Render mail in the enqueue endpoint

Author: ben-z

apps/mailer/src/enqueue.ts

@@ -1,8 +1,70 @@
 import { Emails } from "@watonomous/watcloud-email-templates";
 import { FissionContext, FissionCallback } from "./utils";
+import { render } from "@react-email/components";
+import { waitForAssets } from "@repo/utils/watcloud-uri";
 
-module.exports = async function ({request, response}: FissionContext, cb: FissionCallback) {
-    response.status(200).json({
-        templates: Object.keys(Emails),
-    });
+// Returns the email template with the given name and performs any necessary initialization.
+async function getTemplate(template_name: string, props_array: any[] = []) {
+    const mod = Emails[template_name];
+    if (!mod) {
+        throw new Error(`Template ${template_name} not found`);
+    }
+    if (mod.init) {
+        await Promise.all(props_array.map(mod.init));
+    }
+    await waitForAssets();
+
+    return mod.default;
+}
+
+module.exports = async function ({ request, response }: FissionContext, cb: FissionCallback) {
+    if (request.method !== "POST") {
+        response.status(405).json({
+            error: "Only POST is supported",
+        });
+        return;
+    }
+
+    const template_name = request.body?.template;
+    if (!template_name) {
+        response.status(400).json({
+            error: "Missing template! Supported templates: " + Object.keys(Emails).join(", "),
+        });
+        return;
+    }
+
+    const props = request.body?.props;
+    if (!props) {
+        response.status(400).json({
+            error: "Missing props",
+        });
+        return;
+    }
+
+    if (!Emails[template_name]) {
+        response.status(400).json({
+            error: `Template "${template_name}" not found! Supported templates: ${Object.keys(Emails).join(",")}`,
+        });
+        return;
+    }
+
+    const template = await getTemplate(template_name, [props]);
+
+    const htmlPromise = render(template(props));
+    const textPromise = render(template(props), { plainText: true });
+
+    try {
+        const payload = {
+            html: await htmlPromise,
+            text: await textPromise,
+        };
+    
+        response.status(200).json(payload);
+    } catch (e) {
+        console.error(e);
+        response.status(500).json({
+            error: "Failed to render email: " + e,
+        });
+        return;
+    }
 }