gitpan / rrd-cgi-image Goto Github PK

NAME
    RRD::CGI::Image - accept CGI-style rrdgraph args to build and print
    image

NOTICE
    This is development code - the API may change!

SYNOPSIS
        use RRD::CGI::Image;
            use CGI qw[Vars header];

        my $image = RRD::CGI::Image->new(
                    rrd_base  => '/var/rrd',
                    error_img => '/var/www/.../path/to/graphing_error.png',
            );

            print header( 'image/png' );
            $image->print_graph( Vars() );

METHODS
  new() - create new object to handle your bidding
    Behaves like any other new(), really.

  print_graph() - accepts CGI params, parses them, and prints a graph
    The graph will be sent to the location specified by output_file();
    STDOUT by default.

    In addition to the regular rrdgraph options, you can also add a
    tz=timezone param which will render the graph in the given timezone.

    The key-value pairs need a little translation to get them successfully
    passed through the URL. Your URL or CGI library will probably handle
    most of this automatically. Here's the full examplanation.

    Let's convert a fairly standard set of args for RRDs::graph() to
    GET-style CGI params, starting with:

            RRDs::graph(
                    '/path/to/output/file.png',
                    '--start' => '-1d',
                    '--end' => 'now',
                    '--height' => 200,
                    '--width' => 600,
                    '--imgformat' => 'PNG',
                    '--lower-limit' => 0,
                    '--title' => 'This is a title',
                    '--vertical-label' => 'bps',
                    'DEF:ds0' => '/var/rrd/router/data/router.example.com/gigabitethernet101.rrd:ds0:MAX',
                    'DEF:ds1' => '/var/rrd/router/data/router.example.com/gigabitethernet101.rrd:ds1:MAX',
                    'CDEF:in:ds0,8,*',  # convert bytes to bits
                    'CDEF:out:ds1,8,*',
                    'LINE1:in#33ee33:Input',
                    'LINE1:out#0000ff:Output',
            );

    First, completely drop the first argument. We don't need an output
    filename anymore - that's handled by output_file() instead.

    Next, change the Perl hash-style key-value params to from key > value to
    CGI-style: key=value;

    Next, delete the first half of the path - the rrd_base() - from your DEF
    statements. That will change the DEF lines to:

            'DEF:ds0' => 'router.example.com/gigabitethernet101.rrd:ds0:MAX',
            'DEF:ds1' => 'router.example.com/gigabitethernet101.rrd:ds1:MAX',

    Finally, make sure your params are encoded so they pass through the CGI
    interface. URI::Escape::uri_escape() will, for example, convert the
    hashmarks in LINE1 statements from # to %23. Here's what the LINE1
    entries should look like after encoding:

            'LINE1:in%2333ee33:Input',
            'LINE1:out%230000ff:Output',

    Many of these will be handled automatically if you're relying on a CGI
    or URL module to construct the URL for you.

  output_file() - where will the new graph be created?
    Defaults to STDOUT (-).

  rrd_base() - pathname to your RRD files.
    Users will be able to specify partial paths to the RRDs beneath this
    directory in their DEF declarations but they will be sandboxed into this
    directory. Don't be too permissive - it's a security risk.

    Must end with "/".

  error_img() - pathname (not URL) to an image that says "an error happened".
    Check your webserver's logs to see what went wrong.

  tz() - get/set the timezone for the graph.
    Pertinent if you have RRDs in different timezones.

  normalize_params() - clean up and reassemble the input params
    Called internally.

  print_error_img( $opt_errmsg ) - prints the error_img() file to output_file() location (STDOUT by default) and writes the error to log
  logging() - if true, will print the normalized (processed) params to log
AUTHOR
    Joshua Keroes, "<joshua at cpan.org>"

BUGS
    Please report any bugs or feature requests to "bug-rrd-cgi-image at
    rt.cpan.org", or through the web interface at
    <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=RRD-CGI-Image>. I will
    be notified, and then you'll automatically be notified of progress on
    your bug as I make changes.

SUPPORT
    You can find documentation for this module with the perldoc command.

        perldoc RRD::CGI::Image

    You can also look for information at:

    * RT: CPAN's request tracker
        <http://rt.cpan.org/NoAuth/Bugs.html?Dist=RRD-CGI-Image>

    * AnnoCPAN: Annotated CPAN documentation
        <http://annocpan.org/dist/RRD-CGI-Image>

    * CPAN Ratings
        <http://cpanratings.perl.org/d/RRD-CGI-Image>

    * Search CPAN
        <http://search.cpan.org/dist/RRD-CGI-Image>

SEE ALSO
    RRDs

COPYRIGHT & LICENSE
    Copyright 2008 Joshua Keroes, all rights reserved.

    This program is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself.