📫 MIME Meta Language

Rust implementation of the Emacs MIME message Meta Language.

Creating a MIME message is boring and non-trivial. Therefore, a library called mml has been defined that parses a language called MML (MIME Meta Language) and generates MIME messages.

```eml From: alice@localhost To: bob@localhost Subject: MML simple

<#multipart type=alternative> This is a plain text part. <#part type=text/enriched>

This is a centered enriched part <#/multipart> ```

compiles to:

```eml Subject: MML simple To: bob@localhost From: alice@localhost MIME-Version: 1.0 Date: Tue, 29 Nov 2022 13:07:01 +0000 Content-Type: multipart/alternative; boundary="4CV1Cnp7mXkDyvb55i77DcNSkKzB8HJzaIT84qZe"

--4CV1Cnp7mXkDyvb55i77DcNSkKzB8HJzaIT84qZe Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit

This is a plain text part. --4CV1Cnp7mXkDyvb55i77DcNSkKzB8HJzaIT84qZe Content-Type: text/enriched Content-Transfer-Encoding: 7bit

This is a centered enriched part --4CV1Cnp7mXkDyvb55i77DcNSkKzB8HJzaIT84qZe-- ```

Definition

From the Emacs documentation:

The MML language is very simple. It looks a bit like an SGML application, but it’s not.

The main concept of MML is the part. Each part can be of a different type or use a different charset. The way to delineate a part is with a ‘<#part ...>’ tag. Multipart parts can be introduced with the ‘<#multipart ...>’ tag. Parts are ended by the ‘<#/part>’ or ‘<#/multipart>’ tags. Parts started with the ‘<#part ...>’ tags are also closed by the next open tag.

[…]

Each tag can contain zero or more parameters on the form ‘parameter=value’. The values may be enclosed in quotation marks, but that’s not necessary unless the value contains white space. So ‘filename=/home/user/#hello$^yes’ is perfectly valid.

Features

Compile MML message into MIME message using MmlCompiler builder (requires cargo feature compiler activated by default)
Interpret MIME message as MML message using the MimeInterpreter builder (requires cargo feature interpreter activated by default)
Multiple parts support <#multipart>…<#/multipart>
Inline part support <#part text=mime/type>…<#/part>
Attachment support <#part filename=/path/to/attachment.ext>
PGP support (encrypt, decrypt, sign, verify)

Examples

See ./examples:

sh cargo run --example

Development

The development environment is managed by Nix. Running nix-shell will spawn a shell with everything you need to get started with the lib: cargo, cargo-watch, rust-bin, rust-analyzer, notmuch…

```sh

Start a Nix shell

$ nix-shell

then build the lib

$ cargo build -p mml-lib ```

Contributing

If you find a bug that does not exist yet, please send an email at ~soywod/pimalaya@todo.sr.ht.

If you have a question, please send an email at ~soywod/pimalaya@lists.sr.ht.

If you want to propose a feature or fix a bug, please send a patch at ~soywod/pimalaya@lists.sr.ht using git send-email (see this guide on how to configure it).

If you want to subscribe to the mailing list, please send an email at ~soywod/pimalaya+subscribe@lists.sr.ht.

If you want to unsubscribe to the mailing list, please send an email at ~soywod/pimalaya+unsubscribe@lists.sr.ht.

If you want to discuss about the project, feel free to join the Matrix workspace #pimalaya or contact me directly @soywod.

Credits

Special thanks to the nlnet foundation that helped Himalaya to receive financial support from the NGI Assure program of the European Commission in September, 2022.