Ubuntu Manpage: Mail::SPF::Mod - SPF record modifier base class

Provided by: libmail-spf-perl_3.20240206-1_all

NAME

       Mail::SPF::Mod - SPF record modifier base class

DESCRIPTION

       An object of class Mail::SPF::Mod represents a modifier within an SPF record.  Mail::SPF::Mod cannot be
       instantiated directly.  Create an instance of a concrete sub-class instead.

   Constructors
       The following constructors are provided:

       new(%options): returns Mail::SPF::Mod
           Abstract.  Creates a new SPF record modifier object.

           %options is a list of key/value pairs representing any of the following options:

           text
               A string denoting the unparsed text of the modifier.

           name
               A  string  denoting  the  name  of the modifier.  Required if a generic Mail::SPF::Mod object (as
               opposed to a specific sub-class) is being constructed.

           domain_spec
               Either a plain string or a  Mail::SPF::MacroString  object  denoting  an  optional  "domain-spec"
               parameter of the mechanism.

       new_from_string($text, %options): returns Mail::SPF::Mod; throws Mail::SPF::ENothingToParse,
       Mail::SPF::EInvalidMod
           Abstract.  Creates a new SPF record modifier object by parsing the string and any options given.

   Class methods
       The following class methods are provided:

       name_pattern: returns Regexp
           Returns a regular expression that matches any legal modifier name.

   Instance methods
       The following instance methods are provided:

       text: returns string; throws Mail::SPF::ENoUnparsedText
           Returns  the  unparsed  text  of  the modifier.  Throws a Mail::SPF::ENoUnparsedText exception if the
           modifier was created synthetically instead of being parsed, and no text was provided.

       name: returns string
           Returns the name of the modifier.

       params: returns string
           Abstract.  Returns the modifier's parameters formatted as a string.

           A sub-class of Mail::SPF::Mod does not have to implement this method if it  supports  no  parameters,
           although this is highly unlikely.

       stringify: returns string
           Formats  the  modifier's  name  and  parameters  as  a  string  and returns it.  You can simply use a
           Mail::SPF::Mod object as a string for the same effect, see "OVERLOADING".

       process: throws Mail::SPF::Result, Mail::SPF::Result::Error, Mail::SPF::Exception
           Abstract.  Processes the modifier.  What that means depends on  the  actual  implementation  in  sub-
           classes.  See "MODIFIER TYPES" below.

           This method is abstract and must be implemented by sub-classes of Mail::SPF::Mod.

MODIFIER TYPES

There are different basic types of modifiers, which are described below. All of them are provided by the
Mail::SPF::Mod module.

Global modifiers - Mail::SPF::GlobalMod
SPFv1 (RFC 4408) only knows "global" modifiers. A global modifier may appear anywhere in an SPF record,
but only once. During evaluation of the record, global modifiers are processed after the last mechanism
has been evaluated and an SPF result has been determined.

The following additional class method is provided by Mail::SPF::GlobalMod:

precedence: returns real
Abstract. Returns a real number between 0 and 1 denoting the precedence of the type of the global
modifier. Global modifiers present in an SPF record are processed in the order of their precedence
values, 0 meaning "first".

This method is abstract and must be implemented by sub-classes of Mail::SPF::GlobalMod.

The following specific instance method is provided by Mail::SPF::GlobalMod:

process($server, $request, $result): throws Mail::SPF::Result
Abstract. Processes the modifier. What that means depends on the actual implementation in sub-
classes. Takes both a Mail::SPF::Server and a Mail::SPF::Request object. As global modifiers are
generally processed after an SPF result has already been determined, takes also the current
Mail::SPF::Result. If the modifier wishes to modify the SPF result, it may throw a different
Mail::SPF::Result object.

This method is abstract and must be implemented by sub-classes of Mail::SPF::GlobalMod.

Positional modifiers - Mail::SPF::PositionalMod
Sender ID (RFC 4406) introduces the concept of "positional" modifiers. According to RFC 4406, a
positional modifier must follow a mechanism and applies to that, and only that, mechanism. However,
because this definition is not very useful, and because no positional modifiers have been defined based
on it as of yet, Mail::SPF deviates from RFC 4406 as follows:

A positional modifier may appear anywhere in an SPF record, and it is stateful, i.e. it applies to all
mechanisms and modifiers that follow it. Positional modifiers are generally multiple, i.e. they may
appear any number of times throughout the record. During evaluation of the record, positional modifiers
are processed at exactly the time when they are encountered by the evaluator. Consequently, all
positional modifiers are processed before an SPF result is determined.

The following specific instance method is provided by Mail::SPF::PositionalMod:

process($server, $request): throws Mail::SPF::Result::Error, Mail::SPF::Exception
Abstract. Processes the modifier. What that means depends on the actual implementation in sub-
classes. Takes both a Mail::SPF::Server and a Mail::SPF::Request object. As global modifiers are
generally processed before an SPF result has been determined, no result object is available to the
modifier. The modifier can (at least at this time) not directly modify the final SPF result, however
it may throw an exception to signal an error condition.

This method is abstract and must be implemented by sub-classes of Mail::SPF::PositionalMod.

Unknown modifiers - Mail::SPF::UnknownMod
Both SPFv1 and Sender ID allow unknown modifiers to appear in SPF records in order to allow new modifiers
to be introduced without breaking existing implementations. Obviously, unknown modifiers are neither
global nor positional, but they may appear any number of times throughout the record and are simply
ignored during evaluation of the record.

Also obviously, Mail::SPF::UnknownMod does not support a "process" method.

The following specific instance method is provided by Mail::SPF::UnknownMod:

params: returns string
Returns the modifier's unparsed value as a string.

OVERLOADING

       If a Mail::SPF::Mod object is used as a string, the "stringify" method is used to convert the object into
       a string.

AUTHORS

       Julian Mehnle <julian@mehnle.net>, Shevek <cpan@anarres.org>

perl v5.38.2                                       2024-02-09                                Mail::SPF::Mod(3pm)

NAME

DESCRIPTION

MODIFIER TYPES

OVERLOADING

SEE ALSO

AUTHORS