FHIR Response Utility
Utility for handling the headers, content, and status types for a response
Install
yarn add @asymmetrik/fhir-response-util
Usage
The response utility exposes the following methods which can be used to for different scenarios and different types of responses. They all make certain assumptions about the arguments they receive which are documented below in the arguments section.
This is designed to be used in node-fhir-server-core and similar FHIR servers. There is some pseudocode with each method's description to give an idea of how this might work. If you read the source code for resource controllers in node-fhir-server-core, you can see how we are using this internally.
read
Used when you are returning a Bundle of resources
This will set the correct Content-Type and status code while sending the json back to the client.
const handler = require('@asymmetrik/fhir-response-util');
// Some controller
function getPatientsController(req, res, next) {
// The user may have some service to fetch results
service
.getPatients(req)
.then((bundle) => {
// Assuming bundle contains a bunch of patients
handler.read(req, res, bundle);
})
.catch((err) => {
next(err);
});
}
readOne
Used when you are returning a single resource of any type.
This will set the correct Content-Type and status code while sending the json back to the client.
const handler = require('@asymmetrik/fhir-response-util');
// Some controller
function getPatientController(req, res, next) {
// The user may have some service to fetch results
service
.getPatient(req)
.then((patient) => {
handler.readOne(req, res, patient);
})
.catch((err) => {
next(err);
});
}
create
Used when you are creating a single resource of any type.
This will set the correct Content-Location, Location, and ETag headers. As well as set the correct status code.
const handler = require('@asymmetrik/fhir-response-util');
// Some controller
function createPatientController(req, res, next) {
// The user may have some service to fetch results
service
.create(req)
.then((patient) => {
let json = { id: patient.id, resource_version: patient.meta.versionId };
let options = { type: 'Patient' };
handler.create(req, res, json, options);
})
.catch((err) => {
next(err);
});
}
update
Used when you are updating a single resource of any type
This will set the correct Content-Location, Last-Modified, Location, and ETag headers. As well as set the correct Content-Type and status code.
const handler = require('@asymmetrik/fhir-response-util');
// Some controller
function updatePatientController(req, res, next) {
// The user may have some service to fetch results
service
.update(req)
.then((patient) => {
let json = { id: patient.id, resource_version: patient.meta.versionId, created: false };
let options = { type: 'Patient' };
handler.update(req, res, json, options);
})
.catch((err) => {
next(err);
});
}
remove
Used when you are deleting a single resource of any type
This will set the correct ETag header and status code.
const handler = require('@asymmetrik/fhir-response-util');
// Some controller
function removePatientController(req, res, next) {
// The user may have some service to fetch results
service
.remove(req)
.then((id) => {
let json = { deleted: id };
handler.remove(req, res, json);
})
.catch((err) => {
next(err);
});
}
history
Used when you are querying the history of a resource of any type
This will set the correct Content-Type and status code while sending the json back to the client.
const handler = require('@asymmetrik/fhir-response-util');
// Some controller
function getPatientHistoryController(req, res, next) {
// The user may have some service to fetch results
service
.history(req)
.then((bundle) => {
handler.history(req, res, bundle);
})
.catch((err) => {
next(err);
});
}
Arguments
req and res that you see in each method are from express. res is just a normal response, but request must have a base_version parameter(req.params.base_version). Specifically, it should be one of the valid versions we support in our server, which are '1_0_2', '3_0_1', and '4_0_0'. If you would like us to add more versions for this, just let us know, we use this to determine the correct content-type as well as the url of the resource for the response type and response headers.
read
handler.read(req, res, json);
req
Express request.
Type: Express.req
Required: true
res
Express response.
Type: Express.req
Required: true
json
Bundle FHIR resource.
Type: Object
Required: true
readOne
handler.readOne(req, res, json);
req
Express request.
Type: Express.req
Required: true
res
Express response.
Type: Express.req
Required: true
json
Individual FHIR resource.
Type: Object
Required: true
create
handler.create(req, res, json, options);
req
Express request.
Type: Express.req
Required: true
res
Express response.
Type: Express.req
Required: true
json
Properties from the results. Must have an id
Type: Object
Required: true
json.id
ID of the FHIR resource that was created.
Type: String
Required: true
json.resource_version
If we are using history, which version of the resource did we create.
Type: String
Required: false
options
Additional options needed to set the correct headers in the response.
Type: Object
Required: true
options.type
This helps us set the content-location and location headers. For example, handler.create(req, res, json, { type: 'Patient' }) would allow us to set a header like this, res.set('Location', '4_0_0/Patient/patient-identifier').
Type: 'String'
Required: 'true'
update
handler.update(req, res, json, options);
req
Express request.
Type: Express.req
Required: true
res
Express response.
Type: Express.req
Required: true
json
Properties from the results. Must have an id
Type: Object
Required: true
json.id
ID of the FHIR resource that was created.
Type: String
Required: true
json.resource_version
If we are using history, which version of the resource did we create.
Type: String
Required: false
json.created
Did we create a resource or not. If we created a resource, we need to know so that we can set a res.status of 201, otherwise, we will default to a status of 200.
Type: Boolean
Required: false
options
Additional options needed to set the correct headers in the response.
Type: Object
Required: true
options.type
This helps us set the content-location and location headers. For example, handler.create(req, res, json, { type: 'Patient' }) would allow us to set a header like this, res.set('Location', '4_0_0/Patient/patient-identifier').
Type: 'String'
Required: 'true'
remove
handler.remove(req, res, json);
req
Express request.
Type: Express.req
Required: true
res
Express response.
Type: Express.req
Required: true
json
JSON for the response. Not required but contains the optional deleted property.
Type: Object
Required: false
json.deleted
The deleted property should be the id of the element deleted. For example, handler.remove(req, res, { deleted: 'qwerty-123' }). This allows us to add the identifier as a ETag in the response header.
Type: Object
Required: false
history
handler.history(req, res, json);
req
Express request.
Type: Express.req
Required: true
res
Express response.
Type: Express.req
Required: true
json
Bundle FHIR resource.
Type: Object
Required: true