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libcddb-perl 1.222-1.1
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NAME
    CDDB.pm - a high-level interface to cddb protocol servers (freedb and
    CDDB)

VERSION
    version 1.222

SYNOPSIS
      use CDDB;

      ### Connect to the cddbp server.
      my $cddbp = new CDDB(
        Host  => 'freedb.freedb.org', # default
        Port  => 8880,                # default
        Login => $login_id,           # defaults to %ENV's
      ) or die $!;

      ### Retrieve known genres.
      my @genres = $cddbp->get_genres();

      ### Calculate cddbp ID based on MSF info.
      my @toc = (
        '1    0  2 37',           # track, CD-i MSF (space-delimited)
        '999  1 38 17',           # lead-out track MSF
        '1000 0  0 Error!',       # error track (don't include if ok)
      );
      my (
        $cddbp_id,      # used for further cddbp queries
        $track_numbers, # padded with 0's (for convenience)
        $track_lengths, # length of each track, in MM:SS format
        $track_offsets, # absolute offsets (used for further cddbp queries)
        $total_seconds  # total play time, in seconds (for cddbp queries)
       ) = $cddbp->calculate_id(@toc);

      ### Query discs based on cddbp ID and other information.
      my @discs = $cddbp->get_discs($cddbp_id, $track_offsets, $total_seconds);
      foreach my $disc (@discs) {
        my ($genre, $cddbp_id, $title) = @$disc;
      }

      ### Query disc details (usually done with get_discs() information).
      my $disc_info     = $cddbp->get_disc_details($genre, $cddbp_id);
      my $disc_time     = $disc_info->{'disc length'};
      my $disc_id       = $disc_info->{discid};
      my $disc_title    = $disc_info->{dtitle};
      my @track_offsets = @{$disc_info->{offsets}};
      my @track_seconds = @{$disc_info->{seconds}};
      my @track_titles  = @{$disc_info->{ttitles}};
      # other information may be returned... explore!

      ### Submit a disc via e-mail. (Requires MailTools)

      die "can't submit a disc (no mail modules; see README)"
        unless $cddbp->can_submit_disc();

      # These are useful for prompting the user to fix defaults:
      print "I will send mail through: ", $cddbp->get_mail_host(), "\n";
      print "I assume your e-mail address is: ", $cddbp->get_mail_address(), "\n";

      # Actually submit a disc record.
      $cddbp->submit_disc(
        Genre       => 'classical',
        Id          => 'b811a20c',
        Artist      => 'Various',
        DiscTitle   => 'Cartoon Classics',
        Offsets     => $disc_info->{offsets},   # array reference
        TrackTitles => $disc_info->{ttitles},   # array reference
        From        => 'login@host.domain.etc', # will try to determine
      );

DESCRIPTION
    CDDB protocol (cddbp) servers provide compact disc information for
    programs that need it. This allows such programs to display disc and
    track titles automatically, and it provides extended information like
    liner notes and lyrics.

    This module provides a high-level Perl interface to cddbp servers. With
    it, a Perl program can identify and possibly gather details about a CD
    based on its "table of contents" (the disc's track times and offsets).

    Disc details have been useful for generating CD catalogs, naming mp3
    files, printing CD liners, or even just playing discs in an automated
    jukebox.

    Despite the module's name, it connects to FreeDB servers by default.
    This began at version 1.04, when cddb.com changed its licensing model to
    support end-user applications, not third-party libraries. Connections to
    cddb.com may still work, and patches are welcome to maintain that
    functionality, but it's no longer officially supported.

PUBLIC METHODS
    new PARAMETERS
        Creates a high-level interface to a cddbp server, returning a handle
        to it. The handle is not a filehandle. It is an object. The new()
        constructor provides defaults for just about everything, but
        everything is overrideable if the defaults aren't appropriate.

        The interface will not actually connect to a cddbp server until it's
        used, and a single cddbp interface may actually make several
        connections (to possibly several servers) over the course of its
        use.

        The new() constructor accepts several parameters, all of which have
        reasonable defaults.

        Host and Port describe the cddbp server to connect to. These default
        to 'freedb.freedb.org' and 8880, which is a multiplexor for all the
        other freedb servers.

