.\" Automatically generated by Pod::Man 4.10 (Pod::Simple 3.35) .\" .\" Standard preamble: .\" ======================================================================== .de Sp \" Vertical space (when we can't use .PP) .if t .sp .5v .if n .sp .. .de Vb \" Begin verbatim text .ft CW .nf .ne \\$1 .. .de Ve \" End verbatim text .ft R .fi .. .\" Set up some character translations and predefined strings. \*(-- will .\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left .\" double quote, and \*(R" will give a right double quote. \*(C+ will .\" give a nicer C++. Capital omega is used to do unbreakable dashes and .\" therefore won't be available. \*(C` and \*(C' expand to `' in nroff, .\" nothing in troff, for use with C<>. .tr \(*W- .ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p' .ie n \{\ . ds -- \(*W- . ds PI pi . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch . ds L" "" . ds R" "" . ds C` "" . ds C' "" 'br\} .el\{\ . ds -- \|\(em\| . ds PI \(*p . ds L" `` . ds R" '' . ds C` . ds C' 'br\} .\" .\" Escape single quotes in literal strings from groff's Unicode transform. .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" .\" If the F register is >0, we'll generate index entries on stderr for .\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index .\" entries marked with X<> in POD. Of course, you'll have to process the .\" output yourself in some meaningful fashion. .\" .\" Avoid warning from groff about undefined register 'F'. .de IX .. .nr rF 0 .if \n(.g .if rF .nr rF 1 .if (\n(rF:(\n(.g==0)) \{\ . if \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{\ . nr % 0 . nr F 2 . \} . \} .\} .rr rF .\" ======================================================================== .\" .IX Title "Encode::MIME::Header 3perl" .TH Encode::MIME::Header 3perl "2020-07-21" "perl v5.28.1" "Perl Programmers Reference Guide" .\" For nroff, turn off justification. Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH "NAME" Encode::MIME::Header \-\- MIME encoding for an unstructured email header .SH "SYNOPSIS" .IX Header "SYNOPSIS" .Vb 1 \& use Encode qw(encode decode); \& \& my $mime_str = encode("MIME\-Header", "Sample:Text \eN{U+263A}"); \& # $mime_str is "=?UTF\-8?B?U2FtcGxlOlRleHQg4pi6?=" \& \& my $mime_q_str = encode("MIME\-Q", "Sample:Text \eN{U+263A}"); \& # $mime_q_str is "=?UTF\-8?Q?Sample=3AText_=E2=98=BA?=" \& \& my $str = decode("MIME\-Header", \& "=?ISO\-8859\-1?B?SWYgeW91IGNhbiByZWFkIHRoaXMgeW8=?=\er\en " . \& "=?ISO\-8859\-2?B?dSB1bmRlcnN0YW5kIHRoZSBleGFtcGxlLg==?=" \& ); \& # $str is "If you can read this you understand the example." \& \& use Encode qw(decode :fallbacks); \& use Encode::MIME::Header; \& local $Encode::MIME::Header::STRICT_DECODE = 1; \& my $strict_string = decode("MIME\-Header", $mime_string, FB_CROAK); \& # use strict decoding and croak on errors .Ve .SH "ABSTRACT" .IX Header "ABSTRACT" This module implements \s-1RFC 2047\s0 \s-1MIME\s0 encoding for an unstructured field body of the email header. It can also be used for \s-1RFC 822\s0 'text' token. However, it cannot be used directly for the whole header with the field name or for the structured header fields like From, To, Cc, Message-Id, etc... There are 3 encoding names supported by this module: \f(CW\*(C`MIME\-Header\*(C'\fR, \f(CW\*(C`MIME\-B\*(C'\fR and \&\f(CW\*(C`MIME\-Q\*(C'\fR. .SH "DESCRIPTION" .IX Header "DESCRIPTION" Decode method takes an unstructured field body of the email header (or \&\s-1RFC 822\s0 'text' token) as its input and decodes each \s-1MIME\s0 encoded-word from input string to a sequence of bytes according to \s-1RFC 2047\s0 and \&\s-1RFC 2231\s0 . Subsequently, each sequence of bytes with the corresponding \s-1MIME\s0 charset is