OWNet(3pm)

🦋 OWNet 🦋

okay bestie, gather round, because this is OWNet(3pm) from the User Contributed Perl Documentation section and it is lowkey iconic 💅

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✨ NAME ✨

OWNet — Light weight access to owserver 🫶

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🌸 SYNOPSIS 🌸

so, OWNet is an easy way to access owserver and thence the 1-wire bus. no cap.

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. it's giving "small but mighty" ✨

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" ;

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🎀 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

Trim whitespace from numeric values

• -trim — trim spaces

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.

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💅 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)

🚨 bestie, heads up: present is deprecated. it's still here, but it's giving "legacy era". 🚨

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

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🌈 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. ⚡

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⭐ 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 🫧

okay bestie, this is the backstage area. no flashy lights, just the machinery. but it's so iconic, fr fr.

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💖 Object properties (All private) 💖

ngl these are all private, so don't go poking at them like they're public API. they're the object's little diary entries.

• ADDR — a literal sting for the IP address, in dotted-quad or host format. lowkey this one does double duty: it's also the flag that says an object is substantiated. like, "yes this is a real one, she's here."
• PORT — a string for the port number (or the service name, bestie). if you're using a service name it must be written like :owserver or the like. no shortcuts, sorry not sorry.
• SG — a flag that gets sent to the server and comes back. it encodes the temperature scale and the display format. in the actual tcp message, persistence is also crammed into this word — but in the object itself it's kept separately. sneaky. 💅
• VERBOSE — print error messages or nah? set by -v when the object is invoked. turn it on and she'll start talking.
• SLASH — adds a / to the end of directory entries. set by -slash when the object is invoked. it's giving "trailing slash aesthetic."
• SOCK — the socket address (an object) used for communication. for persistent connections it stays defined; otherwise it gets deleted between calls. she comes and goes. main character energy but make it ephemeral.
• PERSIST — the state of the socket connection. when it's persistent, the same socket gets reused, which speeds up network communication. slay. ⚡
• VER — the owprotocol version number (currently 0).

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🎀 Private methods 🎀

these are the internal functions, the little helpers running around backstage. all private. do not touch. (iykyk)

• _self — takes either the implicit object reference (if it's called on an object) or the ip address in non-object format. either way, a socket gets created, the persistence bit gets properly set, and the address gets parsed. returns the object reference, or undef on error. every external method (read, write, dir) calls this on the first parameter. she's the one who sets everything up 💅
• _new — takes the command line invocation parameters (for an object or not) and properly parses and sets up the properties in a hash array. the constructor vibes.
• _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, it uses the IANA allocated well known port (4304) for owserver. first it looks in /etc/services, then it just tries 4304. persistence queen.
• _ToServer — sends a message to owserver. formats it in owserver protocol. if a persistent socket fails, it retries after a new socket is created. she's resilient like that 🫶
• _FromServerBinaryParse — reads a specified length from the server.
• _FromServer — reads the whole packet from the server, using _FromServerBinaryParse (first for the header, then for the payload). discards ping packets silently. she doesn't even acknowledge them. iconic.
• _BonjourLookup — uses the mDNS service discovery protocol to find an available owserver. employs NET::Rendezvous (an earlier name for 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)

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✨ AUTHOR ✨

Paul H Alfille <paul.alfille@gmail.com> — we stan, fr fr 👑

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💀 BUGS 💀

support for proper timeout using the "select" function seems broken in perl. this might leave the routines vulnerable to network timing errors. not her fault, blame perl. 😭

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🌈 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 the source code is hosted. the mothership, basically.

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👑 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.

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and that's a wrap bestie 🎀✨ this whole page comes from perl v5.40.1 and it was last touched on 2025-05-04, filed under OWNet(3pm) — go forth and talk to your 1-wire devices, you absolute legend 💖🦋