SYNOPSIS
use Mail::Log::Trace;
my $tracer = Mail::Log::Trace::SUBCLASS->new({log_file => 'path/to/log'});
$tracer->set_message_id('message_id');
$tracer->find_message();
my $from_address = $tracer->get_from_address();
etc.
DESCRIPTION
This is the root-level class for a mail tracer: It allows you to search
for and find messages in maillogs. Accessors are provided for info
common to most maillogs: Specific subclasses may have further accessors
depending on their situation.
Probably the two methods most commonly used (and sort of the point of
this module) are `find_message' and `find_message_info'. Both are simply
stubs for subclasses to implement: The first is defined to find the
first (or first from current location...) mention of the specified
message in the log. Depending on the log format that may or may not be
the only mention, and there may be information missing/incomplete at
that point.
`find_message_info' should find *all* information about a specific
message in the log. (Well, all information about a specific instance of
the message: If there are multiple messages that would match the info
provided it must find info on the first found.) That may mean searching
through the log for other information.
If you just need to find if the message exists, use `find_message': it
will be faster (or at the least, the same speed. It should never be
slower.)
USAGE
This is a an object-orientend module, with specific methods documented
below.
The string coersion is overloaded to return the class name, and the file
we are working with. Boolean currently checks to see if we were able to
open the file. (Which is kinda silly, as we'd throw an error if we
couldn't.)
All times are expected to be in Unix epoc-time format.
new (constructor)
The base constructor for the Mail::Log::Trace classes. It takes inital
values for the following in a hash: `from_address', `to_address',
`message_id', `log_file'. The only required value is the path to the
logfile.
use Mail::Log::Trace;
my $object = Mail::Log::Trace->new({ from_address => 'from@example.com',
to_address => 'to@example.com',
message_id => 'messg.id.string',
log_file => 'path/to/log',
...
});
SETTERS
set_from_address
Sets the from address of the message we are looking for.
set_message_id
Sets the message_id of the message we are looking for. (Check with the
specific parser class for what that means in a particular log format.)
set_recieved_time
Sets the recieved time of the message we are looking for. (The time this
machine got the message.)
set_sent_time
Sets the sent time of the message we are looking for. (The time this
machine sent the message.)
set_relay_host
Sets the relay host of the message we are looking for. Commonly either
the relay we recieved it from, or the relay we sent it to. (Depending on
the logfile.)
set_subject
Sets the subject of the message we are looking for.
set_parser_class
Sets the parser class to use when searching the log file. A subclass
will have a 'default' parser that it will normally use: This is to allow
easy site-specific logfile formats based on more common formats. To use
you would subclass the default parser for the log file format of the
base program to handle the site's specific changes.
Takes the name of a class as a string, and will throw an exception
(`Mail::Log::Exceptions::InvalidParameter') if that class name doesn't
start with Mail::Log::Parse.
set_log
Sets the log file we are searching throuh. Takes a full or relative
path. If it doesn't exist, or can't be read by the current user, it will
throw an exception. (`Mail::Log::Exceptions::LogFile') Note that it does
*not* try to open it immedeately. That will be done at first attempt to
read from the logfile.
set_to_address
Sets the to address of the message we are looking for. Multiple
addresses can be specified, they will all be added, with duplicates
skipped. This method completely clears the array: there will be no
addresses in the list except those given to it. Duplicates will be
consolidated: Only one of any particular address will be in the final
array.
As a special case, passing `undef' to this will set the array to undef.
add_to_address
Adds to the list of to addresses we are looking for. It does *not*
delete the array first.
Duplicates will be consolidated, so that the array will only have one of
any given address. (No matter the order they are given in.)
remove_to_address
Removes a single to address from the array.
GETTERS
get_from_address
Gets the from address. (Either as set using the setter, or as found in
the log.)
get_to_address
Gets the to address array. (Either as set using the setters, or as found
in the log.)
Will return a reference to an array, or 'undef' if the to address has
not been set/found.
get_message_id
Gets the message_id. (Either as set using the setter, or as found in the
log.)
get_subject
Gets the message subject. (Either as set using the setter, or as found
in the log.)
get_recieved_time
Gets the recieved time. (Either as set using the setter, or as found in
the log.)
get_sent_time
Gets the sent time. (Either as set using the setter, or as found in the
log.)
get_relay_host
Gets the relay host. (Either as set using the setter, or as found in the
log.)
get_log
Returns the path to the logfile we are reading.
get_connect_time
Returns the time the remote host connected to this host to send the
message.
get_disconnect_time
Returns the time the remote host disconnected from this host after
sending the message.
get_delay
Returns the total delay in this stage in processing the message.
get_all_info
Returns message info as returned from the parser, for more
direct/complete access.
(It's probably a good idea to avoid using this, but it is useful and
arguably needed under certain circumstances.)
Utility subroutines
clear_message_info
Clears *all* known information on the current message, but not on the
log.
Use to start searching for a new message.
find_message
Finds the first/next occurance of a message in the log. Can be passed
any of the above information in a hash format.
