Disclaimer: This is a personal web page. Contents written here do not represent the position of my employer.
Saturday, February 08, 2020
Xamarin forks and whatnots
- In Linux(GTK), cold storage mode when pairing was broken, because the absence of internet connection was not being detected properly. The bug was in a 3rd-party nuget library we were using: Xam.Plugin.Connectivity. But we couldn't migrate to Xamarin.Essentials for this feature because Xamarin.Essentials lacks support for some platforms that we already supported (not officially, but we know geewallet worked on them even if we haven't released binaries/packages for all of them yet). The solution? We forked Xamarin.Essentials to include support for these platforms (macOS and Linux), fixed the bug in our fork, and published our fork in nuget under the name `DotNetEssentials`. Whenever Xamarin.Essentials starts supporting these platforms, we will stop using our fork.
- The clipboard functionality in geewallet depended on another 3rd-party nuget library: Xamarin.Plugins.Clipboard. The GTK bits of this were actually contributed by me to their github repository as a Pull Request some time ago, so we just packaged the same code to include it in our new DotNetEssentials fork. One dependency less to care about!
- Xamarin.Forms had a strange bug that caused some buttons sometimes to not be re-enabled. This bug has been fixed by one of our developers and its fix was included in the new pre-release of Xamarin.Forms 4.5, so we have upgraded geewallet to use this new version instead of v4.3.
PS: Apologies if the previous blogpost to this one shows up in planets again, as it might be a side-effect of updating its links to point to the new git repo!
Sunday, January 05, 2020
- Make it even more user friendly: blockchain addresses are akin to the numeric IP addresses of the early 80s when DNS still didn’t exist. We plan to use either ENS or IPNS or BNS or OpenCAP so that people can identify recipients much more easily.
- Implement Layer2 technologies: we’re already past the proof of concept phase. We have branches that can open channels. The promise of these technologies is instantaneous transactions (no waits!) and ridiculous (if not free) fees.
- Switch the GTK Xamarin.Forms driver to work with the new “GtkSharp” binding under the hood, which doesn’t require glue libraries. (I’ve had quite a few nightmares with native dependencies/libs when building the sandboxed snap package!)
- Integrate with some Rust projects: MimbleWimble(Grin) lib, the distributed COMIT project for trustless atomic swaps, or other Layer2-related ones such as rust-lightning.
- Cryptography work: threshold keys or deniable encryption (think "duress" passwords).
- NFC support (find recipients without QR codes!).
- Tizen support (watches!).
- Acceptance testing via UI Selenium tests (look up the Uno Platform).
- Flatpak support: unfortunately I haven’t had time to look at this sandboxing technology, but it shouldn’t be too hard to do, especially considering that there’s already a Mono-based project that supports it: SparkleShare.
- Ubuntu packaging: there’s a patch blocked on some Ubuntu bug that makes the wallet (or any .NET app these days, as it affects the .NET package manager: nuget) not build in Ubuntu 19.10. If this patch is not merged soon, the next LTS of Ubuntu will have this bug :( As far as I understand, what needs to be solved is this issue so that the latest hotfixes are bundled. (BTW I have to thank Timotheus Pokorra, the person in charge to package Mono in Fedora, for his help on this matter so far.)
- GNOME community: I’m in search for a home for this project. I don’t like that it lives in my GitLab username, because it’s not easy to find. One of the reasons I’ve used GitLab is because I love the fact that being open source, many communities are adopting this infrastructure, like Debian and GNOME. That’s why I’ve used as a bug tracker, for merge requests and to run CI jobs. This means that it should be easy to migrate to GNOME’s GitLab, isn’t it? There are unmaintained projects (e.g. banshee, which I couldn’t continue maintaining due to changes in life priorities...) already hosted there, so maybe it’s not much to ask if I could host a maintained one? It's probably the first Gtk-based wallet out there.
- Please don’t ask me to add support for your favourite %coin% or <token>.
PS: If you're still not convinced about these technologies or if you didn't understand that PoW video I posted earlier, I recommend you to go back to basics by watching this other video produced by a mathematician educator which explains it really well.
Wednesday, January 23, 2019
- Xamarin (the company) was bought by Microsoft and, at the same time, Xamarin (the product) was open sourced.
