# interceptors

### MODULE

interceptors

### MODULE SUMMARY

Describe the functions which must be exported by any supplied Orber native interceptor.

### DESCRIPTION

This module contains the mandatory functions for user supplied native interceptors and their intended behaviour. See also the User's Guide.

| Using `Interceptors` 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.

| It is possible to alter the `Data`, `Bin` and `Args` parmeter for the `in_reply` and `out_reply`, `in_reply_encoded`, `in_request_encoded`, `out_reply_encoded` and `out_request_encoded`, `in_request` and `out_request` respectively. But, if it is done incorrectly, the consequences can be serious.

| The `Extra` 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.

| The `Ref` parameter is set to 'undefined' by Orber when calling `new_in_connection` or `new_out_connection` using the first interceptor. The user supplied interceptor may set `NewRef` to any erlang term. If an interceptor change this parameter it will be passed on to the next interceptor in the list uninterpreted.

### EXPORTS

`new_in_connection(Ref, Host, Port) -> NewRef`

Types:

`Ref = term() | undefined`
`Host = string(), e.g., "myHost@myServer" or "012.345.678.910"`
`Port = integer`
`NewRef = term() | {'EXIT', Reason}`

When a new connection is requested by a client side ORB this operation is invoked. If more than one interceptor is supplied, e.g., `{native, ['myInterceptor1', 'myInterceptor2']}`, the return value from 'myInterceptor1' is passed to 'myInterceptor2' as `Ref`. Initially, Orber uses the atom 'undefined' as `Ref` 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 `Ref` parameter can, for example, be used as a unique identifier to mnesia or ets where information/restrictions for this connection is stored.

The Host and Port variables supplied is the peer data of the client ORB which requested a new connection.

If, for some reason, we do not allow the client ORB to connect simply invoke `exit(Reason)`.

`new_out_connection(Ref, Host, Port) -> NewRef`

Types:

`Ref = term() | undefined`
`Host = string(), e.g., "myHost@myServer" or "012.345.678.910"`
`Port = integer`
`NewRef = term() | {'EXIT', Reason}`

When a new connection is set up this function is invoked. Behaves just like `new_in_connection`; the only difference is that the Host and Port variables identifies the target ORB's bootstrap data.

`closed_in_connection(Ref) -> NewRef`

Types:

`Ref = term()`
`NewRef = term()`

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.

The input parameter `Ref` is the return value from `new_in_connection/3`.

`closed_out_connection(Ref) -> NewRef`

Types:

`Ref = term()`
`NewRef = term()`

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.

The input parameter `Ref` is the return value from `new_out_connection/3`.

`in_reply(Ref, Obj, Ctx, Op, Data, Extra) -> Reply`

Types:

`Ref = term()`
`Obj = #objref`
`Ctx = [#'IOP_ServiceContext'{}]`
`Op = atom()`
`Data = [Result, OutParameter1, ..., OutPramaterN]`
`Reply = {NewData, NewExtra}`

When replies are delivered from the server side ORB to the client side ORB this operation is invoked. The `Data` 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 `out` or `inout` in the IDL-specification.

`in_reply_encoded(Ref, Obj, Ctx, Op, Bin, Extra) -> Reply`

Types:

`Ref = term()`
`Obj = #objref`
`Ctx = [#'IOP_ServiceContext'{}]`
`Op = atom()`
`Bin = #binary`
`Reply = {NewBin, NewExtra}`

When replies are delivered from the server side ORB to the client side ORB this operation is invoked. The `Bin` parameter is the reply body still uncoded.

`in_request(Ref, Obj, Ctx, Op, Args, Extra) -> Reply`

Types:

`Ref = term()`
`Obj = #objref`
`Ctx = [#'IOP_ServiceContext'{}]`
`Op = atom()`
`Args = [Argument] - defined in the IDL-specification`
`Reply = {NewArgs, NewExtra}`

When a new request arrives at the server side ORB this operation is invoked.

`in_request_encoded(Ref, Obj, Ctx, Op, Bin, Extra) -> Reply`

Types:

`Ref = term()`
`Obj = #objref`
`Ctx = [#'IOP_ServiceContext'{}]`
`Op = atom()`
`Bin = #binary`
`Reply = {NewBin, NewExtra}`

When a new request arrives at the server side ORB this operation is invoked before decoding the request body.

`out_reply(Ref, Obj, Ctx, Op, Data, Extra) -> Reply`

Types:

`Ref = term()`
`Obj = #objref`
`Ctx = [#'IOP_ServiceContext'{}]`
`Op = atom()`
`Data = [Result, OutParameter1, ..., OutPramaterN]`
`Reply = {NewData, NewExtra}`

After the target object have been invoked this operation is invoked with the result. The `Data` 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 `out` or `inout` in the IDL-specification.

`out_reply_encoded(Ref, Obj, Ctx, Op, Bin, Extra) -> Reply`

Types:

`Ref = term()`
`Obj = #objref`
`Ctx = [#'IOP_ServiceContext'{}]`
`Op = atom()`
`Bin = #binary`
`Reply = {NewBin, NewExtra}`

This operation is similar to `out_reply`; the only difference is that the reply body have been encoded.

`out_request(Ref, Obj, Ctx, Op, Args, Extra) -> Reply`

Types:

`Ref = term()`
`Obj = #objref`
`Ctx = [#'IOP_ServiceContext'{}]`
`Op = atom()`
`Args = [Argument] - defined in the IDL-specification`
`Reply = {NewArgs, NewExtra}`

Before a request is sent to the server side ORB, `out_request` is invoked.

`out_request_encoded(Ref, Obj, Ctx, Op, Bin, Extra) -> Reply`

Types:

`Ref = term()`
`Obj = #objref`
`Ctx = [#'IOP_ServiceContext'{}]`
`Op = atom()`
`Bin = #binary`
`Reply = {NewBin, NewExtra}`

This operation is similar to `out_request`; the only difference is that the request body have been encoded.

### AUTHORS

Support - support@erlang.ericsson.se

orber 3.4.2
Copyright © 1991-2003 Ericsson Utvecklings AB