Bcc headers are stripped in MailComposer

[danielepolencic]

This issue is related to MailComposer and MimeNode.

With MailComposer I can create an email with a Bcc header like this:

const mailcomposer = new MailComposer({
          to,
          cc,
          bcc: ['email@inbcc.com'],
          html: body,
          subject,
          attachments: [],
        })

However, when the email is built, the Bcc is removed:

const payload = await mailcomposer.compile().build()
console.log(payload.toString('ascii'))
// Bcc header is missing in the output

Digging in the code reveals that the Bcc header is removed by MimeNode unless you set keepBcc: true in the constructor.

nodemailer/lib/mime-node/index.js

Line 33 in efc3947

* @param {Boolean} [options.keepBcc] If true, do not exclude Bcc from the generated headers

Unfortunately, there is no way to pass an argument to MailComposer that cascades to MimeNode (at least from my initial investigation).

I can think about two options to make this work:

1. If the bcc is set in MailComposer, make sure that keepBcc is true in MimeNode.
2. Expose the config for MimeNode in MailComposer.

I don't fully grasp the implications of 2) and I suspect it's not straightforward. If 1) is doable, I can raise a PR along the lines of

in

nodemailer/lib/mail-composer/index.js

Lines 471 to 491 in efc3947

	if (!parentNode) {
	node = new MimeNode(element.contentType, {
	filename: element.filename,
	baseBoundary: this.mail.baseBoundary,
	textEncoding: this.mail.textEncoding,
	boundaryPrefix: this.mail.boundaryPrefix,
	disableUrlAccess: this.mail.disableUrlAccess,
	disableFileAccess: this.mail.disableFileAccess,
	normalizeHeaderKey: this.mail.normalizeHeaderKey,
	newline: this.mail.newline
	});
	} else {
	node = parentNode.createChild(element.contentType, {
	filename: element.filename,
	textEncoding: this.mail.textEncoding,
	disableUrlAccess: this.mail.disableUrlAccess,
	disableFileAccess: this.mail.disableFileAccess,
	normalizeHeaderKey: this.mail.normalizeHeaderKey,
	newline: this.mail.newline
	});
	}

add this one liner:

node = new MimeNode(element.contentType, {
                filename: element.filename,
                baseBoundary: this.mail.baseBoundary,
                textEncoding: this.mail.textEncoding,
                boundaryPrefix: this.mail.boundaryPrefix,
                disableUrlAccess: this.mail.disableUrlAccess,
                disableFileAccess: this.mail.disableFileAccess,
                normalizeHeaderKey: this.mail.normalizeHeaderKey,
                newline: this.mail.newline
                keepBcc: !!this.mail.bcc // <-- this line
            });

I believe the same change has to be extended to the next block too.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[jkozieronek]

I can think about two options to make this work:

1. If the bcc is set in MailComposer, make sure that keepBcc is true in MimeNode.
2. Expose the config for MimeNode in MailComposer.

Option 1 is not backwards compatible.
Option 2 is the correct fix. MainComposer.compile() can take optional MineNode options.

Luckily, compile() returns a MimeNode which has the property keepBcc (it's just not exposed in TS types) so you can set it before calling build. See https://nodemailer.com/extras/mailcomposer/#bcc

var mailOptions = {
   ...
   bcc: 'bcc@example.com'
}

var mail = new MailComposer(mailOptions).compile()
mail.keepBcc = true
mail.build(function(err, message){
    process.stdout.write(message);
});

If using TypeScript, just add // @ts-ignore above the offending line until types are fixed.

[danielepolencic]

I can confirm that the code above fixes it. Thanks!

[gojevicmario]

I had the same issue today, @danielepolencic can you reopen this issue?
The solution above is more of a workaround than an actual solution. I believe this was just an oversight when creating the type definitions and shouldn't be a big deal to fix.

[andris9]

The Bcc field usage has been documented here. I agree that this is counterintuitive and bad API design, but it has worked like this for 10+ years already, and I'm not really up to changing Nodemailer's API anymore.

[AnandChowdhary]

The solution above is more of a workaround than an actual solution. I believe this was just an oversight when creating the type definitions and shouldn't be a big deal to fix.

@andris9 I could be wrong, but I think @gojevicmario meant that the type definition in @types/nodemailer does not allow keepBcc:

[andris9]

@AnandChowdhary the typings for Nodemailer are community-maintained. I have no means to modify these. You would have to connect to the persons maintaining the typings file and ask them to update it.

[AnandChowdhary]

Thank you! I have opened a discussion here: DefinitelyTyped/DefinitelyTyped#69409