TNetFile


class description - source file - inheritance tree

class TNetFile : public TFile

    private:
TNetFile TNetFile() void Init(Bool_t create) virtual void Print(Option_t* option) const void PrintError(const char* where, Int_t err) Int_t Recv(Int_t& status, EMessageTypes& kind) virtual Int_t SysClose(Int_t fd) virtual Int_t SysOpen(const char* pathname, Int_t flags, UInt_t mode) virtual Int_t SysStat(Int_t fd, Long_t* id, Long_t* size, Long_t* flags, Long_t* modtime) public:
TNetFile TNetFile(const char* url, Option_t* option, const char* ftitle, Int_t compress = 1, Int_t netopt = 0) virtual void ~TNetFile() static TClass* Class() virtual void Close(Option_t* option) virtual void Flush() Int_t GetErrorCode() const virtual TClass* IsA() const virtual Bool_t IsOpen() const virtual Bool_t ReadBuffer(char* buf, Int_t len) virtual Int_t ReOpen(Option_t* mode) virtual void Seek(Seek_t offset, TFile::ERelativeTo pos = kBeg) virtual void ShowMembers(TMemberInspector& insp, char* parent) virtual void Streamer(TBuffer& b) void StreamerNVirtual(TBuffer& b) virtual Bool_t WriteBuffer(const char* buf, Int_t len)

Data Members

    private:
TUrl fUrl URL of file TString fUser remote user name Seek_t fOffset seek offset TSocket* fSocket connection to rootd server Int_t fProtocol rootd protocol level Int_t fErrorCode error code returned by rootd (matching gRootdErrStr) static Int_t fgClientProtocol client protocol level

Class Description

                                                                      
 TNetFile                                                             
                                                                      
 A TNetFile is like a normal TFile except that it reads and writes    
 its data via a rootd server (for more on the rootd daemon see the    
 source files root/rootd/src/*.cxx). TNetFile file names are in       
 standard URL format with protocol "root" or "roots". The following   
 are valid TNetFile URL's:                                            
                                                                      
    roots://hpsalo/files/aap.root                                     
    root://hpbrun.cern.ch/root/hsimple.root                           
    root://pcna49a:5151/~na49/data/run821.root                        
    root://pcna49d.cern.ch:5050//v1/data/run810.root                  
                                                                      
 The only difference with the well known httpd URL's is that the root 
 of the remote file tree is the user's home directory. Therefore an   
 absolute pathname requires a // after the host or port specifier     
 (see last example). Further the expansion of the standard shell      
 characters, like ~, $, .., are handled as expected.                  
 TNetFile (actually TUrl) uses 1094 as default port for rootd.        
                                                                      
 Connecting to a rootd requires the remote user id and password.      
 TNetFile allows three ways for you to provide your login:            
   1) Setting it globally via the static functions:                   
         TAuthenticate::SetGlobalUser() and                           
         TAuthenticate::SetGlobalPasswd()                             
   2) Getting it from the ~/.netrc file (same file as used by ftp)    
   3) Command line prompt                                             
 The different methods will be tried in the order given above.        
 On machines with AFS rootd will authenticate using AFS (if it was    
 compiled with AFS support).                                          
                                                                      
 If the protocol is specified as "roots" a secure authetication       
 method will be used. The secure method uses the SRP, Secure Remote   
 Passwords, package. SRP uses a so called "asymmetric key exchange    
 protocol" in which no passwords are ever send over the wire. This    
 protocol is safe against all known security attacks. For more see:   
  NetFile 
                                                              
 If the protocol is specified as "rootk" kerberos5 will be used for   
 authentication.
                                                                      
 The rootd daemon lives in the directory $ROOTSYS/bin. It can be      
 started either via inetd or by hand from the command line (no need   
 to be super user). For more info about rootd see the web page:       
  NetFile 
                                                              
                                                                      


