Provided by: libownet-perl_2.8p13+dfsg1-5build1_all bug

NAME

       OWNet - Light weight access to owserver

SYNOPSIS

       OWNet is an easy way to access owserver and thence the 1-wire bus.

       Dallas Semiconductor's 1-wire system uses simple wiring and unique addresses for its
       interesting devices. The One Wire File System (OWFS) is a suite of programs that hide
       1-wire details behind a file system metaphor. owserver connects to the 1-wire bus and
       provides network access.

       OWNet is a perl module that connects to owserver and allows reading, writing and listing
       the 1-wire bus.

       Example perl program that prints the temperature:

        use OWNet ;
        print OWNet::read( "localhost:4304" , "/10.67C6697351FF/temperature" ) ."\n" ;

       There is the alternative object oriented form:

        use OWNet ;
        my $owserver = OWNet->new( "localhost:4304" ) ;
        print $owserver->read( "/10.67C6697351FF/temperature" ) ."\n" ;

SYNTAX

   methods
       new
            my $owserver = OWNet -> new( address ) ;

       read
            OWNet::read( address, path [,size [,offset]] )
            $owserver -> read( path [,size [,offset]] )

       write
            OWNet::write( address, path, value [,offset] )
            $owserver -> write( path, value [,offset] )

       dir
            OWNet::dir( address, path )
            $owserver -> dir( path )

   address
       TCP/IP address of owserver. Valid forms:

       name test.owfs.net:4304
       quad number: 123.231.312.213:4304
       host localhost:4304
       port 4304

   additional arguments
       Additional arguments to add to address

       Temperature scale can also be specified in the address. Same syntax as the other OWFS
       programs:

       -C Celsius (Centigrade)
       -F Fahrenheit
       -K Kelvin
       -R Rankine

       Pressure scale can also be specified in the address. Same syntax as the other OWFS
       programs:

       --mbar     millibar (default)
       --atm      atmosphere
       --mmHg     mm Mercury
       --inHg     inch Mercury
       --psi      pounds per inch^2
       --Pa       pascal

       Device display format (1-wire unique address) can also be specified in the address, with
       the general form of -ff[.]i[[.]c] (family id crc):

       -ff.i   /10.67C6697351FF (default)
       -ffi    /1067C6697351FF
       -ff.i.c /10.67C6697351FF.8D
       -ff.ic  /10.67C6697351FF8D
       -ffi.c  /1067C6697351FF.8D
       -ffic   /1067C6697351FF8D

       Show directories that are themselves directories with a '/' suffix ( e.g.
       /10.67C6697351FF/ )

       -slash  show directory elements

       Warning messages will only be displayed if verbose flag is specified in address

       -v      verbose

   path
       owfs-type path to an item on the 1-wire bus. Valid forms:

       main directories
           Used for the dir method. E.g. "/" "/uncached" "/1F.321432320000/main"

       device directory
           Used for the dir and present method. E.g. "/10.4300AC220000" "/statistics"

       device properties
           Used to read, write. E.g. "/10.4300AC220000/temperature"

   value
       New value for a device property. Used by write.

METHODS

       new Object-oriented (only):

           OWNet::new( address )

           Create a new OWNet object -- corresponds to an owserver.

           Error (and undef return value) if:

           1 Badly formed tcp/ip address
           2 No owserver at address

       read
           Non object-oriented:
               OWNet::read( address , path [ , size [ , offset ] ] )

           Object-oriented:
               $ownet->read( path [ , size [ , offset ] ] )

           Read the value of a 1-wire device property. Returns the (scalar string) value of the
           property.

           size (number of bytes to read) is optional

           offset (number of bytes from start of field to start write) is optional

           Error (and undef return value) if:

           1 (Non object) No owserver at address
           2 (Object form) Not called with a valid OWNet object
           3 Bad path
           4 path not a readable device property

       write
           Non object-oriented:
               OWNet::write( address , path , value [ , offset ] )

           Object-oriented:
               $ownet->write( path , value [ , offset ] )

           Set the value of a 1-wire device property. Returns "1" on success.

           offset (number of bytes from start of field to start write) is optional

           Error (and undef return value) if:

           1 (Non object) No owserver at address
           2 (Object form) Not called with a valid OWNet object
           3 Bad path
           4 path not a writable device property
           5 value incorrect size or format

       dir
           Non object-oriented:
               OWNet::dir( address , path )

           Object-oriented:
               $ownet->dir( path )

           Return a comma-separated list of the entries in path. Entries are equivalent to "fully
           qualified names" -- full path names.

           Error (and undef return value) if:

           1 (Non object) No owserver at address
           2 (Object form) Not called with a valid OWNet object
           3 Bad path
           4 path not a directory

       present (deprecated)
           Non object-oriented:
               OWNet::present( address , path )

           Object-oriented:
               $ownet->present( path )

           Test if a 1-wire device exists.

           Error (and undef return value) if:

           1 (Non object) No owserver at address
           2 (Object form) Not called with a valid OWNet object
           3 Bad path
           4 path not a device

DESCRIPTION

   OWFS
       OWFS is a suite of programs that allows easy access to Dallas Semiconductor's 1-wire bus
       and devices.  OWFS provides a consistent naming scheme, safe multplexing of 1-wire
       traffice, multiple methods of access and display, and network access.  The basic OWFS
       metaphor is a file-system, with the bus beinng the root directory, each device a
       subdirectory, and the the device properties (e.g. voltage, temperature, memory) a file.

