phpman > perldoc > SOAP::Trace(3pm)

NAME
    SOAP::Trace - used only to manage and manipulate the runtime tracing of execution within the
    toolkit

DESCRIPTION
    This class has no methods or objects. It is used only to manage and manipulate the runtime
    tracing of execution within the toolkit. In absence of methods, this section reviews the events
    that may be configured and the ways of configuring them.

SYNOPSIS
    Tracing is enabled by the SOAP::Lite import method. This is usually done at compile-time, though
    it may be done explicitly by calling import directly. The commands for setting up tracing start
    with the keyword +trace. Alternately, +debug may be used; the two are interchangeable. After the
    initial keyword, one or more of the signals detailed here may be specified, optionally with a
    callback to handle them. When specifying multiple signals to be handled by a single callback, it
    is sufficient to list all of them first, followed finally by the callback, as in:

       use SOAP::Lite +trace =>
         method => fault => \&message_level,
         trace => objects => \&lower_level;

    In the fragment, the reference to message_level is installed as the callback for both method and
    fault signals, while lower_level is installed for trace and object events. If callbacks aren't
    explicitly provided, the default tracing action is to log a message to Perl's STDOUT file
    descriptor. Callbacks should expect a one or more arguments passed in, though the nature of the
    arguments varies based on the signal.

    Any signal can be disabled by prefacing the name with a hyphen, such as -result. This is useful
    with the pseudosignal "all," which is shorthand for the full list of signals. The following
    fragment disables only the two signals, while still enabling the rest:

        SOAP::Lite->import(+trace => all => -result => -parameters);

    If the keyword +trace (or +debug) is used without any signals specified, it enables all signals
    (as if all were implied).

    The signals and their meaning follow. Each also bears a note as to whether the signal is
    relevant to a server application, client application, or both.

TRACE SIGNALS
    transport *Client only*
        Triggered in the transport layer just before a request is sent and immediately after a
        response is received. Each time the signal is sent, the sole argument to the callback is the
        relevant object. On requests, this is a HTTP::Request object; for responses, it's a
        HTTP::Response object.

    dispatch *Server only*
        Triggered with the full name of the method being dispatched, just before execution is passed
        to it. It is currently disabled in SOAP::Lite 0.55.

    result *Server only*
        Triggered after the method has been dispatched and is passed the results returned from the
        method as a list. The result values have not yet been serialized when this signal is sent.

    parameters *Server only*
        Triggered before a method call is actually dispatched, with the data that is intended for
        the call itself. The parameters for the method call are passed in as a list, after having
        been deserialized into Perl data.

    headers *Server only*
        This signal should be for triggering on the headers of an incoming message, but it isn't
        implemented as of SOAP::Lite 0.55.

    objects *Client or server*
        Highlights when an object is instantiated or destroyed. It is triggered in the new and
        DESTROY methods of the various SOAP::Lite classes.

    method *Client or server*
        Triggered with the list of arguments whenever the envelope method of SOAP::Serializer is
        invoked with an initial argument of method. The initial string itself isn't passed to the
        callback.

    fault *Client or server*
        As with the method signal earlier, except that this signal is triggered when
        SOAP::Serializer::envelope is called with an initial argument of fault.

    freeform *Client or server*
        Like the two previous, this signal is triggered when the method SOAP::Serializer::envelope
        is called with an initial parameter of freeform. This syntax is used when the method is
        creating SOAP::Data objects from free-form input data.

    trace *Client or server*
        Triggered at the entry-point of many of the more-significant functions. Not all the
        functions within the SOAP::Lite classes trigger this signal. Those that do are primarily the
        highly visible functions described in the interface descriptions for the various classes.

    debug *Client or server*
        Used in the various transport modules to track the contents of requests and responses (as
        ordinary strings, not as objects) at different points along the way.

EXAMPLES
  SELECTING SIGNALS TO TRACE
    The following code snippet will enable tracing for all signals:

      use SOAP::Lite +trace => 'all';

    You can disable tracing for a set of signals by prefixing the signal name with a hyphen.
    Therefore, if you wish to enable tracing for every signal EXCEPT transport signals, then you
    would use the code below:

      use SOAP::Lite +trace => [ qw(all -transport) ];

  LOGGING SIGNALS TO A FILE
    You can optionally provide a subroutine or callback to each signal trace you declare. Each time
    a signal is received, it is passed to the corresponding subroutine. For example, the following
    code effectively logs all fault signals to a file called fault.log:

      use SOAP::Lite +trace => [ fault => \&log_faults ];

      sub log_faults {
        open LOGFILE,">fault.log";
        print LOGFILE, $_[0] . "\n";
        close LOGFILE;
      }

    You can also use a single callback for multiple signals using the code below:

      use SOAP::Lite +trace => [ method, fault => \&log ];

  LOGGING MESSAGE CONTENTS
    The transport signal is unique in the that the signal is not a text string, but the actually
    HTTP::Request being sent (just prior to be sent), or HTTP::Response object (immediately after it
    was received). The following code sample shows how to make use of this:

      use SOAP::Lite +trace => [ transport => \&log_message ];

      sub log_message {
        my ($in) = @_;
        if (class($in) eq "HTTP::Request") {
          # do something...
          print $in->contents; # ...for example
        } elsif (class($in) eq "HTTP::Response") {
          # do something
        }
      }

  ON_DEBUG
    The "on_debug" method is available, as in:

      use SOAP::Lite;
      my $client = SOAP::Lite
        ->uri($NS)
        ->proxy($HOST)
        ->on_debug( sub { print @_; } );

ACKNOWLEDGEMENTS
    Special thanks to O'Reilly publishing which has graciously allowed SOAP::Lite to republish and
    redistribute large excerpts from *Programming Web Services with Perl*, mainly the SOAP::Lite
    reference found in Appendix B.

COPYRIGHT
    Copyright (C) 2000-2004 Paul Kulchenko. All rights reserved.

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

AUTHORS
    Paul Kulchenko (paulclinger AT yahoo.com)

    Randy J. Ray (rjray AT blackperl.com)

    Byrne Reese (byrne AT majordojo.com)