Last night, I shared my first stab at a mobile Fire Eagle client: a Windows Mobile application which posts location updates to the Yahoo! Fire Eagle service.
A couple of the bits of code were fiddly, and are worth sharing.
In this post, I’ll outline how I perform the code behind the OAuth authentication I described in my last post. Hopefully, this might help anyone else wanting to do something similar.
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I wrote a Fire Eagle web service at Open Hack London a few months ago – that gave a nice, mobile-friendly way to share your current location, as stored in Fire Eagle.
Last week, I finally got round to updating my Fire Eagle Guest Pass web service to use the newer OAuth 1.0a.
This got me thinking that I haven’t used it very much since writing it in May… because while it let me share where Fire Eagle thinks I am, I didn’t have an easy mobile-friendly way to tell Fire Eagle where I am in the first place! 🙂
So while I had “how to do OAuth” fresh in my mind, I thought I’d start writing a quick mobile Fire Eagle client.
I wrote it in C# for Windows Mobile. There are a few interesting points in the code that deserve their own blog posts, but first I wanted to quickly show what I’ve got working so far.
I posted yesterday about my quick play with the BBC Web API for programme schedules. I wanted to be able to programmatically find out what programme was on a particular channel at a given time.
The problem with the quick code I came up with was that it only gets me BBC channels. What if I want to know what was on a non-BBC channel?
Andrew pointed me at the Radio Times website, which makes programme schedule data available in XMLTV format.
And Dom pointed me at a neat Python library for parsing XMLTV data.
After my absence, I thought I’d come back with something quick and fun – the result of half an hour’s playing with a new (to me) API.
The problem that I wanted to look into was: What programme was on TV on a given channel at a given time?
And how can I find this out programmatically?
The first thing that I came across was the getProgrammes service in the beta BBC Web API.
As I expect from the forward-thinking BBC, it’s pretty awesome: a simple API that gives you an XML document containing the programmes schedule for the specified time window.
The documentation on the BBC site is pretty self-explanatory. It gives all the information you need to start playing with the API – either using the form on the BBC page, or by sending it a few requests using wget.
I’ve been doing too much Java at work recently, so in the interest of keeping my hand in with some low-level C++, I picked up the code for my mobile twitter client, TwitToday, again.
I originally wrote it at a hackday, but I’ve since come back to tweak it a couple of times to get it to spawn background worker threads, add SIP on-screen keyboard support, and improve support for sending special and accented characters.
After another evening of tweaking, I’ve added a few new minor features:
Transparent text box
When not in use, the text box is now transparent. When it has focus, it is coloured in white as usual.
A few people commented that a bright white text box could dominate a dark Today screen too much, so this is hopefully a nice aesthetic improvement.
I did this by creating a custom windows procedure for the text box.
The windows procedure needed to handle a couple of events:
Handling WM_PAINT by using SetBkMode to make the text box TRANSPARENT
Handling WM_ERASEBKGND by using TODAYM_DRAWWATERMARK to draw the background over the text control’s rectangle.
My CurrentCost desktop software is written in Python, and uses the matplotlib library for plotting graphs.
I am a big fan of matplotlib – you can create some very cool graphs with it. It’s not without it’s issues… for example, I’ve still yet to work out how to do realtime graphing with it that isn’t massively inefficient and resource intensive. But that’s for another post 🙂
One of the nice things that you get with it is a toolbar that lets the user switch between different modes that the mouse supports – zooming, panning, and so on.
Adding the toolbar is straightforward – I create an object of the class NavigationToolbar2Wx and add it to a sizer which in turn I add to the graph Plot.
self.toolbar = Toolbar(self.canvas) self.toolbar.Realize() sizer = wx.BoxSizer(wx.VERTICAL) sizer.Add(self.canvas, 1, wx.EXPAND) sizer.Add(self.toolbar, 0 , wx.LEFT | wx.EXPAND) self.SetSizer(sizer)
The NavigationToolbar2 toolbar provides a number of features but it doesn’t exactly meet my needs so last night I had a go at customising it.
I wanted to:
I couldn’t find this documented clearly anywhere, so thought it was worth sharing the code that I came up with.
Imagine you are in a town or city. Perhaps one which you are unfamiliar with.
You’ve arranged to meet someone, and want to help them find you.
They’re not a close friend or family member, so you don’t want to sign up with something like Google Latitude which feels like quite a long-term thing for people who want to always be able to see where you are.
You don’t want to have to ask them to sign up for some new service like Fire Eagle just to find you.
Maybe they’re a client coming to meet you for a meeting. You want to help them find you, but you’re not sure that you want them to be able to see where you go after the meeting, or what pub you go to that evening.
This is the sort of thing that “Fire Eagle Guest Pass” – my hack entry for Open Hack London 2009 – was written for.
I’ve put together a few pictures to explain what it does on slideshare. They’re not exactly fine art, but hopefully they explain the idea 🙂
Last Saturday was the second HomeCamp. This week has been very busy at work, so I’ve not had the chance to pull together a proper post about it yet, but in the meantime I thought I’d share a little Pachube tip that Usman demonstrated at the event.
I’ve been putting the live readings from my CurrentCost meter into Pachube as an input feed for several months now, but not really had much use for it, other than as an easy way to check my CurrentCost data from my mobile.
Usman showed us an app that lets you get a neat Google chart visualisation of a Pachube feed in just a few clicks:
It’s very simple – go to apps.pachube.com/google_viz, give it the ID of your pachube feed, and it generates the short snippet of code necessary to create the Google chart.
It takes no time at all, and really shows the power of being able to easily pipe together different stuff through pachube.