When I’m hiring, one of the things I always want to see is evidence of personal projects. Over the last two years, GitHub has become an amazing treasure trove of code, with the best social infrastructure I’ve ever seen on a developer site. GitHub profiles let the user set their location, so I started with a few web searches for Berlin developers. This finds hundreds of interesting people, but how do I prioritise them?

Another thing that I look for when building a good team is someone’s personal network. I’ve always believed strongly in spending lots of time at conferences meeting passionate people who are smarter than me. A good developer can make themselves even more productive by knowing who to email, IM or DM to answer a question when they’re stuck.

A recent article by Stowe Boyd on centrality and influence in social networks reminded me of some of the network analysis we use behind the scenes calculating recommendations for the Dopplr Social Atlas. So I wrote some code to query the GitHub API and analyse the social graph of the Berlin subset of their users.

The JRuby code uses Yahoo BOSS to do the web search. After querying the GitHub API for each user’s followers it builds an in-memory graph using the Java Universal Network/Graph Framework. Then it ranks each user node in the graph using the Betweenness Centrality algorithm. You can see the simple source code on my github.

To sanity-check the results I ran it for a couple of cities I already know well: London and San Francisco. Here are the top 5 for each, which seem quite plausible to me:

San Francisco

1. Chris Wanstrath, GitHub
2. Tatsuhiko Miyagawa, Six Apart
3. Leah Culver, Six Apart
4. Square Inc
5. Aman Gupta, ruby eventmachine maintainer

London

1. James Darling
2. London Ruby User Group
3. Mark Norman Francis
4. Dan Webb (recently moved to Twitter in SF)
5. Carlos Villela, Thoughtworks

My choice of metric biases these lists towards connectedness and influence — it can’t measure ability. It’s only measuring GitHub users, and they are biased towards Ruby, Perl and Javascript. But seeing names there that I trust gives me confidence that it’ll help me find interesting people in Berlin.

Hopefully some of those people are reading this blog post right now. Others outside Berlin might be interested to know that Nokia does a superb job of relocating people, with everything taken care of by shipping companies and local agents. If you love the web, Javascript, mobile, user experience, social networks, location, enormous datasets and currywurst, you should get in touch.

Their code is written in PHP and Java respectively, two languages I’m not particularly comfortable in. Translating from their source code, I’ve produced a ruby version and packaged it as a very simple gem. It lacks real documentation or elegant error handling, but it’s easy to figure out.

Use it like this to locate your phone:

$ sudo gem install mattb-findmyiphone --source http://gems.github.com

>> require 'rubygems' ; require 'findmyiphone'
>> i = FindMyIphone.new(username,password)
>> i.locateMe
=> {"status"=>1, "latitude"=>51.546544, "time"=>"8:06 AM", "date"=>"July 23, 2009", "accuracy"=>162.957953, "isLocationAvailable"=>true, "isRecent"=>true, "isLocateFinished"=>true, "statusString"=>"locate status available", "isAccurate"=>false, "isOldLocationResult"=>true, "longitude"=>-0.05744}

And to send a message:

>> i.sendMessage("Unimportant message")
=> {"status"=>1, "time"=>"8:17 AM", "date"=>"July 23, 2009", "unacknowledgedMessagePending"=>true, "statusString"=>"message sent"}

Finally, if you look in the examples directory you’ll find a short script that uses the location data to update Fire Eagle via its API. Fill in the example YAML files with the appropriate credentials and it’ll do the rest.

Of course the code’s all open source and contributions via Github are very welcome.

This talk (based on a previous blog post here) goes into some detail about how I use HTTP, JSON and other web-oriented tech in my iPhone work.

I’m a web developer at heart, and a scripting language user by preference. Coding for the iPhone doesn’t feel as fluid in text handling or HTTP access as the environments I’m used to. Fortunately I’ve been able to find some fantastic open-source libraries and wrappers that make up the difference. Here are my favourites so far:

GTMHTTPFetcher from Google Toolbox for Mac

The iPhone’s native HTTP handling is capable, but low-level and verbose. Rather than handling the many callbacks, NSData objects and options I prefer this wrapper. It has a ton of convenience methods allowing you to specify POST data and basic auth, follow redirects automatically, keep cookies over a session, set headers, and have two simple callbacks for success and error handling. In many ways it’s comparable to jQuery’s $.ajax() one-hit function.

