From the tutorials, I see that it is possible to perform a direct EOD data fetch sending the required fields and identifier lists. Also, it describes how to schedule an extraction through the REST APIs using existing instrument lists and report templates. But is it possible to use existing instrument lists and report templates to make a direct extraction call? That is, be able to get the data directly from the request, rather than an extraction file be generated. If so, could someone point to an example?
The easiest way to retrieve data directly and immediately is by using the OnDemand API calls.
You can refer to an existing instrument list in an OnDemand extraction API call, but not to an existing report template (but that is not really required).
If you are not using the .Net SDK, you can simply follow the explanations in the REST API Tutorial 9. We do not deliver downloadable sample code for this, but you do not really need any as it is just a very simple modification of the OnDemand extraction. You can easily apply the described change to the OnDemand extractions in all the other REST API Tutorials.
An OnDemand extraction defines the report template by the data type defined in the extraction request itself, so you cannot refer to a custom one you predefined and saved on the server.
All you really need to do is specify the content field names in the extraction request, this is quite easy.
You can use below example for immediate scheduling,
"TimeZone": "Central Standard Time",