src/Services/FHIR/FhirUrlResolver.php

   1 <?php
   2
   3 /**
   4  * FhirURLResolver is a simple class that takes in a FHIR base server url and can be used to extract pieces of the URL
   5  * that are needed within the FHIR system such as a resource's relative URI
   6  * @package openemr
   7  * @link      http://www.open-emr.org
   8  * @author    Stephen Nielson <stephen@nielson.org>
   9  * @copyright Copyright (c) 2021 Stephen Nielson <stephen@nielson.org>
  10  * @license   https://github.com/openemr/openemr/blob/master/LICENSE GNU General Public License 3
  11  */
  12
  13 namespace OpenEMR\Services\FHIR;
  14
  15 class FhirUrlResolver
  16 {
  17     private $fhirBaseURL;
  18
  19     private $baseUrlLength;
  20
  21     public function __construct($baseURL)
  22     {
  23         $this->fhirBaseURL = $baseURL;
  24         $this->baseUrlLength = strlen($baseURL);
  25     }
  26
  27     public function getRelativeUrl($url): ?string
  28     {
  29         // extracts everything but the resource/:id portion of a URL from the base url.
  30         // if the URI passed in does not match the base fhir URI we do nothing with it
  31         if (strstr($url, $this->fhirBaseURL) === false) {
  32             return null;
  33         } else {
  34             // grab everything from our string onwards...
  35             $relativeUrl = substr($url, $this->baseUrlLength - 1);
  36             return $relativeUrl !== false ? $relativeUrl : null;
  37         }
  38     }
  39 }