Chromecast, Android, UPnP/DLNA, and Docker

If you're like me, you have at least one machine on your home network that has a UPnP/DLNA server up and running it on.  You may have used a PS3, XBOX360, NeoTV, or any other UPnP/DLNA device to watch media from that UPnP/DLNA server.  And... Like me, you may have grown tired of all these machines and tried to migrate everything to using a Chromecast.  If so, you soon discovered Chromecast has no way to natively play anything via UPnP/DLNA.

This is the situation I found myself in.  I searched the Play store and found BubbleUPnP.  It sounded great, then I tried to use it.  Well by default it can only cast to your Chromecast in the native formats that your Chromecast supports, which as I'm sure is not what the majority of your media is encoded in.

Luckily, BubbleUPnP has a server that will transcode media from whatever format it is in into a format that your Chromecast supports.  The Android app will even automatically find the server for you automatically.  However, the server is kind of tricky to setup and get working.  Fortunately I've been playing with Docker a lot lately.

So if you're trying to cast UPnP/DLNA and you happen to be running a Linux distribution that's capable of running Docker, you can just run the Docker image I've created for the BubbleUPnPServer.

There were existing Docker images of the BubbleUPnPServer, but they all had something weird about them which you can read in more detail at the official page for the image.  But to get you started you just need to run the following command on a machine with Docker installed on your local network.

    docker run -P --net=host rwgrim/docker-bubbleupnpserver

Hope you find this as useful as I have!

Long time no post...

I've been super busy as of late with lots of projects and other stuff, but figured a blog post is long overdue.

As some of you may know, there was a Pidgin Summer of Code project for GObjectification.  As some of you may know, I designed and spec'd out a ton of that project.  I was not the primary mentor for the project, but more of a technical support.  Anyways, when the topic of plugins came up, my GPlugin library got chosen.

My last post on GPlugin was announcing version 0.0.2 in April of 2012!!  Anyways, over the summer, GPlugin's functionality grew leaps and bounds.  The Python loader was finished, a Perl loader was started, a Lua load was completed and the library itself is more or less feature complete.  There's still plenty of things that need to be done, but everything (aside from a bug or two) is completely ready to use!

Last night I released version 0.0.12 which pretty much just fixed an extreme corner case bug that was more of a memory leak and some more unit testing.  At any rate, if you're working on a Glib/GObject based application and want plugins, give GPlugin a go as I could really use some more feedback!

gplugin 0.0.1^H2 released!

After *MANY* months of on again off again coding I'm very proud to announce version 0.0.2 of GPlugin.

Version 0.0.1 had a broken pkg-config file, which I fixed in 0.0.2... I knew I was forgetting to test something...

GPlugin is a library that will give your program GObject based plugins.  Right now it only supports native (compiled plugins), but there are plans for at least a python loader and whatever else anyone wants to write.

During this release I transitioned this project off of guifications.org to bitbucket.  All GPlugin related business (bug reporting, file downloads, etc) should be done at the bitbucket site.

Also, documentation is in the source and will eventually be built/posted once the gobject-introspection guys figure out whats going on with g-ir-doctool.  Right now you can build the docs and open them in yelp, but not devhelp. I'll put something on the bitbucket site soon for how to do that.

Source tarballs can be found here: zip gz bz2

nodm and matchbox window manager and auto starting applications

I'm working on a project for work that is based around a live distro.  For the live distro building, I went with live-build since Debian is by far my favorite distro.  The live build was pretty easy to implement, and I'm not going to bore you with the details when there's plenty of documentation out there, especially the live-manual.  This post is all about how to get Xorg started and how to launch an application when Xorg starts up without diverting files in other packages, or having a match install anything to a users home directory.

The clear start to this task is nodm.  It'll automatically login as a user and start your xsession.  If you don't have an xsession installed, it'll fall back to the normal Debian xsession script that'll just launch an xterm.  This is simple enough, but remember that without a window manager, you're not going to get any of the standard desktop magic that the freedesktop.org window manager specification gives you.  For example, being able to call gtk_window_maximize.

To fix that problem I went with matchbox window manager.  It's very light weight window manager meant mostly for mobile devices and runs apps in full screen, thus eliminating my need to maximize the application window.  Matchbox registers itself as an alternative for x-window-manager under Debian which, in this bare bones approach will start matchbox on boot, but no apps.

Luckily, the matchbox package depends on matchbox-common and matchbox-common contains /usr/bin/matchbox-session.  This script looks for a session script and will execute it, if it doesn't find one, it'll launch matchbox-desktop and matchbox-panel in the background, and then launch matchbox-window-manager in the foreground.  The real awesomeness here, is that matchbox-session checks if there is an executable script named session in /etc/matchbox/.  What this means, is that you can easily create a package that depends on matchbox and install that file.  This fulfills all of our requirements!!  But wait, matchbox-session won't be called from nodm...

Solving that problem is actually a lot easier than you're probably thinking.  Debian's Xsession scripts give a higher priority to x-session-manager which is in the alternatives system.  So all we need to do, is to register matchbox-session as an alternative for x-session-manager.  Once this is done, our custom /etc/matchbox/session will get executed and we're good to go :)

Due to NDA's and stuff, I can't post my exact package here, but here's the jist of it.

Make sure your control file depends on "matchbox" (that's the meta package for matchbox and will pull everything in); you can probably clean it up to just matchbox-common and matchbox-window-manager, but I leave that to you.

Next create a postinst script that contains the following:

#!/bin/sh
set -e
case "$1" in
        configure)
                update-alternatives --install /usr/bin/x-session-manager \
                        x-session-manager /usr/bin/matchbox-session 50
        ;;
esac
#DEBHELPER#

and a prerm which contains the following:

#!/bin/sh
set -e
case "$1" in
        remove)
                update-alternatives --remove x-session-manager /usr/bin/matchbox-session
        ;;
esac
#DEBHELPER#

Then create your custom session script.  Mine looks something like this:

#!/bin/sh
application &
exec matchbox-window-manager

Make sure all three of those are executable, add the session script to your install file, fire off debuild  and you should be good to go.

I hope this helps other, since googling for this earlier came up pretty empty :)

The corporate software world should be ashamed of themselves...

So a few days ago I started tinkering with my Macbook again.  It's been awhile, and I was using macports, so it was seriously out of date.  I upgraded the pieces I immediately needed to test some code.  Then I decided to update the rest of my installed ports over night.  When I got home from work the next day, the updates had failed for numerous reasons.  I spent the majority of the night trying to fix these issues.  After a few hours, I decided to look at homebrew which I just discovered the other day.

So I installed homebrew and started installing stuff, except I was getting a failure with "linking" packages.  I tried sudo brew link package and that seemed to work fine.  But I Google'd it anyways, trying to figure out what was going on since you're not supposed to need sudo for homebrew.  I ended up reinstalling homebrew after making sure /usr/local was set to mode 775 with root:admin for the user and group.  Now, more packages than not are linking correctly.

Now aside from all of this, homebrew was telling me to update XCode to 3.2.6.  Okay, simple task right?  Yeah, not at all.  Now, when I got my Macbook it came with Leopard installed.  At some point I installed XCode from the install disc.  I'm not sure what version, but I'm assuming it was 2.x since I never actually checked it.

Anyways, being computer savvy I went, "hmm, XCode should just update through software updates right?". So I fire up software update and, you guessed it, everything was up to date.  "Um, that's not right" I said.

Okay, so the AppStore, they'll have XCode available, right?  I fired up the AppStore for the first time ever, do a search for XCode, and see XCode 4.  Cool, bonus updates :)  I hit install, and I'm greeted with the following:

Alright, the AppStore is out of the question, because to the best of my knowledge, Lion doesn't support my Macbook and I'm not going to risk $30 to see if I'm right.  So I do a bit of Googling and discover that you can get a free XCode 3.2.6 at developer.apple.com.  So I head over there, and all I see is XCode 4 again.  I also see a link to get some developer access or support for XCode for $100 a year, for a tool they give away for free, there are other frills they throw at you as well, but yeah I'm good.  At any rate I still can't find a link to XCode 3.2.6.

I do some more Googling and find a direct link to the XCode 3.2.6 page.  Once on the page, I hit download and wouldn't you know it, I need an AppleID to download it.  So I say to myself, "It can't be that bad, just username, password, and email right?".  I click the register link, and boy was I wrong.  They want your full name, street address, email address, home phone number, possibly even your first born.  So I threw that option out.

At this point I figure I'm going to have to pirate it.  It's a free download, but let's be honest here, I've already gone through more work than most people will to try and get this setup.  I ask around and no one has it.  I don't want to hit some random site for it, because who knows if it's been tinkered with.  Then it dawns on me...

I never installed XCode from the Snow Leopard install disc.  So I dig through quite a few boxes of computer stuff and eventually find the disc.  I throw it in, go to optional installs, start the XCode installer, and hooray! it'll update my existing install.  The install didn't take horribly long, but when it finishes, I fire up XCode to check the version... 3.2.

Okay, so I'm making progress, I'm on 3.2 now, maybe I'll have updates in software updates now.  So I then fire up software updates, and sure enough, there's an update for XCode to 3.2.6.  After a nearly 700mb download, XCode 3.2.6 is finally installing.  After about another 30 mins, I FINALLY have it installed and up to date.

So what's the point of this post?  Simplicity.  XCode is a free download and as I've mentioned, it comes free on your install disc.  Why in the hell did I have to spend 2 days to get it updated?  Only Apple can answer the question of why they have made their development software such a pain in the ass to install/update.

What I really want to know is, if I'm updating my system which has XCode installed on it, from a disc that's installing the new version of the OS, which just so happens to also have an updated version of XCode on it, why the hell didn't the OS installer run the installer for XCode as well?

What I'm really saying here, is that the OSX installer fragmented my machine instead of automatically running the XCode update or simply asking me during install.  See, they simplified the installer, so what if a few developers have to suffer.  But even then, this is a horrible solution as well since you'll still get the software update to bring XCode back up to 3.2.6 and waste even more time.  Which leads me to the end of my argument.

It is my belief that if you're going to have an update tool (which is kind of like a package manager), it should be able to update software from any version to the current version.  This is, for lack of a better word, simplicity at it's finest.  In the diagram below I have mapped out the course I had to take to update OSX and XCode, this is the black and red edges (arrows for the non-diagram aficionados).  In an ideal and simplified world, I would have only had to have followed the blue edges.

So when people say Windows or OSX are easier, I can now add to my repertoire that I have never had to upgrade a piece of software to an intermediate version to be able to upgrade it to the latest and greatest version under any Linux, ever!

This, once again, has shown me that the corporate software world is completely and utterly disconnected from their user base, so much so that they'll try to trick them out of money to get a tool they give away for free, if you're willing and able to jump through the hoops that they've thrown in your path.  To me, this is nothing more than extortion and they should be ashamed for making it so difficult.

Ugh, I spent all night working on implementing some python bindings the old way... how did I forget about gobject-instrospection... Now I need to learn how to use it too!

using scan-build from clang with cmake

If you've wanted to add static analysis to your C/C++ project which uses CMake but didn't know how, then you'll want to read this.  This post is mostly a note for myself so I don't have to google it later ;)

If you're using Debian it's actually quite easy.  Just install the clang package with:

# apt-get install clang

After that's done installing, change directories into your source directory.  Now typically I use a separate build directory since it helps keep my source clean and allows me to do a build with gcc and clang from the same source directory.

Anyways, since we want to do an analysis with clang's scan-build, we're going to create a new build directory in our top level source directory.  For example:

$ mkdir build-analyze

The next commands will be need to be run from this new directory, so change into it now.

 $ cd build-analyze

 Now we need to generate our build system with cmake and compile it, but we need to point cmake to clang's ccc-analyzer.  In Debian, this program is located in /usr/share/clang/scan-build/ccc-analyzer.

$ cmake -DCMAKE_C_COMPILER=/usr/share/clang/scan-build/ccc-analyzer ..
$ scan-build make

When you're build is finished you will see two lines, like the ones shown below.

scan-build: 6 bugs found.
scan-build: Run 'scan-view /tmp/scan-build-2011-10-19-1' to examine bug reports.

As you can see, it found 6 bugs in my code.  To view the bugs, the easiest way is to run:

$ scan-view /tmp/scan-build-2011-10-19-1

This will start up a local web server, and open it in your default web browser.  From here you can review the bugs and determine how to fix them!

Hope this was helpful!