- Xamarin.Forms is opensource now (TBH not sure if it was proprietary before, or it was always opensource).
- Xamarin.Forms started supporting macOS and Windows UWP.
- Xamarin.Forms 3.0 included support for GTK and WPF.
Tuesday, March 17, 2015
How do you upgrade your distro? A tale of two workarounds
Every classic Linuxer would know why it's very handy to dedicate a separate partition for the /home folder of your tree: you could in theory share it between multiple OSs that you installed in your box (which you choose to run when you start your computer).
Now, I'm guessing that many people reading and nodding to the above, will also know that sharing /home/ is one thing, sharing $HOME (/home/yourUserName) is a completely different beast.
For example: you have a stable distro installed in your box; you decide to install a new version of that distro along the old one, in the same box. You run the new distro with a new account tied to the old /home/yourUserName folder: KABOOM!!! Weird things start happening. Among these:
- The newer versions of your desktop or desktop programs don't run properly with the settings saved in your .dotDirectories (they are to blame because they didn't probably have a settings-conversion feature).
- The newer versions of your desktop or desktop programs have a buggy settings-conversion feature; because your program does not run properly, or as well as it would have run if it had been ran for the first time with no settings saved at all.
- The newer versions of your non-buggy desktop or desktop programs convert your settings to a new format. Then when you go back and run your old distro again, your old-versioned programs stop working because they see settings in a new format which they don't understand. (This is impossible to fix, or very hard.) It's very important that this scenario works, because the migration to the new version of your distro may not be immediate, it may take you some days to figure everything out, and until that happens, you want to still be able to run the stable version of your desktop and desktop programs
To workaround these problems, I have a strategy: I use a different /home/ sub-directory for each distro installed in my system. For example, for distro X version A.B I use /home/knocteXAB/, for distro Y version C.D I use /home/knocteYCD/. The advantage about this is that you can migrate your settings manually and at your own pace. But then, you may be asking, how to really take advantage of sharing the /home folder when using this technique?
Easy: I keep non-settings data (mainly the non-dotfiles) in a different /home/ folder with no associated account in any of the distros. For example: /home/knocte/ (no version suffix). Then, from each of the suffixed /home/ subfolders, I setup symlinks to this other folder, setting the appropriate permissions. For instance:
- /home/knocteXAB/Music -> /home/knocte/Music
- /home/knocteXAB/Documents -> /home/knocte/Documents
- /home/knocteYCD/Music -> /home/knocte/Music
- /home/knocteYCD/Documents -> /home/knocte/Documents
- Debugger not stopping on breakpoints.
- Builds breaking with obscure error messages.
- Debugger opening file in the IDE which was already open, duplicating two tabs for the same file.
So I had to use a workaround for my workaround: clone all my projects in $HOME instead of /home/knocte/Documents/Code/OpenSource/ (yah, I'm this organized ;) ).
I've been trying to fix these problems for a while, without much time on my hands.
But the last weeks a magical thing happened: I decided to finally sit down and try to fix the last two remaining, and my patches were all accepted and merged last week! (at least all the ones fixing symlink-related problems), woo!!!
So the lessons to learn here are:
- Even the slickest workarounds have problems. Try to fix or report settings-conversion bugs!!
- Don't ever quit trying to fix a problem. Some day you'll have the solution and you will realize it was simpler than you thought.
- realpath is your friend.
- MonoDevelop (master branch) is now less buggy and as amazing as (or more than) ever (</PUBLIC_SERVICE_ANNOUNCEMENT>).
