DSTU2

This page is part of the FHIR Specification (v1.0.2: DSTU 2). The current version which supercedes this version is 5.0.0. For a full list of available versions, see the Directory of published versions . Page versions: R5 R4B R4 R3 R2

2.7 Validating Resources

FHIR Infrastructure Work GroupMaturity Level: N/ABallot Status: DSTU 2

This page provides a quick overview of how the FHIR specification supports validation of resources.

In principle, resources can be validated:

  • Against the original specification
  • Against an implementation guide
  • Against a specific profile

Resources can be tested for conformance by:

Note that all these validation methods are incomplete; they can only validate the computable aspects of conformance, but there are always additional rules made in narrative that they are not able to check (e.g. a rule such as "All the clinically important content in the data SHALL be in the narrative", which might be made in an implementation guide, but could never be checked by a conformance tool).

In case of disagreement between these conformance methods, note that:

  • The schema/schematron is the least capable - mainly because it is not connected to a terminology server
  • The java validator is only as good as the underlying definitions, and in particular depends on whether the underlying terminology server supports all the relevant terminologies
  • In general, the server validation operations use or derive from the java validation code, so have the same caveats
  • The final arbiter is human inspection of the content of the resources, and the relevant implementation guides and base specification

Also, note that static testing of resource content is not enough to prove conformance to the specification. For further information, see FHIR Conformance Testing .

2.7.1 Using the XML schema

The XML schema can be used to validate XML represenations of the resources. When validating a resource, you can nominate one of the following schema:

  • fhir-all.xsd: links in all the individual modular schemas
  • fhir-single.xsd: a single large file, mainly provided for schema processors that can't support circular references

In addition, the validation schema includes schematron that can be initiated with transform "iso_svrl_for_xslt2.xsl" included in the XML Tools download. Note that XSLT2 is required to run the schematrons.

When running the schematron, use the file "fhir-invariants.sch". This includes all the schematrons. The individual schematron files for each resource are provided to allow implementers to build their own smaller combined file that covers the relevant resource types for them.

2.7.2 Using the FHIR Validator

The FHIR Validator is a Java jar that is provided as part of the specification, and that is used during the publication process to validate that all the published examples. To execute the FHIR validator, follow the following steps:

  • Download the FHIR Validator
  • Download One of the FHIR definitions (with or without text)
  • Execute the validator, providing the path to the definitions, and a reference to the resource to validate

Here is an example windows batch file that demonstrates the process (using the common utilities wget and 7z : 

 @ECHO OFF

 ECHO get the validator and unzip it 
 wget.exe http://hl7.org/fhir/validator.zip
 7z.exe x validator.zip

 ECHO Get the validation source file (dictionary)
 wget.exe http://hl7.org/fhir/validation-min.xml.zip

 ECHO get an example to validate
 wget.exe http://hl7.org/fhir/patient-example.html -O test-obs.xml

 ECHO validate it. The DAF profile will be loaded out of the definitions in validation-min.zip
 java -jar org.hl7.fhir.validator.jar test-obs.xml -defn validation-min.xml.zip -profile http://hl7.org/fhir/StructureDefinition/daf-patient

 pause

Note that it is not necessary to download the resource first; the http address can be supplied directly: 

 java -jar org.hl7.fhir.validator.jar http://hl7.org/fhir/patient-example.html -defn validation-min.xml.zip -profile http://hl7.org/fhir/StructureDefinition/daf-patient

The validator requires an underlying terminology server. TODO: document this part. for now, hard coded to http://fhir-dev.healthintersections.com.au.

2.7.3 Asking a FHIR Server

The operation validate can be used to check whether a resource conforms to a profile. The simplest way to execute this operation is to post the resource to a server: 

 POST [base]/Patient/$validate?profile=http://hl7.org/fhir/StructureDefinition/daf-patient
 [other HTTP headers]
 
 <Patient>.. resource to check as the body

The server will return an OperationOutcome resource listing issues found in the resource.

There are several things to consider when using this operation:

  • Not all servers support the $validate operation, though some of the public test servers do
  • Servers support the $validate operation generally will only validate against profiles already registered with the server
  • Servers may choose to support either XML, JSON, or both

2.7.4 Via a web interface

Some servers expose the $validate functionality though a web page. For known public implementations, see the FHIR wiki