In a certain scenario, I want to pass a field value(in string format) to the CouchDB and get associated doc (or only its id) which contains that particular string value in one its fields. In case, if no doc contains that particular field value, I would like CouchDB design functions to automatically create one and return the newly created doc.
I can accomplish this by making a GET request followed by a PUT request if there is no doc with that particular field value. Is there any way to get this done with just one POST request?
Design document functions (other than updates) cannot modify the data in any way. So no, this is not possible.
You can write a list function to return you a new document if the results are empty, but it cannot save it automatically.