Add JSON-LD support

app/resto/core/RestoCollection.php

@@ -992,7 +992,8 @@ public function toArray()
             $collectionArray['summaries'] = $summaries;
         }
 
-        return $collectionArray;
+        return $this->context->core['useJSONLD'] ? JSONLDUtil::addDataCatalogMetadata($collectionArray) : $collectionArray;
+
     }
 
     /**

app/resto/core/RestoCollections.php

@@ -271,6 +271,10 @@ public function toArray()
             'collections' => array()
         );
 
+        if ($this->context->core['useJSONLD']) {
+            $collections = JSONLDUtil::addDataCatalogMetadata($collections);
+        }
+
         $totalMatched = 0;
 
         // Compute global summaries

app/resto/core/RestoContext.php

@@ -58,6 +58,9 @@ class RestoContext
 
         // Use cache
         'useCache' => false,
+
+        // Display JSON-LD metadata in catalogs/collections/items
+        'useJSONLD' => false,
 
         // Timezone for date display
         'timezone' => 'Europe/Paris',

app/resto/core/RestoFeature.php

@@ -507,7 +507,7 @@ private function load($options)
         else {
             $this->featureArray = $options['featureArray'];
         }
-
+        
         /*
          * Empty feature or feature is not in input collection
          */

app/resto/core/RestoModel.php

@@ -686,9 +686,18 @@ public function remap($featureArray, $collection)
             }
         }
 
-        return array_merge($featureArray, array(
+        $featureArray = array_merge($featureArray, array(
             'properties' => $properties
         ));
+
+        /*
+         * JSON-LD additionnal metadata
+         */
+        if ( isset($collection) && $collection->context->core['useJSONLD']) {
+            $featureArray = JSONLDUtil::addDatasetsMetadata($featureArray);
+        }
+
+        return $featureArray;
     }
 
     /**

app/resto/core/api/STACAPI.php

@@ -275,7 +275,7 @@ public function getCatalogs($params)
     {
         // This is /catalogs
         if ( !isset($params['segments']) ) {
-            return array(
+            $catalog = array(
                 'stac_version' => STACAPI::STAC_VERSION,
                 'id' => 'catalogs',
                 'type' => 'Catalog',
@@ -286,6 +286,7 @@ public function getCatalogs($params)
                     $this->getRootCatalogLinks($params)
                 )
             );
+            return $this->context->core['useJSONLD'] ? JSONLDUtil::addDataCatalogMetadata($catalog) : $catalog;
         }
 
         // This is /catalogs/*
@@ -1335,7 +1336,7 @@ private function processPath($segments, $params = array())
 
         // The path is the catalog identifier
         $parentAndChilds = $this->getParentAndChilds(join('/', $segments), $params);
-        return array(
+        $catalog = array(
             'stac_version' => STACAPI::STAC_VERSION,
             'id' => $segments[count($segments) -1 ],
             'title' => $parentAndChilds['parent']['title'] ?? '',
@@ -1347,6 +1348,7 @@ private function processPath($segments, $params = array())
             )
         );
 
+        return $this->context->core['useJSONLD'] ? JSONLDUtil::addDataCatalogMetadata($catalog) : $catalog;
     }
 
     /**

app/resto/core/api/ServicesAPI.php

@@ -181,7 +181,7 @@ public function conformance()
     public function hello()
     {
 
-        return array(
+        $hello = array(
             'stac_version' => STACAPI::STAC_VERSION,
             'id' => 'root',
             'type' => 'Catalog',
@@ -269,6 +269,8 @@ public function hello()
             ),
             'conformsTo' => $this->conformsTo()
         );
+
+        return $this->context->core['useJSONLD'] ? JSONLDUtil::addDataCatalogMetadata($hello) : $hello;
     }
 