Tuesday, May 20, 2014
Banshee GSoC-2014 projects under Gnome umbrella
This time, Google has given plenty of slots to the GNOME project, so we could accept many participants, including 3 brilliant students to work on the Banshee project. In case they haven't blogged about it, or didn't give much detail, I'll elaborate a bit about what they will be aiming to do these months:
- Nicholas Little will be working on creating a new extension for Bluetooth synchronization, and if time permits, refactoring our MTP support. In regards to the latter, if you have an Android phone you might have experienced some bugs getting it to work with Banshee lately (our MassStorage synchronization support is great, but the latest versions of Android have been deprecating this mode in favour of MTP, which we never supported very well); we have been working hard on fixing them, but Nicholas is going to try to give it that extra push at the end of the summer, which I'm confident he will do very well (he was the developer who brought Symbian support for the masses -or rather, for his Nokia N95 ;) -, on Banshee 2.9.0). And you may be wondering, why do we need Bluetooth sync? Well, we understand that it's much slower than USB or Wifi, but:
- USB can work for the first sync, but whenever you update your library, I never remember to connect my phone again with my cable, or I'm too lazy to do it. Now imagine that whenever your phone is near your computer (and of course if you have Banshee running), they could negotiate together to update the sync without the need of moving a finger!
- Wifi could work also for the use case I just explained, but getting Wifi to work, compared to Bluetooth, would involve creating an app for the phone that could talk with Banshee. And we all know what are the problems associated with that: we would need to be cross-platform for at least the 3 main mobile platforms out there (well, iOS wouldn't even work neither with this nor with Bluetooth, because there are no public APIs to integrate with the music database of the OS, sigh iTunes...), and that means a lot of maintenance burden (even if we choose a same-language native platform like Xamarin), and a user experience that is not so seamless (as it would require the user to install an app first).
- Marcin Kolny, which has convinced us that he will do a great job given his great patches and the fact that he's already very involved in opensource (maintainer of C++ bindings to GStreamer if I recall correctly), will be working on integration with AcoustID. To summarize it very bluntly, AcoustID is the open-source alternative to Shazam, so thanks to this, if you have many tracks in your library which didn't get ripped properly with tags, or you got from some friend which is not very metadata-driven ;) then you will be able to fix this situation! We will be likely reusing the MetadataFixer extension that we already have in Banshee, to not reinvent the UI wheel.
- Dmitriy Petukhov, a very motivated Russian student, will be helping us get two extensions in shape, which were developed in the last GSoC (more details about this in my previous blog post), but were not ready for mainstream yet. The FanArt.TV extension, which retrieves artist logos and shows them next to your album icons, needs some caching (we could even violate FanArt.TV service's ToS if we don't do this) and UI polish (our ListView widget doesn't play well with differently-sized images, so we need to modify this custom GTK widget to allow rendering rows with different heights). The SongKick extension works great, but also needs caching, and it especially needs GeoLocation to maybe even work autonomously (imagine, you don't even know what SongKick is, and because you installed the banshee-community-extensions package of your distro, you suddenly get told that one of your favorite bands is soon playing a gig near your city!).
I'm very happy about starting the mentoring of these projects this year. And I'm specially jealous about my students... I became mentor of GSoC myself without being GSoC student first! (Maybe I should switch roles in the future?)
Wish them good luck! It was actually just yesterday when GSoC really started! (gotta love mondays)
UPDATE: Fixed embarrassing typo: I meant AcoustID, not OpenID!
Monday, May 05, 2014
GSoC 2013 with Gnome
In summer 2013, Tomasz Maczynski worked on Banshee as a GSoC student, and he did great work! He developed a SongKick extension, and a FanArt.tv one. Both were worked on in the banshee-community-extensions repository. They work very well but there are a few downsides about this work, which we didn't have time to fix:
- The FanArt.TV extension depended on some Banshee API that hasn't been added yet to mainline. The patch to add it lived in bugzilla for a while, in a bug about a feature request to have images in the artist list. The reason for not committing the patch even if I had already reviewed it was because I was wary about it, since it allowed FanArt.TV to hook its ArtistList widget, but wouldn't be really extension friendly. What I mean is that if there was other extension that wanted to also attach a different ArtistList, it would conflict with FanArt extension when enabled at the same time. The ideal thing would be to expose this functionality as an extension point, so that if more than one extension attached a new kind of ArtistList widget, the user could switch between the two from the UI when both extensions were enabled. When I mentioned this in the bug, awesome Banshee-extension developer Frank Ziegler jumped in and created the extension interface necessary for this. I've been reviewing the patches in the last days (couldn't do it before because I really wanted to release 2.9.1 and 2.6.2 versions before landing this work) and I'll likely commit them this week.
