FHIR API for .Net programmers by Mirjam Baltus

FHIR API
for .Net programmers
Mirjam Baltus
FHIR Developer Days
November 24, 2014
© 2012 HL7 ® International. Licensed under Creative Commons. HL7 & Health Level Seven are registered trademarks of Health Level Seven International. Reg. U.S. TM Office.

Who am I?
 Name: Mirjam Baltus-Bakker
 Company: Furore, Amsterdam
 Background:
 ICT trainer
 Furore FHIR team
 Contact:
 m.baltus@furore.com

Using the Reference Implementations
HL7.FHIR SUPPORT API

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…

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 = new
CodeableConcept("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 = new
FhirDateTime("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(@"publishobservation-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 useful
result = 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 m.baltus@furore.com

FHIR API for .Net programmers by Mirjam Baltus

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to FHIR API for .Net programmers by Mirjam Baltus

Similar to FHIR API for .Net programmers by Mirjam Baltus (20)

Recently uploaded

Recently uploaded (20)

FHIR API for .Net programmers by Mirjam Baltus