Dead letters

app/emailer.js

@@ -17,20 +17,17 @@ module.exports = {
           Promise.reject("smtp not configured.") :
           transporter.verify().then(_ => config.smtp.host || "???");
   },
-  // returns a promise after sending the email and logging the trailing arguments
+  // returns an empty promise after sending the email.
   // see https://nodemailer.com/message/
-  sendMail(email, ...logArgs) {
-    return transporter.sendMail(email).then(info => {
-      const date = dt.getNow().toString();
-      const logMessage = `Sent email ${date}:\n` + JSON.stringify(logArgs, null, " ");
-      console.log(logMessage);
-      return Promise.resolve(true); // don't log to the file for now; conflicts with php/node paths
-      // tbd: would it be better to log to console only, and configure docker with "local"
-      // it does compression, and auto rotation.
-      // https://docs.docker.com/config/containers/logging/configure/
-      // const logFile = config.email.logfile;
-      // return !logFile ? Promise.resolve(true) :
-      //        fsp.writeFile(config.email.logfile, logMessage+"\n", {flag: 'a'});
+  sendMail(email) {
+    return transporter.sendMail(email).then(_ => {
+      return Promise.resolve(true);
     });
+  },
+
+  // returns true if the passed email address was on the block list.
+  isDeadLetter(address) {
+    const parts = (process.env.DEAD_LETTERS || "").split(";").filter(Boolean);
+    return parts.some(p => address.endsWith(p));
   }
 };

app/endpoints/manage_event.js

@@ -135,8 +135,10 @@ function updateEvent(evt, values, statusList) {
 // promises a sent email
 // evt is a CalEvent; dailies is an array of CalDaily.
 function sendConfirmationEmail(evt, dailies) {
+  const isDeadLetter = emailer.isDeadLetter(evt.email);
+
   const url = config.site.url('addevent', `edit-${evt.id}-${evt.password}`);
-  const subject = `Shift2Bikes Secret URL for ${evt.title}`;
+  const subject = !isDeadLetter ? `Shift2Bikes Secret URL for ${evt.title}` : `Shift2Bikes Blocked ${evt.title}`;
   console.debug("sending confirmation for", url);
 
   const dates = dailies
@@ -157,20 +159,25 @@ function sendConfirmationEmail(evt, dailies) {
     help: config.site.helpPage(),
     support: support.address || support, // a string or object
   });
-  console.debug("confirmation email body:\n", body);
   return emailer.sendMail({
     subject,
     text: body,
-    to: {
+    to: !isDeadLetter ? {
       name: evt.name,
       address: evt.email,
-    },
+    } : config.email.moderator,
     from: config.email.sender,
     replyTo: config.email.support,
     bcc: config.email.moderator, // backup copy for debugging and/or moderating
     // html
     // attachments
-  }, evt.name, evt.email, evt.title, url);
+  }).then(_ => {
+    // log after sending:
+    const date = dt.getNow().toString();
+    const header = JSON.stringify([evt.name, evt.email, evt.title, url], null, " ");
+    const logMessage = [date, header, body].join("\n");
+    console.log(!isDeadLetter ? "Sent email" : "** Blocked ** email", logMessage);
+  });
 }
 
 // read json into a javascript object.

app/test/manage_test.js

@@ -26,6 +26,7 @@ const { CalDaily } = require("../models/calDaily");
 const { describe, it, beforeEach, afterEach } = require("node:test");
 const assert = require("node:assert/strict");
 const request = require('supertest');
+const emailer = require("../emailer");
 //
 const manage_api = '/api/manage_event.php';
 
@@ -69,6 +70,17 @@ describe("managing events", () => {
         // console.log(res.body);
       });
   });
+  it("tests dead letters", () => {
+    process.env.DEAD_LETTERS = "example.com";
+    assert.equal(emailer.isDeadLetter("bob@example.com"), true);
+    assert.equal(emailer.isDeadLetter("bob@example.net"), false);
+    assert.equal(emailer.isDeadLetter("bob@example.org"), false);
+    process.env.DEAD_LETTERS = "example.net;.org";
+    assert.equal(emailer.isDeadLetter("bob@example.com"), false);
+    assert.equal(emailer.isDeadLetter("bob@example.net"), true);
+    assert.equal(emailer.isDeadLetter("bob@shifty.org"), true);
+    delete process.env.DEAD_LETTERS;
+  });
   it("fail creation when missing required fields", () => {
     // each time substitute a field value that should fail
     const pairs = [

docker-compose.yml

@@ -75,6 +75,7 @@ services:
         - SMTP_HOST
         - SMTP_USER
         - SMTP_PASS
+        - DEAD_LETTERS
     # by default the node image will run "node"
     # https://github.com/nodejs/docker-node/blob/main/docker-entrypoint.sh
     # override to run npm start; which auto installs from package-lock.json