JSON framework

Having got some data over HTTP from a web API, chances are that it’s available in JSON format. This simple framework extends NSString with a JSONValue method to convert any legal JSON string to nested NSDictionaries and NSArrays. To go the other way, dictionaries and arrays gain a JSONRepresentation method.

libxml2 wrappers for XPath over XML and HTML

Perhaps your web API returns XML, or perhaps you’re getting your data by screenscraping HTML. Did you know that the iPhone ships with libxml2, which has high-performance XML and HTML parsing and a high-quality XPath implementation? Don’t struggle with Cocoa’s NSXMLParser or get bogged down in the complex libxml2 docs; use these two simple wrapper functions, PerformXMLXPathQuery and PerformHTMLXPathQuery, to pull out the structured data you need in a Cocoa-friendly representation.

RegexKitLite for regular expressions

Where would scripting be without regular expressions? Luckily they’re available on the iPhone, but buried deep within the ICU libraries. RegexKitLite extends NSString with core regex string handling, including ’split’ (known as componentsSeparatedByRegex) and a search-and-replace operator (stringByReplacingOccurrencesOfRegex and replaceOccurrencesOfRegex).

FMDB, an Objective C wrapper for sqlite

Every scripting language has convenient database driver wrappers. I was very happy to find that sqlite is available on the iPhone, but unfortunately its interface is all bare-metal C. The simplest wrapper I’ve found so far is FMDB. Apparently somewhat inspired by JDBC, it gives you connection and resultset objects, along with one-liner convenience functions allowing code like [db intForQuery:@"SELECT COUNT(*) FROM things"].

And there’s more…

I’ve used all of the above in a real project, but I’ve got yet more things to explore on my todo list. These include Matt Gemmell’s web-style templating framework MGTemplateEngine, ActorKit for Erlang-style messaging and thread management and the LLVM/Clang Static Analyzer for automatic bug detection. What else do you use?

Flickr place info now includes shape data for many places. See the Flickr code blog for more.

We’ve correlated most of Dopplr’s places with Yahoo WOE IDs using Flickr’s reverse geocoder, so we can use this data too. As an experiment, I wrote some clientside code to overlay this shape data onto the maps we use on Dopplr. Help yourself to the code if you want it: gist.github.com/25502

The March 2008 US conference season is nearly upon us. I’m just on my way back from representing Dopplr at Social Graph Foo Camp (find out more by listening to the Citizen Garden Podcast I participated in after the camp), but I’ll be back here again in three weeks.

I’m spending a few days in New York, where I’ll be hosted by the lovely Chris Shiflett, and then it’s on down to San Diego for ETech. That’ll be swiftly followed by SXSW Interactive where I’ll be on a panel entitled “Creative Collaboration: Building Web Apps Together”, about working in multidisciplinary teams. Finally, a week in San Francisco decompressing and having a few meetings.

I’m particularly excited by the trip to ETech. The last two years have brought smart people together to talk mostly Web 2.0 topics, but this year looks significantly more awesome. Full of genuinely emerging technology, the lineup looks like one Matt Jones and Tony Stark would appreciate.

Some highlights for me include a talk from Google’s economics groups on Prediction Markets, Computing for Socio-economic Development, and the excitingly-titled Antigenic Cartography: Visualizing Viral Evolution for Influenza Vaccine Design. Hope I see you there.

I’m writing my proposal today – I’m planning on pulling the very loose ramble I presented at Barcamp London on messaging architectures into a proper talk. For 2008 I’m very excited about Erlang, XMPP, message brokers such as ActiveMQ and clientside messaging with Comet. The future’s asynchronous and highly concurrent.

I’m looking forward to the face-to-face conversations of the upcoming conference season. Working on Dopplr didn’t leave much time for writing in 2007, and that’s not going to change in the near future. Right now my online tech output is most confined to tiny fragments of ideas on Twitter and random pictures on Flickr (Nokia N810 unboxing; Jawbone unboxing).

If you’ve taken the first steps in tinkering with an Arduino or similar kit, why not take it up a gear and sign up for the Hardcore Hardware Hacking Weekend in London on July 21st and 22nd? Massimo Banzi, co-creator of Arduino, will be teaching advanced hardware skills and I’ll be there to explain how to plug it all into software and the internet. I’m especially looking forward to hearing from guest speaker Moritz Waldemeyer. Places are limited and going fast.

The theme this year was ‘The Ubiquitous Web’. HTTP isn’t just for computers any more, and I’m particularly interested in how developers like me can learn to make their own network-connected objects in the real world. To spread the word, I gave a lightning talk on my experiences with the Arduino hardware hacking boards and other toys from tinker.it.

I put the slides on SlideShare.

I made a recording of the audio from the talk on my laptop’s microphone, and I’ve synchronised it with video of the slides in this Flash movie:

If you prefer, there’s also the audio-only MP3.