        Utf8 is a boolean flag. If true, utf-8 will be used when submitting
        CD info, and for interpreting the data reveived. This requires the
        Encode module (and probably perl version at least 5.8.0). The
        default is true if the Encode module can be loaded. Otherwise, it
        will be false, meaning we fall back to ASCII.

        Protocol_Version sets the cddbp version to use. CDDB.pm will not
        connect to servers that don't support the version specified here.
        The requested protocol version defaults to 1 if Utf8 is off, and to
        6 if it is on.

        Login is the login ID you want to advertise to the cddbp server. It
        defaults to the login ID your computer assigns you, if that can be
        determined. The default login ID is determined by the presence of a
        LOGNAME or USER environment variable, or by the getpwuid() function.
        On Windows systems, it defaults to "win32usr" if no default method
        can be found and no Login parameter is set.

        Submit_Address is the e-mail address where new disc submissions go.
        This defaults to 'freedb-submit@freedb.org'. Note, that testing
        submissions should be done via "test-submit@freedb.org".

        Client_Name and Client_Version describe the client software used to
        connect to the cddbp server. They default to 'CDDB.pm' and CDDB.pm's
        version number. If developers change this, please consult freedb's
        web site for a list of client names already in use.

        Debug enables verbose operational information on STDERR when set to
        true. It's normally not needed, but it can help explain why a
        program is failing. If someone finds a reproduceable bug, the Debug
        output and a test program would be a big help towards having it
        fixed. In case of submission, if this flag is on, a copy of the
        submission e-mail will be sent to the *From* address.

    get_genres
        Takes no parameters. Returns a list of genres known by the cddbp
        server, or undef if there is a problem retrieving them.

    calculate_id TOC
        The cddb protocol defines an ID as a hash of track lengths and the
        number of tracks, with an added checksum. The most basic information
        required to calculate this is the CD table of contents (the CD-i
        track offsets, in "MSF" [Minutes, Seconds, Frames] format).

        Note however that there is no standard way to acquire this
        information from a CD-ROM device. Therefore this module does not try
        to read the TOC itself. Instead, developers must combine CDDB.pm
        with a CD library which works with their system. The AudioCD suite
        of modules is recommended: it has system specific code for MacOS,
        Linux and FreeBSD. CDDB.pm's author has used external programs like
        dagrab to fetch the offsets. Actual CDs aren't always necessary: the
        author has heard of people generating TOC information from mp3 file
        lengths.

        That said, see parse_cdinfo() for a routine to parse "cdinfo" output
        into a table of contents list suitable for calculate_id().

        calculate_id() accepts TOC information as a list of strings. Each
        string contains four fields, separated by whitespace:

        offset 0: the track number

        Track numbers start with 1 and run sequentially through the number
        of tracks on a disc. Note: data tracks count on hybrid audio/data
        CDs.

        CDDB.pm understands two special track numbers. Track 999 holds the
        lead-out information, which is required by the cddb protocol. Track
        1000 holds information about errors which have occurred while
        physically reading the disc.

        offset 1: the track start time, minutes field

        Tracks are often addressed on audio CDs using "MSF" offsets. This
        stands for Minutes, Seconds, and Frames (fractions of a second). The
        combination pinpoints the exact disc frame where a song starts.

        Field 1 contains the M part of MSF. It is ignored for error tracks,
        but it still must contain a number. Zero is suggested.

        offset 2: the track start time, seconds field

        This field contains the S part of MSF. It is ignored for error
        tracks, but it still must contain a number. Zero is suggested.

        offset 3: the track start time, frames field

        This field contains the F part of MSF. For error tracks, it contains
        a description of the error.

        Example track file. Note: the comments should not appear in the
        file.

