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NAME

Mail::Message::Field::Full - one line of a message header

INHERITANCE

 Mail::Message::Field::Full
   is a Mail::Message::Field
   is a Mail::Reporter

 Mail::Message::Field::Full is extended by
   Mail::Message::Field::Addresses
   Mail::Message::Field::Unstructured

SYNOPSIS

 !! UNDER CONSTRUCTION !!
 !! THE DETAILS OF THIS MODULE ARE NOT FINISHED YET!!

 # Getting to understand the complexity of a header field ...

 my $fast = $msg->head->get('subject');
 my $full = Mail::Message::Field::Full->from($fast);

 my $full = $msg->head->get('subject')->study;  # same
 my $full = $msg->head->study('subject');       # same
 my $full = $msg->get('subject');               # same

 # ... or build a complex header field yourself

 my @encode = (charset => 'jp', use_continuations => 1);

 my $f = Mail::Message::Field::Full
            ->new('Content-Type' => 'text/html');
 $f->addExtra(" and more", @encode);

 $f->addPhrase("text ", @encode);
 $f->addPhrase(" and more text", language => 'en-GB' );

 $f->addAttribute('filename=passwd');
 $f->addAttribute(filename => 'passwd', @encode);

 my $attr = Mail::Message::Field::Attribute->new(...);
 $f->addAttribute($attr);

 $f->addComment('just me', $encode);

DESCRIPTION

This is the full implementation of a header field: it will be quite slow, because header fields can be very complex. Of course, this class delivers the optimal result, but for a quite large penalty in performance and memory consumption.

This class supports the common header description from RFC2822 (formerly RFC822), the extensions with respect to character-set encodings as specified in RFC2047, and the extensions on language specification and long parameter wrapping from RFC2231. If you do not need the latter two, then the Mail::Message::Field::Fast and Mail::Message::Field::Flex are enough for your application.

Header fields

Folding

Performance consideration

OVERLOADED

overload: ""

overload: +0

overload: <=>

overload: bool

overload: cmp

METHODS

Constructors

$obj->clone

Mail::Message::Field::Full->from(FIELD, OPTIONS)

    Convert any FIELD (a Mail::Message::Field object) into a new Mail::Message::Field::Full object. This conversion is done the hard way: the string which is produced by the original object is parsed again. Usually, the string which is parsed is exactly the line (or lines) as found in the original input source, which is a good thing because Full fields are much more carefull with the actual content.

    OPTIONS are passed to the constructor (see new()). In any case, some extensions of this Full field class is returned. It depends on which field is created what kind of class we get.

    Example:

     my $fast = $msg->head->get('subject');
     my $full = Mail::Message::Field::Full->from($fast);
    
     my $full = $msg->head->get('subject')->study;  # same
     my $full = $msg->head->study('subject');       # same
     my $full = $msg->get('subject');               # same

Mail::Message::Field::Full->new(DATA)

    Creating a new field object the correct way is a lot of work, because there is so much freedom in the RFCs, but at the same time so many restrictions. Most fields are implemented, but if you have your own field (and do no want to contribute it to Mail::Box), then simply call new on your own package.

    You have the choice to instantiate the object as string or in prepared parts:

    • new LINE

      Pass a LINE as it could be found in a file: a (possibly folded) line which is terminated by a new-line.

    • new NAME, BODY, [ATTRIBUTES], OPTIONS

      A set of values which shape the line.

    The NAME is a wellformed header name (you may use wellformedName()) to be sure about the casing. The BODY is a string, one object, or an ref-array of objects. In case of objects, they must fit to the constructor of the field: the types which are accepted may differ. The optional ATTRIBUTE list contains Mail::Message::Field::Attribute objects. Finally, there are some OPTIONS.

