Dynamically executing an expression rule by retrieving the rule name from DB

RE: Dynamically executing an expression rule by retrieving the rule name from DB

ashwing — Sun, 09 Jun 2024 20:31:31 GMT

Hi! Can you please elaborate on this?

RE: Dynamically executing an expression rule by retrieving the rule name from DB

Mathieu Drouin — Mon, 10 Jul 2023 12:51:48 GMT

For those wondering, here's an example of what I meant using the apply function in combination with the getrulereferencebyname in the Content Tools plugin.

Again, I don't recommend this approach as it becomes very difficult to find dependencies in your application and troubleshooting becomes difficult. The API approach is more robust IMO.

a!localVariables(
  apply(getrulereferencebyname("S_DynamicRule"), {""})
)

RE: Dynamically executing an expression rule by retrieving the rule name from DB

Mathieu Drouin — Mon, 10 Jul 2023 12:16:12 GMT

Interesting. Care to elaborate?

RE: Dynamically executing an expression rule by retrieving the rule name from DB

Arka.Maity — Mon, 10 Jul 2023 11:51:28 GMT

Not required to use apply function

RE: Dynamically executing an expression rule by retrieving the rule name from DB

Mathieu Drouin — Mon, 10 Jul 2023 09:42:25 GMT

Yeah as I mentioned earlier, it is possible to do with the apply function.

docs.appian.com/.../fnc_looping_apply.html

Though I do get the impression that Appian may want us to move away from using this function given the blurb they put at the too strongly suggesting to use forEach instead.

RE: Dynamically executing an expression rule by retrieving the rule name from DB

Arka.Maity — Mon, 10 Jul 2023 07:26:25 GMT

Hi Actually you can execute the rule by its UUID/Name.

RE: Dynamically executing an expression rule by retrieving the rule name from DB

Mike Schmitt — Thu, 06 Jul 2023 13:34:19 GMT

You can get a rule name by its UUID via the "getContentDetailsByUUID" rule found in a particular plug-in (probably Content Tools). However that doesn't change the fact that, as far as I know, there's no supported way to execute an expression rule by its name. (edit: Mathieu mentions below that the function "getrulereferencebyname" can do this. however as noted, this is cumbersome and confusing to use, and relies on old / potentially-deprecated features.)

This is why Mathieu raised the idea yesterday of executing Web API calls - because for these it's trivially easy to execute a call based on just the result of a string look-up (the API endpoint name is already just a string), and the other end of the API call can be paired to a Web API that points to its own expression rule (so if each person makes an expression rule for themselves, they'd also make a Web API object that calls it, and requires certain universal parameters that you enforce). Thus you'd just store the Endpoint Name in the DB.

RE: Dynamically executing an expression rule by retrieving the rule name from DB

Nandini Devi Balakrishnan — Thu, 06 Jul 2023 13:03:40 GMT

Is there any way to execute an expression rule by its UUID/Name. The UUID/Name of the rules to be executed will be saved in the DB, during the runtime the system should read the UUID/Name and execute the rule corresponding to it.

RE: Dynamically executing an expression rule by retrieving the rule name from DB

Mathieu Drouin — Wed, 05 Jul 2023 16:31:41 GMT

Not much different than if you were calling an external API.

You just expose a Web API and create an Connected System + Integration to consume it.

Maybe this can help: docs.appian.com/.../Designing_Web_APIs.html

RE: Dynamically executing an expression rule by retrieving the rule name from DB

Nandini Devi Balakrishnan — Wed, 05 Jul 2023 16:29:12 GMT

Thanks for the suggestion. One quick question though, how do you call an Web API from within Appian and how to handle authentications when the call is made from Appian

RE: Dynamically executing an expression rule by retrieving the rule name from DB

Mathieu Drouin — Wed, 05 Jul 2023 16:21:28 GMT

You can try to use the apply function. But I don't really recommend it.

If you want to avoid dependencies I think the best approach would be to have each app expose a Web API for the tasks and basically just call those APIs.