I’m revamping the inner workings of a mail sending tool to use commons-email. I wanted to make sure I set the text body parts to the appropriate transfer encoding to allow for non-ASCII languages to be used. My failed attempts and final success are documented below.
1. [bad] Set Message ‘Content-transfer-encoding’
The problem with this is that everything in the message is processed as “quoted-printable” which will turn your multipart boundaries into useless wastes of text.
// this chews up your multipart boundary
HtmlEmail email = new HtmlEmail();
email.addHeader("Content-transfer-encoding", "quoted-printable");
So rather than having this in your raw email (note reported and actual boundary match):
Content-Type: multipart/alternative;
boundary="----=_Part_7_1164835397.1283397465477"
------=_Part_7_1164835397.1283397465477
Content-Type: text/plain; charset=UTF-8
You end up with this in your raw email (note: actual boundary has = replaced by =3D):
Content-Type: multipart/alternative;
boundary="----=_Part_7_1164835397.1283397465477"
----=3D_Part_7_1164835397.1283397465477
Content-Type: text/plain; charset=UTF-8
2. [useless] Setting Each Body Part’s transfer encoding
I’ll save you the pain. This begins to turn commons-email back into javamail. It saves you nothing, adds lots of code, doesn’t really work and, given the next solution, is the wrong approach.
3. [Best!] Let commons-email do it’s job
The solution I ended up with is to just let commons-email figure it out. My test text is “You get that thing I sent you?\n3x6=18\nåæÆД. This has several non-ASCII characters that are just ripe for conversion. The raw bit of email I find is:
------=_Part_4_644193719.1283397465436
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable
You get that thing I sent you?
3x6=3D18
=C3=A5=C3=A6=C3=86=C3=90
The content-transfer-encoding is set as I expected and the content has been properly escaped. Kudus to the commons-email team for making this just happen.
Carlibrated 