WP5: Guide to installing gSOAP

This guide describes how to use gSOAP C/C++ package for GSI-secured WebServices. It expects you to already understand webservices and GSI (Grid Security Infrastructure).

• Download gSOAP and GSI-plugin
• Install gSOAP and compile plugin
• Make GSI-enabled client
• Make GSI-enabled server
• client for multiple services

Download gSOAP and GSI-plugin

• gsoap-linux-2.6.tar.gz from gSOAP download
• gsoap-gsi-plugin-2.0.tgz from GSI plugin page

Install gSOAP and GSI plugin

• soapcpp2 - gsoap parser and WSDL generator
• wsdl2h - gsoap WSDL-to-.h convertor
• stdsoap2.c - gsoap library
• stdsoap2.h - gsoap header
• gsi.c - GSI plugin library
• gsi.h - GSI plugin header

tar xzvf gsoap-linux-2.6.tar.gz
tar xzvf gsoap-gsi-plugin-2.0.tgz
mkdir gsisoap/
cp gsoap-linux-2.6/soapcpp2 gsisoap/
cp gsoap-linux-2.6/wsdl2h gsisoap/
cp gsoap-linux-2.6/stdsoap2.c gsisoap/
cp gsoap-linux-2.6/stdsoap2.h gsisoap/
cp gsoap-gsi-plugin-2.0/src/common/gsi.c gsisoap/
cp gsoap-gsi-plugin-2.0/include/gsi.h gsisoap/

$GLOBUS_LOCATION/sbin/globus-build -install-only gcc32dbgpthr \
        globus_io-2.2.tar.gz
$GLOBUS_LOCATION/sbin/globus-build -install-only gcc32dbgpthr \
	globus_gram_protocol-2.1.tar.gz
$GLOBUS_LOCATION/sbin/globus-build -install-only gcc32dbgpthr \
	globus_gram_client-2.2.tar.gz

Make GSI-enabled client

//gsoap ns service name:       VersionService
//gsoap ns service type:       Version
//gsoap ns service port:       httpg://localhost:8080
//gsoap ns service namespace:  http://localhost:8080/axis/services/Version
//gsoap ns service method-style:       getVersion rpc
//gsoap ns service method-encoding:    getVersion literal
//gsoap ns service method-action:      getVersion ""
int ns__getVersion(
  struct ns__getVersionResponse { char * getVersionReturn; } *
  );

That is how gSOAP specifies webservices' interface. This example is intentionally defined so that it matches the "Version" webservice installed by default in Apache Axis, as described in in webservices in Java guide, so you can test interoperability with that. In fact, if you have the Axis server running, you can create this file with command:

gsisoap/wsdl2h -c -o version.h http://localhost:8080/axis/services/Version?wsdl

You also need the implementation of the client, so create a file named client.c and write there:

#include "verH.h"
#include "gsi.h"
#include "ver.nsmap"

int gsi_authorization_callback (struct soap* soap) {
    struct gsi_plugin_data *data;
    data = (struct gsi_plugin_data *) soap_lookup_plugin (soap, GSI_PLUGIN_ID);
    printf("Connected to: %s\n",data->server_identity);
    return 0;
}

int main(int argc,char** argv) {
    char *url = NULL;
    int numrepeat=1;
    struct soap soap;
    struct gsi_plugin_data *data;
    struct ns__getVersionResponse out; 
    int rc,i;
    for(i=1;i<argc;i++) {
	if(strcmp(argv[i],"-n")==0) {
	    if(i+1<argc) {
		sscanf(argv[i+1],"%d",&numrepeat);
		i++;
		continue;
	    } 
	}
	if(strcmp(argv[i],"-url")==0) {
	    if(i+1<argc) {
		url=argv[i+1];
		i++;
		continue;
	    } 
	}
	printf("Usage: verclient [-n times] [-url url]\n");
	exit(1);
    }

   if(url==NULL||strncmp(url,"httpg:",5)==0) {
    //init GSI stuff
    globus_assert (globus_module_activate (GLOBUS_COMMON_MODULE) == GLOBUS_SUCCESS);
    soap_init2(&soap, SOAP_IO_KEEPALIVE, SOAP_IO_KEEPALIVE);
    soap_set_namespaces(&soap,ver_namespaces);

    if (soap_register_plugin (&soap, globus_gsi)) {
      soap_print_fault (&soap, stderr);
      exit (1);
    }
    /* setup of authorization callback */
    data = (struct gsi_plugin_data *) soap_lookup_plugin (&soap, GSI_PLUGIN_ID);
    data->gsi_authorization_callback = gsi_authorization_callback;
    /* we begin acquiring our credential */
    rc = gsi_acquire_credential(&soap);
    if(rc < 0) exit(1);
    /* setup of GSI channel */
    gsi_set_delegation(&soap, GLOBUS_TRUE);
    gsi_set_replay(&soap, GLOBUS_TRUE);
    gsi_set_sequence(&soap, GLOBUS_TRUE);
    gsi_set_confidentiality(&soap, GLOBUS_TRUE);
    gsi_set_integrity(&soap, GLOBUS_TRUE);

