Issue #3284690: Provide a service for querying the Soil Data Access API

services:

  nrcs.soil_data_access:

    class: Drupal\farm_nrcs\SoilDataAccess

    arguments: [ '@http_client' ]

  nrcs_map_render_event_subscriber:

    class: Drupal\farm_nrcs\EventSubscriber\MapRenderEventSubscriber

    tags:

<?php

namespace Drupal\farm_nrcs;

use Drupal\Component\Serialization\Json;

use GuzzleHttp\Client;

use GuzzleHttp\Exception\RequestException;

use Symfony\Component\DependencyInjection\ContainerInterface;

/**

 * Soil Data Access.

 */

class SoilDataAccess implements SoilDataAccessInterface {

  /**

   * The HTTP client.

   *

   * @var \GuzzleHttp\Client

   */

  protected $httpClient;

  /**

   * Class constructor.

   *

   * @param \GuzzleHttp\Client $http_client

   *   The HTTP client.

   */

  public function __construct(Client $http_client) {

    $this->httpClient = $http_client;

  }

  /**

   * {@inheritdoc}

   */

  public static function create(ContainerInterface $container) {

    return new static(

      $container->get('http_client'),

    );

  }

  /**

   * {@inheritdoc}

   */

  public function mapunitWktQuery(string $wkt): array {

    // Define the columns to query.

    $columns = [

      'muname',

      'musym',

      'nationalmusym',

    ];

    // Assemble the SQL query that will be sent to the Soil Data Access API.

    $parts = [];

    foreach ($columns as $col) {

      $parts[] =  'MU.' . $col;

    }

    $query = "SELECT " . implode(', ', $parts) . " FROM SDA_Get_Mukey_from_intersection_with_WktWgs84('" . $wkt . "') K LEFT JOIN mapunit MU ON K.mukey = MU.mukey";

    // Run the query.

    $response = $this->tabularRestQuery($query);

    // Create an associative array of data.

    $data = [];

    if (!empty($response['Table'])) {

      foreach ($response['Table'] as $i => $result) {

        foreach ($result as $j => $value) {

          $data[$i][$columns[$j]] = $value;

        }

      }

    }

    // Return the data.

    return $data;

  }

  /**

   * {@inheritdoc}

   */

  public function tabularRestQuery(string $query): array {

    // Send request to the Soil Data Access API.

    try {

      $url = 'https://sdmdataaccess.sc.egov.usda.gov/tabular/post.rest';

      $options = [

        'headers' => [

          'Content-Type' => 'application/json',

          'Accept' => 'application/json',

        ],

        'json' => [

          'query' => $query,

          'format' => 'json',

        ],

      ];

      /** @var \GuzzleHttp\Psr7\Response $response */

      $response = $this->httpClient->request('POST', $url, $options);

    }

    catch (RequestException $e) {

      watchdog_exception('farmier', $e);

    }

    // Decode the JSON response and return the result.

    return Json::decode($response->getBody()->getContents());

  }

}

<?php

namespace Drupal\farm_nrcs;

/**

 * Soil Data Access interface.

 */

interface SoilDataAccessInterface {

  /**

   * Query for mapunit data by a given WKT geometry.

   *

   * @param string $wkt

   *   The WKT geometry to query for.

   *

   * @return array

   *   Returns an array of mapunit data. Each result is an associative array

   *   with muname, musym, and nationalmusym values.

   */

  public function mapunitWktQuery(string $wkt): array;

  /**

   * Send an SQL query to the Soil Data Access tabular REST API endpoint.

   *

   * @param string $query

   *   The WKT geometry to query for.

   *

   * @return array

   *   Returns data from the API endpoint, decoded from JSON.

   */

  public function tabularRestQuery(string $query): array;

}

<?php

namespace Drupal\Tests\farm_nrcs\Kernel;

use Drupal\KernelTests\KernelTestBase;

/**

 * Tests for the NRCS Soil Data Access service.

 *

 * @group farm

 */

class SoilDataAccessTest extends KernelTestBase {

  /**

   * {@inheritdoc}

   */

  protected static $modules = [

    'farm_nrcs',

  ];

  /**

   * Test Soil Data Access service.

   */

  public function testSoilDataAccessService() {

    // Test getting data for a specific point.

    $expected = [

      [

        'muname' => 'Paxton and Montauk fine sandy loams, 3 to 8 percent slopes',

        'musym' => '84B',

        'nationalmusym' => '2t2qn',

      ],

    ];

    $data = \Drupal::service('nrcs.soil_data_access')->mapunitWktQuery('POINT(-71.82165840851076 41.87079806075624)');

    $this->assertNotEmpty($data);

    $this->assertEquals($expected, $data);

    // Test getting data for a polygon.

    $expected = [

      [

        'muname' => 'Canton and Charlton fine sandy loams, 3 to 15 percent slopes, extremely stony',

        'musym' => '62C',

        'nationalmusym' => '2wks7',

      ],

      [

        'muname' => 'Paxton and Montauk fine sandy loams, 3 to 8 percent slopes',

        'musym' => '84B',

        'nationalmusym' => '2t2qn',

      ]

    ];

    $data = \Drupal::service('nrcs.soil_data_access')->mapunitWktQuery('POLYGON((-71.81960962792417 41.8692198884186,-71.81904972300649 41.869218787257466,-71.81903355459855 41.868068944318594,-71.81954571476324 41.86796457836036,-71.81960962792417 41.8692198884186))');

    $this->assertNotEmpty($data);

    $this->assertEquals($expected, $data);

  }

}