The GNOME Platform, Awn, and the Cloud

Benjamin Otte recently wrote about desktop-web integration in the GNOME desktop. It's kind of interesting that he calls himself "not web enabled", given that he's the main developer of the swfdec library and associated applications. I agree with most of what he wrote, but there are a few comments I would like to make.

Benjamin asks:

Why does dconf (or GConf) not store my settings in the cloud so it uses the same settings on my university login?

As I understand it, this is one of the features of Conduit. There's a bug in Awn regarding config synchronization via Conduit. I'm probably going to look into how that works when I resume work on the config interface for libdesktop-agnostic.

There is an erroneous statement in his post:

We don't even have a http library that knows cookies.

libsoup has had (non-persistent) cookie support since 2.23.1, and persistent support will be in 2.26.0.

And then there's the main point:

[GNOME is] doing a very bad job at integrating the web into the desktop. Apart from epiphany (and the weather applet), what application does GNOME ship that speak http?

I believe there are two main reasons for this: One is GNOME developers are not "web-enabled". [...] The other, related reason is that we don't have the software to do this.

In Awn-land, we have several web-enabled applets:

• arss
• comics
• digg
• lastfm
• meebo
• pandora
• rtm
• weather
• webapplet

In particular, webapplet is a work in progress framework, which will allow what is essentially an applet version of Mozilla Prism. It currently uses WebKit as the backend, although there is also a Gecko-based backend planned. The rest of the applets listed are written in Python. In particular, the digg, meebo, pandora, and rtm applets use the gtkmozembed Python bindings to view the respective websites. Here lies one of the problems of the web-enabling the GNOME platform. This library is acknowledged to be less than ideal. If you look at the source code of the applets, you'll see that there are some ugly hacks in order to make them work properly on Ubuntu systems. Webapplet is slated to replace that ugliness.

One of my side projects is a status aggregator applet. It's supposed to aggregate all of these social networking status feeds and also to sync all of your personal statuses. One of said social networking websites returns complex, site-specific HTML that obviously needs to be sanitized/canonicalized. The easiest (but not necessarily most memory-efficient) method of performing that task is to use the DOM. There is not currently a DOM library for the GNOME platform. There is a libgdom3 project (written in Vala) which I believe is being / will be used by the gnome2-globalmenu project, but it is unfinished. There is also an old, unmaintained library called gdome2 based on libxml2. I'm not even sure if anyone actually uses that library anymore (its last release was in 2003). I avoided using gtkmozembed and friends based on the experiences described above. I settled on a promising feature request for WebKit: a GObject/C DOM binding. (As an aside, the WebKit bug linked is a fascinating case study on several levels: conflicting coding standards, conflicting developer personalities, and some interesting coding/reviewing.) It's very nice - I can manipulate document fragments as if I were using JavaScript in a web page, among other things. I eagerly await that feature being committed to WebKit trunk.It is an important stepping stone when it comes to working with the web.

Another side project that I'm currently working on is a developer dashboard applet. It's kind of like the previous applet, except as applied to software projects. I was originally going to write it in Vala, which meant that I would have to write an interface to (at least) the Launchpad API, which meant implementing at least three specifications in Vala: OAuth, URI templates, and WADL. I finished the first two (I haven't yet decided whether to release my URI templates implementation as a separate library - the implementation plus the test app is 451 source lines of code), and WADL is a very complex specification. So, I decided to postpone working on the WADL library and instead am currently working on a prototype applet using Python and launchpadlib. Implementations for those three specifications and many others (including AtomPub) should be included in the GNOME platform if it wants to be web-enabled.

Announcement: OAuth Client Library

For the past week or so, I've been working on various web services-related libraries, in the hopes of writing some sort of Launchpad dashboard applet for Awn. I think it would be nice to have new/recently changed bugs in Awn/Awn Extras at a glance in the dock, among other things. The first somewhat complete component is an OAuth client library. I finished the initial implementation (plaintext signature only) in under nine hours, and after the Awn 0.3.2 release (and a bit of frustration), I added HMAC-SHA1 signature support with the help of RFCs 2104 and 2202 (using GLib's checksum API). I've tested it with both the OAuth example Python server and the Launchpad API.

Also included in the source are two small test programs: one tests the HMAC-SHA1 implementation, and the other tests the OAuth implementation in its entirety. The latter uses .ini-style config files to define keys/secrets/URIs/etc. for a service.

There are a few things that still need to be done, in order for it to be a "complete" implementation. I probably want to replace my handwritten HMAC-SHA1 implementation with a libgcrypt-based one (although I'd have to figure out how to create bindings for Vala), which would also enable me to add RSA-SHA1 signature support. Additionally, I should probably add an asynchronous equivalent to the current synchronous API. Finally, it would be nice if it integrated better with libsoup's existing authentication structure. Currently, I just generate an Authorization: header to be manually added.

The next component I'm working on is a WADL dispatcher library. I don't like the idea of a library generating code (as I presume wadl2java does). We'll see how this turns out.