Developers interested in testing the Uniform Clearinghouse APIs at the GPO Clearinghouse can do so using [http://curl.haxx.se/ curl], a command line tool that acts as an HTTP client. The Clearinghouse APIs use [http://xmlrpc.scripting.com/default.html XML-RPC] over HTTPS. It is straightforward to make XML-RPC calls using your GPO Clearinghouse experimenter certificate.

= Calling get_version =
 1. Use the [https://portal.geni.net GPO Portal] to access your experimenter certificate. If you don't already have an account on the GPO Clearinghouse, follow the instructions to access the portal or request an account.
 1. Go to the [https://portal.geni.net/secure/profile.php profile page], select the "SSL" tab, and either create or download your certificate.
  a. The downloaded file will contain a private key and a certificate
 1. Create a file called `get_version.xml` that contains an XML-RPC invocation of the `get_version` API method which takes no parameters:
{{{
#!xml
<?xml version="1.0"?>
<methodCall> 
<methodName>get_version</methodName>
<params></params>
</methodCall>
}}}
 1. Use curl to call get_version at the GPO Clearinghouse Slice Authority:
{{{
curl -H "Content-type: text/xml" --cert geni-username.pem --data @get_version.xml https://ch.geni.net/SA
}}}
 1. Other authorities also respond to `get_version` so the same call can be made to the Member Authority by changing the URL:
{{{
curl -H "Content-type: text/xml" --cert geni-username.pem --data @get_version.xml https://ch.geni.net/SA
}}}
 1. The Service Registry does not require client authentication so it can be called without an experimenter certificate:
{{{
curl -H "Content-type: text/xml" --data @get_version.xml https://ch.geni.net:8444/SR
}}}
= Responses =
Responses from the [wiki:UniformClearinghouseAPIV2 Uniform Clearinghouse API] always have three values: `code`, `value`, and `output`.
 * '''code''' is an integer that indicates the status of the invocation. Zero means success. Any other value is an error code.
 * '''value''' holds the actual data of the return if '''code''' is zero.
 * '''output''' holds a user readable error message if '''code''' is non-zero.

Here is the response from the Service Registry to the get_version call after [http://xmlprettyprint.com/ pretty printing]:
{{{
#!xml
<?xml version="1.0"?>
<methodResponse>
    <params>
        <param>
            <value>
                <struct>
                    <member>
                        <name>output</name>
                        <value>
                            <nil/>
                        </value>
                    </member>
                    <member>
                        <name>code</name>
                        <value>
                            <int>0</int>
                        </value>
                    </member>
                    <member>
                        <name>value</name>
                        <value>
                            <struct>
                                <member>
                                    <name>API_VERSIONS</name>
                                    <value>
                                        <struct>
                                            <member>
                                                <name>2.0</name>
                                                <value>
                                                    <string>https://ch.geni.net:8444/SR/</string>
                                                </value>
                                            </member>
                                        </struct>
                                    </value>
                                </member>
                                <member>
                                    <name>SERVICE_TYPES</name>
                                    <value>
                                        <array>
                                            <data>
                                                <value>
                                                    <string>IRODS</string>
                                                </value>
                                                <value>
                                                    <string>PROJECT_AUTHORITY</string>
                                                </value>
                                                <value>
                                                    <string>AUTHORIZATION_SERVICE</string>
                                                </value>
                                                <value>
                                                    <string>CERTIFICATE_AUTHORITY</string>
                                                </value>
                                                <value>
                                                    <string>KEY_MANAGER</string>
                                                </value>
                                                <value>
                                                    <string>CREDENTIAL_STORE</string>
                                                </value>
                                                <value>
                                                    <string>MEMBER_AUTHORITY</string>
                                                </value>
                                                <value>
                                                    <string>SLICE_AUTHORITY</string>
                                                </value>
                                                <value>
                                                    <string>PGCH</string>
                                                </value>
                                                <value>
                                                    <string>AGGREGATE_MANAGER</string>
                                                </value>
                                                <value>
                                                    <string>LOGGING_SERVICE</string>
                                                </value>
                                                <value>
                                                    <string>WIMAX_SITE</string>
                                                </value>
                                            </data>
                                        </array>
                                    </value>
                                </member>
                                <member>
                                    <name>IMPLEMENTATION</name>
                                    <value>
                                        <struct>
                                            <member>
                                                <name>code_version</name>
                                                <value>
                                                    <string>360c1c8c63cefac33aed5237bb422e4d9de14ed4</string>
                                                </value>
                                            </member>
                                            <member>
                                                <name>code_url</name>
                                                <value>
                                                    <string>http://trac.gpolab.bbn.com/chapi</string>
                                                </value>
                                            </member>
                                            <member>
                                                <name>site_update_date</name>
                                                <value>
                                                    <string>2014-02-13 12:02:35.590788</string>
                                                </value>
                                            </member>
                                            <member>
                                                <name>code_release_date</name>
                                                <value>
                                                    <string>2014-02-13 12:02:35.590788</string>
                                                </value>
                                            </member>
                                        </struct>
                                    </value>
                                </member>
                                <member>
                                    <name>FIELDS</name>
                                    <value>
                                        <struct>
                                            <member>
                                                <name>_GENI_SERVICE_CERT_FILENAME</name>
                                                <value>
                                                    <struct>
                                                        <member>
                                                            <name>OBJECT</name>
                                                            <value>
                                                                <string>SERVICE</string>
                                                            </value>
                                                        </member>
                                                        <member>
                                                            <name>TYPE</name>
                                                            <value>
                                                                <string>STRING</string>
                                                            </value>
                                                        </member>
                                                    </struct>
                                                </value>
                                            </member>
                                            <member>
                                                <name>_GENI_SERVICE_ID</name>
                                                <value>
                                                    <struct>
                                                        <member>
                                                            <name>OBJECT</name>
                                                            <value>
                                                                <string>SERVICE</string>
                                                            </value>
                                                        </member>
                                                        <member>
                                                            <name>TYPE</name>
                                                            <value>
                                                                <string>INTEGER</string>
                                                            </value>
                                                        </member>
                                                    </struct>
                                                </value>
                                            </member>
                                        </struct>
                                    </value>
                                </member>
                                <member>
                                    <name>VERSION</name>
                                    <value>
                                        <string>2.0</string>
                                    </value>
                                </member>
                                <member>
                                    <name>SERVICES</name>
                                    <value>
                                        <array>
                                            <data>
                                                <value>
                                                    <string>SERVICE</string>
                                                </value>
                                            </data>
                                        </array>
                                    </value>
                                </member>
                            </struct>
                        </value>
                    </member>
                </struct>
            </value>
        </param>
    </params>
</methodResponse>
}}}

= MA.lookup("Member")... =
Here is a more complicated method call:
{{{
#!xml
<?xml version="1.0"?>
<methodCall>
    <methodName>lookup</methodName>
    <params>
        <param>
            <value>
                <string>MEMBER</string>
            </value>
        </param>
        <param>
            <value>
                <array>
                    <data/>
                </array>
            </value>
        </param>
        <param>
            <value>
                <struct>
                    <member>
                        <name>match</name>
                        <value>
                            <struct>
                                <member>
                                    <name>MEMBER_URN</name>
                                    <value>urn:publicid:IDN+ch-tm.gpolab.bbn.com+user+USERNAME</value>
                                </member>
                            </struct>
                        </value>
                    </member>
                </struct>
            </value>
        </param>
    </params>
</methodCall>
}}}