1 files changed, 100 insertions, 0 deletions
diff --git a/deno/mail-relay/aws/retriever.ts b/deno/mail-relay/aws/retriever.ts
new file mode 100644
index 0000000..756cfc3
--- /dev/null
+++ b/deno/mail-relay/aws/retriever.ts
@@ -0,0 +1,100 @@
+/// <reference types="npm:@types/node" />
+
+import {
+  GetObjectCommand,
+  ListObjectsV2Command,
+  S3Client,
+} from "@aws-sdk/client-s3";
+
+import log from "../log.ts";
+import config from "../config.ts";
+import "../better-js.ts";
+
+import { Mail, MailDeliverer } from "../mail.ts";
+import { AwsContext, s3MoveObject } from "./context.ts";
+
+const AWS_SES_S3_SETUP_TAG = "AMAZON_SES_SETUP_NOTIFICATION";
+
+export class AwsMailRetriever {
+  readonly liveMailPrefix = "mail/live/";
+  readonly archiveMailPrefix = "mail/archive/";
+  readonly mailBucket = config.get("awsMailBucket");
+
+  readonly #s3;
+
+  constructor(
+    aws: AwsContext,
+    public readonly inboundDeliverer: MailDeliverer,
+  ) {
+    this.#s3 = new S3Client(aws);
+  }
+
+  async listLiveMails(): Promise<string[]> {
+    log.info("Begin to retrieve live mails.");
+
+    const listCommand = new ListObjectsV2Command({
+      Bucket: this.mailBucket,
+      Prefix: this.liveMailPrefix,
+    });
+    const res = await this.#s3.send(listCommand);
+
+    if (res.Contents == null) {
+      log.warn("Listing live mails in S3 returns null Content.");
+      return [];
+    }
+
+    const result: string[] = [];
+    for (const object of res.Contents) {
+      if (object.Key == null) {
+        log.warn("Listing live mails in S3 returns an object with no Key.");
+        continue;
+      }
+
+      if (object.Key.endsWith(AWS_SES_S3_SETUP_TAG)) continue;
+
+      result.push(object.Key.slice(this.liveMailPrefix.length));
+    }
+    return result;
+  }
+
+  async deliverS3Mail(s3Key: string, recipients: string[] = []) {
+    log.info(`Begin to deliver s3 mail ${s3Key} to ${recipients.join(" ")}...`);
+
+    log.info(`Fetching s3 mail ${s3Key}...`);
+    const mailPath = `${this.liveMailPrefix}${s3Key}`;
+    const command = new GetObjectCommand({
+      Bucket: this.mailBucket,
+      Key: mailPath,
+    });
+    const res = await this.#s3.send(command);
+
+    if (res.Body == null) {
+      throw new Error("S3 mail returns a null body.");
+    }
+
+    const rawMail = await res.Body.transformToString();
+    log.info(`Done fetching s3 mail ${s3Key}.`);
+
+    log.info(`Delivering s3 mail ${s3Key}...`);
+    const mail = new Mail(rawMail);
+    await this.inboundDeliverer.deliver({ mail, recipients: recipients });
+    log.info(`Done delivering s3 mail ${s3Key}.`);
+
+    const date = mail.startSimpleParse().sections().headers().date();
+    const dateString = date?.toFileNameString(true) ?? "invalid-date";
+    const newPath = `${this.archiveMailPrefix}${dateString}/${s3Key}`;
+
+    log.info(`Archiving s3 mail ${s3Key} to ${newPath}...`);
+    await s3MoveObject(this.#s3, this.mailBucket, mailPath, newPath);
+    log.info(`Done delivering s3 mail ${s3Key}...`);
+  }
+
+  async recycleLiveMails() {
+    log.info("Begin to recycle live mails...");
+    const mails = await this.listLiveMails();
+    log.info(`Found ${mails.length} live mails`);
+    for (const s3Key of mails) {
+      await this.deliverS3Mail(s3Key);
+    }
+  }
+}