FHIR API for .Net programmers by Mirjam Baltus

© 2012 HL7 ® International. Licensed under Creative Commons. HL7 & Health Level Seven are registered trademarks of Health Level Seven International. Reg. U.S. TM Office.

FHIR APIfor .Net programmers

Mirjam Baltus

FHIR Developer Days

November 24, 2014


Who am I?

Name: Mirjam Baltus-Bakker

Company: Furore, Amsterdam

Background:

ICT trainer

Furore FHIR team

Contact:

[email protected]

mailto:[email protected]


HL7.FHIR SUPPORT APIUsing the Reference Implementations


Hl7.Fhir

- Core contents

- Model – classes generated from the spec

- Parsers and Serializers

- REST functionality – FhirClient

- Validation

- Specification

NuGet “FHIR”, or GitHub “fhir-net-api”


A FHIR Resource


A FHIR Resource in C#

public partial class Observation : Hl7.Fhir.Model.Resource

{

// Codes that provides reliability information about an observation

public enum ObservationReliability {Ok, Ongoing, …}

// Codes identifying interpretations of observations

public enum ObservationInterpretation {N, A, L, H }

public partial class ObservationReferenceRangeComponent : Hl7.Fhir.Model.Element

{ … }

public CodeableConcept Name { get; set; }

public List<ObservationReferenceRangeComponent> ReferenceRange { get; set;}

public List<ResourceReference> Performer { get; set; }

}


Primitives are not really primitive…


Primitives are not really primitive…


Resource example

using Hl7.Fhir.Model;

var pat = new Patient();

pat.Name = new List<HumanName>();pat.Name.Add(HumanName.ForFamily("Baltus")

.WithGiven("Mirjam"));

pat.MaritalStatus = newCodeableConcept("http://acme.org/MStat", "M");

pat.BirthDate = "1974-01-20";


Choice elements [x]

public

Hl7.Fhir.Model.CodeableConcept

MaritalStatus { set; get; }

public Hl7.Fhir.Model.Element

Deceased { set; get; }

pat.Deceased =new FhirBoolean(true);

pat.Deceased = newFhirDateTime("2012-01-30");


Hl7.Fhir Core

Model – Resources and Datatypes in the API

Parsers and Serializers

REST functionality – FhirClient

Validation


Parsing example

using Hl7.Fhir.Serialization;

// Suppose we have a JSON string

string str = "{\"resourceType\":\"Patient\",\"name\":" +

"[{\"family\":[\"Baltus\"],\"given\":[\"Mirjam\"]}]}";

// Parse the Patient from the string

var pat = (Patient)FhirParser.ParseResourceFromJson(str);


Parsing example 2

// Create a file-based reader for Xml

XmlReader xr = XmlReader.Create(

new StreamReader(@"publish\observation-example.xml"));

// Parse the Observation from the stream

var obs = (Observation)FhirParser.ParseResource(xr);


Serializing example

// Here’s our Observation again

var obs = (Observation)FhirParser.ParseResource(xr);

// Modify some fields of the observation

obs.Status = Observation.ObservationStatus.Amended;

obs.Value = new Quantity() { Value = 40, Units = "g" };

// Serialize the in-memory observation to Json

var jsonText = FhirSerializer.SerializeResourceToJson(obs);


Hl7.Fhir Core




Validation


REST functionality

REST operations done with FhirClient

using Hl7.Fhir.Rest;

var client = new FhirClient( new Uri("http://acme.org/fhir"));

Operations throw a FhirOperationException

Outcome property with OperationOutcome


Using the FhirClient

var patEntry = client.Read<Patient>("Patient/1");

var pat = patEntry.Resource;var restId = patEntry.Id;var tags = patEntry.Tags;

pat.Name.Add(HumanName.ForFamily("Kramer").WithGiven("Ewout"));

client.Update<Patient>(patEntry);

var myId = ResourceIdentity.Build("Patient","31");


Using the FhirClient

var pat = new Patient() { /* set up data */ };

var patEntry = client.Create(pat);var restId = patEntry.Id;

var newEntry = client.Refresh(patEntry);

client.Delete(patEntry);var location =

new Uri("http://acme.org/fhir/Patient/34");client.Delete(location);


Bundles in C#

Abstraction on top of Atom parser

Bundle = feed, BundleEntry = entry.

Bundle result = new Bundle() { Title = "Demo bundle" };

result.Entries.Add(new ResourceEntry<Patient>()

{ LastUpdated=DateTimeOffset.Now, Resource = new Patient() });

result.Entries.Add(new DeletedEntry()

{ Id = new Uri("http://..."), When = DateTime.Now });

var bundleXml = FhirSerializer.SerializeBundleToXml(result);


Search

var criteria = new string[] { "family=Eve" };Bundle result = client.Search<Patient>(criteria);

while (result != null){

// Do something usefulresult = client.Continue(results);

}


More about search

Please attend one of the presentations in the

next quarter:

Search for Server developers

by Martijn Harthoorn

Search for Client developers

by myself


Validation

DotNetAttributeValidation validates:

Cardinality of an element

Regex patterns of the primitives code, date,

dateTime, id, instant, oid, uri, uuid

Allowed types for a choice element (value[x])

pat.Deceased = new FhirString("Died on 2012-01-30");

Does not validate:

Conformance to ValueSet bindings

Profile conformance


Validation example

using Hl7.Fhir.Validation;

var pat = new Patient() { /* set up data */ };

// Will throw a ValidationException when an error is encountered

DotNetAttributeValidation.Validate(pat);

// Alternatively, use the TryXXXX pattern

var errors = new List<ValidationResult>();

var success = DotNetAttributeValidation.TryValidate(pat, errors);

if(!success) { /* handle errors */ }


Hl7.Fhir Core




Validation


Questions?

http://hl7.org/fhir [email protected]

http://hl7.org/fhir

mailto:[email protected]

Healthcare

FHIR API for .Net programmers by Mirjam Baltus