HTML support in Mail

[vercu]

It would be nice if mail could show html formated emails.

I searched trac but couldn't find an existing ticket.

[grexe]

I would strongly support this feature request. We can discuss and question the usefulness of HTML, the dangers, bloat, etc., but HTML is widely used in newsletters, blog posts and the like, and reading the text version of these feels quite archaic.

To be fair, you can simply click on the HTML attachment usually included at the bottom of an HTML mail message, but this is a bit cumbersome to use and average users won't necessarily do this.

Since WebPositive is now able to render a lot of web sites quite well and is a native application, we could just add a WebPositive replicant inside the mail window and be done, showing off another of Haiku's cool special features.

This should be configurable though, maybe even on a sender and account basis.

[grexe]

I've started on a fresh port of liblitehtml and can already handle most HTML, esp. simple HTML as encountered in HTML mails, there's even a separate spec for that.

Once liblitehtml is stable, I have a tech design for how to control loading of remote resources, so to keep users safe from tracking, scam and other online threats:

Similar to mail daemon, which uses customizable Queries and presents them in the deskbar menu, we can define a Query for "safe contacts", either specific like "META:group == friends", or more general like just TYPE==application/x-person to match all contacts.

Only WHEN this query is satisifed, and optionally HTML mail is enabled in the settings, and the View mode is set to HTML (extending the View menu), THEN we will render the HTML attachment.

HTML mail has a special ContentType and boundary, so we know if it is just a general attachment or if it is the HTML representation of the mail message (see [1]):

using the Content-Type: multipart/alternative, as specified in RFC 1521

and:

The message itself is of type multipart/alternative, and contains two parts, the first of type text/plain, which is read by text-only clients, and the second with text/html, which is read by HTML-capable clients.

Refs: [1] ​https://en.wikipedia.org/wiki/HTML_email