hclientbonj.C File Reference

Detailed Description

Client program which creates and fills a histogram.

Every 1000 fills the histogram is send to the server which displays the histogram.

To run this demo do the following:

• Open three windows
• Start ROOT in all three windows
• Execute in the first window: .x hserv.C (or hserv2.C)
• Execute in the second and third windows: .x hclient.C If you want to run the hserv.C on a different host, just change "localhost" in the TSocket ctor below to the desired hostname.

The script argument "evol" can be used when using a modified version of the script where the clients and server are on systems with different versions of ROOT. When evol is set to kTRUE the socket will support automatic schema evolution between the client and the server.

#include "TBenchmark.h"
#include "TList.h"
#include "TInetAddress.h"
#include "TSocket.h"
#include "TMessage.h"
#include "TH1.h"
#include "TH2.h"
#include "TRandom.h"
#include "TBonjourBrowser.h"
#include "TBonjourResolver.h"
#include "TBonjourRecord.h"


static Bool_t gEvo = kFALSE;

void ConnectToServer(const TInetAddress *hostb, Int_t port)
{
   // Called by the Bonjour resolver with the host and port to which
   // we can connect.

   // Connect only once...
   TBonjourResolver *resolver = (TBonjourResolver*) gTQSender;
   TInetAddress host = *hostb;
   delete resolver;

   printf("ConnectToServer: host = %s, port = %d\n", host.GetHostName(), port);

   //--- Here starts original hclient.C code ---

   // Open connection to server
   TSocket *sock = new TSocket(host.GetHostName(), port);

   // Wait till we get the start message
   char str[32];
   sock->Recv(str, 32);

   // server tells us who we are
   int idx = !strcmp(str, "go 0") ? 0 : 1;

   Float_t messlen  = 0;
   Float_t cmesslen = 0;
   if (idx == 1)
      sock->SetCompressionLevel(1);

   TH1 *hpx;
   if (idx == 0) {
      // Create the histogram
      hpx = new TH1F("hpx","This is the px distribution",100,-4,4);
      hpx->SetFillColor(48);  // set nice fill-color
   } else {
      hpx = new TH2F("hpxpy","py vs px",40,-4,4,40,-4,4);
   }

   TMessage::EnableSchemaEvolutionForAll(gEvo);
   TMessage mess(kMESS_OBJECT);
   //TMessage mess(kMESS_OBJECT | kMESS_ACK);

   // Fill histogram randomly
   gRandom->SetSeed();
   Float_t px, py;
   const int kUPDATE = 1000;
   for (int i = 0; i < 25000; i++) {
      gRandom->Rannor(px,py);
      if (idx == 0)
         hpx->Fill(px);
      else
         hpx->Fill(px,py);
      if (i && (i%kUPDATE) == 0) {
         mess.Reset();              // re-use TMessage object
         mess.WriteObject(hpx);     // write object in message buffer
         sock->Send(mess);          // send message
         messlen  += mess.Length();
         cmesslen += mess.CompLength();
      }
   }
   sock->Send("Finished");          // tell server we are finished

   if (cmesslen > 0)
      printf("Average compression ratio: %g\n", messlen/cmesslen);

   gBenchmark->Show("hclient");

   // Close the socket
   sock->Close();
}

void UpdateBonjourRecords(TList *records)
{
   // Browse for Bonjour record of type "_hserv2._tcp." in domain "local.".
   // When found, create Bonjour resolver to get host and port of this record.

   static Bool_t resolved = kFALSE;

   // we can be called multiple times whenever a new server appears
   printf("UpdateBonjourRecords (resolved = %s)\n", resolved ? "kTRUE" : "kFALSE");

   if (resolved) return;

   // Look for _hserv2._tcp. in local. domain and try to resolve it
   TBonjourRecord *rec;
   TIter next(records);
   while ((rec = (TBonjourRecord*) next())) {
      if (!strcmp(rec->GetRegisteredType(), "_hserv2._tcp.") &&
          !strcmp(rec->GetReplyDomain(), "local.")) {
         rec->Print();
         TBonjourResolver *resolver = new TBonjourResolver;
         resolver->Connect("RecordResolved(TInetAddress*,Int_t)", 0, 0,
                           "ConnectToServer(TInetAddress*,Int_t)");
         resolver->ResolveBonjourRecord(*rec);
         resolved = kTRUE;
      }
   }
}

void hclientbonj(Bool_t evol=kFALSE)
{
   gEvo = evol;

   gBenchmark->Start("hclient");

   TBonjourBrowser *browser = new TBonjourBrowser;
   browser->Connect("CurrentBonjourRecordsChanged(TList*)", 0, 0,
                    "UpdateBonjourRecords(TList*)");
   browser->BrowseForServiceType("_hserv2._tcp");
}

Author

Fons Rademakers

Definition in file hclientbonj.C.