.TH megaco_encoder 3erl "megaco 4.4.3" "Ericsson AB" "Erlang Module Definition"
.SH NAME
megaco_encoder \- Megaco encoder behaviour.
.SH DESCRIPTION
.LP
The following functions should be exported from a \fImegaco_encoder\fR\& callback module:
.SH "DATA TYPES"

.LP

.RS -4
.B
Note:
.RE
Note that the actual definition of (some of) these records depend on the megaco protocol version used\&. For instance, the \fI\&'TransactionReply\&'\fR\& record has two more fields in version 3, so a simple erlang type definition cannot be made here\&.

.LP
.nf

protocol_version() = integer()
segment_no()       = integer()
megaco_message() = #'MegacoMessage{}'
transaction() = {transactionRequest,     transaction_request()}      |
                {transactionPending,     transaction_reply()}        |
                {transactionReply,       transaction_pending()}      |
                {transactionResponseAck, transaction_response_ack()} |
                {segmentReply,           segment_reply()}
transaction_request() = #'TransactionRequest'{}
transaction_pending() = #'TransactionPending'{}
transaction_reply() = #'TransactionReply'{}
transaction_response_ack() = [transaction_ack()]
transaction_ack() = #'TransactionAck'{}
segment_reply() = #'SegmentReply'{}
action_request() = #'ActionRequest'{}
action_reply() = #'ActionReply'{}
command_request() = #'CommandRequest'{}
error_desc()   = #'ErrorDescriptor'{}
    
.fi
.SH EXPORTS
.LP
.B
Module:encode_message(EncodingConfig, Version, Message) -> {ok, Bin} | Error
.br
.RS
.LP
Types:

.RS 3
EncodingConfig = list()
.br
Version = integer()
.br
Message = megaco_message()
.br
Bin = binary()
.br
Error = term()
.br
.RE
.RE
.RS
.LP
Encode a megaco message\&.
.RE

.LP
.B
Module:decode_message(EncodingConfig, Version, Bin) -> {ok, Message} | Error
.br
.RS
.LP
Types:

.RS 3
EncodingConfig = list()
.br
Version = integer() | dynamic
.br
Message = megaco_message()
.br
Bin = binary()
.br
Error = term()
.br
.RE
.RE
.RS
.LP
Decode a megaco message\&.
.LP
Note that if the Version argument is \fIdynamic\fR\&, the decoder should try to figure out the actual version from the message itself and then use the proper decoder, e\&.g\&. version 1\&. 
.br
If on the other hand the Version argument is an integer, it means that this is the expected version of the message and the decoder for that version should be used\&.
.RE

.LP
.B
Module:decode_mini_message(EncodingConfig, Version, Bin) -> {ok, Message} | Error
.br
.RS
.LP
Types:

.RS 3
EncodingConfig = list()
.br
Version = integer() | dynamic
.br
Message = megaco_message()
.br
Bin = binary()
.br
Error = term()
.br
.RE
.RE
.RS
.LP
Perform a minimal decode of a megaco message\&.
.LP
The purpose of this function is to do a minimal decode of Megaco message\&. A successfull result is a \fI\&'MegacoMessage\&'\fR\& in which only version and mid has been initiated\&. This function is used by the megaco_messenger module when the \fIdecode_message/3\fR\& function fails to figure out the mid (the actual sender) of the message\&.
.LP
Note again that a successfull decode only returns a partially initiated message\&.
.RE

.LP
.B
Module:encode_transaction(EncodingConfig, Version, Transaction) -> OK | Error
.br
.RS
.LP
Types:

.RS 3
EncodingConfig = list()
.br
Version = integer()
.br
Transaction = transaction()
.br
OK = {ok, Bin}
.br
Bin = binary()
.br
Error = {error, Reason}
.br
Reason = not_implemented | OtherReason
.br
OtherReason = term()
.br
.RE
.RE
.RS
.LP
Encode a megaco transaction\&. If this, for whatever reason, is not supported, the function should return the error reason \fInot_implemented\fR\&\&.
.LP
This functionality is used both when the transaction sender is used and for segmentation\&. So, for either of those to work, this function \fImust\fR\& be fully supported!
.RE

.LP
.B
Module:encode_action_requests(EncodingConfig, Version, ARs) -> OK | Error
.br
.RS
.LP
Types:

.RS 3
EncodingConfig = list()
.br
Version = integer()
.br
ARs = action_requests()
.br
action_requests() = [action_request()]
.br
OK = {ok, Bin}
.br
Bin = binary()
.br
Error = {error, Reason}
.br
Reason = not_implemented | OtherReason
.br
OtherReason = term()
.br
.RE
.RE
.RS
.LP
Encode megaco action requests\&. This function is called when the user calls the function encode_actions/3\&. If that function is never used or if the codec cannot support this (the encoding of individual actions), then return with error reason \fInot_implemented\fR\&\&.
.RE

.LP
.B
Module:encode_action_reply(EncodingConfig, Version, AR) -> OK | Error
.br
.RS
.LP
Types:

.RS 3
EncodingConfig = list()
.br
Version = integer()
.br
AR = action_reply()
.br
OK = {ok, Bin}
.br
Bin = binary()
.br
Error = {error, Reason}
.br
Reason = not_implemented | OtherReason
.br
OtherReason = term()
.br
.RE
.RE
.RS
.LP
Encode a megaco action reply\&. If this, for whatever reason, is not supported, the function should return the error reason \fInot_implemented\fR\&\&.
.LP
This function is used when segmentation has been configured\&. So, for this to work, this function \fImust\fR\& be fully supported!
.RE