   1-Wire
       1-wire is a protocol allowing simple connection of inexpensive devices.  Each device has a
       unique ID number (used in its OWFS address) and is individually addressable.  The bus
       itself is extremely simple -- a data line and a ground. The data line also provides power.
       1-wire devices come in a variety of packages -- chips, commercial boxes, and iButtons
       (stainless steel cans).  1-wire devices have a variety of capabilities, from simple ID to
       complex voltage, temperature, current measurements, memory, and switch control.

   Programs
       Connection to the 1-wire bus is either done by bit-banging a digital pin on the processor,
       or by using a bus master -- USB, serial, i2c, parallel.  The heavy-weight OWFS programs:
       owserver owfs owhttpd owftpd and the heavy-weight perl module OW all link in the full OWFS
       library and can connect directly to the bus master(s) and/or to owserver.

       OWNet is a light-weight module. It connects only to an owserver, does not link in the OWFS
       library, and should be more portable..

   Object-oriented
       OWNet can be used in either a classical (non-object-oriented) manner, or with objects.
       The object stored the ip address of the owserver and a network socket to communicate.
       OWNet will use persistent tcp connections for the object form -- potentially a performance
       boost over a slow network.

EXAMPLES

   owserver
       owserver is a separate process that must be accessible on the network. It allows multiple
       clients, and can connect to many physical 1-wire adapters and 1-wire devices. It's address
       must be discoverable -- either set on the command line, or at it's default location, or by
       using Bonjour (zeroconf) service discovery.

       An example owserver invocation for a serial adapter and explicitly chooses the default
       port:

        owserver -d /dev/ttyS0 -p 4304

   OWNet
        use OWNet ;

        # Create owserver object
        my $owserver = OWNet->new('localhost:4304 -v -F') ; #default location, verbose errors, Fahrenheit degrees
        # my $owserver = OWNet->new() ; #simpler, again default location, no error messages, default Celsius

        #print directory
        print $owserver->dir('/') ;

        #print temperature from known device (DS18S20,  ID: 10.13224366A280)
        print "Temperature: ".$owserver->read('/uncached/10.13224366A280/temperature') ;

        # Now for some fun -- a tree of everything:
        sub Tree($$) {
          my $ow = shift ;
          my $path = shift ;

          print "$path\t" ;

          # first try to read
          my $value = $ow->read($path) ;
          if ( defined($value) ) {
            print "$value\n";
            return ;
          }

          # not readable, try as directory
          my $dirstring = $ow->dir($path) ;
          if ( defined($dirstring) ) {
            print "<directory>\n" ;
            my @dir = split /,/ ,  $ow->dir($path) ;
            foreach (@dir) {
               Tree($ow,$_) ;
            }
            return ;
          }

          # can't read, not directory
          print "<write-only>\n" ;
          return ;
        }

        Tree( $owserver, '/' ) ;

INTERNALS

   Object properties (All private)
       ADDR
           literal sting for the IP address, in dotted-quad or host format. This property is also
           used to indicate a substantiated object.

       PORT
           string for the port number (or service name). Service name must be specified as
           :owserver or the like.

       SG  Flag sent to server, and returned, that encodes temperature scale and display format.
           Persistence is also encoded in this word in the actual tcp message, but kept
           separately in the object.

       VERBOSE
           Print error messages? Set by "-v" in object invocation.

       SLASH
           Add "/" to the end of directory entries. Set by "-slash" in object invocation.

       SOCK
           Socket address (object) for communication. Stays defined for persistent connections,
           else deleted between calls.

       PERSIST
           State of socket connection (persistent means the same socket is used which speeds
           network communication).

       VER owprotocol version number (currently 0)

   Private methods
       _self
           Takes either the implicit object reference (if called on an object) or the ip address
           in non-object format.  In either case a socket is created, the persistence bit is
           properly set, and the address parsed.  Returns the object reference, or undef on
           error.  Called by each external method (read,write,dir) on the first parameter.

       _new
           Takes command line invocation parameters (for an object or not) and properly parses
           and sets up the properties in a hash array.

       _Sock
           Socket processing, including tests for persistence and opening.  If no host is
           specified, localhost (127.0.0.1) is used.  If no port is specified, uses the IANA
           allocated well known port (4304) for owserver. First looks in /etc/services, then just
           tries 4304.

       _ToServer
           Sends a message to owserver. Formats in owserver protocol. If a persistent socket
           fails, retries after new socket created.

       _FromServerBinaryParse
           Reads a specified length from server

       _FromServer
           Reads whole packet from server, using _FromServerBinaryParse (first for header, then
           payload). Discards ping packets silently.

       _BonjourLookup
           Uses the mDNS service discovery protocol to find an available owserver.  Employs
           NET::Rendezvous (an earlier name or Apple's Bonjour) This module is loaded only if
           available. (Uses the method of
           http://sial.org/blog/2006/12/optional_perl_module_loading.html)

AUTHOR

       Paul H Alfille paul.alfille@gmail.com

BUGS

       Support for proper timeout using the "select" function seems broken in perl. This might
       leave the routines vulnerable to network timing errors.

SEE ALSO

       http://www.owfs.org
           Documentation for the full owfs program suite, including man pages for each of the
           supported 1-wire devices, and more extensive explanatation of owfs components.

       http://owfs.sourceforge.net/projects/owfs
           Location where source code is hosted.

COPYRIGHT

       Copyright (c) 2007 Paul H Alfille. All rights reserved.
        This program is free software; you can redistribute it and/or
        modify it under the same terms as Perl itself.