Automatic Temporal Extent Calculation for Collections

CHANGELOG.md

@@ -9,6 +9,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ### Added
 
+- Automatic temporal extent calculation for collections. When serving collections via the `/collections` 
+  and `/collections/{collectionId}` endpoints, if a collection does not have a temporal extent defined, 
+  the server will automatically calculate it from the earliest and latest items in the collection. To use 
+  this feature, simply omit the `extent.temporal.interval` field when ingesting a collection.
 - Asset proxying for generating pre-signed S3 URLs through proxy endpoints `GET
   /collections/{collectionId}/items/{itemId}/assets/{assetKey}` and `GET
   /collections/{collectionId}/assets/{assetKey}`.

README.md

@@ -1496,24 +1496,45 @@ One limitation of the header approach is that API Gateway has a hard limit of 10
 
 ## Ingesting Data
 
-STAC Collections and Items are ingested by the `ingest` Lambda function, however this Lambda is not invoked directly by a user, it consumes records from the `stac-server-<stage>-queue` SQS. To add STAC Items or Collections to the queue, publish them to the SNS Topic `stac-server-<stage>-ingest`.
+STAC Collections and Items are ingested by the `ingest` Lambda function, however this Lambda is not invoked directly
+ by a user, it consumes records from the `stac-server-<stage>-queue` SQS. To add STAC Items or Collections to the
+  queue, publish them to the SNS Topic `stac-server-<stage>-ingest`.
 
-**STAC Collections must be ingested before Items that belong to that Collection.** Items should have the `collection` field populated with the ID of an existing Collection. If an Item is ingested before ingestion of the Collection it contains,
-ingestion will either fail (in the case of a single Item ingest) or if auto-creation of indexes is enabled (default) and multiple Items are ingested in bulk, the auto-created index will have incorrect mappings.
+**STAC Collections must be ingested before Items that belong to that Collection.** Items should have the `collection` 
+field populated with the ID of an existing Collection. If an Item is ingested before ingestion of the Collection it contains,
+ingestion will either fail (in the case of a single Item ingest) or if auto-creation of indexes is enabled (default)
+and multiple Items are ingested in bulk, the auto-created index will have incorrect mappings.
 
-If a collection or item is ingested, and an item with that id already exists in STAC, the new item will completely replace the old item, except the `created` property will be retained and the `updated` property updated
+If a collection or item is ingested, and an item with that id already exists in STAC, the new item will completely 
+replace the old item, except the `created` property will be retained and the `updated` property updated
 to match the time of the new update.
 
-After a collection or item is ingested, the status of the ingest (success or failure) along with details of the collection or item are sent to a post-ingest SNS topic. To take action on items after they are ingested subscribe an endpoint to this topic.
+After a collection or item is ingested, the status of the ingest (success or failure) along with details of the 
+collection or item are sent to a post-ingest SNS topic. To take action on items after they are 
+ingested subscribe an endpoint to this topic.
 
-Messages published to the post-ingest SNS topic include the following atributes that can be used for filtering:
+Messages published to the post-ingest SNS topic include the following attributes that can be used for filtering:
 
 | attribute    | type   | values                   |
 | ------------ | ------ | ------------------------ |
 | recordType   | String | `Collection` or `Item`   |
 | ingestStatus | String | `successful` or `failed` |
 | collection   | String |                          |
 
+### Automatic Temporal Extent
+
+When ingesting Collections, the `extent.temporal.interval` field can be omitted to enable automatic temporal 
+extent calculation. When a collection is requested via the API, if it doesn't have a temporal extent defined, 
+stac-server will automatically calculate it by finding the earliest and latest `datetime` values from the items 
+in that collection. Collections with no items will have a temporal extent of `[[null, null]]`. This feature allows 
+temporal extents to stay current as items are added or removed without requiring manual collection updates. 
+The temporal extent is calculated dynamically each time the collection is requested, so it automatically reflects 
+the current state of items without requiring collection updates or persisting changes to the collection document.
+
+After a collection or item is ingested, the status of the ingest (success or failure) along with details of the c
+ollection or item are sent to a post-ingest SNS topic. To take action on items after they are ingested
+ subscribe an endpoint to this topic.
+
 ### Ingest actions
 
 In addition to ingesting Item and Collection JSON, the ingestion pipeline can also execute

src/lib/api.js

@@ -1254,6 +1254,35 @@ const deleteUnusedFields = (collection) => {
   delete collection.aggregations
 }
 
+/**
+ * Populate temporal extent for a collection from its items if not already defined
+ * @param {Object} backend - Database backend
+ * @param {Object} collection - Collection object
+ * @returns {Promise<void>}
+ */
+const populateTemporalExtentIfMissing = async (backend, collection) => {
+  const id = collection.id
+
+  // Check if collection already has a temporal extent defined
+  const start = collection.extent?.temporal?.interval?.[0]?.[0]
+  const end = collection.extent?.temporal?.interval?.[0]?.[1]
+  const hasTemporalExtent = start != null || end != null
+
+  if (!hasTemporalExtent) {
+    const temporalExtent = await backend.getTemporalExtentFromItems(id)
+    if (temporalExtent) {
+      // Initialize extent structure if it doesn't exist
+      if (!collection.extent) {
+        collection.extent = {}
+      }
+      if (!collection.extent.temporal) {
+        collection.extent.temporal = {}
+      }
+      collection.extent.temporal.interval = temporalExtent
+    }
+  }
+}
+
 const getCollections = async function (backend, endpoint, parameters, headers) {
   // TODO: implement proper pagination, as this will only return up to
   // COLLECTION_LIMIT collections
@@ -1267,6 +1296,10 @@ const getCollections = async function (backend, endpoint, parameters, headers) {
     (c) => isCollectionIdAllowed(allowedCollectionIds, c.id)
   )
 
+  // Populate temporal extent for each collection from items only if not already defined
+  await Promise.all(collections.map((collection) =>
+    populateTemporalExtentIfMissing(backend, collection)))
+
   for (const collection of collections) {
     deleteUnusedFields(collection)
   }
@@ -1313,6 +1346,9 @@ const getCollection = async function (backend, collectionId, endpoint, parameter
     return new NotFoundError()
   }
 
+  // Populate temporal extent from items only if not already defined
+  await populateTemporalExtentIfMissing(backend, result)
+
   deleteUnusedFields(result)
   addCollectionLinks([result], endpoint)