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

Author: eth3lbert

mirage/route-handlers/crates.js

@@ -159,7 +159,7 @@ export function register(server) {
     if (!crate) return notFound();
 
     let versions = crate.versions;
-    let { nums, sort } = request.queryParams;
+    let { nums, sort, per_page, seek } = request.queryParams;
     if (nums) {
       versions = versions.filter(version => nums.includes(version.num));
     }
@@ -170,9 +170,32 @@ export function register(server) {
     let total = versions.length;
     let include = request.queryParams?.include ?? '';
     let release_tracks = include.split(',').includes('release_tracks') && releaseTracks(crate.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;
+    if (per_page != null) {
+      if (seek != null) {
+        let idx = versions.models.findIndex(it => it.num === seek);
+        versions = versions.slice(idx + 1);
+      }
+      versions = versions.slice(0, per_page);
+
+      if (versions.length >= per_page) {
+        let last = versions.models.at(-1);
+        next_seek = last.num;
+      }
+    }
+    let next_page = null;
+    if (next_seek) {
+      next_page = new URLSearchParams({ ...request.queryParams, seek: next_seek });
+      next_page = `?${next_page}`;
+    }
+
     let resp = {
       ...this.serialize(versions),
-      meta: { total, next_page: null },
+      meta: { total, next_page },
     };
     if (release_tracks && Object.keys(release_tracks).length !== 0) {
       resp.meta.release_tracks = release_tracks;

tests/mirage/crates/versions/list-test.js

@@ -147,6 +147,85 @@ module('Mirage | GET /api/v1/crates/:name/versions', function (hooks) {
     }
   });
 
+  test('supports seek pagination', async function (assert) {
+    let user = this.server.create('user');
+    let crate = this.server.create('crate', { name: 'rand' });
+    this.server.create('version', { crate, num: '1.0.0', created_at: '2010-06-16T21:30:45Z' });
+    this.server.create('version', { crate, num: '1.2.0', rust_version: '1.69', created_at: '2010-06-16T21:30:46Z' });
+    this.server.create('version', { crate, num: '1.1.0', publishedBy: user, created_at: '2010-06-16T21:30:47Z' });
+
+    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 < 10) {
+        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)),
+        [['1.2.0'], ['1.1.0'], ['1.0.0'], []],
+      );
+      assert.deepEqual(
+        responses.map(it => it.meta.next_page),
+        ['?per_page=1&seek=1.2.0', '?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)),
+        [['1.2.0'], ['1.1.0'], ['1.0.0'], []],
+      );
+      assert.deepEqual(
+        responses.map(it => it.meta.next_page),
+        [
+          '?per_page=1&sort=semver&seek=1.2.0',
+          '?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'], ['1.2.0'], ['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=1.2.0',
+          '?per_page=1&sort=date&seek=1.0.0',
+          null,
+        ],
+      );
+    }
+  });
+
   test('supports multiple `ids[]` parameters', async function (assert) {
     let user = this.server.create('user');
     let crate = this.server.create('crate', { name: 'rand' });