Adding Multiple Axis Labels to a Google Chart

Recently I've been working on a project using Google Charts API and I absolutely love it. It makes pretty graphs and shows data really nicely - and it's very painless. I did trip over a little trick today though which took me a little while to work out, so I thought I'd share it here: how to add two levels of label to an axis.

The axes in Google Charts are a bit interesting, because what they display bears absolutely no resemblance to what data is there - you label the axes separately, even if they are numbers. To label multiple things - in this example a scale and some units, you simply specify the axis more than once. To specify which axes should be shown, use chxt (CHart aXis Title) and set something like this:
&chxt=x,y,y

Then add the labels as required, for example:

http://chart.apis.google.com/chart?chxl=1:|Sun|Mon|Tue|Wed|Thu|Fri|Sat|2:||Week+37
&chxr=0,0,20&chxs=0,676767,11.5,0,lt,676767&chxt=y,x,x&chbh=a
&chs=360x240&cht=bvg&chco=CC0057CC,3D7930&chds=0,20
&chd=t1:10.059,12.578,13.6,11.135,11.018,7.104,6.92|50,60,100,40,20,40,30

This produces a graph like this:

You can then add labels (using chxl) and ranges (uses chxr) to your axes as you wish - and even add axis labels to the top and right hand graph edges, using the t and r axes, with as many of each as you'd like, and using their list position as a parameter to the range/label settings. I hope this is useful to someone, as it took me a little bit of research to figure it out.

OAuth Google API for Unregistered Applications

It is pretty common when using OAuth for there to be a relationship between the provider and consumer; as a consumer you usually register with the provider to obtain a consumer key and consumer secret. Google's APIs however do not require this. It is recommended that you register your application, however it is also possible to use OAuth without registering.

To make this work, when you sign your OAuth request Google will accept some default values for consumer key and secret - see their documentation on signing oauth requests. To do this, set both consumer key and secret to the value "anonymous", and proceed as you normally would. The only difference so far as I can see is that the user will be shown a more cautious message when they are prompted to grant access to your application. Personally I think this is a great approach, particularly when prototyping ideas. Registering the applications though is simple and quick so I'd recommend registering for most applications once they get beyond concept stage.

Google Analytics Accounts API

I'm working with Google Analytics at the moment, to pull information about web traffic from analytics into another system. Google have excellent APIs and that makes this job much easier. I'm using pecl_oauth to authenticate users against their google accounts (see my post about using OAuth from PHP), but even after I have a valid google user, working out which analytics accounts they have access to and how to refer to them is a puzzle in itself, so I thought I'd share what I learned.These examples use pecl_http, since I have control of my platform and I find it easy to work with. I've tried to write this with explanations of the overall process in between the code snippets so hopefully this makes the process clear whether or not you will use exactly the same implementation.

Analytics Accounts

Your google account can have access to one or more analytics accounts. For example when I log in I have access to accounts which hold the data for lornajane.net, phpwomen.org, joind.in and a few other things I'm involved with. Only lornajane.net actually belongs to me, the others are accounts created by someone else and which I have access to. The first challenge therefore is to work out which a user has access to - the best place to start is the reference page for the Management API, part of google's own documentation. In a nutshell, we build up a URL like this, being increasingly specific by fleshing out the values in square brackets on subsequent calls:

https://www.google.com/analytics/feeds/datasources/ga/accounts/[accountID]/
webproperties/[webPropertyID]/profiles/[profileID]/goals

First up then, is to get a list of accounts for our authorized user - I already have a valid oauth access token to use in this example Continue reading

Fetching Namespaced XML Elements With SimpleXML

Recently I was working with some google APIs and needed to retrieve some namespaced elements from the result set. This confused me more than I expected it to so here's my code for the next time I need it (and if you use it too, then great!)

I was reading from their analytics data feed API, this returns a few key fields and then multiple <entry> tags, each with namespaced children. The entry tags look something like: Continue reading

Authenticating with OAuth from PHP

I've been looking into OAuth recently and really like what I see, so I started looking at actually starting to play with something that uses it (and isn't twitter). In the pursuit of this, I spent some time walking through the process of how to actually authenticate using OAuth, as a client. I chose Yahoo!'s service, because they have some fabulous developer documentation and have a standard OAuth implementation. Although you don't strictly need any special libraries to handle OAuth, that would be a bit like decoding XML with a regex, so I used the OAuth Package from PECL. For others (including me after I've slept), here's an outline of the process.

Continue reading