Tools for creating PHP classes from the HL7 FHIR Specification

This library requires the use of Composer

A convenient download and generation script is included in this repository. The script will download current major versions of FHIR into the input folder and generate classes for every version in the output folder.

• Run composer install
• Run php ./bin/generate.php

Downloading DSTU1 from http://hl7.org/fhir/DSTU1/fhir-all-xsd.zip
Generating DSTU1
Downloading DSTU2 from http://hl7.org/fhir/DSTU2/fhir-all-xsd.zip
Generating DSTU2
Downloading STU3 from http://hl7.org/fhir/STU3/fhir-all-xsd.zip
Generating STU3
Downloading Build from http://build.fhir.org/fhir-all-xsd.zip
Generating Build
Done

Require entry:

{
  "require": {
    "dcarbone/php-fhir": "dev-master"  
  }
}

The first step is to determine the version of the FHIR spec your implementation supports. Once done, download the appropriate class definition XSDs from http://hl7.org/fhir/directory.html.

Uncompress the XSD's and place them in a directory that is readable by PHP's runtime user.

Next comes the fun:

The class generator utility included with this library is designed to parse the XSD's provided by the FHIR group into PHP classes, complete with markup and type hinting.

There are 2 important things to note with this section:

1. Your exact implementation will probably vary, don't hesitate to ask if you need some help
2. The class generation should be run ONCE per FHIR version. Once the classes have been generated they should only ever be re-generated if your server switches to a new FHIR spec

require __DIR__.'/vendor/autoload.php';

$xsdPath = 'path to wherever you un-zipped the xsd files';

$config = new \DCarbone\PHPFHIR\ClassGenerator\Config(['xsdPath' => $xsdPath]);
$generator = new \DCarbone\PHPFHIR\ClassGenerator\Generator($config);

$generator->generate();

Using the above code will generate class files under the included output directory, under the namespace PHPFHIRGenerated

If you wish the files to be placed under a different directory, pass the path in as the 2nd argument in the generator constructor.

If you wish the classes to have a different base namespace, pass the desired NS name in as the 3rd argument in the generator constructor.

There are a plethora of good HTTP clients you can use to get data out of a FHIR server, so I leave that up to you.

As part of the class generation above, a response parsing class called PHPFHIRResponseParser will be created and added into the root namespace directory. It currently supports JSON and XML response types.

The parser class takes a single optional boolean argument that will determine if it should attempt to load up the generated Autoloader class. By default it will do so, but you are free to configure your own autoloader and not use the generated one if you wish.

require 'path to PHPFHIRResponseParser.php';

$parser = new \\YourConfiguredNamespace\\PHPFHIRResponseParser;

$object = $parser->parse($yourResponseData);

$json = json_encode($object);

// To get an XML string back...
$xml = $object->xmlSerialize();

// To get back an instance of \SimpleXMLElement...
$sxe = $object->xmlSerialize(true);

XML Serialization utilizes SimpleXMLElement.

In some cases, vendors may deviate from the FHIR spec and require some properties of a class to be serialized as xml attributes instead of a child. The generator supports this through the following configuration.

require __DIR__.'/vendor/autoload.php';

$xsdPath = 'path to wherever you un-zipped the xsd files';

$config = new \DCarbone\PHPFHIR\ClassGenerator\Config([
    'xsdPath' => $xsdPath,
    'xmlSerializationAttributeOverrides' => ['SomeFHIRModel' => 'somePropertyName']
);

$generator = new \DCarbone\PHPFHIR\ClassGenerator\Generator($config);

$generator->generate();

Currently this library is being tested against v0.0.82, v1.0.2, and v1.8.0 using the open server available here: http://fhir2.healthintersections.com.au/open/ .

• Implement event or pull-based XML parsing for large responses
• Typecast scalar values in XML responses to proper PHP type
• Attempt to implement Date values into PHP DateTime objects
• Tests...

If you have some suggestions for how this lib could be made more useful, more applicable, easier to use, etc, please let me know.