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indicate in wrapper text whether there's an inline attachment or not
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@problame
problame committed Feb 6, 2024
1 parent 37891cb commit 407a42e
Showing 1 changed file with 86 additions and 81 deletions.
167 changes: 86 additions & 81 deletions src/main.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -112,7 +112,84 @@ fn main() {
},
OriginalMessageBody::Error(_) => None,
};
tracing::debug!(could_parse = original_parsed.is_some(), "parsed message");
tracing::debug!(
could_parse = original_parsed.is_some(),
?original_parsed,
"parsed message"
);

// Try to create an inline attachment for the receivers's convenience of not
// having to double-click the attachment.
//
// This is surprisingly tricky, as the message/rfc822 MIME type only allows
// Content-Transfer-Encoding 7bit, 8bit or binary.
// Any other encoding (quoted-printable, base64) will break in
// Gmail and AppleMail, probably elsewhere. The exact kind of breakage depends:
// in AppleMail, only the `From`, `To`, and `Subject`
// headers are shown inline, and the rest of the message is not visible / accessible.
// In Gmail, it always shows as an attachment and one gets an error when clicking on it.
let re_encoded = (|| {
let Some(original_parsed) = &original_parsed else {
debug!("not parseable");
return None;
};
if original_parsed.ctype.mimetype != "text/plain" {
// TODO: implement support.
// Multi-part would be tricky as we'd possible need to use different
// boundaries to avoid collisions with the boundaries that our wrapper
// message will add.
debug!("not text/plain content-type");
return None;
}
let mut builder = SinglePart::builder();
for header in &original_parsed.headers {
#[derive(Clone)]
struct RawHeader(HeaderName, String);
impl lettre::message::header::Header for RawHeader {
fn name() -> HeaderName {
unimplemented!("not needed, we only use display")
}

fn parse(_: &str) -> Result<Self, Box<dyn std::error::Error + Send + Sync>> {
unimplemented!("not needed, we only use display")
}

fn display(&self) -> lettre::message::header::HeaderValue {
HeaderValue::new(self.0.clone(), self.1.clone())
}
}
impl RawHeader {
fn new(hdr: &mailparse::MailHeader) -> Option<Self> {
let header_name =
HeaderName::new_from_ascii(hdr.get_key()).ok().or_else(|| {
debug!(hdr=?hdr.get_key(), "header is not ascii");
None
})?;
let header_value = hdr.get_value_utf8().ok().or_else(|| {
debug!(hdr=?hdr, "header value is not utf-8");
None
})?;
Some(Self(header_name, header_value))
}
}
builder = builder.header(RawHeader::new(header).or_else(|| {
debug!("can't adapt libraries into each other");
None
})?);
}
Some(
builder.body(
Body::new_with_encoding(
original_parsed.get_body().ok().or_else(|| {
debug!("cannot get body");
None
})?,
lettre::message::header::ContentTransferEncoding::Base64,
)
.unwrap(),
),
)
})();

// Put together the wrapper message
let sender = {
Expand Down Expand Up @@ -209,10 +286,14 @@ fn main() {
writeln!(&mut body, "WARNING: could not determine permissions of the config file, they may or may not be too lax: {e}")?;
},
}
writeln!(
&mut body,
"The original message is attached inline to this wrapper message."
)?;
writeln!(&mut body)?;
{
write!(&mut body, "The original message is attached to this wrapper message.")?;
if re_encoded.is_some() {
write!(&mut body, " For convenience, a re-encoded copy is attached inline.")?;
}
writeln!(&mut body)?;
}
writeln!(&mut body)?;
writeln!(&mut body, "Invocation args: {args}")?;
writeln!(&mut body)?;
Expand Down Expand Up @@ -261,83 +342,7 @@ fn main() {
.multipart({
let mut mp_builder = MultiPart::mixed().singlepart(SinglePart::plain(body));

// Try to create an inline attachment for the receivers's convenience of not
// having to double-click the attachment.
//
// This is surprisingly tricky, as the message/rfc822 MIME type only allows
// Content-Transfer-Encoding 7bit, 8bit or binary.
// Any other encoding (quoted-printable, base64) will break in
// Gmail and AppleMail, probably elsewhere. The exact kind of breakage depends:
// in AppleMail, only the `From`, `To`, and `Subject`
// headers are shown inline, and the rest of the message is not visible / accessible.
// In Gmail, it always shows as an attachment and one gets an error when clicking on it.
//
// So, try to re-encode the message body. If that doesn't work, the user can fallback
// to the attachment.
mp_builder = {
let re_encoded = (|| {
let Some(original_parsed) = original_parsed else {
debug!("not parseable");
return None;
};
if original_parsed.ctype.mimetype != "text/plain" {
debug!("not text/plain content-type");
return None;
}
let mut builder = SinglePart::builder();
for header in &original_parsed.headers {
#[derive(Clone)]
struct RawHeader(HeaderName, String);
impl lettre::message::header::Header for RawHeader {
fn name() -> HeaderName {
unimplemented!("not needed, we only use display")
}

fn parse(
_: &str,
) -> Result<Self, Box<dyn std::error::Error + Send + Sync>>
{
unimplemented!("not needed, we only use display")
}

fn display(&self) -> lettre::message::header::HeaderValue {
HeaderValue::new(self.0.clone(), self.1.clone())
}
}
impl RawHeader {
fn new(hdr: &mailparse::MailHeader) -> Option<Self> {
let header_name = HeaderName::new_from_ascii(hdr.get_key())
.ok()
.or_else(|| {
debug!(hdr=?hdr.get_key(), "header is not ascii");
None
})?;
let header_value = hdr.get_value_utf8().ok().or_else(|| {
debug!(hdr=?hdr, "header value is not utf-8");
None
})?;
Some(Self(header_name, header_value))
}
}
builder = builder.header(RawHeader::new(header).or_else(|| {
debug!("can't adapt libraries into each other");
None
})?);
}
Some(
builder.body(
Body::new_with_encoding(
original_parsed.get_body().ok().or_else(|| {
debug!("cannot get body");
None
})?,
lettre::message::header::ContentTransferEncoding::Base64,
)
.unwrap(),
),
)
})();

if let Some(re_encoded) = re_encoded {
mp_builder.singlepart(
SinglePart::builder()
Expand Down

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