Mozilla Thunderbird API - read/write email

I am developing an extension for Mozilla Thunderbird to encrypt messages in the inbox.Are there any API calls in Thunderbird for reading from or writing to messages in the inbox?

I was going to encrypt all the messages with AES encryption and then I realised that it would change the size of all the messages because AES uses a block cipher which is a fixed size. This would mean I would have to update the index file separately. Before I reach that level of complexity I would like to be able to write a ceasar ci开发者_如何学Pythonpher.

Any help on Thunderbird email message I/O would be greatly appreciated.

---

You can't write to messages as such. For instance, when editing a draft, Thunderbird simply saves a new draft and deletes the previous one.

To read a message, you normally want to stream it. Unfortunately I can't remember how to save a new message to a folder.