<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE erlref SYSTEM "erlref.dtd">

<erlref>
  <header>
    <copyright>
      <year>2001</year><year>2013</year>
      <holder>Ericsson AB. All Rights Reserved.</holder>
    </copyright>
    <legalnotice>
      Licensed under the Apache License, Version 2.0 (the "License");
      you may not use this file except in compliance with the License.
      You may obtain a copy of the License at
 
          http://www.apache.org/licenses/LICENSE-2.0

      Unless required by applicable law or agreed to in writing, software
      distributed under the License is distributed on an "AS IS" BASIS,
      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      See the License for the specific language governing permissions and
      limitations under the License.
    
    </legalnotice>

    <title>interceptors</title>
    <prepared></prepared>
    <responsible></responsible>
    <docno></docno>
    <approved></approved>
    <checked></checked>
    <date>1999-09-03</date>
    <rev>A</rev>
  </header>
  <module>interceptors</module>
  <modulesummary>Describe the functions which must be exported by any supplied Orber native interceptor.</modulesummary>
  <description>
    <p>This module contains the mandatory functions for user supplied native
      interceptors and their intended behavior. See also the User's Guide.</p>
    <warning>
      <p>Using <c>Interceptors</c> may reduce the through-put significantly
        if the supplied interceptors invoke expensive operations. Hence, 
        one should always supply interceptors which cause as little overhead
        as possible.</p>
    </warning>
    <warning>
      <p>It is possible to alter the <c>Data</c>, <c>Bin</c> and <c>Args</c>
        parameter for the <c>in_reply</c> and <c>out_reply</c>, 
        <c>in_reply_encoded</c>, <c>in_request_encoded</c>, 
        <c>out_reply_encoded</c> and <c>out_request_encoded</c>,
        <c>in_request</c> and <c>out_request</c> respectively. But,
        if it is done incorrectly, the consequences can be serious.</p>
    </warning>
    <note>
      <p>The <c>Extra</c> parameter is set to 'undefined' by Orber when calling
        the first interceptor and may be set to any Erlang term.  If an
        interceptor change this parameter it will be passed on to the next
        interceptor in the list uninterpreted.</p>
    </note>
    <note>
      <p>The <c>Ref</c> parameter is set to 'undefined' by Orber when calling
        <c>new_in_connection</c> or <c>new_out_connection</c> using
        the first interceptor. The user supplied interceptor may set <c>NewRef</c>
        to any Erlang term.  If an interceptor change this parameter it will be
        passed on to the next interceptor in the list uninterpreted.</p>
    </note>
  </description>
  <funcs>
    <func>
      <name>new_in_connection(Ref, PeerHost, PeerPort) -> NewRef</name>
      <name>new_in_connection(Ref, PeerHost, PeerPort, SocketHost, SocketPort) -> NewRef</name>
      <fsummary>Invoke when a new client ORB wants to setup a connection</fsummary>
      <type>
        <v>Ref    = term() | undefined</v>
        <v>PeerHost = SocketHost = string(), e.g., "myHost@myServer" or "192.0.0.10"</v>
        <v>PeerPort = SocketPort = integer()</v>
        <v>NewRef = term() | {'EXIT', Reason}</v>
      </type>
      <desc>
        <p>When a new connection is requested by a client side ORB this operation
          is invoked. If more than one interceptor is supplied, e.g., 
          <c>{native, ['myInterceptor1', 'myInterceptor2']}</c>, the return value
          from 'myInterceptor1' is passed to 'myInterceptor2' as <c>Ref</c>.
          Initially, Orber uses the atom 'undefined' as <c>Ref</c> parameter
          when calling the first interceptor. The return value from the last
          interceptor, in the example above 'myInterceptor2', is passed
          to all other functions exported by the interceptors. Hence,
          the <c>Ref</c> parameter can, for example, be used as a unique 
