private static FilterDefinition <BsonDocument> StringQuery(String parameterName, Operator optor, String modifier, ValueExpression operand)
{
switch (optor)
{
case Operator.EQ:
var typedOperand = operand.ToUnescapedString();
switch (modifier)
{
case Modifier.EXACT:
return(Builders <BsonDocument> .Filter.Eq(parameterName, typedOperand));
case Modifier.CONTAINS:
return(Builders <BsonDocument> .Filter.Regex(parameterName, new BsonRegularExpression(new Regex($".*{typedOperand}.*", RegexOptions.IgnoreCase))));
case Modifier.TEXT: //the same behaviour as :phonetic in previous versions.
return(Builders <BsonDocument> .Filter.Regex(parameterName + "soundex", "^" + typedOperand));
//case Modifier.BELOW:
// return Builders<BsonDocument>.Filter.Matches(parameterName, typedOperand + ".*")
case Modifier.NONE:
case null:
//partial from begin
return(Builders <BsonDocument> .Filter.Regex(parameterName, new BsonRegularExpression("^" + typedOperand, "i")));
default:
throw new ArgumentException(
$"Invalid modifier {modifier} on string parameter {parameterName}");
}
case Operator.IN: //We'll only handle choice like :exact
IEnumerable <ValueExpression> opMultiple = ((ChoiceValue)operand).Choices;
return(SafeIn(parameterName, new BsonArray(opMultiple.Select(sv => sv.ToUnescapedString()))));
case Operator.ISNULL:
return(Builders <BsonDocument> .Filter.Or(Builders <BsonDocument> .Filter.Exists(parameterName, false), Builders <BsonDocument> .Filter.Eq(parameterName, BsonNull.Value))); //With only Builders<BsonDocument>.Filter.NotExists, that would exclude resources that have this field with an explicit null in it.
case Operator.NOTNULL:
return(Builders <BsonDocument> .Filter.Ne(parameterName, BsonNull.Value)); //We don't use Builders<BsonDocument>.Filter.Exists, because that would include resources that have this field with an explicit null in it.
default:
throw new ArgumentException(
$"Invalid operator {optor} on string parameter {parameterName}");
}
}