     Option         Defined in       Default      
     attributes                      C<[]>        
     charset                         undef        
     encoding                        C<'q'>       
     extra                           undef        
     force                           false        
     is_structured                   C<depends>   
     language                        undef        
     log            L<Mail::Reporter>  C<'WARNINGS'>
     trace          L<Mail::Reporter>  C<'WARNINGS'>

    . attributes ATTRS

      There are various ways to specify these attributes: pass a reference to an array which list of key-value pairs representing attributes, or reference to a hash containing these pairs, or an array with Mail::Message::Field::Attribute objects.

    . charset STRING

      The body is specified in utf8, and must become 7-bits ascii to be transmited. Specify a charset to which the multi-byte utf8 is converted before it gets encoded. See encode(), which does the job.

    . encoding 'q'|'Q'|'b'|'B'

      Non-ascii characters are encoded using Quoted-Printable ('q' or 'Q') or Base64 ('b' or 'B') encoding.

    . extra STRING

      Text which is appended after the line (preceded by a semicolon).

    . force BOOLEAN

      Enforce encoding in the specified charset, even when it is not needed because the body does not contain any non-ascii characters.

    . is_structured BOOLEAN

      If the name of the field is known, than the internals know whether the field is structured or not. If you call the constructor on your own class which is derived from Mail::Message::Field::Full, the default is true. If you have no own implementation for an unknown field, the boolean is considered false.

      For fields which are not known, true means that a Mail::Message::Field::Structured will be created. The false value will create a Mail::Message::Field::Unstructured.

    . language STRING

      The language used can be specified, however is rarely used my mail clients.

    . log LEVEL

    . trace LEVEL

    Example:

     my $s = Mail::Message::Field::Full->new('Subject: Hello World');
     my $s = Mail::Message::Field::Full->new('Subject', 'Hello World');
    
     my @attrs   = (Mail::Message::Field::Attribute->new(...), ...);
     my @options = (extra => 'the color blue');
     my $t = Mail::Message::Field::Full->new(To => \@addrs, @attrs, @options);

The field

$obj->isStructured

Mail::Message::Field::Full->isStructured

$obj->length

$obj->nrLines

$obj->print([FILEHANDLE])

$obj->size

$obj->string([WRAP])

$obj->toDisclose

Access to the name

$obj->Name

$obj->name

$obj->wellformedName([STRING])

Access to the body

$obj->body

$obj->decodedBody(OPTIONS)

    Returns the unfolded body of the field, where encodings are resolved. The returned line will still contain comments and such. The OPTIONS are passed to the decoder, see decode().

    BE WARNED: if the field is a structured field, the content may change syntax, because of encapsulated special characters. By default, the body is decoded as text, which results in a small difference within comments as well (read the RFC).

$obj->folded

$obj->foldedBody([BODY])

$obj->stripCFWS([STRING])

Mail::Message::Field::Full->stripCFWS([STRING])

$obj->unfoldedBody([BODY, [WRAP]])

Access to the content

$obj->addAttribute(OBJECT|(STRING, OPTIONS)|(NAME,VALUE,OPTIONS))

    Add an attribute to the field. The attributes are added left-to-right into the string representation of the field, although the order of the attributes is un-important, according to the RFCs.

    You may pass a fully prepared Mail::Message::Field::Attribute OBJECT, if you like to do all preparations for correct representation of the data yourself. You may also pass one STRING, which is a fully prepared attribute. This STRING will not be changed, so be careful about quoting and encodings.

    As third possibility, you can specify an attribute NAME and its VALUE. An attribute object will be created for you implicitly in both cases where such object is not supplied, passing the OPTIONS. See Mail::Message::Field::Attribute::new() about the available OPTIONS.

    The attribute object is returned, however, when continuations are used this may be an object you already know about. undef is returned when construction fails (when the attribute is incorrect).

    Example:

     $f->addAttribute('filename=passwd');
     $f->addAttribute(filename => 'passwd', use_continuations => 0);
     my $attr = Mail::Message::Field::Attribute->new(...);
     $f->addAttribute($attr);

$obj->addComment(COMMENT, OPTIONS)

    Creates a comment (see createComment()) and adds it immediately to this field. Empty or undefined COMMENTs are ignored. The created comment is returned.

