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emersion / go-message

✉️ A streaming Go library for the Internet Message Format and mail messages
MIT License
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Add extended charset support for writing #166

Closed jtb6 closed 1 year ago

jtb6 commented 1 year ago

Adds a CharsetWriter func to mirror CharsetReader, but for writing. The main use case for this (that prompted me to make this PR) is the ability to use Entity's WriteTo func for all messages that the library already supports for reading.

The existing write behavior for utf-8 and us-ascii is persisted; this primarily just adds support for other charsets.

emersion commented 1 year ago

This feature has been rejected in the past.

Why would one want to use anything other than UTF-8 when writing messages?

jtb6 commented 1 year ago

@emersion For Latin languages, I agree that UTF-8 feels like it's a strictly better choice, and has almost universal adoption. Globally, there are some other encodings that have a decent amount of use (i.e. GB18030 for Chinese, Shift JIS & EUC-JP for Japanese, etc.). I agree that UTF-8 is equally a good choice for representing those languages, but I feel like the consumer of the library should be welcome to opt in to whatever charset they might want to use (or need to use, if integrating with a legacy system).

Again, I agree with you that UTF-8 is probably the best choice if I'm choosing to craft and send an email. My argument for this change is that we let the developer using the library make that choice, since we can't assume that UTF-8 always meets the needs of their project. (In particular, I am such a developer trying to support crafting emails of various charsets, which is not possible without this change)

emersion commented 1 year ago

That doesn't seem like a compelling explanation to me, sorry.