Merge pull request #37 from camptocamp/ogc-api-better-collection-info…

…-fetch

OGC API: misc improvements

src/ogc-api/endpoint.spec.ts

@@ -51,8 +51,16 @@ beforeAll(() => {
   };
 });
 
+jest.useFakeTimers();
+
 describe('OgcApiEndpoint', () => {
   let endpoint: OgcApiEndpoint;
+
+  afterEach(async () => {
+    // this will exhaust all microtasks, effectively preventing rejected promises from leaking between tests
+    await jest.runAllTimersAsync();
+  });
+
   describe('nominal case', () => {
     beforeEach(() => {
       endpoint = new OgcApiEndpoint('http://local/sample-data/');
@@ -216,6 +224,7 @@ describe('OgcApiEndpoint', () => {
             'application/vnd.ogc.fg+json;compatibility=geojson',
             'text/html',
           ],
+          bulkDownloadLinks: {},
           extent: {
             spatial: {
               bbox: [
@@ -266,6 +275,7 @@ describe('OgcApiEndpoint', () => {
           description:
             'Sample metadata records from Dutch Nationaal georegister',
           formats: ['application/geo+json', 'application/ld+json', 'text/html'],
+          bulkDownloadLinks: {},
           keywords: ['netherlands', 'open data', 'georegister'],
           extent: {
             spatial: {
@@ -343,6 +353,7 @@ describe('OgcApiEndpoint', () => {
             'application/vnd.ogc.fg+json;compatibility=geojson',
             'text/html',
           ],
+          bulkDownloadLinks: {},
           extent: {
             spatial: {
               bbox: [
@@ -1549,10 +1560,11 @@ describe('OgcApiEndpoint', () => {
   });
   describe('a failure happens while parsing the endpoint capabilities', () => {
     beforeEach(() => {
-      endpoint = new OgcApiEndpoint('http://local/sample-data/notjson'); // not actually json
+      // endpoint = new OgcApiEndpoint('http://local/sample-data/notjson'); // not actually json
     });
     describe('#info', () => {
       it('throws an explicit error', async () => {
+        endpoint = new OgcApiEndpoint('http://local/sample-data/notjson'); // not actually json
         await expect(endpoint.info).rejects.toEqual(
           new EndpointError(
             `The endpoint appears non-conforming, the following error was encountered:
@@ -1713,6 +1725,33 @@ The document at http://local/nonexisting?f=json could not be fetched.`
           ]);
         });
       });
+      describe('#getCollectionInfo', () => {
+        it('returns a collection info', async () => {
+          await expect(
+            endpoint.getCollectionInfo('aires-covoiturage')
+          ).resolves.toStrictEqual({
+            crs: ['http://www.opengis.net/def/crs/OGC/1.3/CRS84', 'EPSG:4326'],
+            formats: ['application/geo+json'],
+            bulkDownloadLinks: {
+              'application/geo+json':
+                'https://my.server.org/sample-data-2/collections/aires-covoiturage/items?f=geojson&limit=-1',
+              'application/json':
+                'https://my.server.org/sample-data-2/collections/aires-covoiturage/items?f=json&limit=-1',
+              'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet':
+                'https://my.server.org/sample-data-2/collections/aires-covoiturage/items?f=ooxml&limit=-1',
+              'application/x-shapefile':
+                'https://my.server.org/sample-data-2/collections/aires-covoiturage/items?f=shapefile&limit=-1',
+              'text/csv;charset=UTF-8':
+                'https://my.server.org/sample-data-2/collections/aires-covoiturage/items?f=csv&limit=-1',
+            },
+            id: 'aires-covoiturage',
+            itemType: 'feature',
+            queryables: [],
+            sortables: [],
+            title: 'aires-covoiturage',
+          });
+        });
+      });
     });
   });
 });

src/ogc-api/endpoint.ts

@@ -22,6 +22,7 @@ import {
   fetchLink,
   fetchRoot,
   getLinkUrl,
+  hasLinks,
 } from './link-utils.js';
 import { EndpointError } from '../shared/errors.js';
 import { BoundingBox, CrsCode, MimeType } from '../shared/models.js';
@@ -30,49 +31,66 @@ import { BoundingBox, CrsCode, MimeType } from '../shared/models.js';
  * Represents an OGC API endpoint advertising various collections and services.
  */
 export default class OgcApiEndpoint {
-  private root: Promise<OgcApiDocument>;
-  private conformance: Promise<OgcApiDocument>;
-  private data: Promise<OgcApiDocument>;
+  // these are cached results because the getters rely on HTTP requests; to avoid
+  // unhandled promise rejections the getters are evaluated lazily
+  private root_: Promise<OgcApiDocument>;
+  private conformance_: Promise<OgcApiDocument>;
+  private data_: Promise<OgcApiDocument>;
 
