Start a process as an action from external URL

RE: Start a process as an action from external URL

Stefan Helzle — Tue, 09 May 2023 14:37:29 GMT

Feel free to post a product enhancement request to Appian.

There is a way to do it, but I agree, it is not the most straight forward one.

RE: Start a process as an action from external URL

lorenzot0001 — Tue, 09 May 2023 14:19:42 GMT

The process would be started, however, and so I should find a way to know that this happened and stop it somehow... It sounds very tricky. It feels strange to me that there is no way to achieve this. It sounds as a reasonable request that Appian should satisfy in a simpler way.

RE: Start a process as an action from external URL

Stefan Helzle — Tue, 09 May 2023 14:15:42 GMT

Nothing, but in case the task is still not there, you can return a status code to tell that system to try it again later.

RE: Start a process as an action from external URL

lorenzot0001 — Tue, 09 May 2023 14:13:23 GMT

You mean that the external system should make a call to start the process and then a second one to retrieve the task? I don't think that this would be totally safe too. What should ensure the task would be created in the moment of the second call, if the start process api can respond before the task is created?

RE: Start a process as an action from external URL

Stefan Helzle — Tue, 09 May 2023 13:56:57 GMT

Would it be possible to implement that in an asynchronous way? One call to start the process, and a second to get the task id?

RE: Start a process as an action from external URL

lorenzot0001 — Tue, 09 May 2023 13:05:09 GMT

I would need to pass input parameters from the external system in that form. I don't think I would be able to do that with a start form process. Is there a way?

RE: Start a process as an action from external URL

Peter Lewis — Tue, 09 May 2023 12:59:47 GMT

I don't think there's really a way to prevent race conditions - even with the plug-in I would guess that you could end up with scenarios where the task was not created yet by the time you run the process.

Can you just link to a start form or is it actually necessary to start a process for this scenario?

RE: Start a process as an action from external URL

lorenzot0001 — Mon, 08 May 2023 19:07:00 GMT

I think my issue is solved in the other post I opened to highlight it https://community.appian.com/discussions/f/integrations/28612/start-process-via-api-and-put-task-url-in-the-response/112392 .

The issue seems to be that the process report has a little delay in fetching updated data. Using the function getactivetaskidsforprocess() instead of the process report seems to have solved the issue (I will test it extensively).

Thank you very much for your support, anyway. You are a great community.

RE: Start a process as an action from external URL

Stefan Helzle — Mon, 08 May 2023 18:29:19 GMT

Peter Lewis, do you have any ideas?

RE: Start a process as an action from external URL

lorenzot0001 — Mon, 08 May 2023 18:09:52 GMT

We tried, but unfortunately it didn't work. Still same error.

RE: Start a process as an action from external URL

Stefan Helzle — Mon, 08 May 2023 18:04:40 GMT

OK. Thanks. I think this is an edge case of how a process model reacts on the end of the chain and ehan that task becomes active.

Can you try to extent the chain after the task.

RE: Start a process as an action from external URL

lorenzot0001 — Mon, 08 May 2023 17:36:05 GMT

We tried but the we still have the same error, occurring randomly. Here is the new code.

a!httpResponse(
statusCode: 200,
headers: {
a!httpHeader(name: "Content-Type", value: "application/json")
},
body: a!toJson({
taskUrl: a!urlfortask(
taskIds: index(index(index(a!queryProcessAnalytics(
report: cons!LM_TR_BY_PID,
contextProcessIds: {
index(index(fv!processInfo, "pp", null), "id", null)
},
query: a!query(pagingInfo: a!pagingInfo(1,1))
), "data", null), "c4", null), 1, null)
)
})
)

The report that we are using is a task report of type "Tasks by process".

RE: Start a process as an action from external URL

Stefan Helzle — Mon, 08 May 2023 17:26:56 GMT

Hm ... Can you try to use a process report and queryProcessAnalytics instead of that plugin function?

RE: Start a process as an action from external URL

lorenzot0001 — Mon, 08 May 2023 16:32:01 GMT

We start the process with a!startProcess and we value the onSuccess parameter of that rule like this:

a!httpResponse(
statusCode: 200,
headers: {
a!httpHeader(name: "Content-Type", value: "application/json")
},
body: a!toJson({
taskUrl: a!urlfortask(
index(rule!LM_getTaskDetailsByPid(
pid: index(index(fv!processInfo, "pp", null), "id", null)
), "taskId", null)
)
})
)

where rule!LM_getTaskDetailsByPid is a rule that, given a process id, retrieves the id of the active task of the process in the taskId component using a task report and query analytics.

It seems that sometimes the system tries to evaluate LM_getTaskDetailsByPid before the process reached the user input task.

Thank you very much for your help, really appreciated!

RE: Start a process as an action from external URL

Stefan Helzle — Mon, 08 May 2023 16:26:49 GMT

Hm, we did not see this issue years ago. How do you obtain the task id?

RE: Start a process as an action from external URL

lorenzot0001 — Mon, 08 May 2023 16:17:22 GMT

Hi Stefan, how did you achieve this? We built an API which start the process, we chained the start node to the first user input task and we retrieve the task url in the api upon building the response.

This appears not to be working always. It appears to work fine 80% or the times, but sometimes it seems that the api builds the response before the process assignes the task!

RE: Start a process as an action from external URL

lorenzot0001 — Mon, 08 May 2023 16:02:14 GMT

This appears not to be working always. It appears to work fine 80% or the times, but sometimes it seems that the api builds the response before the process assignes the task!

RE: Start a process as an action from external URL

mislavu0001 — Tue, 21 Sep 2021 07:18:13 GMT

Ok, clear, thank you

RE: Start a process as an action from external URL

Stefan Helzle — Tue, 21 Sep 2021 07:14:13 GMT

Not directly. One option might be to use an embedded interface. Not sure about the restrictions in that specific case.

RE: Start a process as an action from external URL

mislavu0001 — Tue, 21 Sep 2021 06:26:46 GMT

Hi Stefan, thank you for your feedback. I was thinking about this possibility, but can we open a start form this way. Our intention is not to start the process instance but only open a start form from a link. Maybe I am not aware, but is there a function which can return a 'start form' task id if process instance is not started? End user can click the link in external system several times and we don't want to start the process instance each time, actually we want to start it if this first 'start form' is submitted.

RE: Start a process as an action from external URL

Stefan Helzle — Mon, 20 Sep 2021 14:13:58 GMT

We implemented the following pattern for this. An API call passes the necessary data to Appian and starts a process. The API call returns the URL to the task. The other system forwards the user to this task.