Call the register's REDCap API once

The only function in the package that speaks to the request register, and the only one that builds its URL. The register is read and written with a token rather than with the module, which is the mechanism the channel's first design set aside: the argument against it was that the friction grows with the number of projects, and here the project is one, and one forever.

Usage

register_call(url, token, params)

Arguments

url

Hostname of the instance hosting the register, optionally followed by the path REDCap is mounted under. A scheme is dropped rather than honored, so a base handed over as http is corrected instead of silently downgrading the channel.

token

The API token of the service account, sent in the body.

params

Named list of REDCap API parameters, without token, format and returnFormat, which are set here.

Value

A list with ok, errors and payload, shaped like the module client's answer because it answers the same kind of question.

Details

The answer is recognized by its shape and never by its status code. An instance whose API is switched off answers 200 with an HTML page, exactly as a disabled module answers 200 with a sentence, and a client that inferred success from the status would fail inside the JSON parser reporting an error that does not name the cause.