public void AstFilter_should_handle_nested_elemMatch()
{
var ast = AstFilter.ElemMatch(
new AstFilterField("Details.A", BsonValueSerializer.Instance),
AstFilter.ElemMatch(
new AstFilterField("@<elem>", BsonValueSerializer.Instance),
AstFilter.Regex(new AstFilterField("DeviceName", BsonValueSerializer.Instance), ".Name0.", "")));
var rendered = ast.Render();
rendered.Should().Be("{ 'Details.A' : { $elemMatch : { $elemMatch : { DeviceName : /.Name0./ } } } }");
}
public static AstFilter Translate(TranslationContext context, MethodCallExpression expression)
{
if (AllWithContainsInPredicateMethodToFilterTranslator.CanTranslate(expression, out var arrayFieldExpression, out var arrayConstantExpression))
{
return(AllWithContainsInPredicateMethodToFilterTranslator.Translate(context, arrayFieldExpression, arrayConstantExpression));
}
if (AnyWithContainsInPredicateMethodToFilterTranslator.CanTranslate(expression, out arrayFieldExpression, out arrayConstantExpression))
{
return(AnyWithContainsInPredicateMethodToFilterTranslator.Translate(context, arrayFieldExpression, arrayConstantExpression));
}
var method = expression.Method;
var arguments = expression.Arguments;
if (method.IsOneOf(EnumerableMethod.All, EnumerableMethod.Any, EnumerableMethod.AnyWithPredicate))
{
var sourceExpression = arguments[0];
var(field, filter) = FilteredEnumerableFilterFieldTranslator.Translate(context, sourceExpression);
if (method.IsOneOf(EnumerableMethod.All, EnumerableMethod.AnyWithPredicate))
{
var predicateLambda = (LambdaExpression)arguments[1];
var parameterExpression = predicateLambda.Parameters.Single();
var elementSerializer = ArraySerializerHelper.GetItemSerializer(field.Serializer);
var parameterSymbol = context.CreateSymbol(parameterExpression, "@<elem>", elementSerializer); // @<elem> represents the implied element
var predicateContext = context.WithSingleSymbol(parameterSymbol); // @<elem> is the only symbol visible inside an $elemMatch
var predicateFilter = ExpressionToFilterTranslator.Translate(predicateContext, predicateLambda.Body, exprOk: false);
filter = AstFilter.Combine(filter, predicateFilter);
}
if (method.Is(EnumerableMethod.All))
{
return(AstFilter.Not(AstFilter.ElemMatch(field, AstFilter.Not(filter))));
}
else
{
if (filter == null)
{
return(AstFilter.And(AstFilter.Ne(field, BsonNull.Value), AstFilter.Not(AstFilter.Size(field, 0))));
}
else
{
return(AstFilter.ElemMatch(field, filter));
}
}
}
throw new ExpressionNotSupportedException(expression);
}
private static AstFilter Translate(TranslationContext context, Expression expression, Expression sourceExpression, Expression itemExpression)
{
if (itemExpression.NodeType == ExpressionType.Constant)
{
var sourceField = ExpressionToFilterFieldTranslator.Translate(context, sourceExpression);
var itemSerializer = ArraySerializerHelper.GetItemSerializer(sourceField.Serializer);
var value = itemExpression.GetConstantValue <object>(containingExpression: expression);
var serializedValue = SerializationHelper.SerializeValue(itemSerializer, value);
return(AstFilter.ElemMatch(sourceField, AstFilter.Eq(AstFilter.Field("@<elem>", itemSerializer), serializedValue))); // @<elem> represents the implied element
}
var itemField = ExpressionToFilterFieldTranslator.Translate(context, itemExpression);
var sourceValues = sourceExpression.GetConstantValue <IEnumerable>(containingExpression: expression);
var serializedValues = SerializationHelper.SerializeValues(itemField.Serializer, sourceValues);
return(AstFilter.In(itemField, serializedValues));
}