             1   0  2 37  # track 1 starts at 00:02 and 37 frames
             2   1 38 17  # track 2 starts at 01:38 and 17 frames
             3  11 57 30  # track 3 starts at 11:57 and 30 frames
             ...
           999  75 16  5  # leadout starts at 75:16 and  5 frames

        Track 1000 should not be present if everything is okay:

          1000   0  0  Error reading TOC: no disc in drive

        In scalar context, calculate_id() returns just the cddbp ID. In a
        list context, it returns an array containing the following values:

          (
            $cddbp_id,
            $track_numbers,
            $track_lengths,
            $track_offsets,
            $total_seconds
          ) = $cddbp->calculate_id(@toc);

          print(
            "cddbp ID      = $cddbp_id\n",        # b811a20c
            "track numbers = @$track_numbers\n",  # 001 002 003 ...
            "track lengths = @$track_lengths\n",  # 01:36 10:19 04:29 ...
            "track offsets = @$track_offsets\n",  # 187 7367 53805 ...
            "total seconds = $total_seconds\n",   # 4514
          );

        CDDBP_ID

        The 0th returned value is the hashed cddbp ID, required for any
        queries or submissions involving this disc.

        TRACK_NUMBERS

        The 1st returned value is a reference to a list of track numbers,
        one for each track (excluding the lead-out), padded to three
        characters with leading zeroes. These values are provided for
        convenience, but they are not required by cddbp servers.

        TRACK_LENGTHS

        The 2nd returned value is a reference to a list of track lengths,
        one for each track (excluding the lead-out), in HH:MM format. These
        values are returned as a convenience. They are not required by cddbp
        servers.

        TRACK_OFFSETS

        The 3rd returned value is a reference to a list of absolute track
        offsets, in frames. They are calculated from the MSF values, and
        they are required by get_discs() and submit_disc().

        TOTAL_SECONDS

        The 4th and final value is the total playing time for the CD, in
        seconds. The get_discs() function needs it.

    get_discs CDDBP_ID, TRACK_OFFSETS, TOTAL_SECONDS
        get_discs() asks the cddbp server for a summary of all the CDs
        matching a given cddbp ID, track offsets, and total playing time.
        These values can be retrieved from calculade_id().

          my @id_info       = $cddbp->calculate_id(@toc);
          my $cddbp_id      = $id_info->[0];
          my $track_offsets = $id_info->[3];
          my $total_seconds = $id_info->[4];

        get_discs() returns an array of matching discs, each of which is
        represented by an array reference. It returns an empty array if the
        query succeeded but did not match, and it returns undef on error.

          my @discs = $cddbp->get_discs( $cddbp_id, $track_offsets, $total_seconds );
          foreach my $disc (@discs) {
            my ($disc_genre, $disc_id, $disc_title) = @$disc;
            print(
              "disc id    = $disc_id\n",
              "disc genre = $disc_genre\n",
              "disc title = $disc_title\n",
            );
          }

        DISC_GENRE is the genre this disc falls into, as determined by
        whoever submitted or last edited the disc. The genre is required
        when requesting a disc's details. See get_genres() for how to
        retrieve a list of cddbp genres.

        CDDBP_ID is the cddbp ID of this disc. Cddbp servers perform fuzzy
        matches, returning near misses as well as direct hits on a cddbp ID,
        so knowing the exact ID for a disc is important when submitting
        changes or requesting a particular near-miss' details.

        DISC_TITLE is the disc's title, which may help a human to pick the
        correct disc out of several close mathches.

    get_discs_by_toc TOC
        This function acts as a macro, combining calculate_id() and
        get_discs() calls into one function. It takes the same parameters as
        calculate_id(), and it returns the same information as get_discs().

    get_discs_by_query QUERY_STRING
        Fetch discs by a pre-built cddbp query string. Some disc querying
        programs report this string, and get_discs_by_query() is a
        convenient way to use that.

        Cddb protocol query strings look like:

          cddb query $cddbp_id $track_count @offsets $total_seconds

    get_disc_details DISC_GENRE, CDDBP_ID
        This function fetches a disc's detailed information from a cddbp
        server. It takes two parameters: the DISC_GENRE and the CDDP_ID.
        These parameters usually come from a call to get_discs().

        The disc's details are returned in a reference to a fairly complex
        hash. It includes information normally stored in comments. The most
        common entries in this hash include:

          $disc_details = get_disc_details( $disc_genre, $cddbp_id );

        $disc_details->{"disc length"}

        The disc length is commonly stored in the form "### seconds", where
        ### is the disc's total playing time in seconds. It may hold other
        time formats.

