Presence of thoughts
Jabber is so final a long time. Webex and its competitors are the most effective fashionable technique of messaging. But Cisco IM&P, a companion server to Cisco Call Manager, remains to be one of the best ways to subscribe to consumer presence updates.
Suppose you’ve got a gaggle of workers to whom you assign duties as they arrive in. If you possibly can watch the presence of that group, you’ll know who is on the market, who’s away, who’s on the cellphone, and many others. You can construct an utility that robotically assigns duties based on the presence of the customers.
The Presence Web Services (PWS) API, a function of Cisco IM&P, is good for this sort of utility. In my expertise as a former developer help engineer, I seen many builders don’t fairly perceive the best way to use PWS correctly. I hope that by the point you’re performed studying this, you’ll have a very good grasp of all the things concerned in making PWS give you the results you want.
Here’s a condensed breakdown of the steps:
- Log in an utility consumer with app username and password
a. This operation returns the appliance consumer session key - Use the appliance consumer session key to log in an finish consumer
a. This operation returns an finish consumer session key - Create an online service to deal with presence notifications
a. Run this internet service to pay attention on a typical port, e.g., 8080 - Use the appliance consumer session key to register the URL of your internet service as an endpoint
a. This returns an endpoint ID - Use the top consumer session key to subscribe to a number of finish consumer contacts
a. This returns a subscription ID - Create a script to fetch the subscribed presence, utilizing the subscription ID
a. For instance, get_subscribed_presence.py
In steps 1 and a pair of, there’s a selection referred to as “force=”. If you set “force=true”, the server will return a brand new session key each time. I like to recommend you employ “force=false”, in order that it retains re-using the identical session key. This covers a large number of programming sins.
In Step 3, it is very important use a typical port, like 80, 82, 8080, and many others. If your internet service is predicated on Python and you employ the Flask library, the default port for Flask is 5000, which won’t work. You should inform flask to make use of one of many frequent ports, as an alternative.
Once you’ve got accomplished steps 1 by 5, any change within the presence of the contacts in your step 5 subscription will set off a REST GET operation on the endpoint. The GET will go two parameters: The subscription id which ought to at all times be 1 with these scripts, and etype, which ought to at all times be “PRESENCE_NOTIFICATION”.
Your utility ought to then use the subscription ID to fetch all of the presence adjustments for that subscription. The API for that’s getSubscribedPresence. The script that invokes getSubscribedPresence is, coincidentally, get_subscribed_presence.py.
The pattern scripts use REST, however you can too use SOAP.
No problemo!
A typical downside happens while you run your endpoint after a contact’s presence already modified. The server will ship a presence notification to the endpoint, however the endpoint isn’t working, in order that notification by no means will get to the endpoint, and the endpoint doesn’t fetch the subscribed presence data. This is an issue as a result of, if for any purpose you don’t fetch the presence values on that subscription, the server will cease sending future notifications till you do.
So, the script you create in Step 6 is a fail-safe. Suppose a contact, Carlotta Tendant, switches from AVAILABLE to AWAY. The server will notify the online service on the endpoint URL {that a} change in presence occurred. If your endpoint isn’t lively, or it doesn’t decide up the notification and fetch the presence data, the server will cease sending presence notifications till you fetch that presence data.
It is necessary to know that the presence notification doesn’t ship any contact data or the truth that Carlotta is now AWAY; it simply notifies the online service {that a} presence has modified for a number of contacts for that subscription. Your internet service should fetch the details about the contact and the contact’s presence.
To keep away from the potential for missed notifications, run the get_subscribed_presence.py script as soon as all the things is about up and prepared and your endpoint is working. This grabs the knowledge for the customers and their presence, and thus clears the queue for the server to ship new presence notifications.
There is one more reason the online service might not obtain a notification. If the Cisco IM&P server CPU utilization reaches 80% or increased, the server stops sending notifications till the CPU utilization drops under 80%. Here’s the best way to compensate for that chance. Write your app to carry out a get subscribed presence at an interval of each 10 minutes (or whichever appears greatest), simply to guarantee that if, for any purpose, your utility didn’t act on a presence notification, the queue will clear, and notifications will proceed.
Scripts
WARNING: Don’t use my pattern scripts on a manufacturing server. These are for educational functions solely.
My pattern scripts are as follows:
pws-create.py
pws-delete.py
endpoint.py
get_subscribed_presence.py
And there are some information information the script makes use of to get details about the server, the host for the endpoint, app consumer, finish consumer, and the contacts on your presence subscription.
serverparams.json (factors to your Cisco IM&P server and the host IP handle for the endpoint)
appuser.json (has the appliance username and password)
enduser.json (has the top consumer title. You use the session key out of your utility consumer login)
contacts.checklist (the checklist of contacts for which you’ll subscribe to get presence notifications)
Order Up
Here’s the way you run the scripts, so as.
- python3 pws-delete.py
- This removes all endpoints and subscriptions so you can begin contemporary
- python3 pws-create.py
- This units up the endpoint and subscribes to the presence of contacts in checklist. It makes use of serverparams.json to establish your Cisco IM&P server and the IP handle of the host the place your endpoint will run.
- python3 endpoint.py
- This is the endpoint script. It makes use of the Flask Python library to work as an online service.
- python3 get_subscribed_presence.py 1 BASIC_PRESENCE (or RICH_PRESENCE)
- You run this after the endpoint internet service is up and working. This clears out any pending subscription updates and notifications in order that the queue is empty and future notifications will work.
If you have a look at the code within the pattern endpoint script, for the online service endpoint doesn’t embrace the code to fetch the subscription presence. I put all that into the get_subscribed_presence.py script. My endpoint merely executes the script externally like so:
subprocess.run("python3 get_subscribed_presence.py "+id+" "+etype, shell=True)
The endpoint will know the worth of id and etype and go the values when it runs get_subscribed_presence.py. If you need to run the script your self, nonetheless, you could go values on the command line, for instance:
python3 get_subscribed_presence.py 1 BASIC_PRESENCE
You can even use RICH_PRESENCE as an alternative if that’s what you need. If you’re performed all the things accurately, the subscription id will at all times be 1, which is why you go the quantity 1 to the script on the command line.
The pattern script doesn’t do something with the presence data. It prints it to the console the place you run the endpoint internet service. Your utility should carry out your wanted job, comparable to updating a show of contacts and their presence.
Resources
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