HealthVault SDK provides a very useful feature to check under its hood! One can turn-on the tracing for the SDK very easily. The trace log is very helpful for

• Debugging the SDK
• Looking at the raw-xml exchanged between your application and HealthVault platform. The Raw XML in turn is very useful if you are:
  • Trying to write-xml in the thing types
  • Trying to write a HealthVault wrapper library in you favorite language
  • Just curious to look under the hood:)

To look at the trace log add the following in configuration section of your web.config. One you run you application with settings below, a sdk.log file will be generated in the base directory of the website. You can also provide an absolute path for sdk.log to a directory where you web process has a write access.

NOTE: In case the file doesn’t get generated, make sure your web process has write access to the directory sdk.log is getting generated in.

Alrite finally i got the OpenSSL Crypto to work HealthVault. It took some Ninja hacking and quite a lot of debugging to figure out what was going wrong with signing of a xml for getting an authentication token from HealthVault. Turns out that my signing code was dead on but HealthVault didn’t quite like the white space in the “content” section. I wont belabor you more but the short of the long is that now OpenHealthVault can talk to HealthVault and get itself authenticated. As usual the code is at http://svn.vitraag.com/openhealthvault and the application in action is at http://openhealthvault.vitraag.com. Well now its time to get a user to be authenticated with HealthVault Shell and the Rails goodies, I expect these to flow rather smoothly.

Next part : Doing User Authentication

My last post explained a little about challenges of OpenSSL to achieve the healthvault signing for opensource LAMP/R platforms. In this post i’m showing below an actual snippet for talking to the public methods of healthvault platform.

      
        GetServiceDefinition
        1
        05a059c9-c309-46af-9b86-b06d42510550
        en
        US
        2010-01-01T00:00:00Z
        36000
        0.0.0.1
        
    

Sean is starting a series detailing his adventure with healthvault .NET applcations. In the same spirit i’m going to build the ruby on rails application and library through a series of posts here. The application is live at http://openhealthvault.vitraag.com and the source code is in the SVN repository at http://svn.vitraag.com/openhealthvault.

Next part: Getting the Auth Token

This is my first post in an N-series indulgence in trying to evaluate HealthVault to work with Ruby On Rails or Pythons DJango. As you know we HealthVault released a Java library – and it works in a platform independant fashion on most of platforms. I will attempt to outline some of the challenges here lets starting with -

Step 1: Authentication & Authorization -

• Support for Crytography – RSA and Hash Method Authenticaion Code (SHA1/ SHA256)
  • The Java library comes with Sun’s implementation of the above Java.Security. However in LAMP/R world the only respectable alterative is OpenSSL.
  • While Java is everywhere but you might have to install your flavor of OpenSSL in addition to the web-framework. However having a robust framework makes rest of work easy.
• Exporting the private key from Windows generated pfx certificate to be used with one of the offerings.
  • While in theory it should just work but their are some format issues which will need to be dealt with getting key material to be used with the above option.

I’m going to try the Step 1 with Python & OpenSSL and lets see where I go with it.

Next Part: Talking to the public methods of healthvault platform.