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fhem-mirror/fhem/docs/fhem_api.txt
2022-02-09 11:06:37 +00:00

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FHEM Application Programming Interface for Modules.
Description of the fhem.pl functions offered to modules, and used Modules
interfaces.
NOTE: if there is a difference between this description and fhem.pl, then this
document is to be fixed, and not fhem.pl.
Global Variables
================
------
$addTimerStacktrace
if set to one, InternalTimer calls will add a stacktrace to the internal hash
holding all the Timers. Used by fhemdebug
$auth_refresh
if set one, refresh the authorization caches. Used by the allowed module.
$cmdFromAnalyze
holds the command which will be executed by eval. Used by the __WARN__
handler or stacktrace to report better error messages.
$devcount
global devicecounter, used to give a unique sequential number (NR) to each
created device. Devices are saved in NR order.
$featurelevel
supported FHEM feature level. Its default value is the current FHEM version,
(6.1, etc), and can be set by the user to a lower level by the attribute
featurelevel to have more backward compatibility, if the module supports it.
$fhemForked
set to 1 if we are in a forked process. Set only, if the fhemFork() routine
is used for forking.
$fhemTestFile
file to include if -t is specified. Uset for Unit tests, see the t
subdirectory for details.
$fhem_started
set to the current UNIX time upon FHEM startup.
$haveInet6
set to true if the IO::Socker::INET6 module is available and the global
variable useInet6 is set.
$init_done
set to one, if the fhem.cfg and fhem.state are processed.
The global INITIALIZED trigger is sent after this value is set to one,
InternalTimers are processed next.
$internal_data
global variable, to avoid data copying between modules. E.g. FileLog_get will
set this variable when the outfile parameter is specified as "-".
$lastDefChange
this variable is increased each time a definition or attribute changes. Used
by modules to invalidate their private caches.
$lastWarningMsg
set to the last __WARN__ message.
$nextat
set to the time of the next InternalTimer call.
$numCPUs
number of CPUs, if running on a Linux system.
$reread_active
set to one while the rereadcfg operation is active.
$selectTimestamp
set to the time before the last select was started. Can be used to identify
busy loops, where a select was not called betweeen function calls.
$winService
the Windows Service object.
------
%attr
hash of Attributes. The Attributes are reerences by Devicename.
%cmds
hash of available FHEM Commands. The command Name is specified by the hash
key.
Mandatory entries:
- Fn
String, holding the name of the function to be called. The function will be
called with the Client-Hash (Source-Channel of the command) and the
command-line parameters as one string, without the command name.
- Hlp
One-line help, displayed by the help command
Optional entries:
- ReplacedBy
Name of the new entry
- Modulename
Name of the module to load when this command is entered (autoloading the
command)
- ClientFilter
Name of a module, this command is only valid if it is entered through this
channel (e.g. quit is only valid for telnet connections)
%data
Global variable, can be used by modules or enduser to store arbitrary data.
%defs
hash of FHEM definitions.
Mandatory entries:
- NAME: name od the FHEM definition
- FUUID: unique id, remains the same even after renaming
- TYPE: name of the corresponding module or global
- NR: number of this definition, used when saving
- STATE: the "general" state of the device
Note: this entry ist set by the framework from the developer
supplied state Reading, if the user does not override it by the
stateFormat attribute.
- DEF: additional parameters at definition
Optional entries
- CFGFN: name of the configuration file the definition is coming from, used
to save it again to this file
- CL: input channel from where the definition was entered (telnet, FHEMWEB,
etc). Set temporarily for DefFn/SetFn/GetFn/DeleteFn/ModifyFn/etc calls
- EXCEPT_FD: the Filedescriptor to be monitored by select. Note: in order to
be used, selectlist must be filled.
- FD: the Filedescriptor to be monitored by select. Note: in order to be
used, selectlist must be filled.
- TEMPORARY: if set, do not save this definition, nor trigger the
structure-change flag
- VOLATILE: if set, save this definition to the state file, and do not
trigger the structure-change flag
- .AttrList
List of device specific attributes. If absent, the module specific ones
will be used by getAllAttr()
- NTFY_ORDER
The order in which the NotifyFn functions of the different devices are
called. If not specified, is set to 50-name, or
$module{NotifyOrderPrefix}-name
%inform
telnet connections to be notified for generated events.
%intAt
hash of InternalTimer entries. Maintained in parallel to the intAtA array.
Mandatory filed for each entry:
- TRIGGERTIME: UNIX timestamp
- FN: function name or reference to be called
- ARG: parameter to call the function with when the timer triggers
- atNr: key in the hash, for cross-referencing to the array. Optional field:
- STACKTRACE: set if $addTimerStacktrace is specified, holding the current
(as of the time of calling InternalTimer) stack trace.