          identifier to mnesia or ets where information/restrictions for
          this connection is stored.</p>
        <p>The PeerHost and PeerPort variables supplied data of
          the client ORB which requested a new connection. SocketHost 
          and SocketPort are the local interface and port the client
          connected to.</p>
        <p>If, for some reason, we do not allow the client ORB to connect
          simply invoke <c>exit(Reason)</c>.</p>
      </desc>
    </func>
    <func>
      <name>new_out_connection(Ref, PeerHost, PeerPort) -> NewRef</name>
      <name>new_out_connection(Ref, PeerHost, PeerPort, SocketHost, SocketPort) -> NewRef</name>
      <fsummary>Invoke when setting up a new connection to a server side  ORB</fsummary>
      <type>
        <v>Ref    = term() | undefined</v>
        <v>PeerHost = SocketHost = string(), e.g., "myHost@myServer" or "192.0.0.10"</v>
        <v>PeerPort = SocketPort = integer()</v>
        <v>NewRef = term() | {'EXIT', Reason}</v>
      </type>
      <desc>
        <p>When a new connection is set up this function is invoked. Behaves
          just like <c>new_in_connection</c>; the only difference is that
          the PeerHost and PeerPort variables identifies the target ORB's bootstrap
          data and SocketHost and SocketPort are the local interface and port
          the client ORB connected via.</p>
      </desc>
    </func>
    <func>
      <name>closed_in_connection(Ref) -> NewRef</name>
      <fsummary>Invoke when an existing connection to a client side ORB have been terminated</fsummary>
      <type>
        <v>Ref    = term()</v>
        <v>NewRef = term()</v>
      </type>
      <desc>
        <p>When an existing connection is terminated this operation is invoked.
          The main purpose of this function is to make it possible for a user
          to clean up all data associated with the associated connection.</p>
        <p>The input parameter <c>Ref</c> is the return value from 
          <c>new_in_connection/3</c>.</p>
      </desc>
    </func>
    <func>
      <name>closed_out_connection(Ref) -> NewRef</name>
      <fsummary>Invoke when an existing connection to a server side ORB have been terminated</fsummary>
      <type>
        <v>Ref    = term()</v>
        <v>NewRef = term()</v>
      </type>
      <desc>
        <p>When an existing connection is terminated this operation is invoked.
          The main purpose of this function is to make it possible for a user
          to clean up all data associated with the associated connection.</p>
        <p>The input parameter <c>Ref</c> is the return value from 
          <c>new_out_connection/3</c>.</p>
      </desc>
    </func>
    <func>
      <name>in_reply(Ref, Obj, Ctx, Op, Data, Extra) -> Reply</name>
      <fsummary>Invoke when replies arrives at the client side ORB</fsummary>
      <type>
        <v>Ref   = term()</v>
        <v>Obj   = #objref</v>
        <v>Ctx   = [#'IOP_ServiceContext'{}]</v>
        <v>Op    = atom()</v>
        <v>Data  = [Result, OutParameter1, ..., OutPramaterN]</v>
        <v>Reply = {NewData, NewExtra}</v>
      </type>
      <desc>
        <p>When replies are delivered from the server side ORB to the client side
          ORB this operation is invoked. The <c>Data</c> parameter is a list in which
          the first element is the return value value from the target object and
          the rest is a all parameters defined as <c>out</c> or <c>inout</c> in
          the IDL-specification.</p>
      </desc>
    </func>
    <func>
      <name>in_reply_encoded(Ref, Obj, Ctx, Op, Bin, Extra) -> Reply</name>
      <fsummary>Invoke when replies arrives at the client side ORB with undecoded reply body</fsummary>
      <type>
        <v>Ref   = term()</v>
        <v>Obj   = #objref</v>
        <v>Ctx   = [#'IOP_ServiceContext'{}]</v>
        <v>Op    = atom()</v>
        <v>Bin   = #binary</v>
        <v>Reply = {NewBin, NewExtra}</v>
      </type>
      <desc>
