File "src/xpl/classes/xplmessage.lua
"
The object class for xPL messages. It has all the regular message properties (some depending on whether it was parsed/received or created). several methods and an iterator are available to manipulate the key-value list.
No global will be created, it just returns the xplmessage class. The main xPL module will create a global xpl.classes.xplmessage
to access it.
Copyright © 2011 Thijs Schreijer
Release: Version 0.1, LuaxPL framework.
Tables
key-value pair | Internal representation of a key-value pair. |
xplmessage fields/properties | Members of the xplmessage object |
Functions
msg:__tostring () | Meta method to format the message as a string value for transmission |
msg:add (key, value) | Add a key value pair to the message body. |
msg:eachkvp () | Creates an iterator for the key-value pair list. |
msg:getindex (key, occurence) | Gets the index of a key. |
msg:getkey (index) | Gets the key at a given index |
msg:getvalue (key, occurence) | get a value from the message body by key |
msg:initialize () | Initializes the xplmessage. |
msg:matchfilter (filter) | matches the message against an xplfilter |
msg:parse (msgstring) | Turn a message string into a message object. |
msg:send () | Transmits the message onto the xPL network |
msg:setvalue (key, value) | sets value of a key-value pair in the message body. |
Tables
- key-value pair
- Internal representation of a key-value pair. A table with 2 keys, key and value.
Fields
-
key
: thekey
of the key-value pair -
value
: thevalue
of the key-value pair
-
- xplmessage fields/properties
- Members of the xplmessage object
Fields
-
type
: the xpl message type;"xpl-cmnd", "xpl-trig", "xpl-stat"
-
from
: origin of message;"[IP address]:[port]"
(when the internal LuaxPL hub is used),"EXTERNAL_HUB"
or"CREATED"
(when the message was locally created and not received from the network) -
hop
: hop count -
source
: source address of the message -
sourcevendor
: vendor part of source address (only available if parsed) -
sourcedevice
: device part of source address (only available if parsed) -
sourceinstance
: instance part of source address (only available if parsed) -
target
: target address of the message -
targetvendor
: vendor part of source address (only available if parsed, '*' if target address is '*') -
targetdevice
: device part of source address (only available if parsed, '*' if target address is '*') -
targetinstance
: instance part of source address (only available if parsed, '*' if target address is '*') -
schema
: message schema of the message -
schemaclass
: class part of the message schema (only available if parsed) -
schematype
: type part of the message schema (only available if parsed) -
kvp
: list of key value pairs, where each pair is defined as;kvp[i] = { key = 'key value',
value = 'value value'}
Seemsg:eachkvp()
for an iterator.
-
Functions
- msg:__tostring ()
-
Meta method to format the message as a string value for transmission
Usage:
-- Create a new message
local msg = xpl.classes.xplmessage:new({})
 
print(msg) -- this will invoke the __tostring() meta methodReturn value:
message as string that can be transmitted onto the xPL network - msg:add (key, value)
-
Add a key value pair to the message body.
Parameters:
-
key
: (string) the key (duplicates are allowed) -
value
: the value to store
Return value:
key-value pair inserted (table with 2 keys;key
andvalue
) -
- msg:eachkvp ()
-
Creates an iterator for the key-value pair list. The iterator will use the order as specified in the message.
Usage:
for key, value, i in msg:eachkvp() do
print("KVP ", i, " has key = ", key, ", value = ", value)
endReturn value:
iterator function - msg:getindex (key, occurence)
-
Gets the index of a key.
Parameters:
-
key
: thekey
to be sought in the mesage body -
occurence
: (optional) in case of duplicate keys the occurence can be specified (default 1)
Return value:
index
of thekey
(at mentioned occurence) in the message body ornil
if not found -
- msg:getkey (index)
-
Gets the key at a given index
Parameters:
-
index
: the index for the message body key-value pair whose key to return
Return value:
key (string) if found ornil
otherwise -
- msg:getvalue (key, occurence)
-
get a value from the message body by key
Parameters:
-
key
: either thekey
or theindex
of the key-value pair sought -
occurence
: optional, if akey
is specified, the occurence to return if there are duplicates (default 1), will be ignored if anindex
was provided
Return value:
value (string) as set in the key-value pair, ornil
if not found -
- msg:initialize ()
- Initializes the xplmessage. Will be called upon instantiation of an object and hence has little use other than when subclassing the xplmessage object into a new class.
- msg:matchfilter (filter)
-
matches the message against an xplfilter
Parameters:
-
filter
: xplfilters object (contains list of filters). In case the filter isnil
it will returntrue
(default xpl behaviour with absent filters).
Return value:
true
orfalse
based upon matching the filter or not. -
- msg:parse (msgstring)
-
Turn a message string into a message object. if called as a method, the parsed message is loaded into the existing object. If called as a function on the super class, a new message object will be created.
Parameters:
-
msgstring
: the string containing the message to be parsed
Usage:
-- load a parsed message into the object
local msg, remainder = xpl.classes.xplmessage:new({})
msg, remainder = msg:parse(messagestring)
 
-- parse directly to a new message
local msg, remainder = xpl.classes.xplmessage.parse(messagestring)Return values:
- parsed message object
- remainder of input string (characters positioned after the parsed message), or
nil
if there is no remainder
-
- msg:send ()
-
Transmits the message onto the xPL network
Return value:
true
if succesfull,nil
+ error otherwise - msg:setvalue (key, value)
-
sets value of a key-value pair in the message body.
Parameters:
-
key
: either thekey
orindex
of the key-value pair whose value to update. If a key, then the 1st occurrence will be updated. -
value
: the value to set for the specified key/index
Return value:
key-value pair updated (table with 2 keys;key
andvalue
), ornil
+ error if the key or index wasn't found -