/// <summary>
/// This method is called after a new
/// <see cref="T:System.Data.Entity.Core.Common.CommandTrees.DbCommandTree" /> has been created.
/// The tree that is used after interception can be changed by setting
/// <see cref="P:System.Data.Entity.Infrastructure.Interception.DbCommandTreeInterceptionContext.Result" />
/// while intercepting.
/// </summary>
/// <param name="interceptionContext">Contextual information associated with the call.</param>
public void TreeCreated(DbCommandTreeInterceptionContext interceptionContext)
{
var dbQueryCommandTree = interceptionContext.Result as DbQueryCommandTree;
if (dbQueryCommandTree != null && interceptionContext.DbContexts.Count() == 1)
{
var context = interceptionContext.DbContexts.First();
// Visit first to find filter ID && hook
var visitorFilter = new QueryFilterInterceptorDbFilterExpression();
var queryFiltered = dbQueryCommandTree.Query.Accept(visitorFilter);
if (!string.IsNullOrEmpty(visitorFilter.HookID))
{
if (!QueryFilterManager.DbExpressionByHook.ContainsKey(visitorFilter.HookID))
{
QueryFilterManager.DbExpressionByHook.TryAdd(visitorFilter.HookID, queryFiltered);
}
}
else
{
var filterByContext = QueryFilterManager.AddOrGetFilterContext(context);
filterByContext.ClearCacheRequired = true;
var filterQuery = new QueryFilterInterceptorApply
{
InstanceFilters = filterByContext
};
if (visitorFilter.FilterID != null && visitorFilter.FilterID.Count > 0)
{
foreach (var filter in visitorFilter.FilterID)
{
if (filter == QueryFilterManager.DisableAllFilter)
{
// Disable all filter in the context!
filterQuery.ApplyFilterList.Add(interceptorFilter => false);
}
else if (filter.StartsWith(QueryFilterManager.EnableFilterById, StringComparison.InvariantCulture))
{
// Enable all specific filter
var filters = filter.Substring(QueryFilterManager.EnableFilterById.Length).Split(new[] { ";" }, StringSplitOptions.RemoveEmptyEntries);
if (filters.Length == 0)
{
filterQuery.ApplyFilterList.Add(interceptorFilter => false);
}
foreach (var applyFilter in filters)
{
filterQuery.ApplyFilterList.Add(interceptorFilter => interceptorFilter.UniqueKey.ToString() == applyFilter ? true : (bool?)null);
}
}
}
}
// VISIT filter
var visitor = new QueryFilterInterceptorDbScanExpression
{
Context = context,
InstanceFilterContext = filterByContext,
FilterQuery = filterQuery
};
var newQuery = queryFiltered.Accept(visitor);
// CREATE a new Query
interceptionContext.Result = new DbQueryCommandTree(dbQueryCommandTree.MetadataWorkspace, dbQueryCommandTree.DataSpace, newQuery, true);
}
}
}
