AnalyzePlatypus · May 13, 2020 08:11 · May 13, 2020
diff --git a/lambda-gmail-compose.md b/lambda-gmail-compose.md
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+# Sending email with serverless functions
+
+You can deploy this function on any of the serverless platforms - AWS Lambda, Google Cloud Functions, Azure Functions, Netlify, Cloudflare Workers, etc.
+
+1. Create a new function and paste in the following code. 
+2. You will need to add `nodemailer` to your `package.json` (`npm i nodemailer`), and follow your platform's instructions on bundling dependencies.
+3. Obtain Gmail API credentials for your account. You will need `clientID`, `clientSecret`, and `refreshToken`. Follow [this YouTube tutorial](https://www.youtube.com/watch?v=JJ44WA_eV8E)
+4. Expose these credentials as the follwing environment variables:
+```
+GMAIL_EMAIL_ADDRESS
+GMAIL_API_CLIENT_ID
+GMAIL_API_CLIENT_SECRET
+GMAIL_API_REFRESH_TOKEN
+```
+
+5. Deploy!
+
+
+```js
+  // Docs on event and context https://www.netlify.com/docs/functions/#the-handler-method
+const nodemailer = require("nodemailer");
+
+function createMailClient() {
+  return nodemailer.createTransport({
+    host: "smtp.gmail.com",
+    port: 587,
+    secure: false, // true for 465, false for other ports
+    auth: {
+      type: 'OAuth2',
+      user: process.env.GMAIL_EMAIL_ADDRESS,
+      clientId: process.env.GMAIL_API_CLIENT_ID,
+      clientSecret: process.env.GMAIL_API_CLIENT_SECRET,
+      refreshToken: process.env.GMAIL_API_REFRESH_TOKEN,
+    }
+  });
+}
+
+
+const mailClient = createMailClient();
+
+exports.handler = async (event, context) => {
+  try {
+    const json = JSON.parse(event.body);
+    const gmailResponse = await mailClient.sendMail({
+      from: '"Benedict Arnold" <[email protected]>', // sender address
+      to: "Sir Henry Clinton <[email protected]>", // list of receivers
+      subject: json.subject,
+      text: json.text, // plain text body
+      html: json.html
+    });
+
+    return {
+      statusCode: 200,
+      body: "Message sent!" + gmailResponse.messageId
+    }
+  } catch (err) {
+    return { statusCode: 500, body: err.toString() }
+  }
+}
+```