====Python Live Data API====

This API allows you to create Python applications that utilise ARDI live data. 

===Usage Example===

<code>
from ardi.api import core, subscription

server = "myardisiteurl"

ardi = core.ARDICore(server)
ardi.Connect()

sub = subscription.ARDISubscription(ardi)
sub.AddCode('20:22:measurement')

def ProcessNewValues(code,value):
    echo '  ' + code + ' = ' + str(value)

sub.SetCallback(ProcessNewValues,False)
sub.Connect()
</code>

===How It Works===

This is a quick breakdown of how the above example operates.

1) Create an **ARDICore** object and connect it to the ARDI server.

<code>
ardi = core.ARDICore(server)
ardi.Connect()
</code>

This loads all of the settings of your ARDI server, including the location of the consolidator.

2) Create an **ARDISubscription** for live data, passing the ARDICore we just created.

<code>
sub = subscription.ARDISubscription(ardi)
</code>

This prepares the subscription by telling it the consolidator details. It does //not// connect to the server yet.

3) Add all of the [[data points|data points]] that you need to monitor

<code>
sub.AddCode('20:22:measurement')
</code>

You can add as many data points as you need.

4) Define and Set the Callback Function

<code>
def ProcessNewValues(code,value):
    echo '  ' + code + ' = ' + str(value)

sub.SetCallback(ProcessNewValues,False)
</code>

The callback function is invoked every time a value changes. Create the function (it can be a class member if you're implementing this in a class) and call **SetCallback** on the **ARDISubscription**.

5) Start the Subscription

<code>
sub.Connect()
</code>

Note that the **Connect** function is a //blocking// function - it will stop the code from proceeding.

If you'd like to continue with other tasks, we suggest running this function in a separate thread.

If you'd like to be able to stop the function in a timely manner, we suggest installing a //signal handler//. In the handler, you can call **Disconnect** on the subscription - this will stop the subscription after a short delay and allow you to terminate the program gracefully.