     /**

app/resto/core/utils/JSONLDUtil.php

@@ -0,0 +1,226 @@
+<?php
+/*
+ * Copyright 2018 Jérôme Gasperi
+ *
+ * Licensed under the Apache License, version 2.0 (the "License");
+ * You may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+
+/**
+ * JSON-LD additionnal metadata
+ */
+class JSONLDUtil
+{
+
+    public static $STAC_BROWSER_URL = 'https://radiantearth.github.io/stac-browser/#/external/';
+
+    /**
+     * Add additionnal DataCatalog JSON-LD metadata
+     * 
+     * See STAC discussion here - https://github.com/radiantearth/stac-spec/issues/378
+     *
+     * @param array $catalog
+     * @return array
+     */
+    public static function addDataCatalogMetadata($catalog)
+    {
+
+        // Parse links
+        $isPartOf = array();
+        $hasPart = array();
+        $dataset = array();
+        $url = null;
+
+        for ($i = 0, $ii = count($catalog['links']); $i < $ii; $i++) {
+
+            if ($catalog['links'][$i]['rel'] === 'self') {
+                $url = $catalog['links'][$i]['href'];
+            }
+
+            else if ($catalog['links'][$i]['rel'] === 'parent') {
+                $isPartOf = array(
+                    '@type' => 'DataCatalog',
+                    'name' => $catalog['links'][$i]['title'] ?? '',
+                    'isBaseOn' => $catalog['links'][$i]['href'],
+                    'url' =>  JSONLDUtil::$STAC_BROWSER_URL . (explode('://', $catalog['links'][$i]['href'])[1])
+                );
+            }
+
+            else if ($catalog['links'][$i]['rel'] === 'child') {
+                $hasPart[] = array(
+                    '@type' => 'DataCatalog',
+                    'name' => $catalog['links'][$i]['title'] ?? '',
+                    'isBaseOn' => $catalog['links'][$i]['href'],
+                    'url' =>  JSONLDUtil::$STAC_BROWSER_URL . (explode('://', $catalog['links'][$i]['href'])[1])
+                );
+            }
+
+            else if ($catalog['links'][$i]['rel'] === 'item') {
+                $id = isset($catalog['links'][$i]['id']) ? $catalog['links'][$i]['id'] : end(explode('/', $catalog['links'][$i]['href']));
+                $dataset[] = array(
+                    'identifier' => $i,
+                    'name' => $catalog['links'][$i]['title'] ?? $id,
+                    'isBaseOn' => $catalog['links'][$i]['href'],
+                    'url' =>  JSONLDUtil::$STAC_BROWSER_URL . (explode('://',$catalog['links'][$i]['href'])[1])
+                );
+            }
+
+        }
+
+        $jsonld = JSONLDUtil::getCommonMetadata($catalog, $url);
+
+        if ( isset($catalog['extent'])) {
+
+            if ( isset($catalog['extent']['spatial']['bbox']) ) {
+                $jsonld['spatialCoverage'] = array(
+                    '@type' => 'Place',
+                    'geo' => array(
+                        '@type' => 'GeoShape',
+                        'box' => join(' ', $catalog['extent']['spatial']['bbox'][0])
+                    )
+                );
+            }
+
+            if ( isset($catalog['extent']['temporal']['interval']) ) {
+                $jsonld['temporalCoverage'] = join('/', array($catalog['extent']['temporal']['interval'][0][0] ?? '..', $catalog['extent']['temporal']['interval'][0][1] ?? '..'));
+            }
+
+        }
+
+        if ( isset($isPartOf) ) {
+            $jsonld['isPartOf'] = $isPartOf;
+        }
+
+        if ( !empty($hasPart) ) {
+            $jsonld['hasPart'] = $hasPart;
+        }
+
+        if ( !empty($dataset) ) {
+            $jsonld['dataset'] = $dataset;
+        }
+
+        return array_merge($catalog, $jsonld);
+    }
+
+
+    /**
+     * Add additionnal Datasets JSON-LD metadata
+     *
+     * @param array $item
+     * @return array
+     */
+    public static function addDatasetsMetadata($item)
+    {
+
+        $url = null;
+        $thumbnail = null;
+        $includedInDataCatalog = array();
+        $distribution = array();
+
+        for ($i = 0, $ii = count($item['links']); $i < $ii; $i++) {
+            if ($item['links'][$i]['rel'] === 'self') {
+                $url = $item['links'][$i]['href'];
