private void AddPreflightOperations(ServiceEndpoint endpoint, List <OperationDescription> corsOperations)
{
Dictionary <string, PreflightOperationBehavior> uriTemplates =
new Dictionary <string, PreflightOperationBehavior>(StringComparer.OrdinalIgnoreCase);
foreach (var operation in corsOperations)
{
if (operation.Behaviors.Find <WebGetAttribute>() != null || operation.IsOneWay)
{
// no need to add preflight operation for GET requests, no support for 1-way messages
continue;
}
string originalUriTemplate;
WebInvokeAttribute originalWia = operation.Behaviors.Find <WebInvokeAttribute>();
if (originalWia != null && originalWia.UriTemplate != null)
{
originalUriTemplate = NormalizeTemplate(originalWia.UriTemplate);
}
else
{
originalUriTemplate = operation.Name;
}
string originalMethod = originalWia != null && originalWia.Method != null ? originalWia.Method : "POST";
if (uriTemplates.ContainsKey(originalUriTemplate))
{
// there is already an OPTIONS operation for this URI, we can reuse it
PreflightOperationBehavior operationBehavior = uriTemplates[originalUriTemplate];
operationBehavior.AddAllowedMethod(originalMethod);
}
else
{
ContractDescription contract = operation.DeclaringContract;
OperationDescription preflightOperation;
PreflightOperationBehavior preflightOperationBehavior;
CreatePreflightOperation(operation, originalUriTemplate, originalMethod, contract,
out preflightOperation, out preflightOperationBehavior);
uriTemplates.Add(originalUriTemplate, preflightOperationBehavior);
contract.Operations.Add(preflightOperation);
}
}
}
private static void CreatePreflightOperation(OperationDescription operation, string originalUriTemplate,
string originalMethod, ContractDescription contract, out OperationDescription preflightOperation,
out PreflightOperationBehavior preflightOperationBehavior)
{
preflightOperation = new OperationDescription(operation.Name + CorsConstants.PreflightSuffix, contract);
MessageDescription inputMessage =
new MessageDescription(operation.Messages[0].Action + CorsConstants.PreflightSuffix,
MessageDirection.Input);
inputMessage.Body.Parts.Add(new MessagePartDescription("input", contract.Namespace)
{
Index = 0, Type = typeof(Message)
});
preflightOperation.Messages.Add(inputMessage);
MessageDescription outputMessage =
new MessageDescription(operation.Messages[1].Action + CorsConstants.PreflightSuffix,
MessageDirection.Output);
outputMessage.Body.ReturnValue =
new MessagePartDescription(preflightOperation.Name + "Return", contract.Namespace)
{
Type = typeof(Message)
};
preflightOperation.Messages.Add(outputMessage);
WebInvokeAttribute wia = new WebInvokeAttribute();
wia.UriTemplate = originalUriTemplate;
wia.Method = "OPTIONS";
preflightOperation.Behaviors.Add(wia);
preflightOperation.Behaviors.Add(new DataContractSerializerOperationBehavior(preflightOperation));
preflightOperationBehavior = new PreflightOperationBehavior(preflightOperation);
preflightOperationBehavior.AddAllowedMethod(originalMethod);
preflightOperation.Behaviors.Add(preflightOperationBehavior);
}