phpman > perldoc > RPC::XML::Client(3pm)

NAME
    RPC::XML::Client - An XML-RPC client class

SYNOPSIS
        require RPC::XML;
        require RPC::XML::Client;

        $cli = RPC::XML::Client->new('http://www.localhost.net/RPCSERV');
        $resp = $cli->send_request('system.listMethods');

        print ref $resp ? join(', ', @{$resp->value}) : "Error: $resp";

DESCRIPTION
    This is an XML-RPC client built upon the RPC::XML data classes, and using LWP::UserAgent and
    HTTP::Request for the communication layer. This client supports the full XML-RPC specification.

SUBROUTINES/METHODS
    The following methods are available:

    new (URI [, ARGS])
        Creates a new client object that will route its requests to the URL provided. The
        constructor creates a HTTP::Request object and a LWP::UserAgent object, which are stored on
        the client object. When requests are made, these objects are ready to go, with the headers
        set appropriately. The return value of this method is a reference to the new object. The
        "URI" argument may be a string or an object from the URI class from CPAN.

        Any additional arguments are treated as key-value pairs. Most are attached to the object
        itself without change. The following are recognized by "new" and treated specially:

        parser
            If this parameter is passed, the value following it is expected to be an array
            reference. The contents of that array are passed to the new method of the
            RPC::XML::ParserFactory-generated object that the client object caches for its use. See
            the RPC::XML::ParserFactory manual page for a list of recognized parameters to the
            constructor.

        useragent
            This is similar to the "parser" argument above, and also expects an array reference to
            follow it. The contents are passed to the constructor of the LWP::UserAgent class when
            creating that component of the client object. See the manual page for LWP::UserAgent for
            supported values.

        error_handler
            If passed, the value must be a code reference that will be invoked when a request
            results in a transport-level error. The closure will receive a single argument, the text
            of the error message from the failed communication attempt. It is expected to return a
            single value (assuming it returns at all).

        fault_handler
            If passed, the value must be a code reference. This one is invoked when a request
            results in a fault response from the server. The closure will receive a single argument,
            a RPC::XML::fault instance that can be used to retrieve the code and text-string of the
            fault. It is expected to return a single value (if it returns at all).

        combined_handler
            If this parameter is specified, it too must have a code reference as a value. It is
            installed as the handler for both faults and errors. Should either of the other
            parameters be passed in addition to this one, they will take precedence over this
            (more-specific wins out over less). As a combined handler, the closure will get a string
            (non-reference) in cases of errors, and an instance of RPC::XML::fault in cases of
            faults. This allows the developer to install a simple default handler, while later
            providing a more specific one by means of the methods listed below.

        message_file_thresh
            If this key is passed, the value associated with it is assumed to be a numerical limit
            to the size of in-memory messages. Any out-bound request that would be larger than this
            when stringified is instead written to an anonynous temporary file, and spooled from
            there instead. This is useful for cases in which the request includes RPC::XML::base64
            objects that are themselves spooled from file-handles. This test is independent of
            compression, so even if compression of a request would drop it below this threshold, it
            will be spooled anyway. The file itself is created via File::Temp with UNLINK=>1, so
            once it is freed the disk space is immediately freed.

        message_temp_dir
            If a message is to be spooled to a temporary file, this key can define a specific
            directory in which to open those files. If this is not given, then the "tmpdir" method
            from the File::Spec package is used, instead.

        request_as_string
            For aiding in debugging, you can pass this key with a non-false value to enable a step
            in each request cycle that saves a stringified version of the request XML as a private
            key on the client object. The request will be saved to the key
            "_xmlrpc_request_as_string", and will endure until the next request is made by the
            client object.

        See the section on the effects of callbacks on return values, below.

    uri ([URI])
        Returns the URI that the invoking object is set to communicate with for requests. If a
        string or "URI" class object is passed as an argument, then the URI is set to the new value.
        In either case, the pre-existing value is returned.

    useragent
        Returns the LWP::UserAgent object instance stored on the client object. It is not possible
        to assign a new such object, though direct access to it should allow for any header
        modifications or other needed operations.

    request
        Returns the HTTP::Request object. As with the above, it is not allowed to assign a new
        object, but access to this value should allow for any needed operations.

    simple_request (ARGS)
        This is a somewhat friendlier wrapper around the next routine ("send_request") that returns
        Perl-level data rather than an object reference. The arguments may be the same as one would
        pass to the RPC::XML::request constructor, or there may be a single request object as an
        argument. The return value will be a native Perl value. If the return value is "undef", an
        error has occurred and "simple_request" has placed the error message in the global variable
        $RPC::XML::ERROR.

    send_request (ARGS)
        Sends a request to the server and attempts to parse the returned data. The argument may be
        an object of the RPC::XML::request class, or it may be the arguments to the constructor for
        the request class. The return value will be either an error string or a data-type object. If
        the error encountered was a run-time error within the RPC request itself, then the call will
        return a "RPC::XML::fault" value rather than an error string.

