EML Attactment Issue

[samrocks1011]

What I did: We are using your code to decode the real-time SMTP mail and add footer text at the end of the mail. After necessary changes, we encode the mail again and if the original mail contains eml files(message/rfc822) as an attachment, the eml file is converted in base64 content, which is not supported as per RFC ( https://www.w3.org/Protocols/rfc1341/7_3_Message.html ) . We have found the issue in encode.go file where any attachment is found it was setting the Encoding to base64.

What I expected: We changed the encode.go file on the 89 line. Below is the code.

cte := te7Bit
if len(p.Content) > 0 {
if strings.Contains(p.ContentType, "message") {
cte = 6
} else {
cte = teBase64
}
// cte = teBase64
if p.TextContent() {
cte = selectTransferEncoding(p.Content, false)
if p.Charset == "" {
p.Charset = utf8
}
}
// RFC 2045: 7bit is assumed if CTE header not present.
switch cte {
case teBase64:
p.Header.Set(hnContentEncoding, cteBase64)
case teQuoted:
p.Header.Set(hnContentEncoding, cteQuotedPrintable)
}
}

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What I got:

Release or branch I am using:

(Please attach a sample message if you feel it will help reproduce the issue)