WS_SERVICE_MESSAGE_RECEIVE_CALLBACK callback function (webservices.h)

Article
02/22/2024

Invoked when a WS_MESSAGE is received on an endpoint configured with a WS_SERVICE_CONTRACT which has defaultMessageHandlerCallback set.

The incoming WS_MESSAGE, the serviceProxy along with other parameters is made available to the callback through WS_OPERATION_CONTEXT.

Syntax

WS_SERVICE_MESSAGE_RECEIVE_CALLBACK WsServiceMessageReceiveCallback;

HRESULT WsServiceMessageReceiveCallback(
  [in]           const WS_OPERATION_CONTEXT *context,
  [in, optional] const WS_ASYNC_CONTEXT *asyncContext,
  [in, optional] WS_ERROR *error
)
{...}

Parameters

[in] context

The context within which this callback is being invoked.

[in, optional] asyncContext

Specifies whether the callback can run asynchronously.

[in, optional] error

Specifies where additional error information should be stored if the function fails.

Return value

This callback function does not return a value.

Remarks

When defined, callback would disallow all concurrency on a session based channel. If concurrency on a session based channel is desirable an application should not define WS_SERVICE_MESSAGE_RECEIVE_CALLBACK on the WS_SERVICE_CONTRACT.

At the time of the invocation of the callback, service model has performed WsReadMessageStart on the receiving WS_MESSAGE. It is the responsibility of the application implementing WS_SERVICE_MESSAGE_RECEIVE_CALLBACK to process the body and perform WsReadMessageEnd operation.

If the callback fails, the underlying channel is aborted.

Examples

Defining a WS_SERVICE_MESSAGE_RECEIVE_CALLBACK


// Method contract for the service
static WS_SERVICE_CONTRACT calculatorContract = 
{
    NULL, 
    NULL, 
    DefaultMessageHandlerCallback, // WS_SERVICE_MESSAGE_RECEIVE_CALLBACK
    NULL
};

Accessing the incoming WS_MESSAGE property

HRESULT CALLBACK MessageRecieved(const WS_OPERATION_CONTEXT* context, const WS_ASYNC_CONTEXT* asyncContext, WS_ERROR* error)
{
    :
    hr = WsGetOperationContextProperty(context, WS_OPERATION_CONTEXT_PROPERTY_INPUT_MESSAGE, &requestMessage, sizeof(requestMessage), NULL, error);
    :
}

Requirements

Requirement	Value
Minimum supported client	Windows 7 [desktop apps \| UWP apps]
Minimum supported server	Windows Server 2008 R2 [desktop apps \| UWP apps]
Target Platform	Windows
Header	webservices.h

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