feat: implement the empty operation (#12)

This will implement the `empty` action available in the console(`rm
--recursive` in the cli). I want the behavior to be drawn from the
behavior of the cli; the function will return a list of keys that
were deleted. I'm also thinking about adding a `quiet` option that
simply returns the keys that failed to delete, but probably not for
the first version.

deps.ts

@@ -15,3 +15,4 @@ export function sha256Hex(data: string | Uint8Array): string {
 }
 export { default as parseXML } from "https://raw.githubusercontent.com/nekobato/deno-xml-parser/0bc4c2bd2f5fad36d274279978ca57eec57c680c/index.ts";
 export { decode as decodeXMLEntities } from "https://deno.land/x/[email protected]/lib/xml-entities.js";
+export { pooledMap } from "https://deno.land/[email protected]/async/pool.ts";

src/bucket.ts

@@ -2,6 +2,7 @@ import {
   AWSSignerV4,
   decodeXMLEntities,
   parseXML,
+  pooledMap,
   sha256Hex,
 } from "../deps.ts";
 import type { S3Config } from "./client.ts";
@@ -486,6 +487,28 @@ export class S3Bucket {
       deleteMarker: resp.headers.get("x-amz-delete-marker") === "true",
     };
   }
+
+  /**
+   * Deletes all objects in the bucket recursively. Returns a list of deleted keys.
+   */
+  async empty(): Promise<string[]> {
+    const deleted: string[] = [];
+    for await (
+      let k of pooledMap(
+        50,
+        this.listAllObjects({ batchSize: 1000 }),
+        async (o) => {
+          if (o.key) {
+            await this.deleteObject(o.key!);
+            return o.key!;
+          }
+        },
+      )
+    ) {
+      deleted.push(k!);
+    }
+    return deleted;
+  }
 }
 
 function encodeURIS3(input: string): string {

src/bucket_test.ts

@@ -221,3 +221,32 @@ Deno.test({
     }
   },
 });
+
+Deno.test({
+  name: "empty bucket",
+  async fn() {
+    // setup
+    const content = encoder.encode("Test1");
+    const keys = [
+      "fooz",
+      "bar",
+      "foo/sub2",
+      "foo/sub3/subsub",
+      "baz",
+      "fruits/blueberry",
+      "fruits/banana",
+      "fruits/strawberry",
+      "fruits/apple",
+      "fruits/orange",
+    ];
+
+    for (let k of keys) {
+      await bucket.putObject(k, content, { contentType: "text/plain" });
+    }
+
+    const deleted = await bucket.empty();
+    deleted.sort();
+    keys.sort();
+    assertEquals(deleted, keys);
+  },
+});