Consolidated Clinical Document Architecture (C-CDA) Data Library

Intended Use

This library provides a (read-only) data object for HL7 v3 XML data which can be converted to a PHP array, \stdClass object, or JSON string. It is not intended for modifying the data structure or exporting XML.

Supported Versions/Formats

<Insert documentation about which HL7 v3 (i.e. C-CDA) implementations are supported here>

Library Installation Requirements

• PHP 7 (or greater)

• Simple XML (PHP Extension)

• JSON (PHP Extension)

How to Use

Including the Library in your Project with Composer

You can manually add the library to your project's composer.json file or use the following command:

composer require uhin/ccda-parser

Then be sure to include the Composer bootstrap file:

include_once('vendor/autoload.php');

Instantiating a Data Object

There are factory methods for creating the data object from a (valid) XML file:

$ccdaDocument = \Uhin\Ccda\Models\CcdaDocument::getDocumentFromFilepath('/path/to/ccda.xml');

from a (valid) XML string:

$ccdaDocument = \Uhin\Ccda\Models\CcdaDocument::getDocumentFromXmlString('<ClinicalDocument />');

and from a \SimpleXMLElement object:

$ccdaDocument = \Uhin\Ccda\Models\CcdaDocument::getDocumentFromSimpleXmlElement($simpleXmlElement);

Accessing the Data Object's Properties

Once you have created the \Uhin\Ccda\Models\CcdaDocument object, you can access its attributes directly:

// The XML data is stored as a \SimpleXMLElement object
$ccdaDocument->simpleXmlElement

// The data object converts that XML data into an array (i.e. dictionary)
$ccdaDocument->data

Converting the Data Object into Desired Formats

You can use the data object's conversion methods to get the XML data in different formats:

// Get the data as an array (i.e. dictionary)
$ccdaDocument->toArray()

// Get the data as a \stdClass object
$ccdaDocument->toStdClass()

// Get the data as a JSON-encoded string
$ccdaDocument->toJson()

// Also returns a JSON-encoded string (used for type-casting to a string)
$ccdaDocument->__toString()
(string) $ccdaDocument

Notes about Structure

This basic XML data:

<ClinicalDocument xmlns:randomNamespace="http://www.w3.org/2001/XMLSchema-instance">
    <globalChild randomNamespace:namespacedAttribute="random value 1" globalAttribute="random value 2">global child value</globalChild>
    <randomNamespace:namespacedChild randomNamespace:namespacedAttribute="random value 3" globalAttribute="random value 4">namespaced child value</randomNamespace:namespacedChild>
</ClinicalDocument>

will be converted into this JSON object:

{
	"ClinicalDocument": {
		"randomNamespace": {
			"namespacedChild": {
				"randomNamespace": {
					"attribute:namespacedAttribute": "random value 3"
				},
				"attribute:globalAttribute": "random value 4",
				"value": "namespaced child value"
			}
		},
		"globalChild": {
			"randomNamespace": {
				"attribute:namespacedAttribute": "random value 1"
			},
			"attribute:globalAttribute": "random value 2",
			"value": "global child value"
		}
	}
}

Because attribute names can conflict with the names of child elements (or there can be a value attribute which would conflict with the way the XML element value is parsed), attributes are prepended with a prefix and a prefix delimiter. The default prefix is attribute and the default prefix delimiter is : (colon). If you would like to use a different prefix and/or delimiter, simply set the following attributes:

$ccdaDocument->elementAttributePrefix = 'differentAttributePrefix'
$ccdaDocument->elementAttributePrefixDelimiter = '-'

And the data attribute and conversion methods will all be updated with the new structure:

{
	"ClinicalDocument": {
		"randomNamespace": {
			"namespacedChild": {
				"randomNamespace": {
					"differentAttributePrefix-namespacedAttribute": "random value 3"
				},
				"differentAttributePrefix-globalAttribute": "random value 4",
				"value": "namespaced child value"
			}
		},
		"globalChild": {
			"randomNamespace": {
				"differentAttributePrefix-namespacedAttribute": "random value 1"
			},
			"differentAttributePrefix-globalAttribute": "random value 2",
			"value": "global child value"
		}
	}
}

Additional Information

• HL7 Standard: CDA^® Release 2

• Consolidated CDA^® Overview

• Clinical Document Architecture (CDA^®) Wikipedia Entry

About Us

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