Invoking start process smart service and update constant smart service in Expression Rule

Question

Hi, 
 
 May I know how to invoke a start process smart service and update constant smart service in an expression rule. 
 
 Thanks, 
 Balaji.R

Josh · Answer

You can put the start process and update constant smart service function calls inside an expression rule, but that expression rule needs to be called within a!save() from a SAIL interface or from a Web API. docs.appian.com/.../Start_Process_Smart_Service.html

aloks0189 · Answer

Hi rp_balaji I believe Web API is the best choice for you where you can invoke smart service function. 
 
And you can invoke this Web API using integration object and you can call this integration object, where ever you want to (if it's a get call) using rule! 
 
And you can try performing update constant operation with in the same process which you are trying to invoke using Web API, this should do your job. 
 
Hope this will help you.

Josh · Answer

Hi Balaji, 
 
That makes sense. I have followed the design pattern that mentioned to achieve this in the past. 
 
Depending on your circumstances you could also redesign the application to either A) Always get the OAuth token when making a request instead of caching it or B) Set up a process model that retrieves the OAuth token value, stores it to the constant, then sets a new instance to run when the token expires (In my experience when you grab the OAuth token it includes a field telling you when it will expire.)

Josh · Answer

According to docs.appian.com/.../Expressions.html , "Expressions do not modify any data inside or outside the Appian system."