshot/PACKAGENAME

I'd appreciate a CC to <email address hidden> in case I miss any updated on this bug report.

Christoph

I was thinking that method 4) with:

http://screenshots.debian.net/screenshot-ubuntu/PACKAGENAME
or
http://screenshots.debian.net/thumbnail-ubuntu/PACKAGENAME

Would be the easiest to implement for us and hopefully for you as well. Michael will be back tomorrow and so can put his point of view across as well :-)

I couldn't find an SVG (or another high-resolution) version of the Ubuntu logo. Attached to this bug are the Gimp files (XCF) for the large and small dummy screenshot I created for Debian. If someone uses these to provide Ubuntu dummy graphics files then I can concentrate on adding Ubuntu support. Okay?

sorry for messing you around Christoph but with regards to a feature request it might be best if there was a way we could detect whether there was no screenshot available :-(

Also this way the branding would be easy for other distros, say Linux Mint wanted to brand it; without putting more work on you, it would scale better.

Is there an easy way which we could do this that wouldn't be too much work for you?

I will ask Canonical's IS team to set up a proxy that initially passes requests directly to screenshots.debian.net, but that could cache heavily-requested screenshots in the future if necessary, as well as providing its own 404 image.

In the meantime, the Store should be sending its own User-Agent: header, including version number and OS version, if it is not already. Something like: "Software Store/0.3.4 (N;) Ubuntu/9.10 (karmic)". That way screenshots.debian.net (or any future server) can vary the results it returns, based on the OS and version. (There are elements missing from that string, e.g. eventually we might want screenshots to match the requested language, but we can leave that for now.)

Christoph, I don't see you subscribed, but in case you see this: It's perfectly legitimate to return an image as the body of a 404 response. I suggest you do this, so that Synaptic etc can continue to work unmodified, but proxies can save your bandwidth by requesting the body only if the header has a response code of 200.

I talked to Michael Vogt and we decided that at first I'll implement a http://screenshots.debian.net/screenshots-ubuntu/%s URL schema that will return a 404 if no screenshot is available. I'll get back to you as soon as the web site is updated. I hope I find time this evening to do that. The change is pretty trivial.

I'm open to anything. If that 404 stuff doesn't work then let's find a better solution. :)

I'll also check if I can return the dummy image along with the 404 code. I haven't yet done that with my web framework. But should be possible.

I made it send the user-agent string now.

I just played with the JS code and I don't think we can use xmlhttp here because the security model will prevent access from a file:/// url to a http:// url (request not going to the same site). So we need to code this in python.

This bug was fixed in the package software-center - 0.4.5

---------------
software-center (0.4.5) karmic; urgency=low

  * softwarecenter/view/appdetailsview.py:
    - avoid blocking if the authentication dialog comes up
      (LP: #436413)
  * softwarecenter/view/appdetailsview.py:
    - switch to use urls that return 404 if a package has no
      screenshot
  * softwarecenter/view/widgets/imagedialog.py,
    softwarecenter/view/appdetailsview.py:
    - merge lp:~mvo/software-center/ubuntu-404 that implements 404
      handling and show ubuntu branded dummy image (LP: #425874)
  * softwarecenter/view/appview.py:
    - support environment to switch sorting for searches:
      SOFTWARE_CENTER_SEARCHES_SORT_MODE={popcon,alphabetic,xapian}
      (to be able to test the different mode quickly)
  * softwarecenter/view/appdetailsview.py:
    - fix crash when no icon can be found (LP: #442040, LP: #440306)
  * softwarecenter/view/catview.py:
    - do not crash if no icon can be found (LP: #441171)
  * data/templates/CategoriesView.html:
    - disable drag-n-drop (LP: #440446)

 -- Michael Vogt <email address hidden> Mon, 05 Oct 2009 18:23:27 +0200