   } else {

    //plain HTTP
    soap_init(&soap);
    soap_set_namespaces(&soap,ver_namespaces);
   }

   for(i=numrepeat;i>0;i--) {
    if(i==1) {
    /* before issuing the last call, we must tell gSOAP that we are going
     to close the connection after this last call
     so that gSOAP can handle Keep-Alive correctly
    */
    soap_clr_omode(&soap, SOAP_IO_KEEPALIVE);
    }
    //call
    if(soap_call_ns__getVersion(&soap,url,NULL,&out) == SOAP_OK) {
      if(strlen(out.getVersionReturn)>50) {
         printf("result: getVersion() = %.50s\n", out.getVersionReturn);
         printf("%d bytes received\n", strlen(out.getVersionReturn));
      } else {
         printf("result: getVersion() = %s\n", out.getVersionReturn);
      }
    } else {// an error occurred 
      soap_print_fault(&soap, stderr);
      exit(1);
    }
   }

    //clean up
    soap_done (&soap);
   if(url==NULL||strncmp(url,"httpg:",5)==0) {
    globus_assert (globus_module_deactivate (GLOBUS_COMMON_MODULE) == GLOBUS_SUCCESS);
   }
}

//intentionaly left empty

#directory for generating "env*" files
ENVDIR=envdir
#directory for generating "ver*" files
VERDIR=verdir
#directory with gSOAP and GSI plugin files
GSISOAP=gsisoap

#flavor of threads to use
GLOBUS_FLAVOR=gcc32dbg
#Globus libraries
LDFLAGS= -L$(GLOBUS_LOCATION)/lib \
		-lglobus_gram_client_$(GLOBUS_FLAVOR) \
		-lglobus_gram_protocol_$(GLOBUS_FLAVOR) \
		-lglobus_gss_assist_$(GLOBUS_FLAVOR) \
		-lglobus_gssapi_gsi_$(GLOBUS_FLAVOR) \
		-lglobus_common_$(GLOBUS_FLAVOR)

#Globus, gSOAP and GSI-plugin includes
CFLAGS=-I$(GSISOAP) -I$(GLOBUS_LOCATION)/include/$(GLOBUS_FLAVOR) \
		-DDEBUG -O2 -g

all: verclient verserver


#GSI
gsi.o: $(GSISOAP)/gsi.c
	gcc $(CFLAGS) -c $(GSISOAP)/gsi.c

#empty definition for standard namespaces and headers
envC.o: env.h
	mkdir $(ENVDIR)
	$(GSISOAP)/soapcpp2 -c -penv -d $(ENVDIR) env.h
	gcc $(CFLAGS) -I$(ENVDIR) -c $(ENVDIR)/envC.c

#main gSOAP library without namespaces
stdsoap2.o: $(GSISOAP)/stdsoap2.c
	gcc $(CFLAGS) -DWITH_NONAMESPACES -c $(GSISOAP)/stdsoap2.c

#libraries specific to Version service
verClientLib.o: $(VERDIR)/verClientLib.c
	gcc $(CFLAGS) -c $(VERDIR)/verClientLib.c 

verServerLib.o: $(VERDIR)/verServerLib.c
	gcc $(CFLAGS) -c $(VERDIR)/verServerLib.c 
		
#generates files for Version library
$(VERDIR)/verClientLib.c: version.h
	mkdir $(VERDIR)
	$(GSISOAP)/soapcpp2 -c -pver -d $(VERDIR) -n version.h
$(VERDIR)/verServerLib.c: version.h
	mkdir $(VERDIR)
	$(GSISOAP)/soapcpp2 -c -pver -d $(VERDIR) -n version.h

verclient:  client.c envC.o verClientLib.o stdsoap2.o gsi.o
	gcc $(CFLAGS) -I$(VERDIR) \
		-o verclient client.c \
		verClientLib.o envC.o stdsoap2.o gsi.o \
		$(LDFLAGS)

verserver:  server.c envC.o  stdsoap2.o verServerLib.o gsi.o
	gcc $(CFLAGS) -I$(VERDIR) \
		-o verserver server.c \
		verServerLib.o envC.o stdsoap2.o gsi.o \
		$(LDFLAGS)

clean:
	rm -f verClient.c verclient verserver VersionService* *.log ver[VSHC]* core *.xsd *.o env[A-Z]*
	rm -rf $(VERDIR) $(ENVDIR)