-  /**
-   * Creates a new OGC API endpoint.
-   * @param baseUrl Base URL used to query the endpoint. Note that this can point to nested
-   * documents inside the endpoint, such as `/collections`, `/collections/items` etc.
-   */
-  constructor(private baseUrl: string) {
-    this.root = fetchRoot(this.baseUrl).catch((e) => {
-      throw new Error(`The endpoint appears non-conforming, the following error was encountered:
+  private get root(): Promise<OgcApiDocument> {
+    if (!this.root_) {
+      this.root_ = fetchRoot(this.baseUrl).catch((e) => {
+        throw new Error(`The endpoint appears non-conforming, the following error was encountered:
 ${e.message}`);
-    });
-    this.conformance = this.root
-      .then((root) =>
+      });
+    }
+    return this.root_;
+  }
+  private get conformance(): Promise<OgcApiDocument> {
+    if (!this.conformance_) {
+      this.conformance_ = this.root.then((root) =>
         fetchLink(
           root,
           ['conformance', 'http://www.opengis.net/def/rel/ogc/1.0/conformance'],
           this.baseUrl
         )
+      );
+    }
+    return this.conformance_;
+  }
+  private get collectionsUrl(): Promise<string> {
+    return this.root.then((root) =>
+      getLinkUrl(
+        root,
+        ['data', 'http://www.opengis.net/def/rel/ogc/1.0/data'],
+        this.baseUrl
       )
-      .catch(() => null);
-    this.data = this.root
-      .then((root) =>
-        fetchLink(
-          root,
-          ['data', 'http://www.opengis.net/def/rel/ogc/1.0/data'],
-          this.baseUrl
-        )
-      )
-      .then(async (data) => {
-        // check if there's a collection in the path; if yes, keep only this one
-        const singleCollection = await fetchCollectionRoot(this.baseUrl);
-        if (singleCollection !== null && Array.isArray(data.collections)) {
-          data.collections = data.collections.filter(
-            (collection) => collection.id === singleCollection.id
-          );
-        }
-        return data;
-      })
-      .catch(() => null);
+    );
   }
+  private get data(): Promise<OgcApiDocument> {
+    if (!this.data_) {
+      this.data_ = this.collectionsUrl
+        .then(fetchDocument)
+        .then(async (data) => {
+          // check if there's a collection in the path; if yes, keep only this one
+          const singleCollection = await fetchCollectionRoot(this.baseUrl);
+          if (singleCollection !== null && Array.isArray(data.collections)) {
+            data.collections = data.collections.filter(
+              (collection) => collection.id === singleCollection.id
+            );
+          }
+          return data;
+        });
+    }
+    return this.data_;
+  }
+
+  /**
+   * Creates a new OGC API endpoint.
+   * @param baseUrl Base URL used to query the endpoint. Note that this can point to nested
+   * documents inside the endpoint, such as `/collections`, `/collections/items` etc.
+   */
+  constructor(private baseUrl: string) {}
 
   /**
    * A Promise which resolves to the endpoint information.
@@ -155,7 +173,14 @@ ${e.message}`);
           (collection) => collection.id === collectionId
         );
       })
-      .then((collection) => fetchLink(collection, 'self', this.baseUrl));
+      .then(async (collection) => {
+        // if a self link is there, use it!
+        if (hasLinks(collection, ['self'])) {
+          return fetchLink(collection, 'self', this.baseUrl);
+        }
+        // otherwise build a URL for the collection
+        return fetchDocument(`${await this.collectionsUrl}/${collectionId}`);
+      });
   }
 
   /**

src/ogc-api/info.ts

@@ -102,7 +102,13 @@ export function parseBaseCollectionInfo(
   const formats = links
     .filter((link) => link.rel === 'items')
     .map((link) => link.type);
-  return { formats, ...props } as OgcApiCollectionInfo;
+  const bulkDownloadLinks = links
+    .filter((link) => link.rel === 'enclosure')
+    .reduce((acc, link) => {
+      acc[link.type] = link.href;
+      return acc;
+    }, {});
+  return { formats, bulkDownloadLinks, ...props } as OgcApiCollectionInfo;
 }
 
 export function parseCollectionParameters(

src/ogc-api/model.ts

@@ -31,7 +31,8 @@ export interface OgcApiCollectionInfo {
   description: string;
   id: string;
   itemType: 'feature' | 'record';
-  formats: MimeType[];
+  formats: MimeType[]; // these formats are accessible through the /items API
+  bulkDownloadLinks: Record<string, MimeType>; // map between formats and bulk download links (no filtering, pagination etc.)
   crs: CrsCode[];
   storageCrs?: CrsCode;
   itemCount: number;