CMR-10118: Update default paging functionality for CMR-STAC

serverless.dev.yml

@@ -9,6 +9,7 @@ provider:
     CMR_LB_URL: "https://cmr.sit.earthdata.nasa.gov"
     GRAPHQL_URL: "https://graphql.sit.earthdata.nasa.gov/api"
     STAC_VERSION: "1.0.0"
+    PAGE_SIZE: "100"
 
 functions:
   stac:

serverless.yml

@@ -15,6 +15,7 @@ provider:
     CMR_LB_URL: ${param:cmr-lb-url, "http://${cf:${opt:stage}.servicesDnsName}"}
     GRAPHQL_URL: ${param:graphql-url, "https://graphql${self:custom.stagePrefix.${opt:stage}}.earthdata.nasa.gov/api"}
     STAC_VERSION: "1.0.0"
+    PAGE_SIZE: "100"
     LOG_LEVEL: INFO
 
 custom:

src/__tests__/providerCatalog.spec.ts

@@ -13,8 +13,9 @@ import ItemSpec from "../../resources/item-spec/json-schema/item.json";
 
 import { Link } from "../@types/StacCatalog";
 import { createApp } from "../app";
-import * as Provider from "../domains/providers";
 import * as Collections from "../domains/collections";
+import * as Provider from "../domains/providers";
+import * as stac from "../domains/stac";
 import { generateSTACCollections } from "../utils/testUtils";
 
 const stacApp = createApp();
@@ -165,6 +166,59 @@ describe("GET /:provider", () => {
       });
     });
 
+    describe("when there are more results available", () => {
+      it("includes a 'next' link with the correct query parameters", async () => {
+        sandbox.stub(stac, "CMR_QUERY_MAX").value(100);
+        sandbox
+          .stub(Provider, "getProviders")
+          .resolves([null, [{ "provider-id": "TEST", "short-name": "TEST" }]]);
+        const mockCollections = generateSTACCollections(100);
+        sandbox.stub(Collections, "getCollectionIds").resolves({
+          count: 100,
+          cursor: "nextPageCursor",
+          items: mockCollections.map((coll) => ({
+            id: `${coll.id}`,
+            title: coll.title ?? faker.random.words(4),
+          })),
+        });
+
+        const { body: catalog } = await request(stacApp).get(`/stac/TEST`);
+
+        const nextLink = catalog.links.find((l: Link) => l.rel === "next");
+        expect(nextLink).to.exist;
+        expect(nextLink.rel).to.equal("next");
+        expect(nextLink.type).to.equal("application/json");
+        expect(nextLink.title).to.equal("Next page of results");
+
+        const nextUrl = new URL(nextLink.href);
+        expect(nextUrl.pathname).to.equal("/stac/TEST");
+      });
+    });
+
+    describe("when there are no more results available", () => {
+      it("does not include a 'next' link", async () => {
+        sandbox.stub(stac, "CMR_QUERY_MAX").value(100);
+        sandbox
+          .stub(Provider, "getProviders")
+          .resolves([null, [{ "provider-id": "TEST", "short-name": "TEST" }]]);
+
+        const mockCollections = generateSTACCollections(10);
+        sandbox.stub(Collections, "getCollectionIds").resolves({
+          count: 10,
+          cursor: null,
+          items: mockCollections.map((coll) => ({
+            id: `${coll.id}`,
+            title: coll.title ?? faker.random.words(4),
+          })),
+        });
+
+        const { body: catalog } = await request(stacApp).get("/stac/TEST");
+
+        const nextLink = catalog.links.find((l: Link) => l.rel === "next");
+        expect(nextLink).to.not.exist;
+      });
+    });
+
     describe(`given the provider has a collection`, () => {
       it("has a child link for that collection without query parameters", async function () {
         sandbox

src/domains/collections.ts

@@ -16,7 +16,7 @@ import {
 
 import { cmrSpatialToExtent } from "./bounding-box";
 
-import { extractAssets, MAX_SIGNED_INTEGER, paginateQuery } from "./stac";
+import { CMR_QUERY_MAX, extractAssets, paginateQuery } from "./stac";
 
 const CMR_ROOT = process.env.CMR_URL;
 const STAC_VERSION = process.env.STAC_VERSION ?? "1.0.0";
@@ -356,7 +356,7 @@ export const getAllCollectionIds = async (
   cursor: string | null;
   items: { id: string; title: string }[];
 }> => {
-  params.limit = MAX_SIGNED_INTEGER;
+  params.limit = CMR_QUERY_MAX;
 
   return await getCollectionIds(params, opts);
 };

src/domains/stac.ts

@@ -205,8 +205,8 @@ export const extractAssets = (
     {} as AssetLinks
   );
 const GRAPHQL_URL = process.env.GRAPHQL_URL ?? "http://localhost:3013";
-export const CMR_QUERY_MAX = 2000;
-export const MAX_SIGNED_INTEGER = 2 ** 31 - 1;
+
+export const CMR_QUERY_MAX = Number(process.env.PAGE_SIZE);
 
 const pointToQuery = (point: GeoJSONPoint) => point.coordinates.join(",");
 