        $disc_details->{discid}

        This is a rehash (get it?) of the cddbp ID. It should match the
        CDDBP_ID given to get_disc_details().

        $disc_details->{dtitle}

        This is the disc's title. I do not know whether it will match the
        one returned by get_discs().

        $disc_details->{offsets}

        This is a reference to a list of absolute disc track offsets,
        similar to the TRACK_OFFSETS returned by calculate_id().

        $disc_details->{seconds}

        This is a reference to a list of track length, in seconds.

        $disc_details->{ttitles}

        This is a reference to a list of track titles. These are the droids
        you are looking for.

        $disc_details->{"processed by"}

        This is a comment field identifying the name and version of the
        cddbp server which accepted and entered the disc record into the
        database.

        $disc_details->{revision}

        This is the disc record's version number, used as a sanity check
        (semaphore?) to prevent simultaneous revisions. Revisions start at 0
        for new submissions and are incremented for every correction. It is
        the responsibility of the submitter (be it a person or a program
        using CDDB.pm) to provide a correct revision number.

        $disc_details->{"submitted via"}

        This is the name and version of the software that submitted this
        cddbp record. The main intention is to identify records that are
        submitted by broken software so they can be purged or corrected.

        $disc_details->{xmcd_record}

        The xmcd_record field contains a copy of the entire unprocessed
        cddbp response that generated all the other fields.

        $disc_details->{genre}

        This is merely a copy of DISC_GENRE, since it's otherwise not
        possible to determine it from the hash.

    parse_xmcd_file XMCD_FILE_CONTENTS, [GENRE]
        Parses an array ref of lines read from an XMCD file into the
        disc_details hash described above. If the GENRE parameter is set it
        will be included in disc_details.

    can_submit_disc
        Returns true or false, depending on whether CDDB.pm has enough
        dependent modules to submit discs. If it returns false, you are
        missing Mail::Internet, Mail::Header, or MIME::QuotedPrint.

    get_mail_address
        Returns what CDDB.pm thinks your e-mail address is, or what it was
        last set to. It was added to fetch the default e-mail address so
        users can see it and have an opportunity to correct it.

          my $mail_from = $cddb->get_mail_address();
          print "New e-mail address (or blank to keep <$mail_from>): ";
          my $new_mail_from = <STDIN>;
          $new_mail_from =~ s/^\s+//;
          $new_mail_from =~ s/\s+$//;
          $new_mail_from =~ s/\s+/ /g;
          $mail_from = $new_mail_from if length $new_mail_from;

          $cddbp->submit_disc(
            ...,
            From => $mail_from,
          );

    get_mail_host
        Returns what CDDB.pm thinks your SMTP host is, or what it was last
        set to. It was added to fetch the default e-mail transfer host so
        users can see it and have an opportunity to correct it.

          my $mail_host = $cddb->get_mail_host();
          print "New e-mail host (or blank to keep <$mail_host>): ";
          my $new_mail_host = <STDIN>;
          $new_mail_host =~ s/^\s+//;
          $new_mail_host =~ s/\s+$//;
          $new_mail_host =~ s/\s+/ /g;
          $mail_host = $new_mail_host if length $new_mail_host;

          $cddbp->submit_disc(
            ...,
            Host => $mail_host,
          );

    parse_cdinfo CDINFO_FILE
        Generates a table of contents suitable for calculate_id() based on
        the output of a program called "cdinfo". CDINFO_FILE may either be a
        text file, or it may be the cdinfo program itself.

          my @toc = parse_cdinfo("cdinfo.txt"); # read cdinfo.txt
          my @toc = parse_cdinfo("cdinfo|");    # run cdinfo directly

        The table of contents can be passed directly to calculate_id().

    submit_disc DISC_DETAILS
        submit_disc() submits a disc record to a cddbp server. Currently it
        only uses e-mail, although it will try different ways to send that.
        It returns true or false depending on whether it was able to send
        the submission e-mail.