TNetFile(const char *url, Option_t *option, const char *ftitle, Int_t compress, Int_t netopt) : TFile(url, "NET", ftitle, compress), fUrl(url)
 Create a NetFile object. A net file is the same as a TFile
 except that it is being accessed via a rootd server. The url
 argument must be of the form: root[s|k]://host.dom.ain/file.root.
 When protocol is "roots" try using SRP authentication.
 When protocol is "rootk" try using kerberos5 authentication.
 If the file specified in the URL does not exist, is not accessable
 or can not be created the kZombie bit will be set in the TNetFile
 object. Use IsZombie() to see if the file is accessable.
 If the remote daemon thinks the file is still connected, while you are
 sure this is not the case you can force open the file by preceding the
 option argument with an "-", e.g.: "-recreate". Do this only
 in cases when you are very sure nobody else is using the file.
 To bypass the writelock on a file, to allow the reading of a file
 that is being written by another process, explicitely specify the
 "+read" option ("read" being the default option).
 The netopt argument can be used to specify the size of the tcp window in
 bytes (for more info see: http://www.psc.edu/networking/perf_tune.html).
 The default and minimum tcp window size is 65535 bytes.
 If netopt < -1 then |netopt| is the number of parallel sockets that will
 be used to connect to rootd. This option should be used on fat pipes
 (i.e. high bandwidth, high latency links). The ideal number of parallel
 sockets depends on the bandwidth*delay product. Generally 5-7 is a good
 number.
 For a description of the option and other arguments see the TFile ctor.
 The preferred interface to this constructor is via TFile::Open().

~TNetFile()
 TNetFile dtor. Send close message and close socket.

Int_t SysOpen(const char * /*file*/, Int_t /*flags*/, UInt_t /*mode*/)
 Open a remote file. Requires fOption to be set correctly.

Int_t SysClose(Int_t /*fd*/)
 Close currently open file.

Int_t SysStat(Int_t, Long_t *id, Long_t *size, Long_t *flags, Long_t *modtime)
 Return file stat information. The interface and return value is
 identical to TSystem::GetPathInfo().

void Close(Option_t *opt)
 Close remote file.

void Flush()
 Flush file to disk.

void Init(Bool_t create)
 Initialize a TNetFile object.

Bool_t IsOpen() const
 Retruns kTRUE if file is open, kFALSE otherwise.

void Print(Option_t *) const
 Print some info about the net file.

void PrintError(const char *where, Int_t err)
 Print error string depending on error code.

Int_t ReOpen(Option_t *mode)
 Reopen a file with a different access mode, like from READ to
 UPDATE or from NEW, CREATE, RECREATE, UPDATE to READ. Thus the
 mode argument can be either "READ" or "UPDATE". The method returns
 0 in case the mode was successfully modified, 1 in case the mode
 did not change (was already as requested or wrong input arguments)
 and -1 in case of failure, in which case the file cannot be used
 anymore.

Bool_t ReadBuffer(char *buf, Int_t len)
 Read specified byte range from remote file via rootd daemon.
 Returns kTRUE in case of error.

Bool_t WriteBuffer(const char *buf, Int_t len)
 Write specified byte range to remote file via rootd daemon.
 Returns kTRUE in case of error.

Int_t Recv(Int_t &status, EMessageTypes &kind)
 Return status from rootd server and message kind. Returns -1 in
 case of error otherwise 8 (sizeof 2 words, status and kind).

void Seek(Seek_t offset, ERelativeTo pos)
 Set position from where to start reading.



Inline Functions


           TNetFile TNetFile(const char* url, Option_t* option, const char* ftitle, Int_t compress = 1, Int_t netopt = 0)
              Int_t GetErrorCode() const
            TClass* Class()
            TClass* IsA() const
               void ShowMembers(TMemberInspector& insp, char* parent)
               void Streamer(TBuffer& b)
               void StreamerNVirtual(TBuffer& b)


Author: Fons Rademakers 14/08/97
Last update: root/net:$Name: $:$Id: TNetFile.cxx,v 1.31 2003/02/05 15:11:12 rdm Exp $
Copyright (C) 1995-2000, Rene Brun and Fons Rademakers. *


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