%logInform
hash of functions to be called for each Log call. Used e.g by FHEMWEB to show
the FHEM-Log or notify, when the readLog attribute is set.
%modules
hash of the modules. Modules are loaded only on request, e.g. when define is
specified.
Mandatory Entries:
- ORDER: used for notifying devices for dispatched raw messages
Optional Entries:
- AttrFn: name of the function to be called when an attribute is set or
deleted. Function parameters: set or del, and an array of parameters.
- AttrList: list of supported attributes. Used if the device hash (%defs) has
no .AttrList entry.
- AuthenticateFn: name of the function called to check if a connection is
authenticated. Called with the hash of the authentication-instance, the
connection hash, and the authentication arguments. Returns 0 if the
authentication is not needed, 1 if authenticated and 2 if the
authentication failed.
- AuthorizeFn: name of the function called to check if an operation is
authorized. Called with the hash of the authorization-instance, the
connection hash, the type of the check (cmd or devicename), the
authorization arguments, and a $silent parameter. Returns 1 if authorized
and 0 else.
- CanAuthenticate: set by the module to 1 if it requires authentication. Used
for Security-Checks.
- Clients: list of potential modules which will be notified by Dispatch.
- DefFn: the function called upon definition of a device. Called with the
prefilled §defs hash and the command-line parameters as one string.
- DelayedShutdownFn: called before FHEM shutdown, this function can delay the
shutdown if returns 1. Called with the instance of the device.
- DeleteFn: the function called upon deleting a definition, called with the
hash of the device to be deleted.
- defptr: hash of module-specific data, will be restored after a reload
operation.
- ExceptFn: function called when the select exception-Field reported an
action. Called with the hash of the device, selectlist mus be filled, and
EXCEP_FD must be set in the device hash.
- FingerPrintFn: name of a function to prepare data for duplicate detection.
- GetFn: name of the function to be called when the get command is called.
Parameters: hash of the device, and an array of parameters
- ldata: hash of module-specific data, will be restored after a reload
operation.
- LOADED: set to 1 if the module is loaded
- Match: Regexp used in Dispatch, to identify if a message is relevant for a
module. Set in the logical module.
- MatchList: Hash of Modulename=>regexps, in order to search the right module
in Dispatch. Set in the physical module, used after no defined instance is
found to process the data, to trigger a module load.
- NotifyFn: name of the function to be called when an event is triggered.
Parameters: hash of the notify device, hash of the device producing the
events. The events themselves are available by calling the deviceEvents
function.
- NotifyOrderPrefix: used to crate the NTFY_ORDER, if it is not set
explicitely by the module.
- ParseFn: Name of a function called by Dispatch to interpret data received
by the physical (aka IO) module. Called with the IO-Instance and the raw
data.
- parseParams: if set, the SetFn/GetFn/DefFn parameters are called with the
results of the parseParams function and not an array, which consists of the
space separated command line.
- ReadFn: name of the function to be called if dta is available. Called with
the hash of the instance. In order to be called, %selectlist must contain a
hash of the entry, and FD must contain the Filedescriptor to be monitored.
- ReadyFn: called for all definitions in the %readyfnlist. On unix/osx/linux
this is used to check if a device becomes available again, on Windows it is
used to check if it has data, as serial devices on windows do not support
the select call.
- RenameFn: called when a device is renamed, with the new and the old name as
parameters.
- SetFn: name of the function to be called when the set command is called.
Parameters: hash of the device, and an array of parameters.
- ShutdownFn: called before FHEM-shutdown, to enable a cleanup.
- StateFn: called from the setstate command, to align internal values to the
state. Called with the device name, timestamp, readingname and value as
parameters.
- WriteFn: name of the function used to Write data to the device (called by
IOWrite). Parameters: hash of the IO Device, and an array of data.
- UndefFn: called from rereadcfg and delete to clean up (close
filedescriptors, etc). Called with the hash of the device instance.
%ntfyHash
hash of devices to be notified. If cleared, it will be recomputed before
any device can be notified. Note: this computation is CPU intensive.
%prioQueues
List of (low-)priority queues, added by PrioQueue_add
%readyfnlist
List of devices scheduled for calling their ReadyFn
%selectlist
List of devices scheduled for calling their ReadFn/WriteFn or ExceptFn, if
the select of the corresponding FD/EXCEPT_FD returns activity.
%value
hash used for featurelist <= 5.6, holding the value of each device.
Replaced by the Value() function for featurelist > 5.6
@intAtA
array of InternalTimer entries, see the %intAt hash for details.
@structChangeHist
array of structural changes not saved.