feat: email client prototype

backend/mail-plugin/src/cli.ts

@@ -0,0 +1,123 @@
+import {config} from 'dotenv';
+import {ImapFlow} from 'imapflow';
+import express from 'express';
+
+config({path: '.env.local'});
+
+const app = express();
+const port = process.env.PORT || 4000;
+
+app.use(async (request, response, next) => {
+  try {
+    const [user, pass] = Buffer.from(request.headers['authorization']!.replace(/^Basic /, ''), 'base64')
+      .toString('utf8')
+      .split(':');
+
+    const client = new ImapFlow({
+      host: 'imap.server.uni-frankfurt.de',
+      port: 993,
+      secure: true,
+      emitLogs: false,
+      auth: {user, pass},
+    });
+    response.locals.client = client;
+
+    await client.connect();
+    response.on('finish', async () => {
+      await client.logout();
+      client.close();
+    });
+
+    next();
+  } catch {
+    response.status(401).send();
+  }
+});
+
+app.get('/', async (_request, response) => {
+  const result = await response.locals.client.listTree();
+  response.json(result);
+});
+
+app.get('/:mailbox', async (request, response) => {
+  try {
+    await response.locals.client.mailboxOpen(request.params.mailbox);
+    const since = Number(request.query.since) || undefined;
+    const preData = await response.locals.client.status(request.params.mailbox, {messages: true});
+    if (preData.messages === 0) {
+      response.json([]);
+      return;
+    }
+
+    const data = response.locals.client.fetch(
+      '1:*',
+      {},
+      {
+        // caution, BigInt can throw
+        changedSince: typeof since === 'string' ? BigInt(since) : undefined,
+      },
+    );
+
+    const messages = [];
+    for await (const message of data) {
+      messages.push(message.seq.toString());
+    }
+    response.json(messages);
+  } catch (error) {
+    console.error(error);
+    response.status(404).send();
+  }
+});
+
+app.get('/:mailbox/:id', async (request, response) => {
+  try {
+    await response.locals.client.mailboxOpen(request.params.mailbox);
+    const message = await response.locals.client.fetchOne(request.params.id, {
+      envelope: true,
+      labels: true,
+      flags: true,
+      bodyStructure: true,
+    });
+    response.json({
+      bodyStructure: message.bodyStructure,
+      labels: [...(message.labels ?? [])],
+      flags: [...(message.flags ?? [])],
+      envelope: message.envelope,
+      seq: message.seq,
+    });
+  } catch (error) {
+    console.error(error);
+    response.status(404).send();
+  }
+});
+
+app.get('/:mailbox/:id/:part', async (request, response) => {
+  try {
+    await response.locals.client.mailboxOpen(request.params.mailbox, {readOnly: true});
+    if (request.query.raw) {
+      const message = await response.locals.client.fetchOne(request.params.id, {
+        bodyParts: [`${request.params.part}.mime`, request.params.part],
+      });
+
+      response.write(message.bodyParts.get(`${request.params.part}.mime`));
+      response.write(message.bodyParts.get(request.params.part));
+
+      response.end();
+    } else {
+      const message = await response.locals.client.download(request.params.id, request.params.part);
+      message.content.on('data', chunk => {
+        response.write(chunk);
+      });
+      message.content.on('end', () => {
+        response.end();
+      });
+    }
+  } catch (error) {
+    console.error(error);
+    response.status(404).send();
+  }
+});
+
+app.listen(port, () => {
+  console.log(`Server listening on port ${port}`);
+});