Reference external data

A questionnaire may reference external information. If so, you must provide a DataCaptureConfig by implementing the DataCaptureConfig.Provider interface in your application's Application class. Be sure to provide the same configuration throughout your application's lifecycle to avoid any configuration issues.

Value sets

If a value set is not included as a contained resource within the questionnaire or structure map that references it, you must provide an implementation of ExternalAnswerValueSetResolver.resolve() which describes how to translate a value set's canonical URL to the list of actual codes:

class FhirApplication : Application(), DataCaptureConfig.Provider {

  private val dataCaptureConfiguration by lazy {
    DataCaptureConfig(
      valueSetResolverExternal =
        object : ExternalAnswerValueSetResolver {
          override suspend fun resolve(uri: String): List<Coding> {
            return lookupCodesFromDb(uri)
          }
        }
    )
  }

  override fun getDataCaptureConfig(): DataCaptureConfig {
    return dataCaptureConfiguration
  }
}

ExternalAnswerValueSetResolver is used for any URI that does not look like an internal reference where the URI starts with #.

FHIR NPM packages

FHIR resources published in FHIR Packages can be used to provide context while performing StructureMap-based data extraction.