“The slogan ‘press on’ has solved and always will solve the problems of the human race.”
— Calvin Coolidge
In the previous installment in this series, we created a new Scripted REST API Resource and referenced another nonexistent function in our Script Include. Now it is time to create that function, which will perform some of the work required to register a new client instance and then hand off the remaining tasks to an asynchronous Subflow so that the function can return the results without waiting for all of the other instances to be notified of the new client instance. The only thing to be done in the function will be to insert the new client instance into the database and kick off the Subflow. But before we do that, we need to first check to make sure that the Client has not already registered with the Host.
var result = {body: {error: {}, status: 'failure'}};
var mbrGR = new GlideRecord('x_11556_col_store_member_organization');
if (mbrGR.get('instance', data.instance)) {
result.status = 400;
result.body.error.message = 'Duplicate registration error';
result.body.error.detail = 'This instance has already been registered with this store.';
} else {
...
As we did before, we construct our result object with the expectation of failure, since there are more error conditions than the one successful path through the logic. In the case of an instance that has already been registered, we respond with a 400 Bad Request HTTP Response Code and accompanying error details. If the instance is not already in the database, then we attempt to insert it.
mbrGR.initialize();
mbrGR.name = data.name;
mbrGR.instance = data.instance;
mbrGR.email = data.email;
mbrGR.description = data.description;
mbrGR.token = data.sys_id;
mbrGR.active = true;
mbrGR.host = false;
mbrGR.accepted = new GlideDateTime();
if (mbrGR.insert()) {
result.status = 202;
delete result.body.error;
result.body.info = {};
result.body.info.message = 'Registration complete';
result.body.info.detail = 'This instance has been successfully registered with this store.';
result.body.status = 'success';
...
If the new record was inserted successfully, then we response with a 202 Accepted HTTP Response Code, indicating that the registration was accepted, but the complete registration process (notifying all of the other instances) is not yet complete. At this point, all we have left to do is to initiate the Subflow to handle the rest of the process. We haven’t built the Subflow just yet, but for the purposes of this exercise, we can just assume that it is out there and then we can build it out later. There a couple of different ways to launch an asynchronous Subflow in the background, the original way, and the newer, preferred method. Both methods use the Scripted Flow API. Here is the way that we used to do this:
sn_fd.FlowAPI.startSubflow('New_Collaboration_Store_Instance', {new_instance: data.instance});
… and here is way that ServiceNow would like you to do it now:
sn_fd.FlowAPI.getRunner()
.subflow('New_Collaboration_Store_Instance')
.inBackground()
.withInputs({new_instance: data.instance})
.run();
Right now, both methods will work, and I’m still using the older, simpler way, but one day I’m going to need to switch over.
There should never be a problem inserting the new record, but just in case, we make that a conditional, and if for some reason it fails, we respond with a 500 Internal Server Error HTTP Response Code.
result.status = 500;
result.body.error.message = 'Internal server error';
result.body.error.detail = 'There was a problem processing this registration request.';
That’s it for all of the little parts and pieces. Here is the entire function, all put together.
processRegistrationRequest: function(data) {
var result = {body: {error: {}, status: 'failure'}};
var mbrGR = new GlideRecord('x_11556_col_store_member_organization');
if (mbrGR.get('instance', data.instance)) {
result.status = 400;
result.body.error.message = 'Duplicate registration error';
result.body.error.detail = 'This instance has already been registered with this store.';
} else {
mbrGR.initialize();
mbrGR.name = data.name;
mbrGR.instance = data.instance;
mbrGR.email = data.email;
mbrGR.description = data.description;
mbrGR.token = data.sys_id;
mbrGR.active = true;
mbrGR.host = false;
mbrGR.accepted = new GlideDateTime();
if (mbrGR.insert()) {
result.status = 202;
delete result.body.error;
result.body.info = {};
result.body.info.message = 'Registration complete';
result.body.info.detail = 'This instance has been successfully registered with this store.';
result.body.status = 'success';
sn_fd.FlowAPI.startSubflow('New_Collaboration_Store_Instance', {new_instance: data.instance});
} else {
result.status = 500;
result.body.error.message = 'Internal server error';
result.body.error.detail = 'There was a problem processing this registration request.';
}
}
return result;
}
Now we have completed the nonexistent function that was referenced in the REST API Resource, but we have also now referenced a new nonexistent Subflow that we will need to build out before things are complete. That sounds like a good subject for our next installment.