        The rest of CDDB.pm will work without the ability to submit discs.
        While cddbp submissions are relatively rare, most CD collections
        will have one or two discs not present in the system. Please submit
        new discs to the system: the amazing number of existing discs got
        there because others submitted them before you needed them.

        submit_disc() takes six required parameters and two optional ones.
        The parameters are named, like hash elements, and can appear in any
        order.

        Genre => DISC_GENRE

        This is the disc's genre. It must be one of the genres that the
        server knows. See get_genres().

        Id => CDDBP_ID

        This is the cddbp ID that identifies the disc. It should come from
        calculate_id() if this is a new submission, or from
        get_disc_details() if this is a revision.

        Artist => DISC_ARTIST

        This is the disc's artist, a freeform text field describing the
        party responsible for the album. It will need to be entered from the
        disc's notes for new submissions, or it can come from
        get_disc_details() on subsequent revisions.

        DiscTitle => DISC_TITLE

        This is the disc's title, a freeform text field describing the
        album. It must be entered from the disc's notes for new submissions.
        It can come from get_disc_details() on subsequent revisions.

        Offsets => TRACK_OFFSETS

        This is a reference to an array of absolute track offsets, as
        provided by calculate_id().

        TrackTitles => TRACK_TITLES

        This is a reference to an array of track titles, either entered by a
        human or provided by get_disc_details().

        From => EMAIL_ADDRESS

        This is the disc submitter's e-mail address. It's not required, and
        CDDB.pm will try to figure one out on its own if an address is
        omitted. It may be more reliable to provide your own, however.

        The default return address may not be a deliverable one, especially
        if CDDB.pm is being used on a dial-up machine that isn't running its
        own MTA. If the current machine has its own MTA, problems still may
        occur if the machine's Internet address changes.

        Host => SMTP_HOST

        This is the SMTP host to contact when sending mail. It's not
        required, and CDDB.pm will try to figure one out on its own. It will
        look at the SMTPHOSTS environment variable is not defined, it will
        try 'mail' and 'localhost' before finally failing.

        Revision => REVISION

        The revision number. Should be 1 for new submissions, and one higher
        than the previous one for updates. The previous revision number is
        available as the "revision" field in the hash returned by
        get_disc_details().

PRIVATE METHODS
    Documented as being not documented.

EXAMPLES
    Please see the cddb.t program in the t (tests) directory. It exercises
    every aspect of CDDB.pm, including submissions.

COMPATIBILITY
    CDDB.pm uses standard Perl modules. It has been tested at one point or
    another on OS/2, MacOS and FreeBSD systems, as well as the systems
    listed at:

      http://testers.cpan.org/search?request=dist&dist=CDDB

    If you want to submit disc information to the CDDB, you will need to
    install two other modules:

      Mail::Internet will allow CDDB.pm to send email submissions, and it
      automagically includes Mail::Header.

      MIME::QuotedPrint will allow CDDB.pm to send non-ASCII text
      unscathed.  Currently only ISO-8859-1 and ASCII are supported.

    All other features will work without these modules.

KNOWN TEST FAILURES
    The last test in the "make test" suite will try to send a sample
    submission to the CDDB if MailTools is present. It expects to find an
    SMTP host in the SMTPHOST environment variable. It will fall back to
    "mail" if SMTPHOST doesn't exist. If neither works, the test will be
    skipped. To see why it's skipped:

      make test TEST_VERBOSE=1

    Some of the tests (most notably numbers 25, 27 and 29) compare data
    returned by a cddbp server against a stored copy of a previous query.
    These tests fail occasionally since the database is constantly in flux.
    Starting with version 1.00, the test program uses fuzzy comparisons that
    should fail less. Version 1.04 saw even fuzzier comparisons. Please
    report any problems so they can be fixed.

LINKS
  BUG TRACKER
    https://rt.cpan.org/Dist/Display.html?Status=Active&Queue=CDDB

  REPOSITORY
    http://github.com/rcaputo/cddb-perl
    http://gitorious.org/cddb-freedb-perl

  OTHER RESOURCES
    http://search.cpan.org/dist/CDDB/

CONTACT AND COPYRIGHT
    Copyright 1998-2013 Rocco Caputo. All rights reserved. This program is
    free software; you can redistribute it and/or modify it under the same
    terms as Perl itself.