Add initial backfill package

deno.json

@@ -2,6 +2,7 @@
   "workspace": [
     "./packages/amqp",
     "./packages/astro",
+    "./packages/backfill",
     "./packages/cfworkers",
     "./packages/cli",
     "./packages/debugger",

packages/backfill/README.md

@@ -0,0 +1,79 @@
+<!-- deno-fmt-ignore-file -->
+
+@fedify/backfill: ActivityPub backfill for Fedify
+=================================================
+
+[![JSR][JSR badge]][JSR]
+[![npm][npm badge]][npm]
+[![Follow @fedify@hollo.social][@fedify@hollo.social badge]][@fedify@hollo.social]
+
+*This package is available since Fedify 2.3.0.*
+
+This package provides ActivityPub conversation backfill support for the
+[Fedify] ecosystem.  It can retrieve post-like objects from a seed object's
+context collection, following the direct FEP-f228-style path where the
+context dereferences to a `Collection`, `OrderedCollection`, `CollectionPage`,
+or `OrderedCollectionPage`.
+
+[JSR badge]: https://jsr.io/badges/@fedify/backfill
+[JSR]: https://jsr.io/@fedify/backfill
+[npm badge]: https://img.shields.io/npm/v/@fedify/backfill?logo=npm
+[npm]: https://www.npmjs.com/package/@fedify/backfill
+[@fedify@hollo.social badge]: https://fedi-badge.deno.dev/@fedify@hollo.social/followers.svg
+[@fedify@hollo.social]: https://hollo.social/@fedify
+[Fedify]: https://fedify.dev/
+
+
+Installation
+------------
+
+::: code-group
+
+~~~~ sh [Deno]
+deno add jsr:@fedify/backfill
+~~~~
+
+~~~~ sh [npm]
+npm add @fedify/backfill
+~~~~
+
+~~~~ sh [pnpm]
+pnpm add @fedify/backfill
+~~~~
+
+~~~~ sh [Yarn]
+yarn add @fedify/backfill
+~~~~
+
+~~~~ sh [Bun]
+bun add @fedify/backfill
+~~~~
+
+:::
+
+
+Usage
+-----
+
+The `backfill()` function accepts a backfill context, a seed object, and
+traversal options:
+
+~~~~ typescript
+import { backfill } from "@fedify/backfill";
+import { lookupObject } from "@fedify/vocab";
+
+const documentLoader = (iri: URL, options?: { signal?: AbortSignal }) =>
+  lookupObject(iri, { signal: options?.signal });
+
+for await (
+  const item of backfill({ documentLoader }, note, {
+    maxItems: 20,
+    maxRequests: 50,
+  })
+) {
+  console.log(item.id?.href);
+}
+~~~~
+
+The seed object itself is not yielded.  If it appears in the discovered
+collection, it is skipped by ID.

packages/backfill/deno.json

@@ -0,0 +1,22 @@
+{
+  "name": "@fedify/backfill",
+  "version": "2.3.0",
+  "license": "MIT",
+  "exports": {
+    ".": "./src/mod.ts"
+  },
+  "exclude": [
+    "dist/",
+    "node_modules/"
+  ],
+  "publish": {
+    "exclude": [
+      "**/*.test.ts",
+      "tsdown.config.ts"
+    ]
+  },
+  "tasks": {
+    "check": "deno fmt --check && deno lint && deno check src/**/*.ts",
+    "test": "deno test"
+  }
+}

packages/backfill/package.json

@@ -0,0 +1,68 @@
+{
+  "name": "@fedify/backfill",
+  "version": "2.3.0",
+  "description": "ActivityPub backfill support for Fedify",
+  "keywords": [
+    "Fedify",
+    "ActivityPub",
+    "Fediverse",
+    "Backfill"
+  ],
+  "author": {
+    "name": "Jiwon Kwon",
+    "email": "work@kwonjiwon.org"
+  },
+  "homepage": "https://fedify.dev/",
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/fedify-dev/fedify.git",
+    "directory": "packages/backfill"
+  },
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/fedify-dev/fedify/issues"
+  },
+  "funding": [
+    "https://opencollective.com/fedify",
+    "https://github.com/sponsors/dahlia"
+  ],
+  "type": "module",
+  "main": "./dist/mod.cjs",
+  "module": "./dist/mod.js",
+  "types": "./dist/mod.d.ts",
+  "exports": {
+    ".": {
+      "types": {
+        "import": "./dist/mod.d.ts",
+        "require": "./dist/mod.d.cts",
+        "default": "./dist/mod.d.ts"
+      },
+      "import": "./dist/mod.js",
+      "require": "./dist/mod.cjs",
+      "default": "./dist/mod.js"
+    },
+    "./package.json": "./package.json"
+  },
+  "files": [
+    "dist/",
+    "package.json",
+    "README.md"
+  ],
+  "dependencies": {
+    "@fedify/vocab": "workspace:*"
+  },
+  "devDependencies": {
+    "tsdown": "catalog:",
+    "typescript": "catalog:"
+  },
+  "scripts": {
+    "build:self": "tsdown",
+    "build": "pnpm --filter @fedify/backfill... run build:self",
+    "prepack": "pnpm build",
+    "prepublish": "pnpm build",
+    "pretest": "pnpm build",
+    "test": "cd dist/ && node --test",
+    "pretest:bun": "pnpm build",
+    "test:bun": "cd dist/ && bun test --timeout 60000"
+  }
+}