Default is to search *forward* in the log: If you have already done a
search, this will start searching where the previous search ended. To
start over at the beginning of the logfile, set `from_start' as true in
the parameter hash.
This method needs to be overridden by the subclass: by default it will
throw an `Mail::Log::Exceptions::Unimplemented' error.
find_message_info
Finds as much information as possible about a specific occurance of a
message in the logfile. Acts much the same as find_message, other than
the fact that once it finds a message it will do any searching necarry
to find all information on that message connection.
(Also needs to be implemented by subclasses.)
SUBCLASSING
There are two ways to subclass Mail::Log::Trace: The standard way, and
the automatic way. The old way is fairly straightforward: You create the
accessors for all the subclass-specific information, and overide
`find_message', `find_message_info', and `_parse_args'. (Making sure for
`_parse_args' that you call the SUPER version.)
Or you can try to let Mail::Log::Trace do as much of that as possible,
and only do `find_message' and `find_message_info'.
To do the latter, you need to override several of the following list of
methods:
_requested_public_accessors
_requested_public_set_only
_requested_public_get_only
_requested_array_accessors
_requested_special_accessors
_requested_cleared_parameters
_set_as_message_info
That looks like a long list, but it is very rare that you'll need to
override all of them, and all they need to do is return a static list of
keys that you want the relevant action taken on.
The first five build accessors for you, of the form `get_$key',
`set_$key' for standard public, `_get_$key' and `_set_key' for private
accessors (note that if you request a private setter, you'll also get a
*public* getter, and vice-versa), and `get_$key', `set_$key', `add_$key'
and `remove_$key' for keys which store arrays. All of these have been
heavily optimised for speed.
The last two set what keys are cleared when you call
`clear_message_info' and what keys will be checked when `_parse_args' is
called. (If none of those are present, an exception will be thrown,
saying there is no message-specific data.)
`_requested_special_accessors' requires a little more discussion. Unlike
the rest, it expects not an array, but a hash (not a hashref: a hash).
The keys of the hash are the keys that will have accessors built for
them (public, single, only), and the values are code references to
parsing/validation functions.
An example:
sub _requested_special_accessors {
return ( year => sub { my ($self, $year) = @_;
return '____INVALID__VALUE____' if $year < 1970;
my $maillog = $self->_get_log_parser();
if (defined($maillog)) {
$maillog->set_year($year);
}
return $year;
},
);
};
The above is from Mail::Log::Trace::Postfix, and is for the key 'year'.
The coderef in this case does both validation and some extra action. The
action is to call `$self-'_get_log_parser()->set_year()> on the year
being passed. (Because in this case the parser needs to have the year to
return info correctly.) The validation is to check to make sure the year
is greater than 1970. (The birth of UNIX, so we are unlikey to handle
any logs earlier than that.) If it is not, the special value
`____INVALID__VALUE____' is returned. This will cause an exception to be
thrown. If the value is valid, it is returned.
The purpose of all the above is to allow subclasses to check values, do
any parsing that is needed, and to any other actions that may be needed.
(This is in contrast to the normal accessors, which just store the value
given blindly.)
Note that `undef' should always be considered a valid value.
Normally keys should be in the 'public_accessors' list: those accessors
are much faster.
These accessors are built at *run time*, when the object is first
created. This means object creation is fairly expensive.
Of course, you still need to write `find_message' and
`find_message_info'...
Mail::Log::Trace is a cached inside-out object. If you don't know what
that means, you can probably ignore it. However if you need to store
object state data (and aren't using the convience accessors), it may be
useful to know that `$$self == refaddr $self'.
UTILITY SUBROUTINES
THESE ARE ONLY FOR USE BY SUBCLASSES
There are a few subroutines especially for use by subclasses.
_set_message_raw_info
Give this the raw message info, in whatever format the parser gives it.
The user should hopefully never want it, but just in case...
_set_log_parser
Sets the log parser. Takes a reference to a parser object.
_get_log_parser
Returns the log parser object.
_get_parser_class
Returns the name of the class the user wants you to use to parse the
file.
Please take it under advisement.
BUGS
None known at the moment... (I am nervious about the way I'm storing
some of these coderefs. So far I haven't run into problems, but I'm not
entirely sure there aren't any. If you start getting weird behaviour
when using multiple Mail::Log::Trace subclasses at once, please tell
me.)
REQUIRES
Scalar::Util, Mail::Log::Exceptions.
Some subclass, and probably a Mail::Log::Parse class to be useful.
HISTORY
1.1.0 Dec 23, 2008 - Major re-write to make subclassing easier. Or
possibly more confusing.
1.00.03 Dec 5, 2208 - Licence clarification.
1.00.02 Dec 2, 2008 - I really mean it this time.
1.00.01 Dec 1, 2008 - Requirements fix, no code changes.
1.00.00 Nov 28, 2008 - original version.
AUTHOR
Daniel T. Staal
CPAN ID: DSTAAL
dstaal@usa.net
COPYRIGHT
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
This copyright will expire in 30 years, or five years after the author's
death, whichever occurs last, at which time the code be released to the
public domain.