$obj->addExtra(STRING)

    Adds a string to the line, which is not an attribute however does start with a semi-colon. Empty or undefined STRINGs are ignored.

$obj->addPhrase(STRING, OPTIONS)

    Create a phrase (see createPhrase()) and immediately add it to this field. Empty or undefined values of STRING are ignored. The created phrase is returned.

$obj->addresses

$obj->attribute(NAME [, VALUE])

$obj->attributes

    Returns a list with all attributes, which are all Mail::Message::Field::Attribute objects. The attributes are not ordered in any way. The list may be empty. Double attributes or continuations are folded into one.

$obj->comment([STRING])

$obj->createComment(STRING, OPTIONS)

Mail::Message::Field::Full->createComment(STRING, OPTIONS)

    Create a comment to become part in a field. Comments are automatically included within parenthesis. Matching pairs of parenthesis are permitted within the STRING. When a non-matching parenthesis are used, it is only permitted with an escape (a backslash) in front of them. These backslashes will be added automatically if needed (don't worry!). Backslashes will stay, except at the end, where it will be doubled.

    The OPTIONS are charset, language, and encoding as always. See addComment(). The created comment is returned.

$obj->createPhrase(STRING, OPTIONS)

Mail::Message::Field::Full->createPhrase(STRING, OPTIONS)

    A phrase is a text which plays a well defined role. This is the main difference with comments, which have do specified meaning. Some special characters in the phrase will cause it to be surrounded with double quotes: do not specify them yourself.

    The OPTIONS are charset, language, and encoding as always. See addPhrase().

$obj->toDate([TIME])

Mail::Message::Field::Full->toDate([TIME])

$obj->toInt

Other methods

$obj->dateToTimestamp(STRING)

Mail::Message::Field::Full->dateToTimestamp(STRING)

Internals

$obj->consume(LINE | (NAME,BODY|OBJECTS))

$obj->consumeComment(STRING)

Mail::Message::Field::Full->consumeComment(STRING)

    Try to read a comment from the STRING. When successful, the comment without encapsulation parenthesis is returned, together with the rest of the string.

$obj->consumeDotAtom(STRING)

    Returns three elemens: the atom-text, the rest string, and the concatenated comments. Both atom and comments can be undef.

$obj->consumePhrase(STRING)

Mail::Message::Field::Full->consumePhrase(STRING)

    Take the STRING, and try to strip-off a valid phrase. In the obsolete phrase syntax, any sequence of words is accepted as phrase (as long as certain special characters are not used). RFC2882 is stricter: only one word or a quoted string is allowed. As always, the obsolete syntax is accepted, and the new syntax is produced.

    This method returns two elements: the phrase (or undef) followed by the resulting string. The phrase will be removed from the optional quotes. Be warned that "" will return an empty, valid phrase.

    Example:

     my ($phrase, $rest) = $field->consumePhrase( q["hi!" <sales@example.com>] );

$obj->decode(STRING, OPTIONS)

Mail::Message::Field::Full->decode(STRING, OPTIONS)

    Decode field encoded STRING to an utf8 string. The input STRING is part of a header field, and as such, may contain encoded words in =?...?.?...?= format defined by RFC2047. The STRING may contain multiple encoded parts, maybe using different character sets.

    Be warned: you MUST first interpret the field into parts, like phrases and comments, and then decode each part separately, otherwise the decoded text may interfere with your markup characters.

    Be warned: language information, which is defined in RFC2231, is ignored.

     Option   Defined in  Default
     is_text              C<1>   

    . is_text BOOLEAN

      Encoding on text is slightly more complicated than encoding structured data, because it contains blanks. Visible blanks have to be ignored between two encoded words in the text, but not when an encoded word follows or preceeds an unencoded word. Phrases and comments are texts.