- The FanART.TV extension uses Hyena's ListView widget to show images. This is the main widget that Banshee uses for showing the tracks in the main view. It's a great custom widget because it allows very fast rendering of data coming from an SQLite database, but it wasn't optimized for rendering images. The main disadvantage of it is in the case that images have different heights, because the ListView will just allocate a height for each row equal to the tallest of the images used. This means that the widget shown could be a bit ugly if you have many artists in your library and some of them have very differently sized images. Tomasz worked on this a bit, but couldn't finish it because of lack of time (we have a WIP patch). But fortunately this will be fixed this summer!
- Both SongKick and FanArt.TV don't implement caching yet. This is not only important to save bandwidth from the point of view of the client, but also from the point of view of the server! (We could even violate their ToS if we didn't implement this, IIRC.) Fortunately this will be fixed this summer!
- SongKick extension provides several ways to discover gigs: searching by city, by artist, etc. It even suggests you artists extracted from your library that composed songs which you marked with a high rating! But IMO this is not enough, SongKick extension should even be smarter and query ahead of time looking for your favorite artists *and* near your area (doing the latter via GeoLocation). Fortunately this will be fixed this summer! (and we will use Gnome infrastructure for it)
That is all folks! Stay tuned for the next blog post, which will explain the plan for GSoC 2014 (this year I get to mentor three students!).
Sunday, May 04, 2014
Belated Gnome .NET Hackfest post
- I got my house refurbished in the last months, which has been such a long planning endeavour, and a real stressful PITA while it was being done.
- Before the above started, and after it was finished, I had to move, so that's 2 moves! (I hate moving)
- I've been kind of busy in regards to Gnome-related contributions: we released Banshee 2.6.2, GStreamer-Sharp 0.99.0, Banshee 2.9.1, and a big etcetera (including pre-mentoring for GSoC! more about that in a subsequent post).
- Hylke Bons, sparkleshare creator, Red Hat designer.
- Mirco Bauer, smuxi creator and debian developer (mono packager).
- Jo Shields, debian developer (mono packager), Collabora sysadmin.
- Robert Nordan, Pinta contributor.
- Jared Jennings, Tomboy contributor.
- Stephen Shaw, ex-Novell coworker (build developer), and currently at Xamarin. (Yes, I was Stephen's team-mate when at Novell, but had never met him in person!)
- Stefan Hammer, Tomboy contributor and hackfest local-host.
- Timo Dörr, Tomboy and Banshee contributor, GSoC student.
- Stephan Sundermann, GSoC student for GStreamerSharp and Bindinator.
(BTW I didn't include the awesome Bertrand Lorentz, fellow Banshee co-maintainer and GtkSharp gatekeeper, in the list, because I had already met him before, it wasn't my first time!).
And it was with the latter Stephan (not Stefan) the one I ended up spending more time with, because we decided to work on the new GStreamerSharp bindings since the 2nd day of the hackfest (the 1st day I mainly worked with Bertrand to release Banshee 2.9.0, our first Gtk3 compatible release, which he already blogged about).
So what was special about this work?
- GStreamerSharp 0.10.x releases were not compatible with GStreamer 1.x releases, so this had to be fixed soon. However, much of the architecture of this old version of the bindings used many manually crafted binding code.
- Stephan, by using the new Bindinator (a GObjectIntrospection metadata parser that outputs GAPI metadata, that allows generating .NET bindings, created by Andreia Gaita) in his GSoC, created a better foundation for the new bindings.
- He targetted GI metadata from GStreamer 1.0 and 1.2 versions (the jump from 0.10 to 1.0 was a big and not easy leap, since lots of APIs were modified and deprecated).
- We needed to polish them enough to make Banshee be able to consume them without glitches.
Main kudos should go to him though. I mainly added Banshee expertise, gtk-sharp contributing expertise, and lots of motivation (or at least I thought).
We had a big success: a Banshee playing audio with GStreamerSharp. Unfortunately video playback was freezing. But some months later after the hackfest we fixed it, and we released first GStreamerSharp 1.0 preview, which we called "0.99.0", and we released the first Banshee release that depends on this work: 2.9.1.
And it was my first time in Austria (and in Vienna). Overall a great experience, and I need to mention our awesome sponsors: