Tag Archives: Coding

Podcasting with UUPC (and podcats)

Posted on November 25, 2010 | 2 Comments

On Monday I was surprised and delighted to be asked to join the team from the Ubuntu UK Podcast (aka @uupc) as a guest presenter. I’ve been a listener and friend of the show for a long time, I knew several of the regular team, and since I work not far from “Studio A” it was fairly straightforward to jump in at short notice.

I had a blast recording with Tony, Laura and Mark! The amount of work and polish that goes into each show is fantastic, I can tell you. I was also very impressed with their studio setup. My own podcast is recorded using Skype, and although I do own a small mixer, it’s really nothing compared to Tony’s much larger desk. Each of us had a proper mic, too. Oh, and there was a Very Large Clock. There was also a small experiment in streaming to a small audience (the magic-fu was served up on Twitter and in the #ubuntu-uk-podcast IRC channel, so you should hang out in those places in case it happens again!).

Most importantly, we were supported by the UUPC PODCATS.

I gave a brief intro to myself at the start of the show. If you’ve just discovered me via my guest appearance on UUPC then feel free to follow me on Twitter or read more about me here on my site.

Below, I’ll just recap and expand on my Linux credentials, because it’s not something I’ve really blogged about before.

My Linux experience

I started out using Linux with some early SuSE version in the late 90s just after leaving university. Then I switched to RedHat, which was in the phase of spinning out the Fedora project, and I did some packaging for a few projects there for a while. I helped out on a bunch of projects around that time, like OpenUT (the initial Unreal Tournament port to Linux – there’s a special thanks to me in the credits for the Linux version!), the brilliant Anjuta IDE, and the Bible software GnomeSword (which is now known as Xiphos). I spent a lot of time helping to do things like triage bugs, coordinate releases, polish the UI for GNOME apps like Anjuta, and basically to some extent “project managing” alongside the actual project leaders, freeing them up to code on their projects while I took on a more technical coordination role communicating to different developers, helping with test, etc.. At the time I was a middleware developer for a large company so I had an appreciation of how things like CVS worked, how to do releases and release notes, working with users etc. – things that are sometimes missed on OSS projects, although all of these things have become better over time. It was a great way for me to deepen my UNIX skills and hone my development abilities too. Plus, I built some great relationships and friendships from working with the community.

Times change, and I had to take a step back from all of that for quite a long time. Although I had a Linux box at home as a server (on dial-up for a long time… yikes!), I otherwise wandered the wastelands of Windows XP and then got a Mac. Fundamentally I believe I see the good and bad aspects in most systems; I believe it’s important to at least try something, and not dismiss it; I did go through a strongly anti-Microsoft phase but with things like XBox 360 Live, a few items in the “Live” family of software, and their new phone operating system, I do have respect for what they’ve done. I struggle a little on the whole “openness” thing – my tendency and first preference is absolutely towards open standards, open source and free collaboration, but then along comes Apple with stuff that just… works… and is so… shiny… and… I’m almost willing to suspend that view. And then I smell coffee and come back to my senses :-)

So what am I doing now? Well, last year I switched to Ubuntu on my work laptop, a Lenovo Thinkpad, and I’ve been through Jaunty, Karmic, Lucid and now Maverick. I do NOT have a Windows partition, I run my whole work life in Ubuntu. I’ve got a Viglen MPC-L (previously featured on UUPC, of course!) running home and weather monitoring with some software called MQTT which I’m involved with as part of my job. I run Linux on my “set-top box”, an Acer Aspire Revo inspired by Popey, with Boxee and other bits. I have a netbook, a first-gen Acer Aspire One running UNE Lucid until they sort out Unity to a point where I feel it’s usable. And, as I mentioned on the show, I’ve recently picked up a cheap (actually, total bargain) Android handset as a development platform- my main phone is one of the Apple devices, sorry! The new phone is an Orange San Francisco, which is a rebadged ZTE Blade – I’ve flashed it to run Android 2.2 and moved a bunch of apps into SD storage, and it’s a lovely little device. Apart from that, I help to do a few things for internal Linux apps we use at work on Ubuntu, and I buzz around Launchpad largely helping to improve quality via bug reports etc. Oh, and I’m lined up to speak at LinuxConf AU in January! (very excited about that!)

So that’s me. I do Linux, I do Ubuntu, and I do a whole bunch of other stuff. Thanks again to the UUPC gang for not throwing me out of the studio! And thank you, dear reader, for listening…

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OS X mosquitto “bites”…

Posted on August 8, 2010 | 12 Comments

In my post last week about the new MQTT support coming to WebSphere MQ I very briefly mentioned that there are some third-party tools that already implement MQTT. One of those I pointed to is the very neat mosquitto broker, a project started by Roger Light.

mosquitto has been around for a while now and is aiming to replicate the functionality of the Really Small Message Broker that is on IBM alphaWorks. One of the neat things about it, from my point of view, is that it there is an Ubuntu PPA repository, so with a couple of apt commands, I can install a running MQTT broker and build my own applications independently (NB there are packages for other Linux distros too, as well as Windows). When I want to do some “heavy lifting” or share data with my ESB, I connect up my local mosquitto broker to pass messages across to WebSphere MQ through the new telemetry channels – because MQTT supports a concept of bridges, and both RSMB and mosquitto both include support for bridging.

I noticed that there wasn’t yet a version available for Mac OS X but figured that it shouldn’t be too difficult to compile and run it on that platform. As it happens, it did turn into a bit of an adventure for a couple of reasons, but at least I learned from the experience. If you’re desperate to build yourself a version to try some MQTT development on the Mac, here’s what I had to do to get it going on Snow Leopard:

  1. Installed mercurial, and a GUI for it called Murky (which requires the hg command line tool from the base mercurial package). The sources for mosquitto are in bitbucket, a Mercurial repository… this is optional of course as I could have just used a source tarball.
  2. Grabbed the latest mosquitto source from bitbucket.
  3. Modified the Makefiles throughout the mosquitto tree to build libraries with a .dylib instead of a .so extension (the default on OS X), and also changed the -soname parameter to -install_name which the OS X version of gcc understands.
  4. At this point the compile was starting to show progress… but failing due to missing symbols… the offender being one from sqlite, _sqlite_enable_load_extension. Turns out that the version of sqlite shipped in OS X 10.6.x is 3.5.4 but it does not have extension loading functionality built in, as evidenced by nm -g /usr/lib/libsqlite3.dylib | grep 'sqlite3_enable'
  5. Downloaded sqlite3.8.0, configured it to install to /usr/local (to avoid overwriting the default OS X shipped version), and built and installed it with no issues.
  6. At this point the compile was pretty smooth, once I modded Makefile link and include lines to point to the new version of sqlite in /usr/local. The only thing that failed was documentation, but that was “optional” :-)
  7. Trying to start the broker failed… because it was trying to load the sqlite3-pcre extension.
  8. Installed git (the source for the sqlite3-pcre extension is in a git repository).
  9. Grabbed the source for sqlite3-pcre and built and installed it using: 
    gcc -shared -o pcre.so -L/usr/local/lib -lsqlite3
          -lpcre -Werror pcre.c -I/usr/local/include
sudo mkdir /usr/local/lib/sqlite3
sudo cp pcre.so /usr/local/lib/sqlite3
  10. The final issue was that the path to the pcre extension is hard-coded into mosquitto/src/conf.c so I modded that to point at the version in /usr/local and recompiled. I’m assuming that this would not generally be required, but it worked as a hack to get me going!
    D’oh. Just realised that this is precisely what the ext_sqlite_regex variable in the mosquitto.conf file is for. Shouldn’t have bothered!

So that was it. Being fair, if I hadn’t been feeling my way through that, I would have installed git and mercurial, grabbed all the lib sources for sqlite3 and pcre and built them, built mosquitto, and been good to go. At this point, the broker and test clients are runnable (assuming the library paths are set up appropriately):

DYLD_LIBRARY_PATH=/usr/local/lib ./mosquitto
DYLD_LIBRARY_PATH=../lib ./mosquitto_pub -t test/andy
        -m "hello world"

If you are interested in seeing this in action, here’s a short (and silent, but annotated) screencast:

The Java GUI application you see in the screencast is the test client shipped in an old IBM SupportPac, IA92, a Java implementation of MQTT. The final release of the WebSphere MQ Telemetry component for WebSphere MQ will contain something similar, considerably enhanced and integrated into WebSphere MQ Explorer.

In other news, Roger recently announced version 0.8 of mosquitto, which now has slightly different packaging and includes C, C++ and Python clients. I hope to give these a test drive shortly!

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Experiments with PHP and MQTT

Posted on February 20, 2009 | 5 Comments

Over the past few days I’ve been playing around with combining lightweight messaging and PHP. There are a couple of reasons for this, but the primary one is that I’d like to extend my prototype iPhone CurrentCost monitoring web application to display more up-to-date information about the state of my home energy usage. I’d planned to do this for a while, but recently Mark Taylor created his own version of the iPhone interface (PDF link) and he has got current readings on the front page. Clearly, I have to compete :-)

Actually, in my system, I’d like to do things a different way. The heart of my setup is a Really Small Message Broker. At the moment, data from the CurrentCost meter comes in over the USB connection and is then published in pieces, or on topics, to the RSMB (temperature and energy readings are separate). These published messages are then read by a script which is subscribing to the topics and squirrelling the historical data into an rrdtool database; and also being pushed up to our IBM broker “in the interweb cloud” via an MQTT broker bridge connection.

So in theory, having the up-to-date information in the web UI should be a simple case of grabbing the MQTT publications on each topic and displaying them. The way I’ve coded things (and would prefer to do things), this involves having the ability to subscribe to MQTT publications from PHP.

I’m not at the end of the road yet, but I do have a starting point.

howitworks.png

I’ve got a front-end test page which currently uses Prototype to send an Ajax request to a server-side PHP script (yes, I have had jQuery recommended to me, and I may well look into that instead of Prototype, but this works).

The server-side script uses the Simple Asynchronous Messaging PHP library. SAM is a wrapper which enables a variety of messaging transports to be supported in PHP, such as MQTT, WebSphere MQ or WebSphere Platform Messaging. Just one thing: I found that in order to get the most recent SAM release to work on Ubuntu on my MPC-L, I had to install IBM’s XMS client SupportPac (for some reason, it won’t build without it, even though it is “optional”) and I also had to delete a spurious empty line from the end of /usr/share/php/SAM/php_sam.php to prevent header issues. Other than that, it was all good.

The script is really simple and basically uses all of the defaults to create a connection to my local RSMB over MQTT. The advantage of this being server-side is that I don’t have to open my RSMB to the Internet, the PHP code can connect via localhost. Once that’s done, it creates a subscription on the topic I’ve asked for, and receives the first data that comes along, then echoes it back to the front-end. I could make it auto-updating with Ajax.PeriodicalUpdater too, but there’s no need to put a load on my server.

Wanna see a quick demo? ;-)

I’m quite pleased with the way this is working. There’s some more plumbing to do, and I’ll almost certainly extend the server-side piece to allow two-way communications (publish as well as subscribe) as well as finer-grained control over the options. As a proof-of-concept though, I think this is looking good.

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TwtrCtr – Tracking Twitter followers with an iPhone

Posted on January 28, 2009 | 3 Comments

twtrctr logo I’ve already mentioned this on Twitter, but so far I haven’t had a chance to write about the culmination of my first “proper” efforts to create a mashup: TwtrCtr.

For those not obsessed with Twitter or their follower numbers, there’s an application you probably haven’t heard of called TwitterCounter. The site provides tools, graphs and APIs for charting the growth of a user’s Twitter followers. It’s interesting, and if you’re slightly obsessive about figures and have a belief that such things “matter”, then you might already spend time checking it and looking at the pretty graphs. It also provides an element of “prediction” based on historical growth trends, and does cool things like allowing users to compare themselves to others and watch the graphs intersect or overlap.

twittercounter website There’s just one issue – although it looks great on the desktop, the site isn’t laid out very well for mobile browsers like Mobile Safari on the iPhone. It also uses a Flash component to display the graph, and since there’s currently no Flash on the iPhone, you get a big blank box in the middle of the screen.

The nice part is that TwitterCounter has a simple REST API which enables a developer to get the raw data about a user’s follower numbers. If you use Twitter clients like Tweetdeck, then you’ll see this in action.

Based on my previous experience of using the iWebkit framework to build an iPhone-optimised web wrapper for the data from my Current Cost meter, I thought it might be interesting to play around with using iWebkit to display the TwitterCounter stats.

iWebkit is a simple HTML framework which provides a set of CSS classes to make your web pages look like native iPhone apps. There are other frameworks out there like iUI and webapp.net, but they depend a lot more on knowledge of AJAX and some more advanced / dynamic coding, whereas iWebkit is all about simplicity – if you know your HTML basics, it is pretty straightforward. As it happens, you can extend it very easily as well – in my case, I combined it with some PHP functions which call out to TwitterCounter and echo the numbers into a table on a web page.

Although I worked with PHP a lot a few years ago, I hadn’t really done much with the language recently. The first thing I did was to create a simple piece of code to call the TwitterCounter API and get back the data for a specific user; and then I displayed it in a web page. Once I’d done that, it was pretty easy to get the whole thing wrapped into two pages of iWebkit template code, and style it all appropriately.

twtrctr mark 1

Revision one of the interface and app ran off my home server, and didn’t look fantastic. My initial thought for a name was “TwitterCounter nano”, but I changed it after realising that it didn’t fit so well as a name on the iPhone home screen :-)

In the screenshot on the left, you’ll also see that the first form I came up with was far from “iPhone native-looking”… the current version of iWebkit didn’t have form CSS classes, so I had to tweak things a little. I also found it was worth digging into the Apple Web Development Guidelines for the iPhone, which gave some hints about how to make some iPhone-specific tweaks like turning off auto-capitalisation for the text entry box (since most usernames are all in lowercase), and how to add a text hint, for example.

twtrctr mark 2 So, the second iteration of the UI looks a lot nicer. It’s also possible to hit the bookmark button in Safari and add the app as a shortcut on the iPhone home screen… (see the icon at the top of the post)… if you do that, and launch TwtrCtr from there, it will act as a full-screen iPhone app with no Safari controls, giving a much more native experience. The user can then navigate by using the controls in the header bar rather than the forward and back buttons provided by the browser.

I added an FAQ page, too, so if you want to know more about the app you can check that out directly on the site. In these days of heightened concern about Twitter security I also thought it would be a good idea to add a note on the front screen to point out that it doesn’t ask for anything more than a username, and it doesn’t log that anywhere, it just passes it on to the TwitterCounter API.

twtrctr display OK, that was a rather long explanation of the evolution of the first page! The important part is actually how the data is displayed. Once you’ve entered a valid Twitter username and hit “Get User Stats”, you get a single-page representation  of the TwitterCounter data for the given user.

The top 2 or three rows are links which will open the user’s profile page, homepage/URL (if one is set… otherwise that row doesn’t display), or display a simple graph / chart which is generated by the Google Chart API. The latter is something high on my list of enhancements, because it looks a little dull at the moment; also, I’m generating the Google Charts URL myself rather than using one of the PHP wrappers to the API, which would probably be a lot simpler.

Don’t look too closely for the rough edges… right now, it doesn’t actually make any effort deal with cases where a user doesn’t exist, or TwitterCounter or Twitter is down…. I know about those small issues :-)

In a nutshell, then – that’s all it is. A mashup which allowed me to explore a bit more iPhone-specific web development, some PHP / REST / XML coding, and a bit of Google Charts stuff as well. I have to say that the TwitterCounter folks (Boris and Arjen in particular) have been brilliant and very helpful and supportive, despite their app having an issue with the Twitter API while I was in the middle of developing this mashup on top of their API! iWebkit is a lot of fun to play with, and very simple as well – I know the developers are working hard to add new features into that framework whilst keeping it simple and aiming it at “non-techies”.

Oh, and incidentally, although the stylesheets make it look like an iPhone app, it should work perfectly well in any desktop or mobile browser – it’s plain old HTML.

I’m not making any claims about how this might develop in the future, but I’ve got a couple of ideas for tweaks that I might make. In the meantime, if you’re an iPhone (or other mobile device) Twitter user, do take a look at http://andypiper.tv/twtrctr and see how it works for you. Let me know what you think, or any ideas for additions you might find useful! Feel free to follow me on Twitter and @ your suggestions and comments to me, too.

Update: TwtrCtr is now linked directly from the TwitterCounter home page! Follow the iPhone link in the page footer! :-)

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Zero

Posted on June 30, 2007 | 3 Comments

When I got back from the WebSphere Services Technical Conference in April, I posted about the level of interest in simplified development, Web Oriented Architecture and Web 2.0.

Yesterday, Project Zero emerged.

We’re talking REST, PHP, Groovy and mashups.

Come and take a look. For full details, read the FAQ and follow the blog. Then, download the code and join the community.

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