        <p>When replies are delivered from the server side ORB to the client side
          ORB this operation is invoked. The <c>Bin</c> parameter is the reply 
          body still uncoded.</p>
      </desc>
    </func>
    <func>
      <name>in_request(Ref, Obj, Ctx, Op, Args, Extra) -> Reply</name>
      <fsummary>Invoke when requests arrive at the server side ORB</fsummary>
      <type>
        <v>Ref   = term()</v>
        <v>Obj   = #objref</v>
        <v>Ctx   = [#'IOP_ServiceContext'{}]</v>
        <v>Op    = atom()</v>
        <v>Args  = [Argument] - defined in the IDL-specification</v>
        <v>Reply = {NewArgs, NewExtra}</v>
      </type>
      <desc>
        <p>When a new request arrives at the server side ORB this operation is 
          invoked.</p>
      </desc>
    </func>
    <func>
      <name>in_request_encoded(Ref, Obj, Ctx, Op, Bin, Extra) -> Reply</name>
      <fsummary>Invoke when requests arrive at the server side ORB with undecoded request body</fsummary>
      <type>
        <v>Ref   = term()</v>
        <v>Obj   = #objref</v>
        <v>Ctx   = [#'IOP_ServiceContext'{}]</v>
        <v>Op    = atom()</v>
        <v>Bin   = #binary</v>
        <v>Reply = {NewBin, NewExtra}</v>
      </type>
      <desc>
        <p>When a new request arrives at the server side ORB this operation is 
          invoked before decoding the request body.</p>
      </desc>
    </func>
    <func>
      <name>out_reply(Ref, Obj, Ctx, Op, Data, Extra) -> Reply</name>
      <fsummary>Invoke after the target object replied</fsummary>
      <type>
        <v>Ref   = term()</v>
        <v>Obj   = #objref</v>
        <v>Ctx   = [#'IOP_ServiceContext'{}]</v>
        <v>Op    = atom()</v>
        <v>Data  = [Result, OutParameter1, ..., OutPramaterN]</v>
        <v>Reply = {NewData, NewExtra}</v>
      </type>
      <desc>
        <p>After the target object have been invoked this operation is invoked
          with the result. The <c>Data</c> parameter is a list in which
          the first element is the return value value from the target object and
          the rest is a all parameters defined as <c>out</c> or <c>inout</c> in
          the IDL-specification.</p>
      </desc>
    </func>
    <func>
      <name>out_reply_encoded(Ref, Obj, Ctx, Op, Bin, Extra) -> Reply</name>
      <fsummary>Invoke after the target object replied with the reply  encoded</fsummary>
      <type>
        <v>Ref   = term()</v>
        <v>Obj   = #objref</v>
        <v>Ctx   = [#'IOP_ServiceContext'{}]</v>
        <v>Op    = atom()</v>
        <v>Bin   = #binary</v>
        <v>Reply = {NewBin, NewExtra}</v>
      </type>
      <desc>
        <p>This operation is similar to <c>out_reply</c>; the only difference is
          that the reply body have been encoded.</p>
      </desc>
    </func>
    <func>
      <name>out_request(Ref, Obj, Ctx, Op, Args, Extra) -> Reply</name>
      <fsummary>Invoke on the client side ORB before encoding and sending the request</fsummary>
      <type>
        <v>Ref   = term()</v>
        <v>Obj   = #objref</v>
        <v>Ctx   = [#'IOP_ServiceContext'{}]</v>
        <v>Op    = atom()</v>
        <v>Args  = [Argument] - defined in the IDL-specification</v>
        <v>Reply = {NewArgs, NewExtra}</v>
      </type>
      <desc>
        <p>Before a request is sent to the server side ORB, <c>out_request</c> is
          invoked.</p>
      </desc>
    </func>
    <func>
      <name>out_request_encoded(Ref, Obj, Ctx, Op, Bin, Extra) -> Reply</name>
      <fsummary>Invoke on the client side ORB before sending the request</fsummary>
      <type>
        <v>Ref   = term()</v>
        <v>Obj   = #objref</v>
        <v>Ctx   = [#'IOP_ServiceContext'{}]</v>
        <v>Op    = atom()</v>
        <v>Bin   = #binary</v>
        <v>Reply = {NewBin, NewExtra}</v>
      </type>
      <desc>
        <p>This operation is similar to <c>out_request</c>; the only
          difference is that the request body have been encoded.</p>
      </desc>
    </func>
  </funcs>
  
</erlref>

