Reading large response body from sn_ws.RESTMessageV2 response in script

[deepak50]

Hi,
I am using sn_ws.RESTMessageV2 in script to read response from one endpoint as below:

 var r = new sn_ws.RESTMessageV2('messagename','httpmethod');
 var response = r.execute();
 var responseBody = response.getBody();

response is in array.

I am getting response body if there less number of records , eg 20 records in array.
but when there are more number of records I am getting response body as blank in script, although I can see it in test http method.

Is there a way to get large response body in script , http method is GET.

Thanks
Deepak  

[sachin_namjoshi]

Is the output of external API is in JSON?

You can will have parse response from JSON and then print values you want to use from JSON response.

Regards,

Sachin

[deepak50]

response is in string. parsing is not the issue.

Issue is when response is of large size , response body is showing as blank. so there is nothing to parse.

[Markus Kraus]

ServiceNow recommends to use 'executeAsync'. This will put your request into the ecc_queue (output queue) and you will see your response there. Please try this and report back, if you get any results that way.

If the payload is larger than a certain threshold, it will be put into a file attached to the input queue where it then can be process further.

If you still do not get any results, the problem might be on the endpoint-side. If you do get results please answer and i will proceed to give some example processing scripts.

EDIT: Another option might be saveResponseBodyAsAttachment (Official Documentation) - this might also help.

[Hitoshi Ozawa · Accepted solution]

Hi Deepak,

Unfortunately, RESTResponseV2 doesn't have getResponseAsStream() method.

So have to use .saveResponseBodyAsAttachment() method. This will require a table and a record to attach the attachment.

https://developer.servicenow.com/dev.do#!/reference/api/sandiego/server/sn_ws-namespace/c_RESTMessag...

var tablename = '<table name>';
var recordSysId = '<record in table to attach file>';
var filename = '<filename>';

var request = new sn_ws.RESTMessageV2('messagename','httpmethod');
request.saveResponseBodyAsAttachment(tablename, recordSysId, filename);
response = request.execute();
httpResponseStatus = response.getStatusCode();

Then if necessary use GlideSysAttachment() method to read attachment as a stream to read the content to use in a script. "attachmentSysId" is the sys_id of the file in the sys_attachment table. .saveResponseBodyAsAttachment() method, unfortunately, doesn't return the sys_id so the table needs to be queried using tablename, recordsysId, and filename to find it.

https://developer.servicenow.com/dev.do#!/reference/api/sandiego/server/no-namespace/c_GlideTextRead...

Furthermore, there is a maximum size of attachment.

https://support.servicenow.com/kb?id=kb_article_view&sysparm_article=KB0718101

and for REST API

https://support.servicenow.com/kb?id=kb_article_view&sysparm_article=KB0747638

In all, it is easier to use paging if the REST API at the other site supports it.