decoded with the Encode module and finally, one output string is returned. Text parts of the input string which do not contain \s-1MIME\s0 encoded-word stay unmodified in the output string. Folded newlines between two consecutive \s-1MIME\s0 encoded-words are discarded, others are preserved in the output string. \&\f(CW\*(C`MIME\-B\*(C'\fR can decode Base64 variant, \f(CW\*(C`MIME\-Q\*(C'\fR can decode Quoted-Printable variant and \f(CW\*(C`MIME\-Header\*(C'\fR can decode both of them. If Encode module does not support particular \s-1MIME\s0 charset or chosen variant then an action based on \s-1CHECK\s0 flags is performed (by default, the \&\s-1MIME\s0 encoded-word is not decoded). .PP Encode method takes a scalar string as its input and uses strict \s-1UTF\-8\s0 encoder for encoding it to \s-1UTF\-8\s0 bytes. Then a sequence of \s-1UTF\-8\s0 bytes is encoded into \s-1MIME\s0 encoded-words (\f(CW\*(C`MIME\-Header\*(C'\fR and \f(CW\*(C`MIME\-B\*(C'\fR use a Base64 variant while \f(CW\*(C`MIME\-Q\*(C'\fR uses a Quoted-Printable variant) where each \s-1MIME\s0 encoded-word is limited to 75 characters. \s-1MIME\s0 encoded-words are separated by \f(CW\*(C`CRLF SPACE\*(C'\fR and joined to one output string. Output string is suitable for unstructured field body of the email header. .PP Both encode and decode methods propagate \&\s-1CHECK\s0 flags when encoding and decoding the \&\s-1MIME\s0 charset. .SH "BUGS" .IX Header "BUGS" Versions prior to 2.22 (part of Encode 2.83) have a malfunctioning decoder and encoder. The \s-1MIME\s0 encoder infamously inserted additional spaces or discarded white spaces between consecutive \s-1MIME\s0 encoded-words, which led to invalid \s-1MIME\s0 headers produced by this module. The \s-1MIME\s0 decoder had a tendency to discard white spaces, incorrectly interpret data or attempt to decode Base64 \&\s-1MIME\s0 encoded-words as Quoted-Printable. These problems were fixed in version 2.22. It is highly recommended not to use any version prior 2.22! .PP Versions prior to 2.24 (part of Encode 2.87) ignored \&\s-1CHECK\s0 flags. The \s-1MIME\s0 encoder used not strict utf8 encoder for input Unicode strings which could lead to invalid \s-1UTF\-8\s0 sequences. \s-1MIME\s0 decoder used also not strict utf8 decoder and additionally called the decode method with a \f(CW\*(C`Encode::FB_PERLQQ\*(C'\fR flag (thus user-specified \&\s-1CHECK\s0 flags were ignored). Moreover, it automatically croaked when a \s-1MIME\s0 encoded-word contained unknown encoding. Since version 2.24, this module uses strict \s-1UTF\-8\s0 encoder and decoder. And \&\s-1CHECK\s0 flags are correctly propagated. .PP Since version 2.22 (part of Encode 2.83), the \s-1MIME\s0 encoder should be fully compliant to \s-1RFC 2047\s0 and \&\s-1RFC 2231\s0 . Due to the aforementioned bugs in previous versions of the \s-1MIME\s0 encoder, there is a \fIless strict\fR compatible mode for the \s-1MIME\s0 decoder which is used by default. It should be able to decode \s-1MIME\s0 encoded-words encoded by pre 2.22 versions of this module. However, note that this is not correct according to \&\s-1RFC 2047\s0 . .PP In default \fInot strict\fR mode the \s-1MIME\s0 decoder attempts to decode every substring which looks like a \s-1MIME\s0 encoded-word. Therefore, the \s-1MIME\s0 encoded-words do not need to be separated by white space. To enforce a correct \fIstrict\fR mode, set variable \f(CW$Encode::MIME::Header::STRICT_DECODE\fR to 1 e.g. by localizing: .PP .Vb 2 \& use Encode::MIME::Header; \& local $Encode::MIME::Header::STRICT_DECODE = 1; .Ve .SH "AUTHORS" .IX Header "AUTHORS" Pali .SH "SEE ALSO" .IX Header "SEE ALSO" Encode, \&\s-1RFC 822\s0 , \&\s-1RFC 2047\s0 , \&\s-1RFC 2231\s0