./verclient -url httpg://localhost:8443/axis/services/Version

Make GSI-enabled server

#include "verH.h"
#include "gsi.h"
#include "ver.nsmap"


static char* returnString = "gSOAP 2.6 server";
int ns__getVersion(struct soap* soap, struct ns__getVersionResponse *out) {

  out->getVersionReturn = returnString;
  return SOAP_OK;
}

int gsi_authorization_callback (struct soap* soap) {
    struct gsi_plugin_data *data;
    data = (struct gsi_plugin_data *) soap_lookup_plugin (soap, GSI_PLUGIN_ID);
    printf("Connected to: %s\n",data->client_identity);
    return 0;
}

int main(int argc,char **argv) {
   struct soap soap;
   int markLarge = 0;
   int size = 1000;
   int port = 8080;
   int rc;
   int i, m, s; // master and slave sockets
   struct gsi_plugin_data *data;


   //options
   for(i=1;i<argc;i++) {
       if(strcmp(argv[i],"-large")==0) {
	       markLarge = 1; 
	       if(i+1<argc) {
		   sscanf(argv[i+1],"%d",&size);
		   i++;
		   continue;
	       }
	       continue;
       }
       printf("Usage: verserver [-large [bytes]]\n");
       exit(1);
   }
   if(markLarge) {
           returnString = (char*)malloc(size+1);
           memset(returnString,'A',size);
	   returnString[size]=0;
   }


   globus_assert (globus_module_activate (GLOBUS_COMMON_MODULE) == GLOBUS_SUCCESS);



  /* we initialize gSOAP for Keep-Alive connections */
  soap_init2(&soap, SOAP_IO_KEEPALIVE, SOAP_IO_KEEPALIVE);
  soap_set_namespaces(&soap,ver_namespaces);

  /* we register the GSI plugin */
  if (soap_register_plugin (&soap, globus_gsi)){
        soap_print_fault (&soap, stderr);
        exit (1);
  }

  /* we begin acquiring our credential */
  rc = gsi_acquire_credential(&soap);
  if(rc < 0)
        exit(1);

  /* setup of authorization callback */
  data = (struct gsi_plugin_data *) soap_lookup_plugin (&soap, GSI_PLUGIN_ID);
  data->gsi_authorization_callback = gsi_authorization_callback;

  /* listen for incoming connections */
  gsi_listen(&soap, NULL, port, 100);

  for (i = 1; ; i++) {
     struct soap *tsoap;
     /* accepting incoming connections */
     /* TODO */ gsi_accept (&soap);
     if (data->connected_fd < 0) continue;
     /* retrieving information about the peer */
     tsoap=soap_copy(&soap);
     fprintf(stderr, "Accepted connection from %s %s\n", data->host, data->port);
     rc = gsi_accept_security_context(tsoap);
     if(rc == 0){
         ver_serve(tsoap); // process RPC request
         soap_destroy(tsoap); // clean up class instances
         soap_end(tsoap); // clean up everything and close socket
	 soap_done(tsoap);
     } else {
	 fprintf(stderr, "security context not accepted\n");
	 soap_receiver_fault(tsoap,"problems",NULL);
	 soap_send_fault(tsoap);
         soap_end(tsoap); // clean up everything and close socket
     }
  }
}

./verserver &
./verclient

A client for multiple services

When you want to write a client which connects to more than one service, the trick (as described in chapter 15.34.2 of gSOAP user guide) is to use switches -p name -n for soapcpp2 compiler, build separate libraries for each service, compile the stdsoap2.c file with option -DWITH_NONAMESPACES, and use call soap_set_namespaces(&soap,name_namespaces) to set appropriate namespaces for calls to each separate service.

However in this moment, when you try to follow the chapter 15.34.2 example, you will find that including headers files for more than one service like

#include "firstStub.h"
#include "secondStub.h"
#include "first.nsmap"
#include "second.nsmap"

produces name clashes. Right now the only solution is to edit these files by hand and remove identical definitions.

Last updated: $Date: 2004/05/22 16:45:33 $