    Example:

     print Mail::Message::Field::Full->decode('=?iso-8859-1?Q?J=F8rgen?=');
        # prints   JE<0slash>rgen

$obj->defaultWrapLength([LENGTH])

$obj->encode(STRING, OPTIONS)

    Encode the (possibly utf8 encoded) STRING to a string which is acceptable to the RFC2047 definition of a header: only containing us-ascii characters.

     Option    Defined in       Default      
     charset                    C<'us-ascii'>
     encoding                   C<'q'>       
     force                      <flase>      
     language                   undef        

    . charset STRING

      STRING is an utf8 string which has to be translated into any byte-wise character set for transport, because MIME-headers can only contain ascii characters.

    . encoding 'q'|'Q'|'b'|'B'

      The character encoding to be used. With q or Q, quoted-printable encoding will be used. With b or B , base64 encoding will be taken.

    . force BOOLEAN

      Encode the string, even when it only contains us-ascii characters. By default, this is off because it decreases readibility of the produced header fields.

    . language STRING

      RFC2231 defines how to specify language encodings in encoded words. The STRING is a strandard iso language name.

$obj->fold(NAME, BODY, [MAXCHARS])

$obj->setWrapLength([LENGTH])

$obj->unfold(STRING)

Error handling

$obj->AUTOLOAD

$obj->defaultTrace([LEVEL, [LEVEL])

Mail::Message::Field::Full->defaultTrace([LEVEL, [LEVEL])

$obj->errors

$obj->log([LEVEL [,STRINGS]])

Mail::Message::Field::Full->log([LEVEL [,STRINGS]])

$obj->logPriority(LEVEL)

Mail::Message::Field::Full->logPriority(LEVEL)

$obj->logSettings

$obj->notImplemented

$obj->report([LEVEL])

$obj->reportAll([LEVEL])

$obj->trace([LEVEL])

$obj->warnings

Cleanup

$obj->DESTROY

$obj->inGlobalDestruction

DIAGNOSTICS

Error: Attributes cannot be added to unstructured fields

Unstructured fields are free format, attributes are not. So: it is not correct to try adding these well-defined strings to an unknown text.

Error: Comments cannot be added to unstructured fields

Unstructured fields are free format, comments are not. So: it is not correct to try adding these well-defined strings to an unknown text.

Error: Extras cannot be added to unstructured fields

Unstructured fields are free format, extras are not. Although an extra is a nearly free format piece of text preceded by a semi-colon, they do (by definition) not interfere with other structured data in fields. So: it is not correct to try adding these to an fully free formatted text because you are never sure the data can be regained correctly.

Warning: Field content is not numerical: $content

The numeric value of a field is requested (for instance the Lines or Content-Length fields should be numerical), however the data contains weird characters.

Warning: Illegal character in charset '$charset'

The field is created with an utf8 string which only contains data from the specified character set. However, that character set can never be a valid name because it contains characters which are not permitted.

Warning: Illegal character in field name $name

A new field is being created which does contain characters not permitted by the RFCs. Using this field in messages may break other e-mail clients or transfer agents, and therefore mutulate or extinguish your message.

Warning: Illegal character in language '$lang'

The field is created with data which is specified to be in a certain language, however, the name of the language cannot be valid: it contains characters which are not permitted by the RFCs.

Warning: Illegal encoding '$encoding', used 'q'

The RFCs only permit base64 (b or B ) or quoted-printable (q or Q) encoding. Other than these four options are illegal.

Error: Package $package does not implement $method.

Fatal error: the specific package (or one of its superclasses) does not implement this method where it should. This message means that some other related classes do implement this method however the class at hand does not. Probably you should investigate this and probably inform the author of the package.

REFERENCES

See the Mail::Box website at http://perl.overmeer.net/mailbox/ for more details.

COPYRIGHTS

Module version 2.041. Written by Mark Overmeer (mark@overmeer.net). See the ChangeLog for other contributors.

Copyright (c) 2001-2003 by the author(s). All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.