+            }
+            else if ($item['links'][$i]['rel'] === 'parent') {
+                $includedInDataCatalog[] = array(
+                    'isBaseOn' => $item['links'][$i]['href'],
+                    'url' => JSONLDUtil::$STAC_BROWSER_URL . (explode('://', $item['links'][$i]['href'])[1])
+                );
+            }
+        }
+
+        foreach (array_keys($item['assets']) as $key) {
+
+            if ( !empty($item['assets'][$key]['roles']) && in_array('thumbnail', $item['assets'][$key]['roles']) ) {
+                $thumbnail = $item['assets'][$key]['href'];
+            }
+
+            $distribution[] = array(
+                'contentUrl' => $item['assets'][$key]['href'],
+                'fileFormat' => $item['assets'][$key]['type'] ?? null,
+                'title' => $item['assets'][$key]['title'] ?? null
+            );
+
+        }
+
+        $jsonld = JSONLDUtil::getCommonMetadata($item, $url);
+
+        if ( isset($item['bbox'])) {
+           $jsonld['spatialCoverage'] = array(
+                '@type' => 'Place',
+                'geo' => array(
+                    '@type' => 'GeoShape',
+                    'box' => join(' ', $item['bbox'])
+                )
+            );
+        }
+
+
+        if ( isset($catalog['extent']['temporal']['interval']) ) {
+            $jsonld['temporalCoverage'] = join('/', array($catalog['extent']['temporal']['interval'][0][0] ?? '..', $catalog['extent']['temporal']['interval'][0][1] ?? '..'));
+        }
+
+        if ( isset($item['properties']['start_datetime']) ) {
+            $jsonld['temporalCoverage'] = join('/', array($item['properties']['start_datetime'] ?? '..', $item['properties']['end_datetime'] ?? '..'));
+        }
+        else if ( isset($item['properties']['datetime']) ) {
+            $jsonld['temporalCoverage'] = $item['properties']['datetime'];
+        }
+
+        if ( isset($thumbnail) ) {
+            $jsonld['image'] = $thumbnail;
+        }
+
+        if ( !empty($distribution) ) {
+            $jsonld['distribution'] = $distribution;
+        }
+
+        return array_merge($item, $jsonld);
+
+    }
+
+    /**
+     * Return common catalog/item JSON-LD metadata
+     * 
+     * @param array $obj
+     * @param string $url
+     */
+    private static function getCommonMetadata($obj, $url)
+    {
+
+        $jsonld = array(
+            // Required
+            '@context' => 'https://schema.org/',
+            '@type' => 'DataCatalog',
+            'name' => $obj['title'] ?? $obj['id'],
+            // Recommended
+            'identifier' => $obj['properties']['sci:doi'] ?? $obj['id'],
+            'isBasedOn' => $url,
+            'url' => JSONLDUtil::$STAC_BROWSER_URL . (explode('://', $url)[1])
+        );
+
+        if ( isset($obj['properties']['sci:citation'] ) ) {
+            $jsonld['citation'] = $obj['properties']['sci:citation'];
+        }
+
+        if ( isset($obj['properties']['sci:publications']) ) {
+            $jsonld['workExample'] = array(
+                'identifier' => $obj['properties']['sci:publications']['doi'] ?? null,
+                'citation' => $obj['properties']['sci:publications']['citation'] ?? null
+            );
+        }
+
+        return $jsonld;
+
+    } 
+
+}

build/resto/config.php.template

@@ -19,6 +19,7 @@ return array(
     'userAutoActivation' => ${USER_AUTOACTIVATION:-true},
     'splitGeometryOnDateLine' => ${SPLIT_GEOMETRY_ON_DATELINE:-true},
     'useCache' => ${USE_CACHE:-false}, 
+    'useJSONLD' => ${USE_JSONLD:-false},
     'corsWhiteList' => array(${CORS_WHITELIST}),
     'htmlSearchEndpoint' => '${SEARCH_OPENSEARCH_HTML_ENDPOINT}',
     'database' => array(

config.env

@@ -114,6 +114,9 @@ JWT_PASSPHRASE="Super secret passphrase"
 ### If null then no cache is used
 #USE_CACHE=false
 
+### True to provide additionnal JSON-LD metadata within catalogs/collections/items
+#USE_JSONLD=false
+
 ### =====================================================================
 ### Search engine configuration
 ### =====================================================================