msw: Add seek pagination support for GET /api/v1/crates/:name/versions

Author: eth3lbert

packages/crates-io-msw/handlers/versions/list.js

@@ -27,13 +27,35 @@ export default http.get('/api/v1/crates/:name/versions', async ({ request, param
 
   let include = url.searchParams.get('include') ?? '';
   let includes = include ? include.split(',') : [];
-
-  let serializedVersions = versions.map(v => serializeVersion(v, { includePublishedBy: true }));
   let meta = { total, next_page: null };
 
   if (includes.includes('release_tracks')) {
     meta.release_tracks = calculateReleaseTracks(versions);
   }
 
+  // seek pagination
+  // A simplified seek encoding is applied here for testing purposes only. It should be opaque in
+  // real-world scenarios.
+  let next_seek = null;
+  let per_page = url.searchParams.get('per_page');
+  if (per_page != null) {
+    let seek = url.searchParams.get('seek');
+    if (seek != null) {
+      let start = versions.findIndex(it => it.num === seek);
+      versions = versions.slice(start + 1);
+    }
+    versions = versions.slice(0, parseInt(per_page));
+
+    if (versions.length == per_page) {
+      next_seek = versions.at(-1).num;
+    }
+  }
+  if (next_seek) {
+    let next_params = new URLSearchParams(url.searchParams);
+    next_params.set('seek', next_seek);
+    meta.next_page = `?${next_params}`;
+  }
+
+  let serializedVersions = versions.map(v => serializeVersion(v, { includePublishedBy: true }));
   return HttpResponse.json({ versions: serializedVersions, meta });
 });

packages/crates-io-msw/handlers/versions/list.test.js

@@ -158,6 +158,85 @@ test('supports multiple `ids[]` parameters', async function () {
   );
 });
 
+test('supports seek pagination', async function () {
+  let user = db.user.create();
+  let crate = db.crate.create({ name: 'rand' });
+  db.version.create({ crate, num: '1.0.0' });
+  db.version.create({ crate, num: '2.0.0-alpha', publishedBy: user });
+  db.version.create({ crate, num: '1.1.0', rust_version: '1.69' });
+
+  async function seek_forwards(queryParams) {
+    let calls = 0;
+    let next_page;
+    let responses = [];
+    let base_url = '/api/v1/crates/rand/versions';
+    let params = new URLSearchParams(queryParams);
+    let url = `${base_url}?${params}`;
+    while ((calls == 0 || next_page) && calls < 50) {
+      if (next_page) {
+        url = `${base_url}${next_page}`;
+      }
+      let response = await fetch(url);
+      calls += 1;
+      assert.strictEqual(response.status, 200);
+      let json = await response.json();
+      responses.push(json);
+      next_page = json.meta.next_page;
+      if (next_page == null) {
+        break;
+      }
+    }
+    return responses;
+  }
+
+  // sort by `semver` by default
+  {
+    let responses = await seek_forwards({ per_page: 1 });
+    assert.deepEqual(
+      responses.map(it => it.versions.map(v => v.num)),
+      [['2.0.0-alpha'], ['1.1.0'], ['1.0.0'], []],
+    );
+    assert.deepEqual(
+      responses.map(it => it.meta.next_page),
+      ['?per_page=1&seek=2.0.0-alpha', '?per_page=1&seek=1.1.0', '?per_page=1&seek=1.0.0', null],
+    );
+  }
+
+  {
+    let responses = await seek_forwards({ per_page: 1, sort: 'semver' });
+    assert.deepEqual(
+      responses.map(it => it.versions.map(v => v.num)),
+      [['2.0.0-alpha'], ['1.1.0'], ['1.0.0'], []],
+    );
+    assert.deepEqual(
+      responses.map(it => it.meta.next_page),
+      [
+        '?per_page=1&sort=semver&seek=2.0.0-alpha',
+        '?per_page=1&sort=semver&seek=1.1.0',
+        '?per_page=1&sort=semver&seek=1.0.0',
+        null,
+      ],
+    );
+  }
+
+  {
+    let responses = await seek_forwards({ per_page: 1, sort: 'date' });
+    assert.deepEqual(
+      responses.map(it => it.versions.map(v => v.num)),
+      [['1.1.0'], ['2.0.0-alpha'], ['1.0.0'], []],
+    );
+    assert.deepEqual(
+      responses.map(it => it.meta.next_page),
+      [
+        '?per_page=1&sort=date&seek=1.1.0',
+        '?per_page=1&sort=date&seek=2.0.0-alpha',
+        '?per_page=1&sort=date&seek=1.0.0',
+        null,
+      ],
+    );
+  }
+});
+
 test('include `release_tracks` meta', async function () {
   let user = db.user.create();
   let crate = db.crate.create({ name: 'rand' });