Item: Validate that collection property is set if link with collectio…

…n rel type is available #1088
philvarner · Apr 15, 2021 · 6c8df30 · 6c8df30
1 parent 90f8d37
commit 6c8df30
Showing 3 changed files with 42 additions and 7 deletions.
diff --git a/examples/extensions-collection/proj-example/proj-example.json b/examples/extensions-collection/proj-example/proj-example.json
@@ -219,6 +219,11 @@
       "rel": "parent",
       "href": "../collection.json",
       "type": "application/json"
+    },
+    {
+      "rel": "collection",
+      "href": "../collection.json",
+      "type": "application/json"
     }
   ],
   "assets": {

diff --git a/item-spec/item-spec.md b/item-spec/item-spec.md
@@ -63,7 +63,7 @@ inherited from GeoJSON.
 | properties | [Properties Object](#properties-object)                                    | **REQUIRED.** A dictionary of additional metadata for the Item. |
 | links      | \[[Link Object](#link-object)]                                             | **REQUIRED.** List of link objects to resources and related URLs. A link with the `rel` set to `self` is strongly recommended. |
 | assets     | Map<string, [Asset Object](#asset-object)>                                 | **REQUIRED.** Dictionary of asset objects that can be downloaded, each with a unique key. |
-| collection | string                                                                     | The `id` of the STAC Collection this Item references to (see [`collection` relation type](#relation-types)). This field is *required* if such a relation type is present. This field provides an easy way for a user to search for any Items that belong in a specified Collection. Must be a non-empty string. |
+| collection | string                                                                     | The `id` of the STAC Collection this Item references to (see [`collection` relation type](#relation-types)). This field is *required* if such a relation type is present and is *not allowed* otherwise. This field provides an easy way for a user to search for any Items that belong in a specified Collection. Must be a non-empty string. |
 
 ### Additional Field Information
 

diff --git a/item-spec/json-schema/item.json b/item-spec/json-schema/item.json
@@ -159,12 +159,42 @@
                   ]
                 }
               ]
-            },
-            "collection": {
-              "title": "Collection ID",
-              "description": "The ID of the STAC Collection this Item references to.",
-              "type": "string",
-              "minLength": 1
+            }
+          },
+          "if": {
+            "properties": {
+              "links": {
+                "contains": {
+                  "required": [
+                    "rel"
+                  ],
+                  "properties": {
+                    "rel": {
+                      "const": "collection"
+                    }
+                  }
+                }
+              }
+            }
+          },
+          "then": {
+            "required": [
+              "collection"
+            ],
+            "properties": {
+              "collection": {
+                "title": "Collection ID",
+                "description": "The ID of the STAC Collection this Item references to.",
+                "type": "string",
+                "minLength": 1
+              }
+            }
+          },
+          "else": {
+            "properties": {
+              "collection": {
+                "not": {}
+              }
             }
           }
         }