        If the return value from "send_request" is not a reference, then it can only mean an error
        on the client-side (a local problem with the arguments and/or syntax, or a transport
        problem). All data-type classes now support a method called "is_fault" that may be easily
        used to determine if the "successful" return value is actually a "RPC::XML::fault" without
        the need to use "UNIVERSAL::ISA".

    error_handler ([CODEREF])
    fault_handler ([CODEREF])
    combined_handler ([CODEREF])
        These accessor methods get (and possibly set, if CODEREF is passed) the specified
        callback/handler. The return value is always the current handler, even when setting a new
        one (allowing for later restoration, if desired).

    credentials (REALM, USERNAME, PASSWORD)
        This sets the username and password for a given authentication realm at the location
        associated with the current request URL. Needed if the RPC location is protected by Basic
        Authentication. Note that changing the target URL of the client object to a different
        (protected) location would require calling this with new credentials for the new realm (even
        if the value of $realm is identical at both locations).

    timeout ([INTEGER])
        Get or set the current time-out value on the underlying LWP::UserAgent object that this
        object uses for sending requests. This is just a proxy through to the method of the same
        name in the LWP::UserAgent class. The return value is the current time-out value (prior to
        change, if a new value is given).

    message_file_thresh
    message_temp_dir
        These methods may be used to retrieve or alter the values of the given keys as defined
        earlier for the "new" method.

  Support for Content Compression
    The RPC::XML::Server class supports compression of requests and responses via the Compress::Zlib
    module available from CPAN. Accordingly, this class also supports compression. The methods used
    for communicating compression support should be compatible with the server and client classes
    from the XMLRPC::Lite class that is a part of the SOAP::Lite package (also available from CPAN).

    Compression support is enabled (or not) behind the scenes; if the Perl installation has
    Compress::Zlib, then RPC::XML::Client can deal with compressed responses. However, since
    outgoing messages are sent before a client generally has the chance to see if a server supports
    compression, these are not compressed by default.

    compress_requests(BOOL)
        If a client is communicating with a server that is known to support compressed messages,
        this method can be used to tell the client object to compress any outgoing messages that are
        longer than the threshold setting in bytes.

    compress_thresh([MIN_LIMIT])
        With no arguments, returns the current compression threshold; messages smaller than this
        number of bytes will not be compressed, regardless of the above method setting. If a number
        is passed, this is set to the new lower-limit. The default value is 4096 (4k).

  Callbacks and Return Values
    If a callback is installed for errors or faults, it will be called before either of
    "send_request" or "simple_request" return. If the callback calls die or otherwise interrupts
    execution, then there is no need to worry about the effect on return values. Otherwise, the
    return value of the callback becomes the return value of the original method ("send_request" or
    "simple_request"). Thus, all callbacks are expected, if they return at all, to return exactly
    one value. It is recommended that any callback return values conform to the expected return
    values. That is, an error callback would return a string, a fault callback would return the
    fault object.

DIAGNOSTICS
    All methods return some type of reference on success, or an error string on failure.
    Non-reference return values should always be interpreted as errors, except in the case of
    "simple_request".

CAVEATS
    This began as a reference implementation in which clarity of process and readability of the code
    took precedence over general efficiency. It is now being maintained as production code, but may
    still have parts that could be written more efficiently.

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

SUPPORT
    *   RT: CPAN's request tracker

        <http://rt.cpan.org/NoAuth/Bugs.html?Dist=RPC-XML>

    *   AnnoCPAN: Annotated CPAN documentation

        <http://annocpan.org/dist/RPC-XML>

    *   CPAN Ratings

        <http://cpanratings.perl.org/d/RPC-XML>

    *   Search CPAN

        <http://search.cpan.org/dist/RPC-XML>

    *   MetaCPAN

        <https://metacpan.org/release/RPC-XML>

    *   Source code on GitHub

        <http://github.com/rjray/rpc-xml>

LICENSE AND COPYRIGHT
    This file and the code within are copyright (c) 2011 by Randy J. Ray.

    Copying and distribution are permitted under the terms of the Artistic License 2.0
    (<http://www.opensource.org/licenses/artistic-license-2.0.php>) or the GNU LGPL 2.1
    (<http://www.opensource.org/licenses/lgpl-2.1.php>).

CREDITS
    The XML-RPC standard is Copyright (c) 1998-2001, UserLand Software, Inc. See
    <http://www.xmlrpc.com> for more information about the XML-RPC specification.

SEE ALSO
    RPC::XML, RPC::XML::Server

AUTHOR
    Randy J. Ray "<rjray AT blackperl.com>"