Re: [Koha-zebra] Perl Zoom Persistent Connections

[Thomas D]

I assume that if the authentication is collective for the client institution
with all client users users sharing the same persistent connection at the
client institution, the user specific authentication issue should be avoided.

Is this cookie ID based connection persistence entirely transparent without
requiring management in PHP/YAZ or other bindings?  I do not find any
documentation for the ID or cookie management.

Will the forthcoming Perl Zoom bindings support persistent connections,
either shared or user specific?

I had given reasons that I had thought that persistent connections were
useful with even one user retrieving large result sets in my previous post
on a different branch of this thread.


Thomas D
 
  Quoting Sebastian Hammer <address@hidden> :
> ---------------- Beginning of the original message ------------------
> 
> 
> Although as Mike points out, Z39.50 is a stateful protocol, it
> is often 
> used in a non-stateful way in a web environment.
> 
> The PHP/YAZ 'persistent' connections means something a little
> different. 
> Basically, it allows the webserver, when PHP is installed as a
> module, to 
> keep connections open to the server between HTTP requests.
> This is a naive 
> type of persistency, as the same connection may be shared
> among different 
> users. However, it does potentially reduce the overheads
> associated with 
> opening connections and initializing associations.. it is
> intended for use 
> in applications with large numbers of transactions where it's
> useful to 
> limit network traffic.. obviously, it does NOT work well if
> user-specific 
> authentication is used against the server.
> 
> PHP/YAZ, in combination with the YAZ proxy, can be used to
> implement a more 
> clever kind of persistency. It can actually keep user-specific
> sessions 
> alive against a target, and associate each new incoming
> request with the 
> right session based on a cookie. To this end, it uses an
> ID-specific 
> extension to Z39.50, which is also supported by the YAZ/ZOOM
> (and YAZ/PHP) API.
> 
> --Sebastian
> 
> At 07:44 PM 8/19/2005 +0200, Thomas D wrote:
> >PHP/YAZ was not written to use Zoom.  PHP/YAZ has persistent
> connections.
> >
> >Persistent connections are kept alive continuously and should
> not require
> >reinitialisation of a new connection for each query, nor
> should they time
> >out arbitrarily when the server determines your connection is
> inactive or
> >becomes 'tired' of serving more results.
> >
> >yaz_connect() parameter options include persistent.
> >
> >This seems ussefull except for the problem of closing a
> persistent connection.
> >
> >"persistent"
> >
> >"    A boolean. If TRUE the connection is persistent; If
> FALSE the
> >connection is not persistent. By default connections are
> persistent."
> >
> >"        Note: If you open a persistent connection, you won't
> be able to
> >close it later with yaz_close()."
> >
> >Yaz_connect. PHP manual. The PHP Group. 2005.
> >http://www.php.net/manual/en/function.yaz-connect.php .
> >
> >
> >Thomas D
> >
> >
> >Quoting Mike Taylor <address@hidden> :
> > > ---------------- Beginning of the original message
> ------------------
> > >
> > > > Date: Fri, 19 Aug 2005 17:31:07 +0200
> > > > From: Thomas D <address@hidden>
> > > >
> > > > Will the forthcoming Perl bindings for Zoom support
> > > persistent
> > > > Z39.50 connections?
> > >
> > > Of course -- that is the only kind of Z39.50 connection.
> > > Z39.50 is
> > > not stateless like HTTP: all communication is of the form
> > >
> > >       open a connection
> > >       while you're still interested {
> > >               send a request
> > >               wait for the response
> > >               do something with it
> > >       }
> > >
> > > > If there will be support for persistent connections,
> will
> > > that
> > > > support include a means to close those connections on
> > > command;
> > > > without killing the process from the shell, removing
> power
> > > to the
> > > > system or some other drastic measure [...]
> > >
> > > Yes, the $zoom->close() method will do this.
> > >
> > > > [...] as may be required for some existing Zoom bindings
> > > with no
> > > > means to close a persistent connection?
> > >
> > > There are none to my knowledge.  The ZOOM Abstract API
> > > mandates a
> > > Close method for Connection object -- see:
> > >       http://zoom.z3950.org/api/zoom-1.4.html#3.2.6
> > > and it is implemented (under the name
> > > ZOOM_connection_destroy()) but
> > > the ZOOM-C binding -- see:
> > >      
> http://indexdata.com/yaz/doc/zoom.tkl#zoom.connections
> > > and also by the current Perl implementation, the
> Net::Z3950
> > > module --
> > > see:
> > >      
> http://perl.z3950.org/docs/Z3950/Connection.html#close()
> > >
> > > I am not quite sure what your question means ...
> > >
> > >  _/|_
> > >
> ___________________________________________________________________
> > > /o ) \/  Mike Taylor  <address@hidden>
> > > http://www.miketaylor.org.uk
> > > )_v__/\  "No one in charge of Christianity seems to be
> that
> > > convinced
> > >       about the product" -- Tim Rice.
> > >
> > >
> > >
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> --
> Sebastian Hammer, Index Data, www.indexdata.com
> Direct phone: (603) 209-6853 Fax: (603) 357-1813
> 
> 
> 
> 
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