Introduction

This is a simple technical utility to offer a simple UI for testing fhirpath expressions with DSTU2 and STU3 [HL7 FHIR][fhir-spec] resources.

It can execute the expressions as either an extract (for use in search expressions) or validate (for use in StructureDefinition constraints)

New Features in v1.0.2:

• Trial support for R4
• Ability to convert/pretty print the source between XML/Json (click on the label you want to format the content to)
• Custom fhirpath function LuhnTest()
• Updated to recent HL7 FHIR NuGet packages 0.96.0

Key features:

• Evaluation FhirPath expressions (extract/validate)
• Parsing of the expression against the schema of the example resource type
• Concurrent support for STU3 and DSTU2 (automatically selecting)
• Support for Xml and Json parsers (automatically detecting)
• Drag and drop example resource files from the file-system

Technically the utility is:

• built on the Microsoft .NET (dotnet) platform
• WPF and UWP versions available
  • Code currently duplicated between the 2 (I plan to share the core processing file sometime)
• uses the HL7 FHIR reference assemblies
  • Core (NuGet packages starting with Hl7.Fhir.<version>) - contains the FhirClient and parsers (Both DSTU2 and STU3)
  • FhirPath (NuGet package Hl7.FhirPath) - the FhirPath evaluator, used by the Core and Specification assemblies
  • Support (NuGet package Hl7.Fhir.Support) - a library with interfaces, abstractions and utility methods that are used by the other packages

Note: Both the UWP and WPF projects include NuGet references to both the DSTU2 and STU3 packages at the same time. This does create a clash of namespaces, which I use the extern alias feature in .net to resolve.

The project file needs to be manually edited to support the setting of the assembly reference alias, as shown below.

  <Target Name="ChangeAliasesOfStrongNameAssemblies" BeforeTargets="FindReferenceAssembliesForReferences;ResolveReferences">
    <ItemGroup>
      <ReferencePath Condition="'%(FileName)' == 'Hl7.Fhir.DSTU2.Core'">
        <Aliases>dstu2</Aliases>
      </ReferencePath>
    </ItemGroup>
    <ItemGroup>
      <ReferencePath Condition="'%(FileName)' == 'Hl7.Fhir.STU3.Core'">
        <Aliases>stu3</Aliases>
      </ReferencePath>
    </ItemGroup>
  </Target>

The name of the target is not important, it can be anything.

Support

Issues can be raised in the GitHub repository at https://github.com/brianpos/fhirpathtester/issues. You are welcome to register your bugs and feature suggestions there. For questions and broader discussions, use the .NET FHIR Implementers chat on Zulip.

Contributing

I would gladly welcome any contributors!

If you want to participate in this project, I'm using Git Flow for branch management, so please submit your commits using pull requests no on the develop branches mentioned above!

GIT branching strategy

• NVIE
• Or see: Git workflow

Licensing

HL7®, FHIR® and the FHIR Mark® are trademarks owned by Health Level Seven International, registered with the United States Patent and Trademark Office.