@@ -553,8 +553,7 @@ export const paginateQuery = async (
   opts: {
     headers?: IncomingHttpHeaders;
   },
-  handler: GraphQLHandler,
-  prevResults: unknown[] = []
+  handler: GraphQLHandler
 ): Promise<GraphQLResults> => {
   const paginatedParams = { ...params };
 
@@ -589,19 +588,7 @@ export const paginateQuery = async (
     if (!data) throw new Error("No data returned from GraphQL during paginated query");
     const { count, cursor, items } = data;
 
-    const totalResults = [...prevResults, ...items];
-    const moreResultsAvailable = totalResults.length !== count && cursor != null;
-    const foundEnough = totalResults.length >= (params.limit ?? -1);
-
-    if (moreResultsAvailable && !foundEnough) {
-      console.debug(
-        `Retrieved ${totalResults.length} of ${params.limit} for ${JSON.stringify(params, null, 2)}`
-      );
-      const nextParams = mergeMaybe({ ...params }, { cursor });
-      return await paginateQuery(gqlQuery, nextParams, opts, handler, totalResults);
-    }
-
-    return { items: totalResults, count, cursor };
+    return { items: items, count, cursor };
   } catch (err: unknown) {
     if (
       !(err instanceof Error) &&

src/routes/catalog.ts

@@ -6,13 +6,14 @@ import { getAllCollectionIds } from "../domains/collections";
 import { conformance } from "../domains/providers";
 import { ServiceUnavailableError } from "../models/errors";
 import { getBaseUrl, mergeMaybe, stacContext } from "../utils";
+import { CMR_QUERY_MAX, stringifyQuery } from "../domains/stac";
 
 const STAC_VERSION = process.env.STAC_VERSION ?? "1.0.0";
 
-const generateSelfLinks = (req: Request): Links => {
+const generateSelfLinks = (req: Request, nextCursor?: string | null, count?: number): Links => {
   const { stacRoot, path, self } = stacContext(req);
 
-  return [
+  const links = [
     {
       rel: "self",
       href: self,
@@ -72,20 +73,43 @@ const generateSelfLinks = (req: Request): Links => {
       title: "HTML documentation",
     },
   ];
+
+  const originalQuery = mergeMaybe(req.query, req.body);
+
+  // Add a 'next' link if there are more results available
+  // This is determined by:
+  //  1. The presence of a nextCursor (indicating more results)
+  //  2. The number of collection equaling CMR_QUERY_MAX (100)
+  // The 'next' link includes the original query parameters plus the new cursor
+  if (nextCursor && count === CMR_QUERY_MAX) {
+    const nextResultsQuery = { ...originalQuery, cursor: nextCursor };
+
+    links.push({
+      rel: "next",
+      href: `${stacRoot}${req.path}?${stringifyQuery(nextResultsQuery)}`,
+      type: "application/json",
+      title: "Next page of results",
+    });
+  }
+
+  return links;
 };
 
 const providerCollections = async (
   req: Request
-): Promise<[null, { id: string; title: string }[]] | [string, null]> => {
-  const { headers, provider } = req;
+): Promise<[null, { id: string; title: string }[], string | null] | [string, null]> => {
+  const { headers, provider, query } = req;
 
   const cloudOnly = headers["cloud-stac"] === "true" ? { cloudHosted: true } : {};
 
-  const query = mergeMaybe({ provider: provider?.["provider-id"] }, { ...cloudOnly });
+  const mergedQuery = mergeMaybe(
+    { provider: provider?.["provider-id"], cursor: query?.cursor },
+    { ...cloudOnly }
+  );
 
   try {
-    const { items } = await getAllCollectionIds(query, { headers });
-    return [null, items];
+    const { items, cursor } = await getAllCollectionIds(mergedQuery, { headers });
+    return [null, items, cursor];
   } catch (err) {
     console.error("A problem occurred querying for collections.", err);
     return [(err as Error).message, null];
@@ -94,15 +118,17 @@ const providerCollections = async (
 
 export const providerCatalogHandler = async (req: Request, res: Response) => {
   const { provider } = req;
+
   if (!provider) throw new ServiceUnavailableError("Could not retrieve provider information");
 
-  const [err, collections] = await providerCollections(req);
+  const [err, collections, cursor] = await providerCollections(req);
 
   if (err) throw new ServiceUnavailableError(err as string);
 
   const { self } = stacContext(req);
 
-  const selfLinks = generateSelfLinks(req);
+  const selfLinks = generateSelfLinks(req, cursor, collections?.length);
+
   const childLinks = (collections ?? []).map(({ id, title }) => ({
     rel: "child",
     href: `${getBaseUrl(self)}/collections/${encodeURIComponent(id)}`,