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[ WORK IN PROGRESS ]

Preliminaries: build machine configuration

Before developing a CREAM's CLI you must configure properly a SL5_64bit machine with EPEL repositories and basic EMI1 software. Instructions are here:

http://wiki.italiangrid.org/twiki/bin/view/CREAM/SystemAdministratorGuideForEMI1#1_3_Installation .

Here are summarized all the steps described in the link above plus some more rpm to install and other settings:

\rm /etc/yum.repos.d/dag.repo
rpm -Uvh http://download.fedora.redhat.com/pub/epel/5/i386/epel-release-5-4.noarch.rpm
wget http://emisoft.web.cern.ch/emisoft/dist/EMI/1/sl5/x86_64/base/emi-release-1.0.0-1.sl5.noarch.rpm
yum -y install ./emi-release-1.0.0-1.sl5.noarch.rpm
wget http://repository.egi.eu/sw/production/cas/1/current/repo-files/egi-trustanchors.repo -O /etc/yum.repos.d/egi-trustanchors.repo
wget http://forge.cnaf.infn.it/frs/download.php/101/disable_yum.sh
chmod +x disable_yum.sh
./ disable_yum.sh
yum clean all; yum update all
yum -y install yum-protectbase.noarch
yum -y install ca-policy-egi-core
yum -y install glite-ce-cream-client-api-c.x86_64
yum -y install glite-lbjp-common-gsoap-plugin
yum -y install boost-devel
yum -y install voms-devel voms-clients

Then, download, build and install gSOAP 2.7.6b from this URL:

https://etics-repository.cern.ch/repository/download/registered/externals/gsoap/2.7.6b/src/

Now create these symlinks:

ln -s /usr/lib64/liblog4cpp.so.4 /usr/lib64/liblog4cpp.so
ln -s /usr/lib64/libclassad.so.1 /usr/lib64/libclassad.so
ln -s /usr/lib64/libclassad_ns.so.1 /usr/lib64/libclassad_ns.so
ln -s /usr/lib64/libcares.so.2 /usr/lib64/libcares.so
ln -s /usr/lib64/libglobus_common.so.0 /usr/lib64/libglobus_common.so
ln -s /usr/lib64/libglobus_gsi_callback.so.0 /usr/lib64/libglobus_gsi_callback.so
ln -s /usr/lib64/libglobus_gssapi_gsi.so.4 /usr/lib64/libglobus_gssapi_gsi.so
ln -s /usr/lib64/libglobus_gsi_credential.so.1 /usr/lib64/libglobus_gsi_credential.so
ln -s /usr/lib64/libltdl.so.3 /usr/lib64/libltdl.so
ln -s /usr/lib64/libglobus_oldgaa.so.0 /usr/lib64/libglobus_oldgaa.so
ln -s /usr/lib64/libglobus_proxy_ssl.so.1 /usr/lib64/libglobus_proxy_ssl.so
ln -s /usr/lib64/libglobus_openssl_error.so.0 /usr/lib64/libglobus_openssl_error.so
ln -s /usr/lib64/libglobus_gsi_proxy_core.so.0 /usr/lib64/libglobus_gsi_proxy_core.so
ln -s /usr/lib64/libglobus_gsi_cert_utils.so.0 /usr/lib64/libglobus_gsi_cert_utils.so
ln -s /usr/lib64/libglobus_gsi_sysconfig.so.1 /usr/lib64/libglobus_gsi_sysconfig.so
ln -s /usr/lib64/libglobus_openssl.so.0 /usr/lib64/libglobus_openssl.so

CLI Development

In the attachments you can find small examples that explain how to use the CREAM Client API C++. You can build them by issuing the commands:

COMPILATION:
g++ -c -I/usr/local/include <EXAMPLE>.cpp
LINKING:
g++ -o <EXAMPLE> <EXAMPLE>.o -lglite_security_gsoap_plugin_276b \
   -lglite_ce_cream_client_soap -lglite_ce_cream_client_util \
   /usr/local/lib/libgsoap++.a -lboost_thread -llog4cpp \
   -lvomsapi -lclassad_ns -lgridsite -lboost_regex

API

Currently, the C++ API implements the following operations:

The API architecture is founded on a super and abstract class AbsCreamProxy that exposes 3 relevant public methods: AbsCreamProxy::setCredential(...), AbsCreamProxy::setConnectionTimeout(...), AbsCreamProxy::execute(...). The method execute(...) is pure virtual.

There're several AbsCreamProxy's subclasses, one for each operation mentioned above: CreamProxy _Start, CreamProxy _Register, CreamProxy _Cancel, and so on. Each of them implements its own execute(...) method, specific for the kind of operation the subclass itself represents; this implementation is responsible for the connection to the remote Web Service (CREAM), sending the SOAP request, receiving the SOAP response and unserializing it and hides the user from any SOAP communication and authentication detail. All the subclasses have protected constructors, so the developer cannot directly create a subclass, but she/he must use a special factory named CreamProxyFactory. For each operation the factory has a make_<OPERATION_NAME>(...) method. The factory's 'make' methods return a pointer to an AbsCreamProxy object (polimorphic object) that allows the developer to handle more instances of different subclasses in the same way (for example to put all of them in a container). The 'make' methods take different parameters depending on the kind of operation is performed by the returned object.

When the user got a pointer to AbsCreamProxy she/he has to invoke the setCredential(...) method in order to set the authentication credentials, optionally invoke the setConnectionTimeout(...) in order to set a maximum socket timeout for the connections with the CREAM service, and then must invoke execute(...) to actually communicate with the service (send SOAP request, receive and parse SOAP response).

It is clear that the developer has to know nothing about subclasses: she/he just uses factory's make methods and the two methods setCredential(...) and execute(...); then the subclasses are not documented at all. The API documentation only describes the AbsCreamProxy, the factory and the data structures to pass as argument of the 'make' methods of the factory.

At the end, the user must delete the pointer to AbsCreamProxy in order to free the heap-memory that the factory allocated.

[ TO BE CONTINUED ... ]

-- AlviseDorigo - 2011-06-14

Topic attachments
I Attachment Action Size Date Who Comment
C source code filecpp tryCancel.cpp manage 4.3 K 2011-06-20 - 08:29 AlviseDorigo  
C source code filecpp tryDelegate.cpp manage 1.3 K 2011-06-15 - 07:03 AlviseDorigo  
C source code filecpp tryInfo.cpp manage 4.6 K 2011-06-20 - 08:29 AlviseDorigo  
C source code filecpp tryList.cpp manage 1.2 K 2011-06-20 - 08:29 AlviseDorigo  
C source code filecpp tryRegister.cpp manage 3.6 K 2011-06-15 - 07:03 AlviseDorigo  
C source code filecpp tryServiceInfo.cpp manage 1.6 K 2011-06-20 - 08:29 AlviseDorigo  
C source code filecpp tryStart.cpp manage 4.6 K 2011-06-15 - 07:03 AlviseDorigo  
C source code filecpp tryStatus.cpp manage 4.5 K 2011-06-20 - 08:29 AlviseDorigo  
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Topic revision: r5 - 2011-07-06 - AlviseDorigo
 

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