Trying to Generate a StartProcessLink in Process Model

Question

Hi, 
 
 I have a use case where I need to redirect a user to a StartForm when user clicks on the link in the email. I'm able to generate this StartProcessLink (Pm has specific process parameters that needs to be sent as well) successfully when I try to execute in an expression rule but when I try to call this expression rule in ProcessModel's Script Task to get the output, it is returning a null value, any suggestions on how to approach it? 
 
 Note: We cannot Trigger a Pm and keep it active as we do not know the time frame of when user would be working in it. It can range from a day to a month 
 
 Any suggestions appreciated. 
 
 Thanks in Advance.

Mike Schmitt · Answer

If you're after a Start Form, it seems like it would be far simpler to simply have the email contain a link directly to a Site tab that's configured to use a start form for that express purpose.

Mike Schmitt · Answer

If you take the back-end outputs of a!startProcessLink(), i'm guessing you could assemble it (manually) into a URL a user could click on. I haven't tried this exactly, so your mileage may vary - and i'd caution you that it's pretty far from a supported use case.

Mike Schmitt · Answer

Given the above I'd reconsider the "process start form on a site tab" approach. Most things that I can think of that you'd pass into a form like this via some Unique ID, could be queried upon the user loading the start form, and persisted to the process variables upon Start Form submission. 
 That or just have the calling process launch a subprocess and assign the user a task, instead of sending them a Start Process Link in an email. I'm still a little unclear why that wouldn't work. But among the various alternative solutions, it seems to me as if you're probably unnecessarily dismissing at least one or two things that would work just fine for your use case, at least given any deatils you've posted here so far(?).

Mike Schmitt · Answer

All of that could be done in the interface on a process start form kept on a site tab. 
 
 email the user (at whatever timing you need) that they've been assigned a new / subsequent work task 
 the email will contain a link to the site tab containing the start form 
 upon loading the start form:
 
 the interface will establish which user is looking at it, and look up (query from the DB, etc) the fact that they have a "task" waiting. 
 other users who navigate to that tab will see a generic / inert interface with no way to start an instance of that process.

Mike Schmitt · Answer

In that case it would be relatively easy to show them different options to pick from and then launch the appropritate one upon form submission (perhaps along with a sensible reminder that they "owe" all the items listed). This seems superior to not being able to do anything, or to having to engineer a brand new solution that defies being actually supported by Appian OOB functionality.